RadReviewEasy

(B) Magnification radiography

A focal-spot size of 0.3 mm or smaller is essential for which of the following procedures? (A) Bone radiography (B) Magnification radiography (C) Tomography (D) Fluoroscopy

(C) 1 and 2 only [Significant scattered radiation is produced when radiographing large or dense body parts and when using high kilovoltage. A radiographic grid is made of alternating lead strips and interspace material; it is placed between the patient and the IR to absorb energetic scatter emerging from the patient. Although a grid prevents much scattered radiation fog from reaching the radiograph, its use does necessitate a significant increase in patient exposure.]

A grid is usually employed 1. when radiographing a large or dense body part. 2. when using high kilovoltage. 3. when less patient dose is required. (A) 1 only (B) 3 only (C) 1 and 2 only (D) 1, 2, and 3

(B) Beyond a certain exposure level, a large number of pixels will be at maximum digital value (black), resulting in loss of visibility of anatomical structures in that region.

"Saturation" of an image in CR means that: (A) The CR reader has difficulty converting insufficient exposure signals to produce a diagnostic image; all electronic enhancement mechanisms are maximized (B) Beyond a certain exposure level, a large number of pixels will be at maximum digital value (black), resulting in loss of visibility of anatomical structures in that region. (C) There is a large amount of scatter radiation that is contributing to loss of anatomical image detail due to loss of contrast, thus decreasing diagnostic quality of the image (D) The CR image reader has adequately, and completely, read all the exposure intensities from the pixels resulting from the exposure

(A) a decrease in receptor exposure [As kilovoltage is increased, more electrons are driven to the anode with greater speed and energy. More high-energy electrons will result in production of more high-energy x-rays. Thus, kilovoltage affects both quantity and quality (energy) of the x-ray beam. However, although kilovoltage and receptor exposure are directly related, they are not directly proportional; that is, twice the radiographic receptor exposure is not achieved by doubling the kilovoltage. If it is desired to double the receptor exposure yet impossible to adjust the mAs, a similar effect can be achieved by increasing the kilovoltage by 15%. Conversely, the receptor exposure may be cut in half by decreasing the kilovoltage by 15%. Therefore, a decrease in kilovoltage will produce fewer x-ray photons, resulting in decreased receptor exposure. A decrease in kilovoltage will produce fewer shades of gray in analog imaging, that is, a shorter-scale, or higher/increased, contrast. Kilovoltage is unrelated to spatial resolution.]

A decrease in kilovoltage will result in (A) a decrease in receptor exposure (B) a decrease in image contrast (C) a decrease in spatial resolution (D) an increase in spatial resolution

(A) a decrease in receptor exposure [As kilovoltage is increased, more electrons are driven to the anode with greater speed and energy. More high-energy electrons will result in production of more high-energy x-rays. Thus, kilovoltage affects both quantity and quality (energy) of the x-ray beam. However, although kilovoltage and receptor exposure are directly related, they are not directly proportional; that is, twice the radiographic receptor exposure is not achieved by doubling the kilovoltage. If it is desired to double the receptor exposure yet impossible to adjust the mAs, a similar effect can be achieved by increasing the kilovoltage by 15%. Conversely, the receptor exposure may be cut in half by decreasing the kilovoltage by 15%. Therefore, a decrease in kilovoltage will produce fewer x-ray photons, resulting in decreased receptor exposure. A decrease in kilovoltage will produce fewer shades of gray in analog imaging, that is, a shorter-scale, or higher/increased, contrast. Kilovoltage is unrelated to spatial resolution.]

A decrease in kilovoltage will result in (A) a decrease in receptor exposure (B) a decrease in image contrast (C) a decrease in spatial resolution (D) an increase in spatial resolution

(B) Photomultiplier tube

A device contained within many CR readers that functions to convert light energy released by the PSP into electrical energy, is called a: (A) Transilluminator (B) Photomultiplier tube (C) Light gate (D) Penetrometer

(C) increase urine output [Diuretics are used to promote urine elimination in individuals whose tissues are retaining excessive fluid. They are used in treating hypertension, congestive heart failure, and edema. Cathartics are used to stimulate defecation (bowel movements); they are used as preparation for some x-ray examinations such as barium enemas. Emetics function to induce vomiting, and antitussives are used to inhibit coughing.]

A diuretic is used to (A) induce vomiting (B) stimulate defecation (C) increase urine output (D) inhibit coughing

(B) skeletal anomalies [During the first trimester, specifically the 2 to 8 weeks of pregnancy (during major organogenesis), if the radiation dose is at least 200 mGy, fetal anomalies can be produced. Skeletal anomalies usually appear if irradiation occurs in the early part of this time period, and neurologic anomalies are formed in the latter part; mental retardation/intellectual disability and childhood malignant diseases, such as cancers or leukemia, can also result from irradiation during the first trimester. Fetal irradiation during the second and third trimester is not likely to produce anomalies, but rather, with sufficient dose, some type of childhood malignant disease. Fetal irradiation during the first 2 weeks of gestation can result in spontaneous abortion. It must be emphasized that the likelihood of producing fetal anomalies at doses below 20 mGy is exceedingly small and that most general diagnostic examinations are likely to deliver fetal doses of less than 10 to 20 mGy.]

A dose of 250 mGy to the fetus during the fourth or fifth week of pregnancy is more likely to cause which of the following: (A) Spontaneous abortion (B) skeletal anomalies (C) neurologic anomalies (D) organogenesis

(C) reciprocity law [The reciprocity law states that a particular milliampere-seconds value, regardless of the milliamperage and exposure time used, will provide identical receptor exposure. Milliampere-seconds is directly proportional to beam intensity and receptor exposure.]

A particular milliampere-seconds value, regardless of the combination of milliamperes and time, will reproduce the same receptor exposure. This is a statement of the (A) line-focus principle (B) inverse-square law (C) reciprocity law (D) law of conservation of energy

(C) reciprocity law [The correct answer is: (C) The reciprocity law states that a particular milliampere-seconds value, regardless of the milliamperage and exposure time used, will provide identical receptor exposure. Milliampere-seconds is directly proportional to beam intensity and receptor exposure.]

A particular milliampere-seconds value, regardless of the combination of milliamperes and time, will reproduce the same receptor exposure. This is a statement of the (A) line-focus principle (B) inverse-square law (C) reciprocity law (D) law of conservation of energy

(C) reciprocity law [The reciprocity law states that a particular milliampere-seconds value, regardless of the milliamperage and exposure time used, will provide identical receptor exposure. Milliampere-seconds is directly proportional to beam intensity and receptor exposure]

A particular milliampere-seconds value, regardless of the combination of milliamperes and time, will reproduce the same receptor exposure. This is a statement of the (A) line-focus principle (B) inverse-square law (C) reciprocity law (D) law of conservation of energy

(B) 1 and 2 only [Oral administration of barium sulfate is used to demonstrate the upper digestive tract: the esophagus; the fundus, body, and pylorus of the stomach; and the small bowel, consisting of duodenum, jejunum, and ileum (i.e. small bowel..not ilium). Consistent care must be taken to read and record patient information accurately and correctly. The large bowel is usually demonstrated via rectal administration of barium.]

A patient is usually required to drink barium sulfate suspension to demonstrate which of the following structures? 1. Esophagus 2. Pylorus 3. Ilium (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) an infusion. [Quantities of medication can be dispensed intravenously over a period of time via an IV infusion. A special infusion pump may be used to precisely regulate the quantity received by the patient. An IV push refers to a rapid injection; the term bolus refers to the quantity of material being injected. The term hypodermic refers to administration of medication by any route other than oral.]

A quantity of medication introduced intravenously over a period of time is termed (A) an IV push. (B) an infusion. (C) a bolus. (D) a hypodermic.

(D) decreased SID [The lead strips in a parallel grid are parallel to one another and, therefore, are not parallel to the x-ray beam. The more divergent the x-ray beam, the more likely there is to be cutoff/decreased receptor exposure at the lateral edges of the image. This problem becomes more pronounced at short SIDs. If there were a centering or tube angle problem, there would be more likely to be a noticeable receptor exposure loss on one side or the other.]

A radiograph made with a parallel grid demonstrates decreased receptor exposure on its lateral edges. This is most likely due to (A) static electrical discharge (B) the grid being off-centered (C) improper tube angle (D) decreased SID

(A) 1 only [A quality control program requires the use of a number of devices to test the efficiency of various components of the imaging system. A star pattern is a resolution testing device that is used to test the effect of focal spot size.]

A star pattern is used to measure 1. focal spot resolution. 2. scatter resolution. 3. SID resolution. (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(A) 1 mSv [Because the established dose-limit formula guideline is used for occupationally exposed persons 18 years of age and older, guidelines had to be established to cover the event that a student entered the clinical component of a radiography educational program prior to age 18. The guideline states that the occupational dose limit for students under 18 years of age is 1 mSv in any given year. It is important to note that this 1 mSv is included in the 0.5 mSv dose limit allowed for the student as a member of the general public.]

A student radiographer who is under 18 years of age must not receive an annual occupational dose of greater than (A) 1 mSv (B) 5 mSv (C) 50 mSv (D) 100 mSv

(B) solid arc, with the angle (in degrees) representative of the exposure time [When a spinning top is used to test the efficiency of a single-phase timer, the result is a series of dots or dashes, with each representing a pulse of radiation. With full-wave-rectified current and a possible 120 dots (pulses) available per second, one should visualize 12 dots at 1/10 s, 24 dots at 1/5 s, 6 dots at 1/20 s, and so on. However, because three-phase equipment is at almost constant potential, a synchronous spinning top must be used, and the result is a solid arc (rather than dots). The number of degrees formed by the arc is measured and equated to a particular exposure time. A multitude of small, mesh-like squares describes a screen contact test. An aluminum step wedge (penetrometer) may be used to demonstrate the effect of kilovoltage on contrast (demonstrating a series of gray tones from white to black), with a greater number of grays demonstrated at higher kilovoltage levels.]

A three-phase timer can be tested for accuracy using a synchronous spinning top. The resulting image looks like a (A) series of dots or dashes, each representative of a radiation pulse (B) solid arc, with the angle (in degrees) representative of the exposure time (C) series of gray tones, from white to black (D) multitude of small, mesh-like squares of uniform sharpness

(A) angina. [Anginal pain, caused by constriction of blood vessels, may be relieved with the administration of a vasodilator such as nitroglycerin. Bradycardia (abnormally slow heartbeat) and cardiac arrest are treated with vasoconstrictors such as dopamine or epinephrine to increase blood pressure. Antihistamines such as diphenhydramine (Benadryl) are used to treat allergic reactions and anaphylactic shock.]

A vasodilator would most likely be used for (A) angina. (B) cardiac arrest. (C) bradycardia. (D) antihistamine.

(B) 1 mGya/hr [X-ray photons produced in the x-ray tube can radiate in directions other than the one desired. The tube housing, therefore, is constructed so that very little of this leakage radiation is permitted to escape. The regulation states that leakage radiation must not exceed 1 mGya/hr at 1 m while the tube is operated at maximum potential.]

According to NCRP regulations, leakage radiation from the x-ray tube must not exceed (A) 10 mGya/hr (B) 1 mGya/hr (C) 10 mGya/min (D) 1 mGya/min

(D) CR

Which of the following possesses the widest dynamic range? (A) ALARA (B) PBL (C) AEC (D) CR

(B) 50 mSv [According to the NCRP, the annual occupational whole-body dose-equivalent limit is 50 mSv. The annual occupational whole-body dose-equivalent limit for students under the age of 18 years is 1 mSv. The annual occupational dose-equivalent limit for the lens of the eye, a particularly radiosensitive organ, is 150 mSv. The annual occupational dose-equivalent limit for the thyroid, skin, and extremities is 500 mSv. The dose-equivalent limit for embryo/fetus of a pregnant radiographer must not exceed 0.5 mSv in 1 month.]

According to the NCRP, the annual occupational whole-body dose-equivalent limit is (A) 1 mSv (B) 50 mSv (C) 150 mSv (D) 500 mSv

(B) 50 mSv [According to the NCRP, the annual occupational whole-body dose-equivalent limit is 50 mSv. The annual occupational whole-body dose-equivalent limit for students under the age of 18 years is 1 mSv. The annual occupational dose-equivalent limit for the lens of the eye, a particularly radiosensitive organ, is 150 mSv. The annual occupational dose-equivalent limit for the thyroid, skin, and extremities is 500 mSv. The total gestational dose-equivalent limit for embryo/fetus of a pregnant radiographer is 5 mSv, not to exceed 0.5 mSv in 1 month.]

According to the NCRP, the annual occupational whole-body dose-equivalent limit is (A) 1 mSv (B) 50 mSv (C) 150 mSv (D) 500 mSv

(D) Intrathecal [A parental route of drug administration is one that bypasses the digestive system. The five parenteral routes require different needle placements: under the skin (subcutaneous), through the skin and into the muscle (intramuscular), between the layers of the skin (intradermal), into a vein (intravenous), and into the subarachnoid space (intrathecal).]

Administration of contrast agents for radiographic demonstration of the spinal canal is performed by which of the following parenteral routes? (A) Subcutaneous (B) Intravenous (C) Intramuscular (D) Intrathecal

(B) 1 and 2 only

Advantages of battery-powered mobile x-ray units include their 1. ability to store a large quantity of energy 2. ability to store energy for extended periods of time 3. lightness and ease of maneuverability (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) Scanned projection radiography (SPR)

All of the following are equipment options that may be used to record the anatomical image in mobile radiography, except: (A) Tethered flat panel (B) Remote (wireless) digital flat panel array (C) Scanned projection radiography (SPR) (D) Conventional radiographic film

(A) 1 only [Collimators or other kinds of beam restrictors limit the amount of tissue being irradiated and, therefore, can reduce patient dose significantly. The use of gonadal shielding protects the reproductive organs from unnecessary radiation exposure and should be employed whenever possible. Grids function to absorb scattered radiation before it reaches the image to cause fog. Grids improve the radiographic image considerably; however, their use requires a significant increase in milliampere-seconds, that is, patient dose.]

All of the following device(s) can be used to reduce patient dose, except 1. grid 2. collimator 3. gonad shield (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) 1 only [Collimators or other kinds of beam restrictors limit the amount of tissue being irradiated and, therefore, can reduce patient dose significantly. The use of gonadal shielding protects the reproductive organs from unnecessary radiation exposure and should be employed whenever possible. Grids function to absorb scattered radiation before it reaches the image to cause fog. Grids improve the radiographic image considerably; however, their use requires a significant increase in milliampere-seconds, that is, patient dose.]

All of the following device(s) can be used to reduce patient dose, except 1. grid 2. collimator 3. gonad shield (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(D) focal spot size.

All of the following have an effect on patient dose except (A) inherent filtration. (B) added filtration. (C) SID. (D) focal spot size.

(A) 1 only [Dual x-ray absorptiometry (DXA) imaging is used to evaluate bone mineral density (BMD). It is the most widely used method of bone densitometry—it is low dose, precise, and uncomplicated to use/perform. DXA uses two photon energies—one for soft tissue and one for bone. Since bone is more dense and attenuates x-ray photons more readily, their attenuation is calculated to represent the degree of bone density. Bone densitometry, DXA, can be used to evaluate bone mineral content of the body, or part of it, to diagnose osteoporosis or to evaluate the effectiveness of treatments for osteoporosis.]

All of the following statements regarding dual x-ray absorptiometry are true, except 1. radiation dose is considerable. 2. two x-ray photon energies are used. 3. photon attenuation by bone is calculated. (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(C) the arm should be in internal rotation. The inferosuperior axial (nontrauma, Lawrence method) projection of the shoulder demonstrates the glenohumeral joint and adjacent structures. The patient is supine with arm abducted 90°, and in external rotation. The (horizontal) CR is directed medially 25° to 30° through the axilla. The coracoid process and lesser tubercle are seen in profile.

All of the following statements regarding the inferosuperior axial (nontrauma, Lawrence method) projection of the shoulder are true, except (A) the coracoid process and lesser tubercle are seen in profile. (B) the arm is abducted about 90° from the body. (C) the arm should be in internal rotation. (D) the CR is directed medially 25° to 30° through the axilla.

(D) a Salem-sump. [A catheter placed in a large vein is called a central venous line. It can be used to deliver frequent medications or nutrition or to monitor cardiac pressures. Catheters can vary in size and number of lumens depending on intended use. The Port-a-Cath is a totally implanted access port, and the peripherally inserted central catheter (PICC) is a peripherally inserted central catheter—they both permit long-term intravenous treatment. The Swan-Ganz catheter is advanced to the pulmonary artery and is used to measure the pumping ability of the heart, to obtain pressure readings, and to introduce medications and IV fluids. The Levin and Salem-sump tubes are NG tubes used for gastric decompression. The Salem-sump tube is radiopaque and has a double lumen. One lumen is for gastric air compression, and the other is for removal of fluids.]

All the following are central venous lines except (A) a Port-a-Cath. (B) a PICC. (C) a Swan-Ganz catheter. (D) a Salem-sump.

(D) focal-spot size [As photon energy increases, more penetration and greater production of scattered radiation occur, producing a longer scale of contrast. As grid ratio increases, more scattered radiation is absorbed, producing a shorter scale of contrast. As OID increases, the distance between the part and the IR acts as a grid, and consequently, less scattered radiation reaches the IR, producing a shorter scale of contrast. Focal-spot size is related only to spatial resolution.]

All the following have an impact on radiographic contrast except (A) photon energy (B) grid ratio (C) OID (D) focal-spot size

(D) focal-spot size [As photon energy increases, more penetration and greater production of scattered radiation occur, producing a longer scale of contrast. As grid ratio increases, more scattered radiation is absorbed, producing a shorter scale of contrast. As OID increases, the distance between the part and the IR acts as a grid, and consequently, less scattered radiation reaches the IR, producing a shorter scale of contrast. Focal-spot size is related only to spatial resolution.]

All the following have an impact on radiographic contrast except (A) photon energy (B) grid ratio (C) OID (D) focal-spot size

(B) beam restriction improves spatial resolution [Beam restriction is used to determine the size of the x-ray field. This size never should be larger than the IR size. Because the size of the irradiated area can be made smaller, patient dose is reduced. Beam restriction reduces the production of scattered radiation that leads to fog and, therefore, improves contrast resolution. Spatial resolution is related to factors affecting recorded detail, not contrast resolution.]

All the following statements regarding beam restriction are true except (A) beam restriction improves contrast resolution (B) beam restriction improves spatial resolution (C) field size should never exceed IR dimensions (D) beam restriction reduces patient dose

(A) three-phase current is constant-potential direct current. [Three-phase current is obtained from three individual alternating currents superimposed on, but out of step with, one another by 120 degrees. The result is an almost constant potential current, with only a very small voltage ripple (4%-13%), producing more x-rays per milliampere-second.]

All the following statements regarding three-phase current are true except (A) three-phase current is constant-potential direct current. (B) three-phase equipment produces more x-rays per milliampere-second. (C) three-phase equipment produces higher-average-energy x-rays than single- phase equipment. (D) the three-phase waveform has less ripple than the single-phase waveform.

(C) At the cathode end

Although the stated focal-spot size is measured directly under the actual focal spot, focal-spot size actually varies along the length of the x-ray beam. At which portion of the x-ray beam is the effective focal spot the largest? (A) At its outer edge (B) Along the path of the central ray (C) At the cathode end (D) At the anode end

(C) At the cathode end

Although the stated focal-spot size is measured directly under the actual focal spot, focal-spot size in fact varies along the length of the x-ray beam. At which portion of the x-ray beam is the effective focal spot the largest? (A) At its outer edge (B) Along the path of the CR (C) At the cathode end (D) At the anode end

(C) At the cathode end [X-ray tube targets are constructed according to the line-focus principle—the focal spot is angled (usually 12-17 degrees) to the vertical. As the actual focal spot is projected downward, it is foreshortened; thus, the effective focal spot is smaller than the actual focal spot. As the focal spot is projected toward the cathode end of the x-ray beam, it becomes larger and approaches its actual size.]

Although the stated focal-spot size is measured directly under the actual focal spot, focal-spot size in fact varies along the length of the x-ray beam. At which portion of the x-ray beam is the effective focal spot the largest? (A) At its outer edge (B) Along the path of the CR (C) At the cathode end (D) At the anode end

(B) 1 and 2 only [Less scattered radiation is generated within a part as the kilovoltage is decreased, as the size of the field is decreased, and as the thickness and density of tissue decrease. As the quantity of scattered radiation decreases from any of these sources, the less is the total receptor exposure.]

An analog x-ray exposure of a particular part is made and restricted to a 14 × 17 in. field size. The same exposure is repeated, but the x-ray beam is restricted to a 4 × 4 in. field. Compared with the first image, the second image will demonstrate 1. less receptor exposure 2. more contrast 3. more receptor exposure (A) 1 only (B) 1 and 2 only (C) 3 only (D) 2 and 3 only

(B) 1 and 2 only [Dilated, twisted veins, or varices, of the esophagus are frequently associated with obstructive liver disease or cirrhosis of the liver. These esophageal veins enlarge and can rupture, causing serious hemorrhage. Achalasia is dilation of the esophagus as a result of the cardiac sphincter's failure to relax and allow food to pass into the stomach. Dysphasia is a speech impairment resulting from a brain lesion; it is unrelated to the esophagus. Dysphagia refers to difficulty swallowing and is the most common esophageal complaint. Hiatal hernia is another common esophageal problem; it is characterized by protrusion of a portion of the stomach through the cardiac sphincter. It is a common condition, and many individuals with the condition are asymptomatic. Each of these conditions of the esophagus may be evaluated with an esophagogram. Positions usually include the posteroanterior, right anterior oblique, and right lateral positions.]

An esophagram would most likely be requested for patients with which of the following esophageal disorders/symptoms? 1. Varices 2. Achalasia 3. Dysphasia (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(C) idiopathic. [Idiopathic refers to a disease of unknown or unclear cause. The term systemic refers to or concerns a (body) system. An epidemic describes a disease that swiftly affects a large number of people in a particular geographic region. Anything that is or can be disease-producing is termed pathogenic.]

An illness of unknown or obscure cause is said to be (A) systemic. (B) epidemic. (C) idiopathic. (D) pathogenic.

(B) 1 and 2 only

An increase in kilovoltage will have which of the following effects? 1. More scattered radiation will be produced. 2. The exposure rate will increase. 3. Radiographic contrast will increase. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only [An increase in kilovoltage (photon energy) will result in a greater number (i.e., exposure rate) of scattered photons (Compton interaction). These scattered photons carry no useful information and contribute to radiation fog, thus decreasing radiographic contrast.]

An increase in kilovoltage will have which of the following effects? 1. More scattered radiation will be produced. 2. The exposure rate will increase. 3. Radiographic contrast will increase. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) Aluminum oxide [Different types of monitoring devices are available for the occupationally exposed. The film badge has photographic lm; the pocket dosimeter contains an ionization chamber; TLDs use lithium uoride crystals. OSL dosimeters are personnel radiation monitors that use aluminum oxide crystals. These crystals, once exposed to ionizing radiation and then subjected to a laser, give off luminescence proportional to the amount of radiation received.]

An optically stimulated luminescence dosimeter contains which of the following detectors? (A) Gadolinium (B) Aluminum oxide (C) Lithium fluoride (D) Photographic film

(B) Aluminum oxide [Different types of monitoring devices are available for the occupationally exposed. The film badge has photographic film; the pocket dosimeter contains an ionization chamber; TLDs use lithium fluoride crystals. OSL dosimeters are personnel radiation monitors that use aluminum oxide crystals. These crystals, once exposed to ionizing radiation and then subjected to a laser, give off luminescence proportional to the amount of radiation received.]

An optically stimulated luminescence dosimeter contains which of the following detectors? (A) Gadolinium (B) Aluminum oxide (C) Lithium fluoride (D) Photographic film

(A) 1 only [DXA imaging is used to evaluate BMD. It is the most widely used method of bone densitometry—it is low- dose, precise, and uncomplicated to use/perform. DXA uses two photon energies—one for soft tissue and one for bone. Since bone is denser and attenuates x-ray photons more readily, their attenuation is calculated to represent the degree of bone density. Soft tissue attenuation information is not used to measure bone density. Any images obtained in DXA/bone densitometry are strictly to evaluate the accuracy of the region of interest (ROI); they are not used for further diagnostic purposes—additional diagnostic examinations are done for any required further evaluation. Bone densitometry/DXA can be used to evaluate bone mineral content of the body or part of it, to diagnose osteoporosis, or to evaluate the effectiveness of treatments for osteoporosis.]

Any images obtained using dual x-ray absorptiometry (DXA) bone densitometry 1. are used to evaluate accuracy of the region of interest (ROI) 2. are used as evaluation for various bone/joint disorders 3. reflect the similar attenuation properties of soft tissue and bone (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(C) 4 [An HVL may be defined as the amount and thickness of absorber necessary to reduce the radiation intensity to half its original value. Thus, the first HVL would reduce the intensity to 50% of its original value, the second to 25%, the third to 12.5%, and the fourth to 6.25% of its original value.]

At least how many HVLs are required to reduce the intensity of a beam of monoenergetic photons to less than 10% of its original value? (A) 2 (B) 3 (C) 4 (D) 5

(A) Phantom image artifact

Backscatter on a digital image can cause an artifact called a (A) Phantom image artifact (B) Moiré artifact (C) Static artifact (D) Grid cutoff artifact

(C) 3 only [In the figure shown, image B is darker because the receptor exposure was greater. Receptor exposure is significantly affected by mAs, SID, and exposure rate. In this case, there is a difference in SID between the two images. As SID decreases, exposure rate increases and receptor exposure increases. Image B is darker (received a greater exposure) than image A because image B was exposed at a shorter SID (and therefore a higher exposure rate).]

Both radiographic images seen in the figure below were made of the same subject using identical exposure factors. Which of the following statements correctly describes these images? 1. Image A illustrates less receptor exposure because a shorter SID was used. 2. Image A illustrates more receptor exposure because the subject was turned PA. 3. Image B illustrates more receptor exposure because a shorter SID was used. (A) 1 only (B) 2 only (C) 3 only (D) 1 and 2 only

(A) osteoblasts. [Osteoblasts are cells of mesodermal origin that are concerned with formation and repair of bone. Osteoclasts are cells concerned with the breakdown and resorption of old or dead bone. An osteoma is a benign bony tumor. An osteon is the microscopic unit of compact bone, consisting of a haversian canal and its surrounding lamellae.]

Cells concerned with the formation and repair of bone are (A) osteoblasts. (B) osteoclasts. (C) osteomas. (D) osteons.

(D) 3, 1, 2

Classify the following tissues in order of increasing radiosensitivity 1. Liver cells 2. Intestinal crypt cells 3. Muscle cells (A) 1, 3, 2 (B) 2, 3, 1 (C) 2, 1, 3 (D) 3, 1, 2

(B) 1 and 2 only [Traditional x-ray imaging involves formation of the x-ray image directly on the IR (film emulsion). In digital imaging, x-rays form an electronic image on a special radiation detector. This electronic image can be manipulated by a computer and stored in the computer memory or displayed as a matrix of intensities. This final digital image is often viewed on a computer monitor and looks just like a traditional x-ray image, but the computer often has the capability of postprocessing image enhancement.]

Components of digital imaging include 1. computer manipulation of the image 2. formation of an electronic image on the radiation detector 3. formation of an x-ray image directly on the emulsion (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) slip rings. [In the 1990s, the implementation of slip ring technology allowed continuous rotation of the x-ray tube (through elimination of cables) and simultaneous couch movement. Sixth-generation CT scanning is termed helical (or spiral) CT—permitting acquisition of volume multislice scanning. Today's helical multislice scanners, employing thousands of detectors (up to 60+ rows), can obtain uninterrupted data acquisition of 128 "slices" per tube rotation and can perform 3D multiplanar reformation (MPR). Fifth-generation CT is electron beam; ultra high-speed CT is used specifically for cardiac imaging.]

Continuous rotation of the CT x-ray tube and detector array, with simultaneous movement of the CT couch, has been accomplished through implementation of (A) additional cables. (B) slip rings. (C) multiple rows of detectors. (D) electron beam CT.

(C) superior vena cava

Deoxygenated blood from the head and thorax is returned to the heart by the (A) pulmonary artery (B) pulmonary veins (C) superior vena cava (D) thoracic aorta

(A) 1 only [Through the action of thermionic emission, as the tungsten filament continually gives up electrons, it gradually becomes thinner with age. This evaporated tungsten frequently is deposited on the inner surface of the glass envelope at the tube window. When this happens, it acts as an additional filter of the x-ray beam, thereby reducing tube output. Also, the tungsten deposit actually may attract electrons from the filament, creating a tube current and causing puncture of the glass envelope.]

Deposition of vaporized tungsten on the inner surface of the x-ray tube glass window 1. acts as additional filtration 2. results in increased tube output 3. results in anode pitting (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only

Disadvantages of using low-kilovoltage technical factors include 1. insufficient penetration 2. increased patient dose 3. diminished resolution (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only [As the kilovoltage is decreased, x-ray-beam energy (i.e., penetration) is also decreased. Consequently, a shorter scale of contrast is obtained. As kilovoltage is reduced, the milliampere-seconds value must be increased accordingly to maintain adequate receptor exposure. This increase in milliampere-seconds results in greater patient dose. Resolution is not related to kV.]

Disadvantages of using low-kilovoltage technical factors include 1. insufficient penetration 2. increased patient dose 3. diminished resolution (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3 [Diseases that are transmitted through the air include TB, rubella ("German measles"), mumps, and influenza. Airborne precautions require the patient to wear a mask to avoid the spread of acid-fast bacilli (in the bronchial secretions of TB patients) or other pathogens during coughing. If the patient is unable or unwilling to wear a mask, the radiographer must wear one. The radiographer should wear gloves, but a gown is required only if flagrant contamination is likely. Patients infected with diseases calling for airborne precautions require a private, specially ventilated (negative-pressure) room. A private room is also indicated for all patients on droplet precautions, that is, with diseases that are transmitted via large droplets expelled from the patient while speaking, sneezing, or coughing. The pathogenic droplets can infect others when they come in contact with the mouth or nasal mucosa or conjunctiva. Rubella ("German measles"), mumps, and influenza are among the diseases spread by droplet contact; a private room is required for the patient, and health care practitioners must use gowns and gloves.]

Diseases whose mode of transmission is through the air include 1. TB. 2. mumps. 3. rubella. (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(A) 1 only [The dorsal decubitus position is obtained with the patient supine and the x-ray beam directed horizontally. The finished image looks similar to a lateral projection of the chest. However, small amounts of fluid will gravitate to the posterior chest, and small amounts of air will rise to the anterior chest. The ventral decubitus position is obtained with the patient prone and the x-ray beam directed horizontally. The finished image can demonstrate small amounts of fluid anteriorly and small amounts of air posteriorly.]

Dorsal decubitus projections of the chest are used to evaluate small amounts of 1. fluid in the posterior chest 2. air in the posterior chest 3. fluid in the anterior chest (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 2 and 3 only [Venous blood is returned to the right atrium via the superior (from the upper body) and inferior (from the lower body) venae cavae. During atrial systole, blood passes from the right atrium through the tricuspid valve into the right ventricle and from the left atrium through the bicuspid/mitral valve into the left ventricle. During ventricular systole, the pulmonary artery (the only artery to carry deoxygenated blood) carries blood from the right ventricle to the lungs for oxygenation, whereas the left ventricle moves oxygenated blood through the aortic semilunar valve into the aorta and to all body tissues.]

During atrial systole, blood flows into the 1. right ventricle via the mitral valve 2. left ventricle via the bicuspid valve 3. right ventricle via the tricuspid valve (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) 1 and 2 only [Occupationally exposed individuals generally receive small amount of low-energy radiation over a long period of time. These individuals, therefore, are concerned with the potential long-term effects of radiation, such as carcinogenesis (including leukemia) and cataractogenesis. However, if a large amount of radiation is delivered to the whole body at one time, the short-term early somatic effects must be considered. If the whole body receives 6 Gy at one time, acute radiation syndrome is likely to occur. Early signs of acute radiation syndrome include nausea, vomiting, diarrhea, fatigue, and leukopenia (decreased white blood cells count); these occur in the first (prodromal) stage of acute radiation syndrome.]

Early symptoms of acute radiation syndrome include 1. leukopenia 2. nausea and vomiting 3. cataracts (A) 1 and 2 only (B) 2 only (C) 1 and 3 only (D) 2 and 3 only

(D) 1, 2, and 3 [Chronic obstructive pulmonary disease (COPD) is the abbreviation for chronic obstructive pulmonary disease; it refers to a group of disorders, including chronic bronchitis, emphysema, asthmatic bronchitis, and bronchiectasis. COPD is irreversible and decreases the ability of the lungs to perform their ventilation functions. There is often less than half the normal expected maximal breathing capacity.]

Examples of COPD include 1. chronic bronchitis. 2. pulmonary emphysema. 3. asthmatic bronchitis. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only [Infectious microorganisms can be transmitted from patients to other patients or to health care workers and from health care workers to patients. They are transmitted by means of either direct or indirect contact. Direct contact involves touch. Diseases transmitted by direct contact include skin infections such as boils and sexually transmitted diseases such as syphilis and AIDS. Direct contact with droplets of nasal or oral secretions from a sneeze or cough is referred to as droplet contact. Indirect contact involves transmission of microorganisms via airborne contamination, fomites, and vectors. Pathogenic microorganisms expelled from the respiratory tract through the mouth or nose can be carried as evaporated droplets through the air or dust and settle on clothing, utensils, or food. Patients with respiratory tract infections or disease transported to the radiology department therefore should wear a mask to prevent such transmission during a cough or sneeze; it is not necessary for the health care worker to wear a mask (as long as the patient does). Many microorganisms can remain infectious while awaiting transmission to another host. A contaminated inanimate object such as a food utensil, doorknob, or IV pole is referred to as a fomite. A vector is an insect or animal carrier of infectious organisms, such as a rabid animal, a mosquito that carries malaria, or a tick that carries Lyme disease. They can transmit disease through either direct or indirect contact.]

Examples of means by which infectious microorganisms can be transmitted via indirect contact include 1. a fomite. 2. a vector. 3. nasal or oral secretions. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only [Infectious microorganisms can be transmitted from patients to other patients or to health care workers and from health care workers to patients. They are transmitted by means of either direct or indirect contact. Direct contact involves touch. Diseases transmitted by direct contact include skin infections such as boils and sexually transmitted diseases such as syphilis and AIDS. Direct contact with droplets of nasal or oral secretions from a sneeze or cough is referred to as droplet contact. Indirect contact involves transmission of microorganisms via airborne contamination, fomites, and vectors. Pathogenic microorganisms expelled from the respiratory tract through the mouth or nose can be carried as evaporated droplets through the air or dust and settle on clothing, utensils, or food. Patients with respiratory tract infections or disease transported to the radiology department therefore should wear a mask to prevent such transmission during a cough or sneeze; it is not necessary for the health care worker to wear a mask (as long as the patient does). Many microorganisms can remain infectious while awaiting transmission to another host. A contaminated inanimate object such as a food utensil, doorknob, or IV pole is referred to as a fomite. A vector is an insect or animal carrier of infectious organisms, such as a rabid animal, a mosquito that carries malaria, or a tick that carries Lyme disease. They can transmit disease through either direct or indirect contact.]

Examples of means by which infectious microorganisms can be transmitted via indirect contact include 1. a fomite. 2. a vector. 3. nasal or oral secretions. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 1 and 3 only [Primary radiation barriers are barriers that protect from the primary, or useful, x-ray beam. Secondary radiation barriers are those that protect from secondary or scattered radiation. Examples of primary barriers are the radiographic room walls, doors, and floors because the primary beam often can be directed toward them. Secondary radiation barriers include lead aprons, gloves, thyroid shields, and the radiographic room ceiling. These will protect from exposure to scattered radiation only. Secondary radiation barriers will not protect from the useful beam.]

Examples of primary radiation barriers include 1. radiographic room walls 2. lead aprons 3. radiographic room floor (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only [Synovial pivot joints are diarthrotic, that is, freely movable. Pivot joints permit rotation motion. Examples include the proximal radioulnar joint that permits supination and pronation of the hand. The atlantoaxial joint is the articulation between C1 and C2 and permits rotation of the head. The temporomandibular joint is diarthrotic, having both hinge and planar movements.]

Examples of synovial pivot articulations include the 1. atlantoaxial joint 2. radioulnar joint 3. temporomandibular joint (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3 only

(B) 1 and 2 only [The quantity of x-ray photons produced at the target is the function of mAs. The quality (wavelength, penetration, energy) of x-ray photons produced at the target is the function of kVp. The kVp also has an effect on exposure rate, because an increase in kVp will increase the number of high-energy x-ray photons produced at the target. Exposure rate decreases with an increase in SID.]

Exposure rate increases with an increase in 1. mA. 2. kVp. 3. SID. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3 [The AEC automatically terminates the exposure when the appropriate receptor exposure has been received by the IR. The important advantage of the AEC (phototimer or ionization chamber) is that it can accurately duplicate receptor exposures. It is very useful in providing accurate comparison in follow-up examinations and in decreasing patient exposure dose by reducing the number of "retakes" needed because of improper exposure. The AEC automatically adjusts the exposure required for body parts with different thicknesses and tissue densities. However, proper functioning of the AEC depends on accurate positioning by the radiographer. The correct photocell(s) must be selected, and the anatomic part of interest must completely cover the photocell to achieve an accurate receptor exposure. If collimation is inadequate and a field size larger than the part is used, excessive scattered radiation from the body or tabletop can cause the AEC to terminate the exposure prematurely, resulting in an underexposed image.]

Factors that determine AEC exposure determination include 1. the thickness and density of the object 2. positioning of the object with respect to the photocell 3. beam restriction (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3 [The AEC automatically terminates the exposure when the appropriate receptor exposure has been received by the IR. The important advantage of the AEC (phototimer or ionization chamber) is that it can accurately duplicate receptor exposures. It is very useful in providing accurate comparison in follow-up examinations and in decreasing patient exposure dose by reducing the number of "retakes" needed because of improper exposure. The AEC automatically adjusts the exposure required for body parts with different thicknesses and tissue densities. However, proper functioning of the AEC depends on accurate positioning by the radiographer. The correct photocell(s) must be selected, and the anatomic part of interest must completely cover the photocell to achieve an accurate receptor exposure. If collimation is inadequate and a field size larger than the part is used, excessive scattered radiation from the body or tabletop can cause the AEC to terminate the exposure prematurely, resulting in an underexposed image.]

Factors that determine AEC exposure determination include 1. the thickness and density of the object 2. positioning of the object with respect to the photocell 3. beam restriction (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) line-focus principle

Figure 5-7 illustrates the (A) inverse-square law (B) line-focus principle (C) reciprocity law (D) anode heel effect

(D) produce an x-ray beam with higher average energy. [The primary beam generally has a total filtration of 2.5 mm Al equivalent for patient protection purposes. In general-purpose radiographic tubes, the glass envelope usually accounts for about 0.5 mm Al equivalent and the collimator provides about 1.0 mm Al equivalent. These are considered inherent filtration. The manufacturer adds another 1.0 mm Al (added filtration) to meet the minimum requirements of 2.5 mm Al equivalent total filtration for radiographic tubes operated above 70 kilovolt peaks (kVp). This type of filter serves to remove the diagnostically useless x-ray photons that only contribute to patient (skin) dose. Because this radiation is "soft" (low energy) and would not reach the image receptor anyway, the x-ray tube total filtration has no effect on receptor exposure. Filtration serves to increase the overall average energy of the beam; it "hardens" the x-ray beam.]

Filtration is added to the x-ray beam to (A) decrease photoelectric interaction. (B) remove the "hard" x-rays. (C) produce a more heterogeneous x-ray beam. (D) produce an x-ray beam with higher average energy.

(B) toward the cathode end of the x-ray beam [Focal-spot blur, or geometric blur, is caused by photons emerging from a large focal spot. Because the projected focal spot is greatest at the cathode end of the x-ray tube, geometric blur is also greatest at the corresponding part (cathode end) of the radiograph. The projected focal-spot size becomes progressively smaller toward the anode end of the x-ray tube.]

Focal-spot blur is greatest (A) toward the anode end of the x-ray beam (B) toward the cathode end of the x-ray beam (C) directly along the course of the CR (D) as the SID is increased

(B) toward the cathode end of the x-ray beam

Focal-spot blur is greatest (A) toward the anode end of the x-ray beam (B) toward the cathode end of the x-ray beam (C) directly along the course of the CR (D) as the SID is increased

(D) Grids [Focusing distance is the term used to specify the optimal SID used with a particular focused grid. It is usually expressed as focal range, indicating the minimum and maximum SID workable with that grid. Lesser or greater distances can result in grid cutoff. Although proper distance is important in computed tomography and chest and magnification radiography, focusing distance is unrelated to them.]

Focusing distance is associated with which of the following? (A) Computed tomography (B) Chest radiography (C) Magnification radiography (D) Grids

(D) Grids

Focusing distance is associated with which of the following? (A) Computed tomography (B) Chest radiography (C) Magnification radiography (D) Grids

(B) PA projection [Because the primary x-ray beam has a poly-energetic (heterogeneous) nature, the entrance or skin dose is significantly greater than the exit dose. This principle may be employed in radiation protection by placing particularly radiosensitive organs away from the primary beam. To place the gonads further from the primary beam and reduce gonadal dose, abdominal radiography should be performed in the posteroanterior (PA) position whenever possible. Dose to the lens is decreased significantly when skull radiographs are performed in the PA position.]

For radiographic examinations of the skull, it is generally preferred that the skull be examined in the (A) AP projection (B) PA projection (C) recumbent position (D) supine position

(C) 1 and 2 only [Verbal defamation of another, or slander, is a type of intentional misconduct. Invasion of privacy (i.e., public discussion of privileged and confidential information) is intentional misconduct. However, if a radiographer leaves a weak patient standing alone to check images or get supplies and that patient falls and sustains an injury, that would be considered unintentional misconduct, or negligence.]

Forms of intentional misconduct include 1. slander. 2. invasion of privacy. 3. negligence. (A) 1 only (B) 2 only (C) 1 and 2 only (D) 1, 2, and 3

(D) at the cathode end of the image. The x-ray tube anode is designed according to the line focus principle, that is, with the focal track beveled (see the figure below). This allows a larger actual focal spot to project a smaller effective focal spot, resulting in improved spatial resolution with less blur. However, because of the target angle, penumbral blur varies along the longitudinal tube axis, being greater at the cathode end of the image and less at the anode end of the image.

Geometric unsharpness is most likely to be greater (A) at long SIDs. (B) at the anode end of the image. (C) with small focal spots. (D) at the cathode end of the image.

(D) at the cathode end of the image. [The x-ray tube anode is designed according to the line focus principle, that is, with the focal track beveled (see the figure below). This allows a larger actual focal spot to project a smaller effective focal spot, resulting in improved spatial resolution with less blur. However, because of the target angle, penumbral blur varies along the longitudinal tube axis, being greater at the cathode end of the image and less at the anode end of the image.]

Geometric unsharpness is most likely to be greater (A) at long SIDs. (B) at the anode end of the image. (C) with small focal spots. (D) at the cathode end of the image.

(D) at the cathode end of the image. [The x-ray tube anode is designed according to the line focus principle, that is, with the focal track beveled. This allows a larger actual focal spot to project a smaller effective focal spot, resulting in improved spatial resolution with less blur. However, because of the target angle, penumbral blur varies along the longitudinal tube axis, being greater at the cathode end of the image and less at the anode end of the image.]

Geometric unsharpness is most likely to be greater (A) at long SIDs. (B) at the anode end of the image. (C) with small focal spots. (D) at the cathode end of the image.

(C) 1 and 3 only [A grid is a thin wafer placed between the patient and the IR to collect scattered radiation. It is made of alternating strips of lead and a radiolucent material such as plastic or aluminum. If the interspace material also were made of lead, little or no radiation would reach the IR, and no image would be formed.]

Grid interspace material can be made of 1. plastic 2. lead 3. aluminum (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(B) They are directly related. [LET expresses the rate at which photon or particulate energy is transferred to (absorbed by) biologic material (through ionization processes); it depends on the type of radiation and absorber characteristics. Relative biologic effectiveness (RBE) describes the degree of response or amount of biologic change that one can expect of the irradiated material. As the amount of transferred energy (LET) increases (from interactions occurring between radiation and biologic material), the amount of biologic effect/damage also will increase; that is, the two are directly related.]

How are LET and biologic response related? (A) They are inversely related. (B) They are directly related. (C) They are related in a reciprocal fashion. (D) They are unrelated.

(B) 75% [Lead aprons are worn by occupationally exposed individuals during fluoroscopic procedures. Lead aprons are available with various lead equivalents; 0.25, 0.5, and 1.0 mm of lead are the most common. The 1.0-mm lead equivalent apron will provide close to 100% protection at most kilovoltage levels, but it is rarely used because it weighs anywhere from 12 to 24 lb. A 0.25-mm lead-equivalent apron will attenuate about 97% of a 50-kVp x-ray beam, 66% of a 75-kVp beam, and 51% of a 100-kVp beam. A 0.5- mm apron will attenuate about 99% of a 50-kVp beam, 88% of a 75-kVp beam, and 75% of a 100-kVp beam.]

How much protection is provided from a 100-kVp x-ray beam when using a 0.50- mm lead-equivalent apron? (A) 40% (B) 75% (C) 88% (D) 99%

(D) Its intensity decreases four times. [Source-to-image-receptor distance (SID) has a significant impact on x-ray beam intensity (other terms are quantity, exposure rate, dose). As the distance between the x-ray tube and image receptor increases, exposure rate/intensity/dose (and therefore receptor exposure) decreases according to the inverse square law. According to the inverse square law, the exposure rate is inversely proportional to the square of the distance; that is, if the SID is doubled, the resulting beam intensity will be one fourth the original intensity; if the SID is cut in half, the resulting beam intensity will be four times the original intensity.]

How will x-ray photon intensity be affected if the SID is doubled? (A) Its intensity increases two times. (B) Its intensity increases four times. (C) Its intensity decreases two times. (D) Its intensity decreases four times.

(D) Its intensity decreases four times. [Source-to-image-receptor distance (SID) has a significant impact on x-ray beam intensity (other terms we could use are quantity, exposure rate and dose). As the distance between the x-ray tube and IR increases, exposure rate/intensity/dose (and receptor exposure) decreases according to the inverse square law. According to the inverse square law, the exposure rate is inversely proportional to the square of the distance; that is, if the SID is doubled, the resulting beam intensity will be one-fourth the original intensity; if the SID is cut in half, the resulting beam intensity will be 4 times the original intensity.]

How will x-ray photon intensity be affected if the source-to-image distance (SID) is doubled? (A) Its intensity increases two times. (B) Its intensity increases four times. (C) Its intensity decreases two times. (D) Its intensity decreases four times.

(A) Contrast would be increased. [OID can affect contrast when it is used as an air gap. If a 6-in. air gap (OID) is introduced between the part and IR, much of the scattered radiation emitted from the body will not reach the IR. The OID thus is acting as a low-ratio grid and increasing image contrast.]

How would the introduction of a 6-in. OID affect image contrast? (A) Contrast would be increased. (B) Contrast would be decreased. (C) Contrast would not change. (D) The scale of contrast would not change.

(A) Contrast would be increased. [OID can affect contrast when it is used as an air gap. If a 6-in. air gap (OID) is introduced between the part and IR, much of the scattered radiation emitted from the body will not reach the IR. The OID thus is acting as a low-ratio grid and increasing image contrast.]

How would the introduction of a 6-in. OID affect image contrast? (A) Contrast would be increased. (B) Contrast would be decreased. (C) Contrast would not change. (D) The scale of contrast would not change.

(A) will be greater than if it were delivered in a number of doses over a long period of time. [The effects of a quantity of radiation delivered to a body are dependent on several factors: the amount of radiation received, the size of the irradiated area, and how the radiation is delivered in time. If the radiation is delivered in portions over a period of time, it is said to be fractionated and has a less harmful effect than if the radiation were delivered all at once. With fractionation, cells have an opportunity to repair, and so some recovery occurs between doses.]

If a quantity of radiation is delivered to a body in a single dose, its effect (A) will be greater than if it were delivered in a number of doses over a long period of time. (B) will be less than if it were delivered a number of doses over a long period of time. (C) has no relation to how it is delivered in time. (D) is solely dependent on the radiation quality.

(A) decrease the milliamperage [Decreasing or increasing the kilovoltage will produce a change in radiographic contrast. The image was overexposed (from excessive exposure time) because the AEC wasn't capable of producing the required extremely short exposure time. To bring the required exposure to an exposure time the AEC is capable of, the mA should be decreased (thus requiring a longer exposure time, within the capability of the AEC).]

If a radiograph, made using AEC, is overexposed because an exposure shorter than the minimum response time was required, the radiographer generally should (A) decrease the milliamperage (B) increase the milliamperage (C) increase the kilovoltage (D) decrease the kilovoltage

(C) 0.003 mGy [The patient is the most important radiation scatterer during both radiography and fluoroscopy. In general, at 1 m from the patient, the intensity is reduced by a factor of 1,000 to about 0.1% of the original intensity. Successive scatterings can reduce the intensity to unimportant levels. Calculate that 0.1% of 3.0 mGy is 0.003 mGy.]

If the ESE for a particular exposure is 3.0 mGy, what will be the intensity of the scattered beam perpendicular to and 1 m from the patient? (A) 0.3 mGy (B) 0.03 mGy (C) 0.003 mGy (D) 3.0 mGy

(C) Lateral cross-table recumbent [Radiography of the paranasal sinuses should be performed in the erect position whenever possible to demonstrate the presence of an air-fluid level. The only way air-fluid levels can be demonstrated is to have the central ray parallel the floor, as in erect, decubitus, and cross-table projections. Therefore, of the choices provided, the cross-table lateral is the only one that will demonstrate air-fluid levels.]

If your patient is unable to stay erect for a paranasal sinus examination, which of the following alternatives should be chosen? (A) Recumbent AP (B) Lateral recumbent (C) Lateral cross-table recumbent (D) Recumbent Waters'

(A) 1 only [The factors that affect the resolution are focal-spot size, source-to-image receptor distance (SID), object-to-image distance (OID), and motion. Resolution is improved using a small focal spot size, largest practical SID, shortest possible OID, and avoiding motion of the part being imaged. The smaller the anode angle, the smaller is the effective focal spot. Filtration affects the overall average photon energy, that is, beam quality. Filtration is unrelated to resolution.]

Image resolution depends on all the following except 1. quantity of filtration. 2. anode angle. 3. OIDs. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 1 and 2 only [The higher the kilovoltage range, the greater is the exposure latitude (margin of error in exposure). Higher kilovoltage produces more energetic photons, is more penetrating, and produces more grays on the radiographic image, lengthening the scale of contrast. As kilovoltage increases, the percentage of scattered radiation also increases.]

In comparison with 60 kV, 80 kV will 1. permit greater exposure latitude 2. produce more scattered radiation 3. produce shorter-scale contrast (A) 1 only (B) 2 only (C) 1 and 2 only (D) 2 and 3 only

(C) 1 and 2 only

In comparison with 60 kV, 80 kV will 1. permit greater exposure latitude 2. produce more scattered radiation 3. produce shorter-scale contrast (A) 1 only (B) 2 only (C) 1 and 2 only (D) 2 and 3 only

(C) Sv [Air kerma (kinetic energy released in matter) is the SI unit of measure of exposure; it's symbol is Gya. Gray (Gy) is the SI unit of absorbed dose; its symbol is Gyt. Sievert is the SI unit of effective dose; its symbol is Sv. The term effective dose is used to describe the product of the average absorbed dose, the type of radiation delivered (Wr), and the radiosensitivity of the exposed tissue (Wt). Becquerel is the SI unit of radioactivity; its symbol is Bq.]

In radiation protection, the product of absorbed dose and the correct weighting factors is used to determine (A) air kerma (B) Gy (C) Sv (D) Bq

(B) 4.5 to 6 mg/100 mL [The BUN level indicates the quantity of nitrogen in the blood in the form of urea. The normal concentration is 8 to 25 mg/100 mL. BUN and creatinine blood chemistry levels should be checked prior to beginning an IVU. An increase in the BUN level often indicates decreased renal function. Increased BUN and/or creatinine levels may forecast an increased possibility of contrast media-induced renal effects and poor visualization of the renal collecting systems. The normal creatinine range is 0.6 to 1.5 mg/100 mL.]

In reviewing a patient's blood chemistry, which of the following blood urea nitrogen (BUN) ranges is considered normal? (A) 0.6 to 1.5 mg/100 mL (B) 4.5 to 6 mg/100 mL (C) 8 to 25 mg/100 mL (D) Up to 50 mg/100 mL

(C) 2 and 3 only [The medial oblique projection of the ankle can be performed either as a 15- to 20-degree oblique or as a 45-degree oblique. The 15- to 20-degree oblique projection demonstrates the ankle mortise, that is, the articulations between the talus, tibia, and fibula. The 45-degree oblique opens the distal tibiofibular joint. In all three cases, although the MSP can change, the plantar surface must be vertical.]

In the 45-degree medial oblique projection of the ankle, the 1. talotibial joint is visualized 2. tibiofibular joint is visualized 3. plantar surface should be vertical (A) 1 only (B) 2 only (C) 2 and 3 only (D) 1, 2, and 3

(D) 15 degrees caudad to C4. [The anterior oblique positions (LAO and RAO) of the cervical spine require a 15-degree caudal angulation and demonstrate the intervertebral foramina closest to the IR. The posterior oblique positions (LPO and RPO) require that the CR be directed cephalad 15 degrees to C4. The posterior oblique positions demonstrate the intervertebral foramina farther away from the IR.]

In the anterior oblique position of the cervical spine, the CR should be directed (A) parallel to C4 (B) perpendicular to C4 (C) 15 degrees cephalad to C4 (D) 15 degrees caudad to C4.

(D) 15 degrees caudad to C4 [The anterior oblique positions (LAO and RAO) of the cervical spine require a 15-degree caudal angulation and demonstrate the intervertebral foramina closest to the IR. The posterior oblique positions (LPO and RPO) require that the CR be directed cephalad 15 degrees to C4. The posterior oblique positions demonstrate the intervertebral foramina farther away from the IR.]

In the anterior oblique position of the cervical spine, the CR should be directed (A) parallel to C4 (B) perpendicular to C4 (C) 15 degrees cephalad to C4 (D) 15 degrees caudad to C4

(B) Medial femoral condyle [For the lateral projection of the knee, the patient is turned onto the affected side. This places the lateral femoral condyle closest to the IR and the medial femoral condyle remote from the IR. Consequently, there is significant magnification of the medial femoral condyle and, unless the central ray is angled slightly cephalad, subsequent obliteration of the joint space.]

In the lateral projection of the knee, the central ray is angled 5° cephalad to prevent superimposition of which of the following structures on the joint space? (A) Lateral femoral condyle (B) Medial femoral condyle (C) Patella (D) Tibial eminence

(A) ejects an inner-shell tungsten electron [Characteristic radiation is one of two kinds of x-rays produced at the tungsten target of the x-ray tube. The incident, or incoming, high-speed electron ejects a K-shell tungsten electron. This leaves a hole in the K shell, and an L-shell electron drops down to fill the K vacancy. Because L electrons are at a higher energy level than K-shell electrons, the L-shell electron gives up the difference in binding energy in the form of a photon, a characteristic x-ray (characteristic of the K shell).]

In the production of characteristic radiation at the tungsten target, the incident electron (A) ejects an inner-shell tungsten electron (B) ejects an outer-shell tungsten electron (C) is deflected, with resulting energy loss (D) is deflected, with resulting energy gain

(A) ejects an inner-shell tungsten electron [Characteristic radiation is one of two kinds of x-rays produced at the tungsten target of the x-ray tube. The incident, or incoming, high-speed electron ejects a K-shell tungsten electron. This leaves a hole in the K shell, and an L-shell electron drops down to fill the K vacancy. Because L electrons are at a higher energy level than K-shell electrons, the L-shell electron gives up the difference in binding energy in the form of a photon, a characteristic x-ray (characteristic of the K shell).]

In the production of characteristic radiation at the tungsten target, the incident electron (A) ejects an inner-shell tungsten electron (B) ejects an outer-shell tungsten electron (C) is deflected, with resulting energy loss (D) is deflected, with resulting energy gain

(B) 1 and 2 only [Double-contrast studies of the large bowel are particularly useful for demonstration of the bowel wall and anything projecting into it, for example, polyps. Polyps are projections of the bowel wall mucous membrane into the bowel lumen. Colitis is inflammation of the large bowel, often associated with ulcerations of the mucosal wall. A single-contrast study most likely would obliterate these mucosal conditions, but coating of the bowel mucosa with barium and subsequent filling of the bowel with air (double contrast) provide optimal delineation. Single-contrast studies will demonstrate projections/outpouchings from the intestinal wall such as diverticulitis.]

In which of the following conditions is a double-contrast BE essential for demonstration of the condition? 1. Polyps 2. Colitis 3. Diverticulosis (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3

Inadequate collimation in CR imaging can result in an image that is too 1. light 2. dark 3. noisy (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 2 and 3 only [The intervertebral foramina of the thoracic and lumbar vertebrae are best demonstrated in the lateral projection. The cervical intervertebral foramina are well demonstrated when placed 45 degrees to the IR and CR.]

Intervertebral foramina will be demonstrated in which of the following projections? 1. Lateral cervical spine 2. Lateral thoracic spine 3. Lateral lumbar spine (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(D) emetic. [Ipecac is a medication used to induce vomiting and is classified as an emetic. This is easy to remember if you think of what an emesis basin is for. A diuretic is a medication that stimulates the production of urine. Lasix (furosemide) is an example of a diuretic. An antipyretic is used to reduce fever. Tylenol (acetaminophen) is an example of an antipyretic. An antihistamine is used to relieve allergic effects. Benadryl (diphenhydramine hydrochloride) is an example of an antihistamine that is often on hand in radiology departments in the event of a minor reaction to contrast media.]

Ipecac is a medication used to induce vomiting and is classified as a(n) (A) diuretic. (B) antipyretic. (C) antihistamine. (D) emetic.

(B) radiolysis [Radiolysis has to do with the irradiation of water molecules and the formation of free radicals. Free radicals contain enough energy to damage other molecules some distance away. They can migrate to and damage a DNA molecule (indirect hit theory).]

Irradiation of water molecules within the body and their resulting breakdown is termed (A) epilation (B) radiolysis (C) proliferation (D) repopulation

(B) 1 and 2 only [When biologic material is irradiated, there are a number of modifying factors that determine what kind and how much response will occur in the material. One of these factors is LET, which expresses the rate at which particulate or photon energy is transferred to the absorber. Because different kinds of radiation have different degrees of penetration in different materials, it is also a useful way of expressing the quality of the radiation.]

LET is best defined as 1. a method of expressing radiation quality 2. a measure of the rate at which radiation energy is transferred to soft tissue 3. absorption of polyenergetic radiation (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3 [Late somatic effects are those that can occur years after initial exposure and are caused by low, chronic exposures. Occupationally exposed personnel are concerned with the late effects of radiation exposure. Bone malignancies, thyroid cancers, leukemia, and skin cancers are examples of carcinogenic somatic effects of radiation. Another example of somatic effects of radiation is cataract formation to the lenses of eyes of individuals accidentally exposed to sufficient quantities of radiation. The lives of many of the early radiation workers were several years shorter than the lives of the general population. Statistics revealed that radiologists, for example, had a shorter life span than physicians of other specialties. Life-span shortening, then, was another somatic effect of radiation. Certainly, these effects should never be experienced today. The human reproductive organs are particularly radiosensitive. Fertility and heredity can be greatly affected by the germ cells produced within the testes (spermatogonia) and ovaries (oogonia). Excessive radiation exposure to the gonads can cause temporary or permanent sterility and/or genetic mutations.]

Late radiation-induced somatic effects include 1. thyroid cancers 2. cataractogenesis 3. skin cancers (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only [Positive contrast medium is radiopaque; negative contrast material is radioparent. Barium sulfate (radiopaque, positive contrast material) is used most frequently for examinations of the intestinal tract, and high-kilovoltage exposure factors are used to penetrate (to see through and behind) the barium. Water-based iodinated contrast media (Conray, Amipaque) are also positive contrast agents. However, the K-edge binding energy of iodine prohibits the use of much greater than 70 kV with these materials. Higher kilovoltage values will obviate the effect of the contrast agent. Air is an example of a negative contrast agent, and high-kilovoltage factors are clearly not indicated.]

Low-kilovoltage exposure factors usually are indicated for radiographic examinations using 1. water-soluble, iodinated media 2. a negative contrast agent 3. barium sulfate (A) 1 only (B) 1 and 2 only (C) 3 only (D) 1 and 3 only

(D) 90% [Artificial/human-made sources of radiation include radioactive fallout, industrial radiation, and medical and dental x-rays. The majority of the general public's exposure to artificial radiation is from medical and dental x-rays, and it is growing every day. The general public's exposure to medical ionizing radiation has quadrupled in the last 25 years! It is our professional obligation, therefore, to keep our patient's radiation dose to a minimum.]

Medical and dental radiation accounts for what percentage of the general public's exposure to human-made radiation? (A) 10% (B) 50% (C) 80% (D) 90%

(D) 1, 2, and 3 [Moving the image intensifier closer to the patient during traditional fluoroscopy reduces the distance between the x-ray tube (source) and the image intensifier (IR), that is, the SID. It follows that the distance between the part being imaged (object) and the image intensifier (IR), that is, the object-to- image distance (OID), is also reduced. The shorter OID produces less magni cation and better image quality. As the SID is reduced, the intensity of the x-ray photons at the image intensifier's input phosphor increases, stimulating the automatic brightness control (ABC) to decrease the milliamperage and thereby decreasing patient dose.]

Moving the image intensifier closer to the patient during traditional fluoroscopy 1. decreases the SID 2. decreases patient dose 3. improves image quality (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(C) 2 and 3 only [Myelography is used to demonstrate encroachment on and compression of the spinal cord as a result of disk herniation, tumor growth, or posttraumatic swelling of the cord. This is accomplished by placing positive or negative contrast medium into the subarachnoid space. Myelography will demonstrate posterior protrusion of herniated intervertebral disks or spinal cord tumors. Anterior protrusion of a herniated intervertebral disk does not impinge on the spinal cord and is not demonstrated in myelography. Internal disk lesions can be demonstrated only by injecting contrast medium into the individual disks (diskography).]

Myelography is a diagnostic examination used to demonstrate 1. internal disk lesions. 2. posttraumatic swelling of the spinal cord. 3. posterior disk herniation. (A) 1 only (B) 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) Spatial resolution is inversely related to OID. [As the distance from the object to the IR (OID) increases, so does magnification distortion, thereby decreasing spatial resolution. Some magnification is inevitable in radiography because it is not possible to place anatomic structures directly on the IR. However, our understanding of how to minimize magnification distortion is an important part of our everyday work.]

OID is related to spatial resolution in which of the following ways? (A) Spatial resolution is directly related to OID. (B) Spatial resolution is inversely related to OID. (C) As OID increases, so does spatial resolution. (D) OID is unrelated to spatial resolution.

(A) Compton scatter [The photoelectric effect and Compton scattering are the two predominant interactions between x-ray photons and matter in diagnostic radiology. In the photoelectric effect, the low-energy-incident photon is absorbed by the tissues being radiographed. In Compton scatter, the high-energy-incident photon uses only part of its energy to eject an outer-shell electron. It retains much of its original energy in the form of a scattered x-ray. Radiologic personnel can be exposed to that high-energy scattered radiation, especially in fluoroscopy and mobile radiography. Lead aprons are used to protect us from exposure to scattered radiation during these procedures.]

Occupational exposure received by the radiographer is mostly from (A) Compton scatter (B) the photoelectric effect (C) coherent scatter (D) pair production

(C) 1/10 [Different types of monitoring devices are available for the occupationally exposed, and anyone who might receive more than one-tenth the annual dose limit must be monitored. Ionization is the fundamental principle of operation of both the film badge and the pocket dosimeter. In the film badge, the film's silver halide emulsion is ionized by x-ray photons. The pocket dosimeter contains an ionization chamber (containing air), and the number of ions formed (of either sign) is equated to exposure dose. TLDs are radiation monitors that use lithium fluoride crystals. Once exposed to ionizing radiation and then heated, these crystals give off light proportional to the amount of radiation received. OSL dosimeters are radiation monitors that use aluminum oxide crystals. These crystals, once exposed to ionizing radiation and then subjected to a laser, give off luminescence proportional to the amount of radiation received.]

Occupational radiation monitoring is required when it is likely that an individual will receive more than what fraction of the annual dose limit? (A) 1⁄2 (B) 1⁄4 (C) 1/10 (D) 1/40

(B) FOV decreases [During fluoroscopic procedures, as field of view (FOV) decreases, magnification of the output screen image increases, and contrast and resolution improve. The focal point on an image intensifier's 6-in. field/mode is further away from the output phosphor than the focal point on the normal mode; therefore, the output image is magnified. Because less minification takes place, the image is not as bright. Exposure factors are increased automatically to compensate for the loss in brightness with smaller FOVs. Focal spot size (FSS) is unrelated to patient dose.]

Patient dose increases as fluoroscopic (A) FOV increases (B) FOV decreases (C) FSS increases (D) FSS decreases

(C) 7 ft [Radiation protection guidelines have established that primary radiation barriers must be 7 ft high. Primary radiation barriers are walls that the primary beam might be directed toward. They usually contain 1.5 mm of lead (1/16 in.), but this may vary depending on use factor, and so on.]

Primary radiation barriers must be at least how high? (A) 5 ft (B) 6 ft (C) 7 ft (D) 8 ft

(C) Display matrix size

Quality Control (QC) testing is used to evaluate digital display monitors in all of the following ways, except (A) Display luminance response (B) Display resolution (C) Display matrix size (D) Display noise

(A) Daily

Quality control testing of digital display monitors should be conducted (A) Daily (B) Weekly (C) Monthly (D) Annually

(B) 1 and 2 only [Radiographic and fluoroscopic equipment is designed to help decrease the exposure dose to patient and operator. One of the design features is the exposure cord. Exposure cords on fixed equipment must be short enough to prevent the exposure from being made outside the control booth. Exposure cords on mobile equipment must be long enough to permit the operator to stand at least 6 ft from the x-ray tube.]

Radiation dose to personnel is reduced by which of the following exposure control cord guidelines? 1. Exposure cords on fixed equipment must be very short. 2. Exposure cords on mobile equipment should be long. 3. Exposure cords on fixed and mobile equipment should be of the coiled, expandable type. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) Gya [As x-ray photons emerge from the x-ray tube they immediately encounter air—before being intercepted by any material. The unit kerma expresses kinetic energy released in matter. Xrays expend kinetic energy as they ionize the air. Joule/kilogram is used to measure air kerma and 1 J/kg = 1 Gya. The subscript a represents air as the absorber. The mGya is the SI unit of measure of radiation exposure/intensity. The SI unit used to describe absorbed dose is Gray (Gyt)—the subscript t represents tissue. It describes tissue in general; various organs and tissue types require assigned specific weighting factors in order to describe the effective dose. Absorbed dose and energy deposited is strongly related to chemical change and biologic damage. The SI unit of measurement to describe effective dose to biologic material is the Sv (Sievert). The Sievert is the unit of occupational radiation exposure.]

Radiation output from a diagnostic x-ray tube is measured in which of the following units of measurement? (A) Gyt (B) Sv (C) Gya (D) Bq

(C) leakage radiation [Scattered and secondary radiations are those that have deviated in direction while passing through a part. Leakage radiation is radiation that emerges from the leaded tube housing in directions other than that of the useful beam. Tube head construction must keep leakage radiation to less than 0.1 R/h at 1 m from the tube. Remnant radiation is the radiation that emerges from the patient to form the radiographic image.]

Radiation that passes through the tube housing in directions other than that of the useful beam is termed (A) scattered radiation (B) secondary radiation (C) leakage radiation (D) remnant radiation

(C) Neurologic anomalies [During the first trimester, specifically the second through eighth weeks of pregnancy (during major organogenesis), if the radiation dose is high enough, fetal anomalies can be produced. Skeletal anomalies usually appear if irradiation occurs in the early part of this time period, and neurologic (CNS) anomalies are formed in the latter part; mental retardation and childhood malignant diseases, such as cancers or leukemia, also can result from irradiation during the first trimester. Fetal irradiation during the second and third trimesters is not likely to produce anomalies but rather, with sufficient dose, some type of childhood malignant disease. Fetal irradiation during the first 2 weeks of gestation can result in spontaneous abortion. None of these responses are likely to occur with exposures less than 250 mGyt. It must be emphasized that the likelihood of producing fetal anomalies at diagnostic imaging doses is exceedingly small and that most general diagnostic examinations are likely to deliver fetal doses of less than 10 mGy.]

Radiation-induced abnormalities to the fetus during the seventh or eighth week of pregnancy is likely to cause which of the following? (A) Spontaneous abortion (B) Skeletal anomalies (C) Neurologic anomalies (D) Organogenesis

(C) Neurologic anomalies [During the first trimester, specifically the second through eighth weeks of pregnancy (during major organogenesis), if the radiation dose is high enough, fetal anomalies can be produced. Skeletal anomalies usually appear if irradiation occurs in the early part of this time period, and neurologic (CNS) anomalies are formed in the latter part; mental retardation and childhood malignant diseases, such as cancers or leukemia, also can result from irradiation during the first trimester. Fetal irradiation during the second and third trimesters is not likely to produce anomalies but rather, with sufficient dose, some type of childhood malignant disease. Fetal irradiation during the first 2 weeks of gestation can result in spontaneous abortion. None of these responses are likely to occur with exposures less than 250 mGyt. It must be emphasized that the likelihood of producing fetal anomalies at diagnostic imaging doses is exceedingly small and that most general diagnostic examinations are likely to deliver fetal doses of less than 10 mGy.]

Radiation-induced abnormalities to the fetus during the seventh or eighth week of pregnancy is likely to cause which of the following? (A) Spontaneous abortion (B) Skeletal anomalies (C) Neurologic anomalies (D) Organogenesis

(C) health-care institution. [Radiographs are the property of the health-care institution and are a part of every patient's permanent medical record. They are often retained on file for about 7 years or, in the case of pediatric patients, until the patient reaches maturity. They are not the personal property of either the radiologist or the referring physician. If a patient changes doctors or needs a second opinion, copies can be requested. The patient may also borrow the originals, which must be returned, or he or she may pay for copies.]

Radiographs are the property of the (A) radiologist. (B) patient. (C) health-care institution. (D) referring physician.

(C) Signal-to-noise ratio [By incorporating two sets of light guides and photodetectors on either side of the IP as it travels through the CR reader, a single laser beam can effectively stimulate release of stored energy from both sides of the phosphor plate. This increases the amount of energy that may be released and used in the form of light to be converted by the photodetectors to an electrical (analog) signal. Therefore, the higher signal intensity increases the SNR, i.e. signal-to-noise ratio (C). Slow scan direction speed refers to the linear travel speed of the phosphor plate through the CR reader (A). The laser light in the CR reader is rapidly reflected by an oscillating polygonal mirror that redirects the beam through a special lens called the f-theta lens, which focuses the light on a cylindrical mirror that reflects the light toward the IP. This light moves back and forth very rapidly to scan the plate transversely, in a raster pattern, and this movement of the laser beam across the IP is therefore called the fast-scan direction (D). The modulation transfer function is a mathematical function that measures the ability of the digital detector to transfer its spatial resolution characteristics to the image (B).]

Recently, dual-sided reading technology has become available in more modern CR readers, in which two sets of photodetectors are used to capture light released from the front and back sides of the phosphor storage plate, or PSP (photostimulable phosphor). This technology enables improved: (A) Slow-scan direction speed (B) Modulation transfer function (C) Signal-to-noise ratio (D) Fast-scan direction speed

(D) SMV [The SMV (Schüller method) projection of the skull requires that the patient's neck be extended, placing the vertex adjacent to the IR holder/upright Bucky so that the IOML is parallel with the IR. This projection is useful for demonstrating the ethmoidal and sphenoidal sinuses, pars petrosae, mandible, and foramina ovale and spinosum. The lateral projection of the skull requires that the patient be in the prone oblique position with the MSP parallel to the IR and the interpupillary line perpendicular to the IR. This position also requires that the IOML (line 3) be parallel to the long axis of the IR. The AP and PA axial projections of the skull require the OML or IOML to be perpendicular to the IR.]

Referring to Figure 2-38, which of the following positions requires that baseline number 3 be parallel to the IR? (A) Parietoacanthial (B) PA axial (Caldwell) (C) AP axial (Towne) (D) SMV

(D) Pixels/mm or pixel density

Sampling frequency in computed radiography (CR) is expressed as: (A) The TFT array size (B) An inverse relationship between focal spot size and matrix size (C) The light spread between the image plate and the light guide of the scanner (D) Pixels/mm or pixel density

(D) 1/32-inch lead [Examples of primary barriers are the lead walls and doors of a radiographic room, that is, any surface that could be struck by the useful beam. Primary protective barriers of typical installations generally consist of walls with 1/16 inch (1.5 mm) lead thickness and 7 feet high. Secondary radiation is defined as leakage and/or scattered radiation. The x-ray tube housing protects from leakage radiation as stated previously. The patient is the source of most scattered radiation. Secondary radiation barriers include that portion of the walls above 7 feet in height; this area requires only 1/32-inch lead. The control booth is also a secondary barrier, toward which the primary beam must never be directed.]

Secondary radiation barriers usually require the following thickness of shielding: (A) 1/4-inch lead (B) 1/8-inch lead (C) 1/16-inch lead (D) 1/32-inch lead

(B) X-ray tube not centered to grid

Which of the following errors is illustrated in the figure below? (A) Patient not centered to IR (B) X-ray tube not centered to grid (C) Inaccurate collimation (D) Unilateral grid cutoff

(B) during the life of the exposed individual

Somatic effects of radiation refer to effects that are manifested (A) in the descendants of the exposed individual (B) during the life of the exposed individual (C) in the exposed individual and his or her descendants (D) in the reproductive cells of the exposed individual

(C) 2 and 3 only [Secondary radiation consists of leakage and scattered radiation. Leakage radiation can be emitted when a defect exists in the tube housing. A significant quantity of scattered radiation is generated within, and emitted from, the patient. Background radiation is naturally occurring radiation that is emitted from the earth and that also exists within our bodies.]

Sources of secondary radiation include 1. background radiation 2. leakage radiation 3. scattered radiation (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) 1 only [As SID increases, so does spatial resolution because magnification is decreased - a direct relationship. Therefore, SID is directly related to spatial resolution. As focal spot size increases, spatial resolution decreases because more penumbral blur is produced. Focal spot size is thus inversely related to spatial resolution - as FSS increases,resolution decreases. Tube current affects receptor exposure and is unrelated to spatial resolution.]

Spatial resolution is directly related to 1. SID. 2. tube current. 3. focal-spot size. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) 1 only [As SID increases, so does spatial resolution because magnification is decreased - a direct relationship. Therefore, SID is directly related to spatial resolution. As focal spot size increases, spatial resolution decreases because more penumbral blur is produced. Focal spot size is thus inversely related to spatial resolution - as FSS increases, resolution decreases. Tube current affects receptor exposure and is unrelated to spatial resolution.]

Spatial resolution is directly related to 1. SID. 2. tube current. 3. focal-spot size. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) 1 only

Spatial resolution is directly related to 1. source-image distance (SID). 2. tube current. 3. focal spot size. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 2 and 3 only [Late effects of radiation can occur in cells that have survived a previous irradiation months or years earlier. These late effects, such as carcinogenesis and genetic effects, are "all-or-nothing" effects—either the organism develops cancer or it does not. Most late effects do not have a threshold dose; that is, any dose, however small, theoretically can induce an effect. Increasing that dose will increase the likelihood of the occurrence but will not affect its severity; these effects are termed stochastic. Tissue reactions (formerly referred to as Deterministic effects) are those that are unlikely to occur below a particular threshold dose and that increase in severity as the dose increases.]

Stochastic effects of radiation are those that 1. have a threshold 2. may be described as "all-or-nothing" effects 3. are late effects (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 2 and 3 only [Late effects of radiation can occur in cells that have survived a previous irradiation months or years earlier. These late effects, such as carcinogenesis and genetic effects, are "all-or-nothing" effects—either the organism develops cancer or it does not. Most late effects do not have a threshold dose; that is, any dose, however small, theoretically can induce an effect. Increasing that dose will increase the likelihood of the occurrence but will not affect its severity; these effects are termed stochastic. Deterministic effects are those that are unlikely to occur below a particular threshold dose and that increase in severity as the dose increases.]

Stochastic effects of radiation are those that 1. have a threshold 2. may be described as "all-or-nothing" effects 3. are late effects (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only

Structures comprising the neural, or vertebral, arch include 1. pedicles 2. laminae 3. body (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) 1 only

Terms that refer to size distortion include 1. magnification 2. attenuation 3. elongation (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(A) 1 only [Distortion is misrepresentation of the actual size or shape of the object being imaged. Size distortion is magnification. Shape distortion is a result of improper alignment of the x-ray tube, the part being radiographed, and the IR; the two types of shape distortion are foreshortening and elongation. The shapes of various structures can be misrepresented radiographically as a result of their position in the body, when the part is out of the central axis of the x-ray beam, or when the CR is angled. Parts sometimes are elongated intentionally for better visualization (e.g., sigmoid colon). Some body parts, because of their position in the body, are foreshortened, such as the carpal scaphoid. Attenuation refers to decreasing beam intensity and is unrelated to distortion.]

Terms that refer to size distortion include 1. magnification 2. attenuation 3. elongation (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(A) rotation distortion [Anatomic details placed away from the path of the CR will be exposed by more divergent rays, resulting in rotation distortion. This is why the CR must be directed to the midpoint of the part of greatest interest. For example, if bilateral hands are requested, they should be examined individually; if imaged simultaneously, the CR will be directed to no anatomic part (between the two hands) and rotation distortion will occur. Magnification occurs when an OID is introduced, or with a decrease in SID. Foreshortening and elongation are the two types of shape distortion—caused by nonalignment of the x-ray tube, part/subject, and IR.]

The CR should be directed to the center of the part of greatest interest to avoid (A) rotation distortion (B) magnification (C) foreshortening (D) elongation

(A) rotation distortion [Anatomic details placed away from the path of the CR will be exposed by more divergent rays, resulting in rotation distortion. This is why the CR must be directed to the midpoint of the part of greatest interest. For example, if bilateral hands are requested, they should be examined individually; if imaged simultaneously, the CR will be directed to no anatomic part (between the two hands) and rotation distortion will occur. Magnification occurs when an OID is introduced, or with a decrease in SID. Foreshortening and elongation are the two types of shape distortion—caused by nonalignment of the x-ray tube, part/subject, and IR.]

The CR should be directed to the center of the part of greatest interest to avoid (A) rotation distortion (B) magnification (C) foreshortening (D) elongation

(B) standard precautions. [Standard blood and body fluid precautions serve to protect health care workers and patients from the spread of diseases such as AIDS and AIDS-related complex. Although the precautions are indicated for all patients, special care must be emphasized when working with patients whose infectious status is unknown (e.g., the emergency trauma patient). Gloves must be worn if the radiographer may come in contact with blood or body fluids. A gown should be worn if the clothing may become contaminated. Blood spills should be cleaned with a solution of 1 part bleach to 10 parts water.]

The Centers for Disease Control and Prevention (CDC) suggests that health care workers protect themselves and their patients from blood and body fluid contamination by using (A) strict isolation precautions. (B) standard precautions. (C) respiratory precautions. (D) sterilization.

(A) absorbed dose. [The SI unit air kerma is used to express kinetic energy released in matter, the unit of exposure and ionization in air. The SI unit used to describe absorbed dose is Gray (Gyt) The SI unit of measurement to describe dose to biologic material is the Sievert (Sv). Various organs and tissue types require assigned specific weighting factors in order to describe the effective dose. Absorbed dose and energy deposited is strongly related to chemical change and biologic damage. The SI unit of measurement to describe effective dose to biologic material is the Sievert (Sv). The Sievert is the unit of occupational radiation exposure.]

The Gray is the unit of (A) absorbed dose. (B) exposure. (C) effective dose. (D) ionization in air.

(C) a minimum of 30 cm. [Lead and distance are the two most important ways to protect from radiation exposure. Fluoroscopy can be particularly hazardous because the source-to-skin distance (SSD) is so much shorter than in overhead radiography. Therefore, it has been established that mobile fluoroscopic equipment must provide at least 30 cm of SSD for protection of the patient. Fixed (stationary) fluoroscopic equipment must provide at least 38 cm SSD.]

The SSD in mobile fluoroscopy must be (A) a minimum of 38 cm. (B) a maximum of 38 cm. (C) a minimum of 30 cm. (D) a maximum of 30 cm.

(C) grid cutoff. [Grids are used in radiography to absorb scattered radiation before it reaches the IR (grid "cleanup"), thus improving radiographic contrast. Contrast obtained with a grid compared with contrast without a grid is termed contrast-improvement factor. The greater the percentage of scattered radiation absorbed compared with absorbed primary radiation, the greater is the "selectivity" of the grid. If a grid absorbs an abnormally large amount of useful radiation as a result of improper centering, tube angle, or tube distance, grid cutoff occurs.]

The absorption of useful radiation by a grid is called (A) grid selectivity. (B) grid cleanup. (C) grid cutoff. (D) latitude.

(C) grid cutoff. [Grids are used in radiography to absorb scattered radiation before it reaches the IR (grid "cleanup"), thus improving radiographic contrast. Contrast obtained with a grid compared with contrast without a grid is termed contrast-improvement factor. The greater the percentage of scattered radiation absorbed compared with absorbed primary radiation, the greater is the "selectivity" of the grid. If a grid absorbs an abnormally large amount of useful radiation as a result of improper centering, tube angle, or tube distance, grid cutoff occurs.]

The absorption of useful radiation by a grid is called (A) grid selectivity. (B) grid cleanup. (C) grid cutoff. (D) latitude.

(C) grid cutoff. [Grids are used in radiography to absorb scattered radiation before it reaches the IR (grid "cleanup"), thus improving radiographic contrast. Contrast obtained with a grid compared with contrast without a grid is termed contrast-improvement factor. The greater the percentage of scattered radiation absorbed compared with absorbed primary radiation, the greater is the "selectivity" of the grid. If a grid absorbs an abnormally large amount of useful radiation as a result of improper centering, tube angle, or tube distance, grid cutoff occurs.]

The absorption of useful radiation by a grid is called (A) grid selectivity. (B) grid cleanup. (C) grid cutoff. (D) latitude.

(B) use factor [Use factor describes the percentage of time that the primary beam is directed toward a particular wall. The use factor is one of the factors considered in determining protective barrier thickness. Another is workload, which is determined by the number of x-ray exposures made per week. Occupancy factor is a reflection of who occupies particular areas (radiation workers or nonradiation workers) and is another factor used in determining radiation barrier thickness.]

The amount of time that x-rays are being produced and directed toward a particular wall is referred to as the (A) workload (B) use factor (C) occupancy factor (D) controlling factor

(B) use factor [Use factor describes the percentage of time that the primary beam is directed toward a particular wall. The use factor is one of the factors considered in determining protective barrier thickness. Another is workload, which is determined by the number of x-ray exposures made per week. Occupancy factor is a reflection of who occupies particular areas (radiation workers or nonradiation workers) and is another factor used in determining radiation barrier thickness.]

The amount of time that x-rays are being produced and directed toward a particular wall is referred to as the (A) workload (B) use factor (C) occupancy factor (D) controlling factor

(C) beta, x-, and gamma radiations. [The occupational dose limit is valid for beta, x-, and gamma radiations. Because alpha radiation is so rapidly ionizing, traditional personal monitors will not record alpha radiation. Because alpha particles are capable of penetrating only a few centimeters of air, they are practically harmless as an external source.]

The annual dose limit for occupationally exposed individuals is valid for (A) alpha, beta, and x-radiations. (B) x- and gamma radiations only. (C) beta, x-, and gamma radiations. (D) all ionizing radiations.

(B) thermionic emission

The electron cloud within the x-ray tube is the product of a process called (A) electrolysis (B) thermionic emission (C) rectification (D) induction

(B) middle ear. [The auditory, or eustachian, tube extends from the middle ear to the nasopharynx. It is 3-4 cm in length and is lined with mucous membrane. Otitis media can result when the auditory tube becomes occluded during inflammatory processes. The middle ear contains the auditory ossicles (i.e., malleus, incus, and stapes). The inner ear contains the cochlea, semicircular canals, and vestibule.]

The auditory, or eustachian, tube extends from the nasopharynx to the (A) external ear. (B) middle ear. (C) inner ear. (D) oropharynx.

(A) asthenic [The four types of body habitus describe differences in visceral shape, position, tone, and motility. One body type is hypersthenic, characterized by the very large individual with short, wide heart and lungs, high transverse stomach and gallbladder, and peripheral colon. The sthenic individual is the average, athletic, most predominant type. The hyposthenic patient is somewhat thinner and a little frailer, with organs positioned somewhat lower. The asthenic type is smaller in the extreme, with a long thorax, a very long, almost pelvic stomach, and a low medial gallbladder. The colon is medial and redundant. Hypersthenic patients usually demonstrate the greatest motility.]

The body habitus characterized by a long and narrow thoracic cavity and low midline stomach and gallbladder is the (A) asthenic (B) hyposthenic (C) sthenic (D) hypersthenic

(C) photostimulable phosphor [Inside the IP is the photostimulable phosphor (PSP). This PSP (or SPS—Storage Phosphor Screen), with its layer of europium-activated barium fluorohalide, serves as the IR because it is exposed in the traditional manner and receives the latent image. The PSP can store the latent image for several hours; after about 8 hours, noticeable image fading will occur. Once the IP is placed into the CR processor (scanner or reader), the PSP plate is removed automatically. The latent image on the PSP is changed to a manifest image as it is scanned by a narrow, high-intensity helium-neon laser to obtain the pixel data. As the PSP is scanned in the reader, it releases a violet light—a process referred to as photostimulated luminescence (PSL).]

The component of a CR image plate (IP) that records the radiologic image is the (A) emulsion (B) helium-neon laser (C) photostimulable phosphor (D) scanner-reader

(C) photostimulable phosphor [Inside the IP is the photostimulable phosphor (PSP). This PSP (or SPS—Storage Phosphor Screen), with its layer of europium-activated barium fluorohalide, serves as the IR because it is exposed in the traditional manner and receives the latent image. The PSP can store the latent image for several hours; after about 8 hours, noticeable image fading will occur. Once the IP is placed into the CR processor (scanner or reader), the PSP plate is removed automatically. The latent image on the PSP is changed to a manifest image as it is scanned by a narrow, high-intensity helium-neon laser to obtain the pixel data. As the PSP is scanned in the reader, it releases a violet light—a process referred to as photostimulated luminescence (PSL).]

The component of a CR image plate (IP) that records the radiologic image is the (A) emulsion (B) helium-neon laser (C) photostimulable phosphor (D) scanner-reader

(C) emphysema [Emphysema is a progressive disorder caused by long-term irritation of the bronchial passages, such as by air pollution or cigarette smoking. Emphysema patients are unable to exhale normally because of the loss of elasticity of the alveolar walls. If emphysema patients receive oxygen, it is usually administered at a very slow rate because their respirations are controlled by the level of carbon dioxide in the blood.]

The condition in which pulmonary alveoli lose their elasticity and become permanently inflated, causing the patient to consciously exhale, is (A) bronchial asthma (B) bronchitis (C) emphysema (D) tuberculosis

(A) 1 only [Lead aprons require certain maintenance and care if they are to continue to provide protection from ionizing radiation. They can be kept clean with a damp cloth. It is very important that they be hung when not in use rather than being folded or left in a heap between examinations. A folded or crumpled position encourages the formation of cracks in the leaded vinyl. Lead aprons should be fluoroscoped (at about 120 kVp) at least once a year to check for development of any cracks. Radiographing the "lead" apron with low kV would be ineffective - high kV would be required if using the radiographic method.]

The correct way(s) to check for cracks in lead aprons is (are) 1. to fluoroscope them once a year 2. to radiograph them at low kilovoltage twice a year 3. by visual inspection (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) nonmalficence. [Fidelity, veracity, nonmalficence, and beneficence are all ethical principles. Nonmalficence is the principle that refers to the prevention of harm. Beneficence is the ethical principle that refers to bringing about good or benefiting others. Fidelity refers to faithfulness, and veracity refers to truthfulness.]

The ethical principle that aspires never to, above all, do harm describes (A) fidelity. (B) veracity. (C) nonmalficence. (D) beneficence.

(C) anode heel effect.

The fact that x-ray intensity across the primary beam can vary as much as 45% describes the (A) line-focus principle. (B) transformer law. (C) anode heel effect. (D) inverse-square law.

(D) spinning top

The device used to test the accuracy of the x-ray timer is the (A) densitometer (B) sensitometer (C) penetrometer (D) spinning top

(C) 1.0 mSv [Whole-body annual occupational DL (dose limit) is 50 mSv. One of the special DL considerations regards radiography students under the age of 18. Their annual whole-body annual occupational DL must not exceed 1.0 mSv. This is the same DL used for the general public who might be exposed to larger amounts of radiation. The usual annual DL for the general public is 5 mSv. The DL to the lens of the eyes is 150 mSv; the DL for skin, hands, and feet is 500 mSv]

The dose equivalent limit for a radiography student under the age of 18 years is (A) 50 mSv (B) 150 mSv (C) 1.0 mSv (D) 500 mSv

(C) 1.0 mSv [Whole-body annual occupational DL (dose limit) is 50 mSv. One of the special DL considerations regards radiography students under the age of 18. Their annual whole-body annual occupational DL must not exceed 1.0 mSv. This is the same DL used for the general public who might be exposed to larger amounts of radiation. The usual annual DL for the general public is 5 mSv. The DL to the lens of the eyes is 150 mSv; the DL for skin, hands, and feet is 500 mSv]

The dose equivalent limit for a radiography student under the age of 18 years is (A) 50 mSv (B) 150 mSv (C) 1.0 mSv (D) 500 mSv

(D) 1, 2, and 3

The effect described as differential absorption is 1. responsible for radiographic contrast 2. a result of attenuating characteristics of tissue 3. minimized by the use of a high peak kilovoltage (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(D) Raster pattern

The electron beam in a television cathode ray tube (CRT) is projected onto the output phosphor in a: (A) Vertical pattern (B) Fixed direct beam (C) Broad field (D) Raster pattern

(B) Portal vein [A cross-sectional image of the abdomen is shown in the figure. The large, homogeneous structure on the right, labeled 14, is the liver. The gallbladder is often seen darker on the medial border of the liver but is not visualized here. The left kidney is labeled 5; the right kidney is seen clearly on the opposite side labeled 11. The vertebra is seen in the center, and the psoas muscles are seen just posterior to the vertebra. Just anterior to the body of the vertebra is the circular aorta, labeled 7. The inferior vena cava (number 12) is seen to the right of the aorta. The circular structure just anterior to the inferior vena cava is the portal vein (number 13). Number 1 is the stomach, number 2 is the splenic/left colic flexure, number 3 is the pancreas, and number 4 is the spleen. Numbers 6 and 10 are portions of the left and right adrenal glands—not normally seen at this level. Number 8 is the celiac trunk; the common hepatic artery is seen branching to the right, and the splenic artery is seen branching to the left. Number 9 is a part of the diaphragmatic crura connecting the vertebrae and diaphragm.]

The figure below illustrates a sectional image of the abdomen. Which of the following is represented by the number 13? (A) Gallbladder (B) Portal vein (C) Inferior vena cava (D) Aorta

(C) a minimum of 30 cm. [Lead and distance are the two most important ways to protect from radiation exposure. Fluoroscopy can be particularly hazardous because the SID is so much shorter than in overhead radiography. Therefore, for patient protection, it has been established that xed (stationary) equipment must provide at least 38 cm source to tabletop/skin distance. Mobile fluoroscopic equipment must provide at least 30 cm source-to-tabletop/skin distance.]

The focal spot-to-table distance, in mobile fluoroscopy, must be (A) a minimum of 38 cm. (B) a maximum of 38 cm. (C) a minimum of 30 cm. (D) a maximum of 30 cm.

(C) 2 and 3 only [Major branches of the common carotid arteries (internal carotids) function to supply the anterior brain, whereas the posterior brain is supplied by the vertebral arteries (branches of the subclavian artery). The brachiocephalic (innominate) artery is unpaired and is one of the three branches of the aortic arch, from which the right common carotid artery is derived. The left common carotid artery comes directly off the aortic arch.]

The four major arteries supplying the brain include the 1. brachiocephalic artery 2. common carotid arteries 3. vertebral arteries (A) 1 and 2 only (B) 1 and 3 only (C) 2 and 3 only (D) 1, 2, and 3

(D) timer accuracy in a three-phase x-ray machine.

The image in Figure 6-6 was obtained while testing (A) rectifier operation in a single-phase x-ray machine. (B) rectifier operation in a three-phase x-ray machine. (C) timer accuracy in a single-phase x-ray machine. (D) timer accuracy in a three-phase x-ray machine.

(A) is much larger than the output phosphor [The image intensifier's input phosphor is 6 to 9 times larger than the output phosphor. It receives the remnant radiation emerging from the patient and converts it into a fluorescent light image. Very close to the input phosphor, separated only by a thin, transparent layer, is the photocathode. The photocathode is made of a photoemissive alloy, usually a cesium and antimony compound. The fluorescent light image strikes the photocathode and is converted to an electron image, which is focused by the electrostatic lenses to the small output phosphor.]

The image intensifier's input phosphor differs from the output phosphor in that the input phosphor (A) is much larger than the output phosphor (B) emits electrons, whereas the output phosphor emits light photons (C) absorbs electrons, whereas the output phosphor absorbs light photons (D) is a fixed size, and the size of the output phosphor can vary

(C) low-milliampere-seconds and high-kilovoltage factors [Quantum noise, or mottle, is a grainy appearance having a spotted or freckled appearance. Low- milliampere-seconds and high-kilovoltage factors are most likely to be the cause of quantum noise/mottle. Grid cutoff is absorption of the useful x-ray beam by the grid and usually results in loss of receptor exposure and visibility of grid lines. The anode heel effect is most pronounced using short SIDs, large IRs, small anode angles, and imaging parts having uneven tissue densities; it is represented by a noticeable receptor exposure difference between the anode and cathode ends of the image.]

The image quality seen in the figure below is most likely the result of (A) an off-level grid (B) pronounced anode heel effect (C) low-milliampere-seconds and high-kilovoltage factors (D) low-kilovoltage and high-milliampere-seconds factors

(C) low-milliampere-seconds and high-kilovoltage factors

The image quality seen in the figure below is most likely the result of (A) an off-level grid (B) pronounced anode heel effect (C) low-milliampere-seconds and high-kilovoltage factors (D) low-kilovoltage and high-milliampere-seconds factors

(D) bacterium. [Streptococcal pharyngitis ("strep throat") is caused by bacteria. To know this, you have to remember that bacteria are classified according to their morphology (i.e., size and shape). The three classifications are spirals, rods (bacilli), and spheres (cocci). Viruses, unlike bacteria, cannot live outside a human cell. Viruses attach themselves to a host cell and invade the cell with their genetic information. Various fungal infections may grow on the skin (cutaneously), or they may enter the skin. Fungal infections that enter the circulatory or lymphatic system can be deadly. Protozoa are one-celled organisms classified by their motility. Ameboids move by locomotion, flagella use their protein tail, cilia possess numerous short protein tails, and sporozoans actually are not mobile.]

The infection streptococcal pharyngitis ("strep throat") is caused by a (A) virus. (B) fungus. (C) protozoon. (D) bacterium.

(D) bacterium. [Streptococcal pharyngitis ("strep throat") is caused by bacteria. To know this, you have to remember that bacteria are classified according to their morphology (i.e., size and shape). The three classifications are spirals, rods (bacilli), and spheres (cocci). Viruses, unlike bacteria, cannot live outside a human cell. Viruses attach themselves to a host cell and invade the cell with their genetic information. Various fungal infections may grow on the skin (cutaneously), or they may enter the skin. Fungal infections that enter the circulatory or lymphatic system can be deadly. Protozoa are one-celled organisms classified by their motility. Ameboids move by locomotion, flagella use their protein tail, cilia possess numerous short protein tails, and sporozoans actually are not mobile.]

The infection streptococcal pharyngitis ("strep throat") is caused by a (A) virus. (B) fungus. (C) protozoon. (D) bacterium.

(A) 1 only [Diagnostic x-ray photons interact with tissue in a number of ways, but mostly they are involved in the production of Compton scatter or the photoelectric effect. Compton scatter is pictured; it occurs when a relatively high-energy (kV) photon uses some of its energy to eject an outer-shell electron. In so doing, the photon is deviated in direction and becomes a scattered photon. Compton scatter causes objectionable scattered radiation fog in large structures such as the abdomen and poses a radiation hazard to personnel during procedures such as fluoroscopy. In the photoelectric effect, a relatively low-energy x-ray photon uses all its energy to eject an inner-shell electron, leaving a hole in the K shell. An L-shell electron then drops down to fill the K vacancy and in so doing emits a characteristic ray whose energy is equal to the difference between the binding energies of the K and L shells. The photoelectric effect occurs with high-atomic-number absorbers such as bone and positive contrast media and is responsible for the production of radiographic contrast. It is helpful for the production of the radiographic image, but it contributes to the dose received by the patient (because it involves complete absorption of the incident photon).]

The interaction between x-ray photons and matter illustrated in Figure 4-22 is most likely to be associated with 1. high kilovoltage 2. high contrast 3. high-atomic-number absorber (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(D) 2 and 3 only [Diagnostic x-ray photons interact with tissue in a number of ways, but most frequently they are involved in the photoelectric effect or in the production of Compton scatter. The photoelectric effect is pictured in Figure A; it occurs when a relatively low-energy x-ray photon uses all its energy to eject an inner-shell electron. That electron is ejected (photoelectron), leaving a "hole" in the K shell and producing a positive ion. An L-shell electron then drops down to fill the K vacancy, and in doing so emits a characteristic ray whose energy is equal to the difference between the binding energies of the K and L shells. The photoelectric effect occurs with high-atomic-number absorbers such as bone and positive contrast media, and is responsible for the production of contrast. Therefore, its occurrence is helpful for the production of the radiographic image, but it contributes significantly to the dose received by the patient (because it involves complete absorption of the incident photon). Scattered radiation, which produces a radiation hazard to the radiographer (as in fluoroscopy), is a product of the Compton scatter interaction occurring with higher energy x-ray photons.]

The interaction between x-ray photons and matter pictured in Figure A is associated with 1. high-energy x-ray photons. 2. ionization. 3. characteristic radiation. (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 2 and 3 only

(A) the photoelectric effect [In the photoelectric effect, the incident (low-energy) photon is completely absorbed and thus contributes to image contrast but significantly impacts patient dose. In Compton scatter, only partial absorption occurs, and most energy emerges as scattered photons. In coherent scatter, no energy is absorbed by the part; it all emerges as scattered photons. Pair production occurs only at very high energy levels, at least 1.02 MeV.]

The interaction between x-ray photons and tissue that contributes to radiographic contrast but that contributes significantly to patient dose is (A) the photoelectric effect (B) Compton scatter (C) coherent scatter (D) pair production

(B) 1 and 2 only [The principal interactions that occur between x-ray photons and body tissues in the diagnostic x-ray range, the photoelectric e ect and Compton scatter, are ionization processes producing photoelectrons and recoil electrons that traverse tissue and subsequently ionize molecules. In the illustrated Compton scatter, a fairly high-energy x-ray photon ejects an outer-shell electron. Although the x-ray photon is deflected with reduced energy (modified scatter), it retains most of its original energy and exits the body as an energetic scattered photon. Because the scattered photon exits the body, it does not pose a radiation hazard to the patient. It can, however, contribute to image fog and pose a radiation hazard to personnel (as in fluoroscopic procedures). In the photoelectric effect, a low- energy x-ray photon uses all its energy to eject an inner-shell electron, leaving an orbital vacancy. An electron from the shell above fills the vacancy and in so doing gives up energy in the form of a characteristic ray. The photoelectric effect is more likely to occur in absorbers having high atomic number and contributes significantly to patient dose because all the photon energy is absorbed by the patient. Coherent (unmodified) scatter does not involve ionization.]

The interaction illustrated below 1. can pose a safety hazard to personnel 2. can have a negative impact on image quality 3. occurs with low-energy incident photons (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only The principal interactions that occur between x-ray photons and body tissues in the diagnostic x-ray range, the photoelectric effect and Compton scatter, are ionization processes producing photoelectrons and recoil electrons that traverse tissue and subsequently ionize molecules. In the illustrated Compton scatter, a fairly high-energy x-ray photon ejects an outer-shell electron. Although the x-ray photon is deflected with reduced energy (modified scatter), it retains most of its original energy and exits the body as an energetic scattered photon. Because the scattered photon exits the body, it does not pose a radiation hazard to the patient. It can, however, contribute to image fog and pose a radiation hazard to personnel (as in fluoroscopic procedures). In the photoelectric effect, a low- energy x-ray photon uses all its energy to eject an inner-shell electron, leaving an orbital vacancy. An electron from the shell above fills the vacancy and in so doing gives up energy in the form of a characteristic ray. The photoelectric effect is more likely to occur in absorbers having high atomic number and contributes significantly to patient dose because all the photon energy is absorbed by the patient. Coherent (unmodified) scatter does not involve ionization.]

The interaction illustrated below 1. can pose a safety hazard to personnel 2. can have a negative impact on image quality 3. occurs with low-energy incident photons (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) AP shoulder internal rotation radiograph. [The greater and lesser tubercles are prominences on the proximal humerus, separated by the bicipital groove. The AP projection of the humerus in external rotation demonstrates the greater tubercle in profile. With the arm placed in internal rotation, the humerus is placed in a true lateral position, and the lesser tubercle is demonstrated.]

The lesser tubercle of the humerus will be visualized in profile in the (A) AP shoulder external rotation radiograph. (B) AP shoulder internal rotation radiograph. (C) AP elbow radiograph. (D) Lateral elbow radiograph.

(C) laminae [The typical vertebra has two parts—the body and the vertebral arch. The body is the dense, anterior bony mass. Posteriorly attached is the vertebral arch, a ring-like structure. The vertebral arch is formed by two pedicles (short, thick processes projecting posteriorly from the body) and two laminae (broad, flat processes projecting posteriorly and medially from the pedicles).]

The long, flat structures that project posteromedially from the pedicles are the (A) transverse processes (B) vertebral arches (C) laminae (D) pedicles

(D) patient dose. [X-rays produced at the target make up a heterogeneous primary beam. There are many "soft," low-energy photons that, if not removed, would contribute only to greater patient (skin) dose. They do not have enough energy to penetrate the patient and expose the film; they just penetrate a small thickness of the patient's tissue and are absorbed. These photons are removed by aluminum filters.]

The major function of filtration is to reduce (A) image noise. (B) scattered radiation. (C) operator dose. (D) patient dose.

(A) hematemesis [Hematemesis refers to vomiting blood. If the blood is dark in color, it is probably gastric in origin; if it is bright red, it is most likely pharyngeal in origin. Expectoration (coughing or spitting up) of blood is called hemoptysis. Blood is originating from the mouth, larynx, or respiratory structure. Hematuria is the condition of blood in the urine. Epistaxis is the medical term for nosebleed.]

The medical term used to describe the vomiting of blood is (A) hematemesis (B) hemoptysis (C) hematuria (D) epistaxis

(A) hematemesis [Hematemesis refers to vomiting blood. If the blood is dark in color, it is probably gastric in origin; if it is bright red, it is most likely pharyngeal in origin. Expectoration (coughing or spitting up) of blood is called hemoptysis. Blood is originating from the mouth, larynx, or respiratory structure. Hematuria is the condition of blood in the urine. Epistaxis is the medical term for nosebleed.]

The medical term used to describe the vomiting of blood is (A) hematemesis (B) hemoptysis (C) hematuria (D) epistaxis

(B) nonmaleficence. [There are many medicolegal terms with which the radiographer should be familiar. Beneficence refers to decisions and actions made to bring about good, ie, to benefit the patient. Nonmaleficence refers to the prevention of harm to the patient. Autonomy refers to the right of every individual to act with personal self-reliance. Veracity refers to telling the truth.]

The moral principle that describes the radiographer's aspiration to do no harm or to allow no act that might cause harm to the patient is termed (A) beneficence. (B) nonmaleficence. (C) autonomy. (D) veracity.

(B) shaped contact (contour) [Gonadal shielding should be used whenever appropriate and possible during radiographic and fluoroscopic examinations. Flat contact shields are useful for simple recumbent studies, but when the examination necessitates obtaining oblique, lateral, or erect projections, flat contact shields are easily displaced and become less efficient. Shaped contact (contour) shields are best because they enclose the male reproductive organs and remain in position for oblique, lateral, and erect projections. Shadow shields that attach to the tube head are particularly useful for surgical sterile fields.]

The most efficient type of male gonadal shielding for use during fluoroscopy is (A) flat contact (B) shaped contact (contour) (C) shadow (D) cylindrical

(A) urinary tract. [Hospital-acquired infections (HAIs) are also referred to as nosocomial. Despite the efforts of infectious disease departments, HAIs continue to be a problem in hospitals today. This is at least partly due to there being a greater number of older, more vulnerable patients and an increase in the number of invasive procedures performed today (i.e., needles and catheters). The most frequent site of HAI is the urinary tract, followed by wounds, the respiratory tract, and blood.]

The most frequent site of hospital-acquired infection is the (A) urinary tract. (B) blood. (C) respiratory tract. (D) digestive tract.

(B) 1 and 2 only [The output phosphor of the image intensifier displays the brighter, minified, and inverted image. From the output phosphor, the light image is conveyed to its destination by some kind of image distributor— either a series of lenses and a mirror or via fiber optics. Fiber optics is often the method of choice where equipment size is of concern (e.g., mobile equipment). The image distributor, that is, the lens or fiber optics, then sends the majority of light to the TV monitor for direct viewing and the remaining light (about 10%) to the IR (e.g., photospot camera).]

The output phosphor can be coupled with the Vidicon TV camera or charge- coupled device (CCD) via 1. fiber optics. 2. an image distributor or lens. 3. closed-circuit TV. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only

The output phosphor can be coupled with the Vidicon TV camera or charge-coupled device (CCD) via 1. fiber optics. 2. an image distributor or lens. 3. closed-circuit TV. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) an inner-shell electron [In the photoelectric effect, a relatively low-energy incident photon uses all its energy to eject an inner-shell electron, leaving a vacancy. An electron from the next shell will drop to fill the vacancy, and a characteristic ray is given up in the transition. This type of interaction is more harmful to the patient because all the photon energy is transferred to tissue.]

The photoelectric effect is an interaction between an x-ray photon and (A) an inner-shell electron (B) an outer-shell electron (C) a nucleus (D) another photon

(B) 1 and 3 only [The photoelectric effect is the interaction between x-ray photons and matter that is largely responsible for patient dose. The photoelectric effect occurs when a relatively low-energy photon uses all its energy to eject an inner-shell electron. That electron is ejected from the atom, leaving a hole in, for example, the K shell. An L-shell electron then drops down to fill the K vacancy and in so doing emits a characteristic ray whose energy equals the difference in binding energies for the K and L shells. The photoelectric effect occurs with high-atomic-number (Z) absorbers such as bone and with positive contrast media.]

The photoelectric effect is more likely to occur with 1. absorbers having a high Z number 2. high-energy incident photons 3. positive contrast media (A) 1 and 2 only (B) 1 and 3 only (C) 2 and 3 only (D) 1, 2, and 3

(D) anode [X-ray tubes are diode tubes; that is, they have two electrodes—a positive electrode called the anode and a negative electrode called the cathode. The cathode filament is heated to incandescence and releases electrons, a process called thermionic emission. During the exposure, these electrons are driven by thousands of volts toward the anode, where they are suddenly decelerated. This deceleration is what produces x-rays. Some x-ray tubes, such as those used in fluoroscopy and in capacitor-discharge mobile units, are required to make short, precise—sometimes multiple—exposures. This need is met by using a grid-controlled tube. A grid-controlled tube uses the molybdenum focusing cup as the switch, permitting very precise control of the tube current (flow of electrons between cathode and anode).]

The positive electrode of the x-ray tube is the (A) capacitor (B) grid (C) cathode (D) anode

(C) 2 and 3 only [The typical diode x-ray tube consists of a positive electrode (the anode) and a negative electrode (the cathode). Electrons are released from the cathode's filament, directed toward the anode by the cathode's focusing cup, and delivered at very high speed to the anode's focal track.]

The primary parts of the cathode include the 1. focal track. 2. filament. 3. focusing cup. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) patient skin dose

The principal function of filtration in the x-ray tube is to reduce (A) patient skin dose (B) operator exposure (C) scattered radiation (D) image noise

(D) 1, 2, and 3 [According to state and federal law, personnel radiation monitor reports must be retained as legal documents. These documents must include such information as the user's personal data, that is, name, birth date, sex, and identification number (usually Social Security Number); type of monitor (i.e., film badge, TLD, or OSL dosimeter); radiation quality; dose equivalent (i.e., deep, eye, and shallow) for that exposure period (usually one month); quarterly accumulated dose equivalent (i.e., deep, eye, and shallow); year-to-date dose equivalent (i.e., deep, eye, and shallow); lifetime dose equivalent (i.e., deep, eye, and shallow); number of monitors received year to date; and inception date (month and year) of the dosimeter.]

The radiographer's radiation monitor report must include which of the following information? 1. Lifetime dose equivalent 2. Quarterly dose equivalent 3. Inception date (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) apposition [Various terms are used to describe the position of fractured ends of long bones. The term apposition is used to describe the alignment, or misalignment, between the ends of fractured long bones. The term angulation describes the direction of misalignment. The term luxation refers to a dislocation. A sprain refers to a wrenched articulation with ligament injury.]

The relationship between the ends of fractured long bones is referred to as (A) angulation (B) apposition (C) luxation (D) sprain

(A) be at least 38 cm [Lead and distance are the two most important ways to protect from radiation exposure. Fluoroscopy can be particularly hazardous because the SID is so much shorter than in overhead radiography. Therefore, it has been established that mobile fluoroscopic equipment must provide at least 30 cm source-to-tabletop/skin distance for the protection of the patient, and fixed or stationary fluoroscopic equipment must provide at least 38 cm source-to-tabletop/skin distance.]

The source-to-table distance in fixed/stationary fluoroscopy must (A) be at least 38 cm (B) not exceed 38 cm (C) be at least 30 cm (D) not exceed 30 cm

(B) Anterior oblique [The (diarthrotic) sternoclavicular joints are formed by the medial (sternal) extremities of the clavicles and the clavicular notches of the manubrium (of the sternum). They can be demonstrated in the LAO and RAO positions. The LAO projection demonstrates the left sternoclavicular joint, whereas the RAO projection demonstrates the joint on the right. The patient is obliqued about 15 degrees with the side of interest adjacent to the IR.]

The sternoclavicular joints will be best demonstrated in which of the following positions? (A) Apical lordotic (B) Anterior oblique (C) Lateral (D) Weight-bearing

(D) gallbladder

The structure labeled number 2 in Figure 6-3, image B is the (A) caudate lobe of liver (B) duodenum (C) colon (D) gallbladder

(B) 21 mGya/min/mA [It is important to limit tabletop exposure during fluoroscopy because the SSD is so much less than in overhead radiography, so a much higher skin dose is delivered to the patient. For this reason, the tabletop exposure rate during fluoroscopy should not exceed 21 mGya/min per mA at 80 kV. Without optional HLC (High Level Control), table top intensity of 100 mGya/min is maximum permitted. When optional HLC is available, the maximum tabletop exposure permitted is 200 mGya/min.]

The tabletop exposure rate during fluoroscopy shall not exceed (A) 10 mGya/min/mA (B) 21 mGya/min/mA (C) 10 mGya/hr (D) 5 R/h

(C) 2 and 3 only

The term differential absorption is related to 1. beam intensity 2. subject contrast 3. pathology (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 2 and 3 only [The radiographic subject, the patient, is composed of many different tissue types of varying densities (i.e., subject contrast), resulting in varying degrees of photon attenuation and absorption. This differential absorption contributes to the various shades of gray in the x-ray image. Normal tissue density may be significantly altered in the presence of pathology. For example, destructive bone disease can cause a dramatic decrease in tissue density. Abnormal accumulation of fluid (as in ascites) will cause a significant increase in tissue density. Muscle atrophy or highly developed muscles similarly will decrease or increase tissue density.]

The term differential absorption is related to 1. beam intensity 2. subject contrast 3. pathology (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 1 and 2 only

The total brightness gain of an image intensifier is the product of 1. flux gain 2. minification gain 3. focusing gain (A) 1 only (B) 2 only (C) 1 and 2 only (D) 1 and 3 only

(B) grid-controlled [X-ray tubes are diode tubes; that is, they have two electrodes—a positive electrode called the anode and a negative electrode called the cathode. The cathode filament is heated to incandescence and releases electrons—a process called thermionic emission. During the exposure, these electrons are driven by thousands of volts toward the anode, where they are suddenly decelerated. That deceleration is what produces x-rays. Some x-ray tubes, such as those used in fluoroscopy and in capacitor-discharge mobile units, are required to make short, precise—sometimes multiple—exposures. This need is met by using a grid-controlled tube. A grid-controlled tube uses the molybdenum focusing cup as the switch, permitting very precise control of the tube current (flow of electrons between cathode and anode).]

The type of x-ray tube designed to turn on and off rapidly, providing multiple short, precise exposures, is (A) high speed (B) grid-controlled (C) diode (D) electrode

(B) 2 only [Magnification radiography is used to enlarge details to a more perceptible degree. Hairline fractures and minute blood vessels are candidates for magnification radiography. The problem of magnification unsharpness is overcome by using a fractional focal spot; larger focal-spot sizes will produce excessive blurring unsharpness. Grids are usually unnecessary in magnification radiography because of the air-gap effect produced by the OID. Direct-exposure technique probably would not be used because of the excessive exposure required.]

The use of which of the following is (are) essential in magnification radiography? 1. High-ratio grid 2. Fractional focal spot 3. Direct exposure technique (A) 1 only (B) 2 only (C) 1 and 3 only (D) 1, 2, and 3

(B) air kerma [The SI unit air kerma is used to express kinetic energy released in matter; it is described as the unit of exposure and identifies ionization in air. The SI unit used to describe absorbed dose is Gray (Gyt) The SI unit of measurement to describe dose to biologic material is the Sievert (Sv). Various organs and tissue types require assigned specific weighting factors in order to describe the effective dose. Absorbed dose and energy deposited is strongly related to chemical change and biologic damage. The SI unit of measurement to describe effective dose to biologic material is the Sievert (Sv). The Sievert is the unit of occupational radiation exposure. The Becquerel is used to measure radioactivity.]

The x-ray unit of exposure defines which of the following? (A) Sievert (B) air kerma (C) Gyt (D) Becqueral

(C) Lithium fluoride [TLDs are personnel radiation monitors that use lithium fluoride crystals. Once exposed to ionizing radiation and then heated, these crystals give off light proportional to the amount of radiation received. TLDs are very accurate personal monitors. Even more accurate are optically stimulated luminescence (OSL) dosimeters. OSL dosimeters use aluminum oxide as their sensitive crystal. Silver halide is in film emulsion used in film badge dosimeters.]

Thermoluminescent dosimetry systems use which of the following crystals? (A) Silver halide (B) Sodium bicarbonate (C) Lithium fluoride (D) Aluminum oxide

(B) electrostatic lenses [The input phosphor of an image intensifier receives remnant radiation emerging from the patient and converts it to a fluorescent light image. Directly adjacent to the input phosphor is the photocathode, which is made of a photoemissive alloy (usually a cesium and antimony compound). The fluorescent light image strikes the photocathode and is converted to an electron image. The electrons are carefully focused, to maintain image resolution, by the electrostatic focusing lenses, through the accelerating anode and to the output phosphor for conversion back to light.]

To maintain image clarity, the path of electron flow from photocathode to output phosphor is controlled by (A) the accelerating anode (B) electrostatic lenses (C) the vacuum glass envelope (D) the input phosphor

(B) electrostatic lenses

To maintain image clarity, the path of electron flow from photocathode to output phosphor is controlled by (A) the accelerating anode (B) electrostatic lenses (C) the vacuum glass envelope (D) the input phosphor

(D) in a lordotic position and direct the central ray at right angles to the coronal plane of the clavicle [The exact axial projection is performed by placing the patient in a lordotic position, leaning against the vertical grid device. This places the clavicle at right angles, or nearly so, to the plane of the IR. The central ray is directed to enter the inferior border of the clavicle, at right angles to its coronal plane. Other axial projections may include a prone position with a 25° to 30° caudal angle. However, none of these produce an exact axial projection of the clavicle.]

To obtain an exact axial projection of the clavicle, place the patient (A) supine and angle the central ray 30° caudally. (B) prone and angle the central ray 30° cephalad. (C) supine and angle the central ray 15° cephalad. (D) in a lordotic position and direct the central ray at right angles to the coronal plane of the clavicle.

(D) in a lordotic position and direct the central ray at right angles to the coronal plane of the clavicle. [The exact axial projection is performed by placing the patient in a lordotic position, leaning against the vertical grid device. This places the clavicle at right angles, or nearly so, to the plane of the IR. The central ray is directed to enter the inferior border of the clavicle, at right angles to its coronal plane. Other axial projections may include a prone position with a 25° to 30° caudal angle. However, none of these produce an exact axial projection of the clavicle.]

To obtain an exact axial projection of the clavicle, place the patient (A) supine and angle the central ray 30° caudally. (B) prone and angle the central ray 30° cephalad. (C) supine and angle the central ray 15° cephalad. (D) in a lordotic position and direct the central ray at right angles to the coronal plane of the clavicle.

(B) 1 and 2 only [Electronic imaging (CR and DR) uses image-capture devices having increased sensitivity compared with film/screen imaging. Therefore, special consideration must be given to the SR emerging from the patient and striking the IR. To reduce the amount of SR that reaches the IR, the x-ray beam should be tightly collimated, and a lead mat should be placed on the x-ray table just posterior to the patient's lumbosacral area. The x-ray photons that would have extended posterior to the patient's skin and simply struck the x-ray table—causing increased SR to reach the IR—will be absorbed by the lead mat. Of course, these same methods are used successfully in improving image quality in screen/film technology as well. The SID is unrelated to scattered radiation production.]

To reduce the amount of scattered radiation reaching the IR in CR/DR imaging of the lumbosacral region, in the lateral projection, which of the following is (are) recommended? 1. Close collimation 2. Lead mat on table posterior to the patient 3. Decreased SID (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only

Types of moving grid mechanisms include 1. oscillating. 2. reciprocating. 3. synchronous. (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 2 and 3 only

(C) 2 and 3 only

Types of shape distortion include 1. magnification 2. elongation 3. foreshortening (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3 [The principal interactions that occur between x-ray photons and body tissues in the diagnostic x-ray range, the photoelectric effect and Compton scatter, are ionization processes producing photoelectrons and recoil electrons that traverse tissue and subsequently ionize molecules. These interactions occur randomly but can lead to molecular damage in the form of impaired function or cell death. The target theory specifies that DNA molecules are the targets of greatest importance and sensitivity; that is, DNA is the key sensitive molecule. However, since the body is 65% to 80% water, most interactions between ionizing radiation and body cells will involve radiolysis of water rather than direct interaction with DNA. The two major types of effects that occur are the direct effect and the indirect effect. The direct effect usually occurs with high-LET radiations and when ionization occurs at the DNA molecule itself. The indirect effect, which occurs most frequently, happens when ionization takes place away from the DNA molecule in cellular water. However, the energy from the interaction can be transferred to the molecule via a free radical (formed by radiolysis of cellular water). Possible damage to the DNA molecule is diverse. A single main-chain/side-rail scission (break) on the DNA molecule is repairable. A double main-chain/side-rail scission may be repaired with difficulty or may result in cell death. A double main-chain/side-rail scission on the same rung of the DNA ladder results in irreparable damage or cell death. Faulty repair of main-chain breakage can result in cross- linking. Damage to the nitrogenous bases, that is, damage to the base itself or to the rungs connecting the main chains, can result in alteration of base sequences, causing a molecular lesion/point mutation. Any subsequent divisions result in daughter cells with incorrect genetic information.]

Types of structural damage to a DNA molecule by ionizing radiation include which of the following? 1. single-side-rail scission 2. double-side-rail scission 3. cross-linking (A) 1 only (B) 2 only (C) 1 and 2 only (D) 1, 2, and 3

(D) 12 cm [Multifield image intensifier tubes are usually either dual-field or tri-field and are designed this way in order to permit magnification imaging. As voltage is applied to the electrostatic focusing lenses, the focal point moves back—closer to the input phosphor—and a smaller portion of the input phosphor is utilized. As a result, the FOV decreases and magnification increases, producing better spatial resolution. At the same time, brightness is decreased requiring an increase in mA (therefore increased patient dose). This increase in mA increases image quality. It can be likened to an increase in signal-to-noise ratio (SNR), with mA being the signal.]

Using a multifield image intensifier tube, which of the following input phosphor diameters will provide the greatest magnification? (A) 35 cm (B) 25 cm (C) 17 cm (D) 12 cm

(A) Midcoronal plane [The midcoronal plane (number 1) divides the body into anterior and posterior halves. A coronal plane is any plane parallel to the midcoronal plane. The midsagittal plane (number 2) divides the body into left and right halves. A sagittal plane is any plane parallel to the midsagittal plane. A transverse or horizontal plane (number 3) is perpendicular to the midsagittal plane and midcoronal plane, dividing the body into superior and inferior portions.]

What is the name of the plane indicated by the number 1 in Figure 6-17? (A) Midcoronal plane (B) Midsagittal plane (C) Transverse plane (D) Horizontal plane

(C) 150 mSv/yr [Whole-body annual DL dose of 50 mSv/yr is calculated to include the especially radiosensitive organs such as the gonads and the blood-forming organs. The annual dose limit to the lens is 150 mSv; the DL to less sensitive organs such as skin, hands, and feet (extremities) is 500 mSv/year.]

What is the annual dose limit (DL) for the lens of the eye? (A) 50 mSv/yr (B) 100 mSv/yr (C) 150 mSv/yr (D) 500 mSv/yr

(C) 2.75 mGy [Patients will occasionally question the radiographer regarding the amount of radiation they are receiving during their examination. Most of these patients are merely curious because they have heard a recent news report about x-rays, or have perhaps studied about x-rays in school recently. It is a good idea for radiographers to have some knowledge of average exposure doses for patients who desire this information. The curious patient can also be referred to the medical physicist for more detailed information. The average PA chest delivers an ESE of about 0.1 mGy. The average AP supine lumbar spine delivers an ESE of about 2.5 - 3 mGy; the average AP thoracic spine about 1.8 mGy; the average AP cervical spine about 1.0 mGy. The average AP pelvis delivers about 1.5 mGy. The average lateral skull about 0.7 mGy, the shoulder about 0.90 mGy, and the extremity about 0.5 mGy.]

What is the approximate ESE for the average AP lumbar spine radiograph? (A) 1.0 mGy (B) 1.75 mGy (C) 2.75 mGy (D) 4.0 mGy

(B) Beam splitter [The light image emitted from the output phosphor of the image intensifier is directed to the TV monitor for viewing and sometimes to recording devices such as a spot-film camera or cine film. The light is directed to these places by a beam splitter or objective lens located between the output phosphor and the TV camera tube (or CCD). The majority of the light will go to the recording device, whereas a small portion goes to the TV so that the procedure may continue to be monitored during filming.]

What is the device that directs the light emitted from the image intensifier to various viewing and imaging apparatus? (A) Output phosphor (B) Beam splitter (C) Spot-film changer (D) Automatic brightness control

(A) As LET increases, RBE increases.

What is the effect on RBE as LET increases? (A) As LET increases, RBE increases. (B) As LET increases, RBE decreases. (C) As LET increases, RBE stabilizes. (D) LET has no effect on RBE.

(C) 0.25 mm Pb [Lead aprons are secondary radiation barriers and must contain at least 0.25-mm Pb equivalent, usually in the form of lead-impregnated vinyl (according to 21 CFR). Many radiology departments routinely use lead aprons containing 0.5 mm Pb (the NCRP recommends 0.5-mm Pb equivalent minimum). These aprons are heavier, but they attenuate a higher percentage of scattered radiation.]

What is the minimum requirement for lead aprons, according to 21 CFR? (A) 0.05 mm Pb (B) 0.50 mm Pb (C) 0.25 mm Pb (D) 1.0 mm Pb

(C) Spondylolisthesis [The forward slipping of one vertebra on the one below it is called spondylolisthesis. Spondylolysis is the breakdown of the pars interarticularis; it may be unilateral or bilateral and results in forward slipping of the involved vertebra—the condition of spondylolisthesis. Inflammation of one or more vertebrae is called spondylitis. Spondylosis refers to degenerative changes occurring in the vertebra.]

What is the name of the condition that results in the forward slipping of one vertebra on the one below it? (A) Spondylitis (B) Spondylolysis (C) Spondylolisthesis (D) Spondylosis

(B) High and horizontal [The position, shape, and motility of various organs can differ greatly from one body habitus to another. The hypersthenic individual is large and heavy; the lungs and heart are high, the stomach is high and transverse, the gallbladder is high and lateral, and the colon is high and peripheral. In contrast, the other habitus extreme is the asthenic individual. This patient is slender and light and has a long and narrow thorax, a low and long stomach, a low and medial gallbladder, and a low medial and redundant colon. The radiographer must consider these characteristic differences when radiographing individuals of various body types.]

What is the position of the stomach in a hypersthenic patient? (A) High and vertical (B) High and horizontal (C) Low and vertical (D) Low and horizontal

(A) As LET increases, RBE increases. [LET increases with the ionizing potential of the radiation; for example, alpha particles are more ionizing than x-radiation; therefore, they have a higher LET. As ionizations and LET increase, there is greater possibility of an effect on living tissue; therefore, the RBE increases. The RBE (sometimes called the quality factor) of diagnostic x-rays is 1, the RBE of fast neutrons is 10, and the RBE of 5-MeV alpha particles is 20.]

What is the relationship between LET and RBE? (A) As LET increases, RBE increases. (B) As LET increases, RBE decreases. (C) As LET decreases, RBE increases. (D) There is no direct relationship between LET and RBE.

(A) 1 only [The Radiation Weighting Factor (W r ) is a number assigned to different types of ionizing radiations in order to better determine their effect on tissue (eg, x-ray vs alpha particles). The W r of different ionizing radiations is dependent on the LET of that particular radiation. The Tissue Weighting Factor (W t ) represents the relative tissue radiosensitivity of irradiated material (eg, muscle vs intestinal epithelium vs bone, etc). To determine Effective Dose (E) the following equation is used: Effective Dose (E) = Radiation Weighting Factor (Wr) × Tissue Weighting Factor (Wt) × Absorbed Dose]

What is used to account for the differences in ionizing characteristics of various radiations, when determining their effect on biologic material? 1. Radiation weighting factors (Wr) 2. Tissue weighting factors (Wt) 3. Absorbed dose (A) 1 only (B) 1 and 3 only (C) 2 and 3 only (D) 1, 2, and 3

(A) 1 only [The tissue weighting factor (W t ) represents the relative tissue radiosensitivity of irradiated material (e.g., muscle vs. intestinal epithelium vs. bone) and is used to account for differences in tissue sensitivity to ionizing radiation when determining effective dose E. The radiation weighting factor (W r ) is a number assigned to different types of ionizing radiations in order to better determine their effect on tissue (e.g., x-ray vs. alpha particles). The W r of different ionizing radiations depends on the LET of that particular radiation. The following formula is used to determine effective dose E: Effective Dose (E) = Radiation Weighting Factor (Wr) × Tissue Weighting Factor (Wt) × Absorbed Dose]

What is used to account for the differences in tissue sensitivity to ionizing radiation when determining effective dose E? 1. Tissue weighting factors (W t ) 2. Radiation weighting factors (W r ) 3. Absorbed dose (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2 ,and 3

(C) 75% [Lead aprons are worn by occupationally exposed individuals during fluoroscopic and mobile x-ray procedures. Lead aprons are available with various lead equivalents; 0.5 and 1.0 mm are the most common. The 1.0-mm lead equivalent apron will provide close to 100% protection at most kVp levels, but it is rarely used because it weighs anywhere from 12 to 24 lb! A 0.25-mm lead equivalent apron will attenuate about 97% of a 50-kVp x-ray beam, 66% of a 75-kVp beam, and 51% of a 100-kVp beam. A 0.5- mm lead equivalent apron will attenuate about 99.9% of a 50-kVp beam, 88% of a 75-kVp beam, and 75% of a 100-kVp beam.]

What percentage of x-ray attenuation does a 0.5-mm lead equivalent apron at 100 kVp provide? (A) 51% (B) 66% (C) 75% (D) 94%

(D) 88% [Lead aprons are worn by occupationally exposed individuals during fluoroscopic and mobile x-ray procedures. Lead aprons are available with various lead equivalents; 0.5- and 1.0-mm lead are the most common. The 1.0-mm lead-equivalent apron will provide close to 100% protection at most kilovoltage levels, but it is used rarely because it weighs anywhere from 12 to 24 lb. A 0.25-mm lead-equivalent apron will attenuate about 97% of a 50-kVp x-ray beam, 66% of a 75-kVp beam, and 51% of a 100-kVp beam. A 0.5-mm lead-equivalent apron will attenuate about 99.9% of a 50-kVp beam, 88% of a 75-kVp beam, and 75% of a 100-kVp beam.]

What percentage of x-ray attenuation does a 0.5-mm lead-equivalent apron at 75 kVp provide? (A) 51% (B) 66% (C) 75% (D) 88%

(B) AP, external rotation [An AP, external rotation, projection of the shoulder is pictured. The hand is supinated, and the arm is in the anatomical position. Therefore, the greater tubercle (number 3) is well visualized. The greater portion of the clavicle is seen, the acromioclavicular joint (number 1), the acromion process (number 2), the coracoid process (number 4), and the glenohumeral joint (number 5). The coronoid process is located on the ulna.]

What projection was used to obtain the image seen in Figure 2-41? (A) AP, internal rotation (B) AP, external rotation (C) AP, neutral position (D) AP axial

(B) angle the CR cephalad [Figure A shows a PA projection of the mandible. The head is positioned PA with the OML perpendicular to the IR. The mandibular body is well demonstrated in this position. With the patient in the PA position, the rami can be better demonstrated with 20° to 25° cephalad angulation. A caudal angle could be employed if the skull was positioned in the AP position.]

What should be done to better demonstrate the mandibular rami seen in PA projection in Figure A? (A) use a perpendicular CR (B) angle the CR cephalad (C) angle the CR caudad (D) oblique the head 15° medial

(A) Dome of the acetabulum [The dome of the acetabulum lies midway between the ASIS and the symphysis pubis. On an adult of average size, a line perpendicular to this point will parallel the plane of the femoral neck. In an AP projection of the hip, the CR should be directed to a point approximately 2 inches down that perpendicular line so as to enter the distal portion of the femoral head.]

What structure can be located midway between the anterosuperior iliac spine (ASIS) and pubic symphysis? (A) Dome of the acetabulum (B) Femoral neck (C) Greater trochanter (D) Iliac crest

(B) Computed radiography [Film radiography used an area x-ray beam, but the IR was film emulsion sandwiched between intensifying screens in a cassette. Computed radiography (CR) also uses an area x-ray beam, but the IR is a photostimulable phosphor such as europium-activated barium fluorohalide coated on an image plate. Digital radiography (DR) can use an area x-ray beam detected by a direct-capture solid-state device. DR can also use a fan-shaped x-ray beam. The fan-shaped beam is "read" by a linear array of detectors.]

What type of x-ray imaging uses an area beam and a photostimulable phosphor as the IR? (A) Film radiography (B) Computed radiography (C) Digital radiography (D) Cineradiography

(B) Computed radiography

What type of x-ray imaging uses an area beam and a photostimulable phosphor as the IR? (A) Film radiography (B) Computed radiography (C) Digital radiography (D) Cineradiography

(C) Tilting x-ray table [Myelography requires that contrast medium be instilled into the lumbar subarachnoid space and distributed via gravity to various levels of the subarachnoid space. This gravitational distribution is accomplished through the use of an x-ray table that is capable of angling or tilting during the procedure.]

Which of the following equipment is mandatory for performance of a myelogram? (A) Cine camera (B) 105-mm spot film (C) Tilting x-ray table (D) Tomography

(B) Autotransformer [Because the high-voltage transformer has a fixed ratio, there must be a means of changing the voltage sent to its primary coil; otherwise, there would be a fixed kilovoltage. The autotransformer makes these changes possible. When kilovoltage is selected on the control panel, the radiographer actually is adjusting the autotransformer and selecting the amount of voltage to send to the high-voltage transformer to be stepped up (to kilovoltage). The filament circuit supplies the proper current and voltage to the x-ray tube filament for proper thermionic emission. The rectifier circuit is responsible for changing AC to unidirectional current.]

When the radiographer selects kilovoltage on the control panel, which device is adjusted? (A) Step-up transformer (B) Autotransformer (C) Filament circuit (D) Rectifier circuit

(D) by a route other than orally [Some medications cannot be taken orally. They may be destroyed by the GI juices or may irritate the GI tract. Medications that are administered by any route other than orally are said to be given parenterally. This can include intravenous, intramuscular, topical, intrathecal, or subcutaneous modes of medication administration.]

When medications are administered parenterally, they are given (A) orally (B) orally or intravenously (C) intravenously or intramuscularly (D) by a route other than orally

(B) Autotransformer [Because the high-voltage transformer has a fixed ratio, there must be a means of changing the voltage sent to its primary coil; otherwise, there would be a fixed kilovoltage. The autotransformer makes these changes possible. When kilovoltage is selected on the control panel, the radiographer actually is adjusting the autotransformer and selecting the amount of voltage to send to the high-voltage transformer to be stepped up (to kilovoltage). The filament circuit supplies the proper current and voltage to the x-ray tube filament for proper thermionic emission. The rectifier circuit is responsible for changing AC to unidirectional current.]

When the radiographer selects kilovoltage on the control panel, which device is adjusted? (A) Step-up transformer (B) Autotransformer (C) Filament circuit (D) Rectifier circuit

(D) mAs: 20; kV: 80; Grid ratio: 10:1; Field size: 8 × 10 in. [Review the groups of factors. First, because the milliampere-seconds value has no effect on the scale of contrast produced, eliminate milliampere-seconds from consideration by drawing a line through the column. Then check the two entries in each column that are likely to produce shorter-scale contrast. For example, in the kilovoltage column, because lower kilovoltage can produce shorter-scale contrast, place checkmarks next to the 70 and 80 kV. Because higher-ratio grids permit less scattered radiation to reach the IR, the 10:1 and 12:1 grids can produce a shorter scale of contrast than the lower-ratio grids; check them. As the volume of irradiated tissue decreases, so does the amount of scattered radiation produced, and consequently, the shorter is the scale of radiographic contrast; therefore, check the 11 × 14 and 8 × 10 in. field sizes. An overview shows that the factors in groups (A) and (C) have more checkmarks, than the factors in group (D), indicating that group (D) is more likely to produce the shortest-scale contrast.]

Which combination of exposure factors most likely will contribute to producing the shortest-scale contrast? (A) mAs: 10; kV: 70; Grid ratio: 5:1; Field size: 14 × 17 in. (B) mAs: 12; kV: 90; Grid ratio: 8:1; Field size: 14 × 17 in. (C) mAs: 15; kV: 90; Grid ratio: 12:1; Field size: 11 × 14 in. (D) mAs: 20; kV: 80; Grid ratio: 10:1; Field size: 8 × 10 in.

(D) mAs: 20; kV: 80; Grid ratio: 10:1; Field size: 8 × 10 in. [Review the groups of factors. First, because the milliampere-seconds value has no effect on the scale of contrast produced, eliminate milliampere-seconds from consideration by drawing a line through the column. Then check the two entries in each column that are likely to produce shorter-scale contrast. For example, in the kilovoltage column, because lower kilovoltage can produce shorter-scale contrast, place checkmarks next to the 70 and 80 kV. Because higher-ratio grids permit less scattered radiation to reach the IR, the 10:1 and 12:1 grids can produce a shorter scale of contrast than the lower-ratio grids; check them. As the volume of irradiated tissue decreases, so does the amount of scattered radiation produced, and consequently, the shorter is the scale of radiographic contrast; therefore, check the 11 × 14 and 8 × 10 in. field sizes. An overview shows that the factors in groups (A) and (C) have more checkmarks, than the factors in group (D), indicating that group (D) is more likely to produce the shortest-scale contrast.]

Which combination of exposure factors most likely will contribute to producing the shortest-scale contrast? (A) mAs: 10; kV: 70; Grid ratio: 5:1; Field size: 14 × 17 in. (B) mAs: 12; kV: 90; Grid ratio: 8:1; Field size: 14 × 17 in. (C) mAs: 15; kV: 90; Grid ratio: 12:1; Field size: 11 × 14 in. (D) mAs: 20; kV: 80; Grid ratio: 10:1; Field size: 8 × 10 in.

(A) Photoelectric effect [The photoelectric effect and Compton scattering are the two predominant interactions between x-ray photons and matter in diagnostic x-ray. In the photoelectric effect, the low-energy incident photon uses all its energy to eject an atom's inner-shell electron. That photon ceases to exist—it has used all its energy to ionize the atom. The part has absorbed the x-ray photon. This interaction contributes to patient dose and produces short-scale contrast. In Compton scatter, the high-energy incident photon uses only part of its energy to eject an outer-shell electron. It retains most of its energy in the form of a scattered x-ray. In pair production, the x-ray photon disappears, and is replaced by two oppositely charged electrons.]

Which interaction between x-ray photons and matter results in total absorption of the incident photon? (A) Photoelectric effect (B) Compton scattering (C) Coherent scattering (D) Pair production

(A) Dose-response curve A [Figure 3-4 illustrates three dose-response curves. Curve A begins at zero, indicating that there is no safe dose, that is, no threshold. Even one x-ray photon theoretically can cause a response. It is a straight (linear) line, indicating that response is proportional to dose; as dose increases, response increases. Radiation-induced cancer, leukemia, and genetic effects follow a linear nonthreshold dose-response relationship. Curve B is another linear curve (response is proportional to dose), but this one illustrates that a particular dose of radiation must be received before a response will occur. That is, there is a threshold dose; this is called a linear threshold curve. Curve C is another threshold curve, but this curve is nonlinear. It illustrates that once the minimum dose is received, a response occurs slowly initially and then increases sharply as exposure increases. This threshold, nonlinear (sigmoid) dose-response curve, illustrates the effect to skin from exposure to high levels of ionizing radiation.]

Which of the dose-response curves seen in Figure 3-4 represents possible genetic effects of ionizing radiation? (A) Dose-response curve A (B) Dose-response curve B (C) Dose-response curve C (D) None of these

(C) 3 only

Which of the dose-response curves shown in Figure 3-7 is representative of radiation-induced skin erythema? 1. Dose-response curve A 2. Dose-response curve B 3. Dose-response curve C (A) 1 only (B) 1 and 2 only (C) 3 only (D) 2 and 3 only

(C) 3 only

Which of the dose-response curves shown in the figure below is representative of radiation-induced skin erythema? 1. Dose-response curve A 2. Dose-response curve B 3. Dose-response curve C (A) 1 only (B) 1 and 2 only (C) 3 only (D) 2 and 3 only

(B) 1 and 2 only [Because the focal spot (track) of an x-ray tube is along the anode's beveled edge, photons produced at the target are able to diverge considerably toward the cathode end of the x-ray tube but are absorbed by the heel of the anode at the opposite end of the tube. This results in a greater number of x-ray photons distributed toward the cathode end, which is known as the anode heel effect. The effect of this restricting heel is most pronounced when the x-ray photons are required to diverge more, as would be the case with short SID, large-size IRs and steeper (smaller) target angles.]

Which of the following can impact the visibility of the anode heel effect? 1. SID 2. IR size 3. Screen speed (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only

Which of the following can impact the visibility of the anode heel effect? 1. SID 2. IR size 3. Screen speed (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) Nerve cells [Muscle cells have a fairly low radiosensitivity, and nerve cells are the least radiosensitive in the body (in fetal life, however, nerve cells are highly radiosensitive). Lymphocytes, a type of white blood cell concerned with the immune system, have the greatest radiosensitivity of all body cells. Spermatids are also highly radiosensitive, although not to the same degree as lymphocytes.]

Which of the following cell types has the lowest radiosensitivity? (A) Nerve cells (B) Muscle cells (C) Spermatids (D) Lymphocytes

(B) Myocytes

Which of the following cells is the least radiosensitive? (A) Myelocytes (B) Myocytes (C) Megakaryocytes (D) Erythroblasts

(B) Compton scatter [In the photoelectric e ect, a relatively low-energy photon uses all its energy to eject an inner-shell electron, leaving a vacancy. An electron from the shell above drops down to fill the vacancy and in so doing gives up a characteristic ray. This type of interaction is most harmful to the patient because all the photon energy is transferred to tissue. In Compton scatter, a high-energy incident photon uses some of its energy to eject an outer-shell electron. In so doing, the incident photon is deflected with reduced energy, but it usually retains most of its energy and exits the body as an energetic scattered ray. This scattered ray will either contribute to image fog or pose a radiation hazard to personnel depending on its direction of exit; thus, Compton scatter contributes the most to occupational exposure. In classic scatter, a low-energy photon interacts with an atom but causes no ionization; the incident photon disappears into the atom and then is released immediately as a photon of identical energy but with changed direction. Thompson scatter is another name for classic scatter.]

Which of the following contributes most to occupational exposure? (A) The photoelectric effect (B) Compton scatter (C) Classic scatter (D) Thompson scatter

(A) The photoelectric effect [In the photoelectric e ect, a relatively low-energy photon uses all its energy to eject an inner-shell electron, leaving a vacancy. An electron from the shell above drops down to fill the vacancy and in so doing emits a characteristic ray. This type of interaction is most harmful to the patient because all the photon energy is transferred to tissue. In Compton scatter, a high-energy incident photon uses some of its energy to eject an outer-shell electron. In so doing, the incident photon is deflected with reduced energy but usually retains most of its energy and exits the body as an energetic scattered ray. The scattered radiation will either contribute to image fog or pose a radiation hazard to personnel depending on its direction of exit. In classic scatter, a low-energy photon interacts with an atom but causes no ionization; the incident photon disappears in the atom and then reappears immediately and is released as a photon of identical energy but with changed direction. Thompson scatter is another name for classic scatter.]

Which of the following contributes most to patient dose? (A) The photoelectric effect (B) Compton scatter (C) Classic scatter (D) Thompson scatter

(D) Number 9 [An anterior view of the forearm is shown. The proximal anterior surface of the ulna (number 8) presents a rather large pointed process at the anterior margin of the semilunar (trochlear) notch (number 5) called the coronoid process (number 6). The olecranon process is identified as number 4, and the radial notch of the ulna is number 7. Distally, the ulnar head is number 9, and the styloid process is labeled 10. The radius (number 12) is the lateral bone of the forearm. The radial head is number 3, the radial neck is number 2, and the radial tuberosity is number 1. Distally, the radial styloid process is labeled 11.]

Which of the following correctly identifies the head of the ulna in the illustration in Figure 6-22? (A) Number 3 (B) Number 4 (C) Number 5 (D) Number 9

(A) Genetically significant dose [The genetically significant dose (GSD) illustrates that large exposures to a few people are cause for little concern when diluted by the total population. On the other hand, we all share the burden of that radiation received by the total population, especially as the use of medical radiation increases, so each individual's share of the total exposure increases.]

Which of the following defines the gonadal dose that, if received by every member of the population, would be expected to produce the same total genetic effect on that population as the actual doses received by each of the individuals? (A) Genetically significant dose (B) Somatically significant dose (C) Maximum permissible dose (D) Lethal dose

(A) Motor [A motor is the device used to convert electrical energy to mechanical energy. The stator and rotor are the two principal parts of an induction motor. A generator converts mechanical energy into electrical energy.]

Which of the following devices converts electrical energy to mechanical energy? (A) Motor (B) Generator (C) Stator (D) Rotor

(A) Motor

Which of the following devices converts electrical energy to mechanical energy? (A) Motor (B) Generator (C) Stator (D) Rotor

(C) Rheostat [The autotransformer operates on the principle of self-induction and functions to select the correct voltage to be sent to the high-voltage transformer to be "stepped up" to kilovoltage. The high-voltage transformer increases the voltage and decreases the current. The rheostat is a type of variable resistor that is used to change voltage or current values. It is found frequently in the filament circuit. A fuse is a device used to protect the circuit elements from overload by opening the circuit in the event of a power surge.]

Which of the following devices is used to control voltage by varying resistance? (A) Autotransformer (B) High-voltage transformer (C) Rheostat (D) Fuse

(A) Compensating filter [A compensating filter is used when the part to be radiographed is of uneven thickness or tissue density (in the chest, mediastinum vs. lungs). The filter (made of aluminum or lead acrylic) is constructed in such a way that it will absorb much of the x-ray beam directed toward the low tissue-density area while not affecting the x-ray photons to directed toward the high tissue-density area. A collimator is used to decrease the production of scattered radiation by limiting the volume of tissue irradiated. The grid functions to trap scattered radiation before it reaches the IR, thus reducing scattered radiation fog. Protective filtration absorbs low energy x-ray photons that contribute only to patient (skin) dose and would never reach the image receptor.]

Which of the following devices is used to overcome severe variation in patient anatomy or tissue density, providing more uniform radiographic density? (A) Compensating filter (B) Grid (C) Collimator (D) Protective filter

(A) Compensating filter

Which of the following devices is used to overcome severe variation in patient anatomy or tissue density, providing more uniform radiographic density? (A) Compensating filter (B) Grid (C) Collimator (D) Protective filter

(C) Smoothing [Image smoothing (C) is a type of spatial frequency filtering performed during digital image post-processing. Also known as low-pass filtering, smoothing can be achieved by averaging each pixel's frequency with surrounding pixel values to remove high-frequency noise. The result is reduction in noise and contrast. Smoothing (low-pass filtering) is useful for viewing small structures such as fine bone tissues. Edge enhancement (A) is a type of post-processing image manipulation, which can be effective for enhancing fractures and small, high-contrast tissues. In digital imaging, after the signal is obtained for each pixel, the signals are averaged to shorten processing time and decrease storage needs. The larger the number of pixels involved in the averaging, the smoother the image appears. The signal strength of one pixel is averaged with the strength of its neighboring pixels. Edge enhancement is achieved when fewer neighboring pixels are included in the signal average. Therefore, the smaller the number of neighboring pixels, the greater the edge enhancement. Windowing (B) is a post-processing method of adjusting the brightness and contrast in the digital image. There are two types of windowing: level and width. Window level adjusts the overall image brightness. When the window level is increased, the image becomes darker. When decreased, the image becomes brighter. Window width adjusts the ratio of white to black, thereby changing image contrast. Narrow window width provides higher contrast (short-scale contrast), whereas wide window width will produce an image with less contrast (long-scale contrast). Aliasing (D) is an image artifact that occurs when the spatial frequency is greater than the Nyquist frequency and the sampling occurs less than twice per cycle. This causes loss of information and a fluctuating signal and wrap-around image is produced, which appears as two superimposed images that are slightly out of alignment, resulting in a moiré effect. The Nyquist theorem states that when sampling a signal (such as the conversion from the analog to digital image), the sampling frequency must be greater than twice the bandwidth of the input signal so that reconstruction of the original image properly displays the anatomy of interest.]

Which of the following digital post-processing methods remove high-frequency noise from the image? (A) Edge enhancement (B) Windowing (C) Smoothing (D) Aliasing

(B) X-ray tube not centered to grid [The radiograph shown demonstrates a 1.5-in. unexposed strip along the length of the film. This occurred because, although the patient was centered correctly to the collimator light and x-ray field, the x-ray tube was not centered to the grid. If the patient was off-center, the entire image would be exposed, and the patient's spine would be off-center. Grid cutoff would not appear as such a sharply delineated line but rather as a gradually decreasing receptor exposure.]

Which of the following errors is illustrated in the figure below? (A) Patient not centered to IR (B) X-ray tube not centered to grid (C) Inaccurate collimation (D) Unilateral grid cutoff

(C) IVU [Wilm's tumor is a rapidly developing tumor of the kidney(s). It is the most common childhood renal tumor, usually affecting only one kidney. Newer treatments are effective in controlling about 90% of these tumors. As the kidneys are affected, an IVU would be the most appropriate of the examinations listed. Other useful examinations would be CT scan and sonography.]

Which of the following examinations most likely would be performed to diagnose Wilm's tumor? (A) BE (B) Upper GI (C) IVU (D) Bone survey

(B) 1 and 2 only [A patient who is having a BE generally is required to have a low-residue diet for 1 or 2 days, followed by cathartics and cleansing enemas prior to the examination. Any retained fecal material can simulate or obscure pathology. A patient who is scheduled for a pyelogram must have the preceding meal withheld to avoid the possibility of aspirating vomitus in case of an allergic reaction. A metastatic survey does not require the use of contrast media, and no patient preparation is necessary.]

Which of the following examinations require(s) restriction of a patient's diet? 1. Barium enema 2. Pyelogram 3. Metastatic survey (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 2 and 3 only

(D) 1, 2, and 3 [Grid ratio is defined as the ratio of the height of the lead strips to the width of the interspace material; the higher the lead strips, the more scattered radiation they will trap and the greater is the grid's efficiency. The greater the number of lead strips per inch, the thinner and less visible they will be on the finished radiograph. The function of a grid is to absorb scattered radiation in order to improve radiographic contrast. The selectivity of a grid is determined by the amount of primary radiation transmitted through the grid divided by the amount of scattered radiation transmitted through the grid.]

Which of the following factors is/are related to grid efficiency? 1. Grid ratio 2. Number of lead strips per inch 3. Amount of scatter transmitted through the grid (A) 1 only (B) 2 only (C) 1 and 2 only (D) 1, 2, and 3

(B) 1 and 2 only [Kilovoltage (kV) and the half-value layer (HVL) effect a change in both the quantity and the quality of the primary beam. The principal qualitative factor of the primary beam is kilo-voltage, but an increase in kilovoltage will also increase the number of photons produced at the target. HVL, defined as the amount of material necessary to decrease the intensity of the beam to one-half, therefore changes both beam quality and beam quantity. Milliamperage (mA) is directly proportional to x-ray intensity (quantity) but is unrelated to the quality of the beam.]

Which of the following factors will affect both the quality and the quantity of the primary beam? 1. HVL 2. kV 3. mA (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only

Which of the following factors will affect both the quality and the quantity of the primary beam? 1. Half-value layer (HVL) 2. Kilovolts (kV) 3. Milliamperes (mA) (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only [Kilovoltage (kV) and the half-value layer (HVL) effect a change in both the quantity and the quality of the primary beam. The principal qualitative factor of the primary beam is kilo-voltage, but an increase in kilovoltage will also increase the number of photons produced at the target. HVL, defined as the amount of material necessary to decrease the intensity of the beam to one-half, therefore changes both beam quality and beam quantity. Milliamperage is directly proportional to x-ray intensity (quantity) but is unrelated to the quality of the beam.]

Which of the following factors will affect both the quality and the quantity of the primary beam? 1. Half-value layer (HVL) 2. Kilovolts (kV) 3. Milliamperes (mA) (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3 [The Bucky slot cover shields the opening at the side of the table because the Bucky tray is parked at the end of the table for the fluoroscopy procedure; this is important because the opening created otherwise would allow scattered radiation to emerge at approximately the level of the operator's gonads. The exposure switch (usually a foot pedal) must be of the "dead man" type; that is, when the foot is released from the switch, there is immediate termination of exposure. The cumulative exposure timer sounds or interrupts the exposure after 5 minutes of fluoro time, thus making the fluoroscopist aware of accumulated fluoro time. In addition, source-to-tabletop distance is restricted to at least 15 in. for stationary equipment and at least 12 in. for mobile equipment. Increased source-to-tabletop distance increases source-to-patient distance, thereby decreasing patient dose.]

Which of the following features of fluoroscopic equipment is (are) designed to minimize radiation exposure to the patient or personnel? 1. Bucky slot cover 2. Exposure switch/foot pedal 3. Cumulative exposure timer (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) Avulsion fracture [An avulsion fracture is a small bony fragment pulled from a bony process as a result of a forceful pull of the attached ligament or tendon. A comminuted fracture is one in which the bone is broken or splintered into pieces. A torus fracture is a greenstick fracture with one cortex buckled and the other intact. A compound fracture is an open fracture in which the fractured ends have perforated the skin.]

Which of the following fracture classifications describes a small bony fragment pulled from a bony process? (A) Avulsion fracture (B) Torus fracture (C) Comminuted fracture (D) Compound fracture

(B) 1 and 3 only [High-kilovoltage exposures produce large amounts of scattered radiation, and high-ratio grids are used often with high-kilovoltage techniques in an effort to absorb more of this scattered radiation. However, as more scattered radiation is absorbed, more primary radiation is absorbed as well. This accounts for the increase in milliampere-seconds required when changing from an 8:1 to a 16:1 grid. In addition, precise centering and positioning become more critical; a small degree of inaccuracy is more likely to cause grid cutoff in a high-ratio grid.]

Which of the following is (are) characteristic(s) of a 16:1 grid? 1. It absorbs more useful radiation than an 8:1 grid. 2. It has more centering latitude than an 8:1 grid. 3. It is used with higher-kilovoltage exposures than an 8:1 grid. (A) 1 only (B) 1 and 3 only (C) 2 and 3 only (D) 1, 2, and 3

(C) Backup timer [A phototimer is one type of automatic exposure device; another is the ionization chamber. When either is installed in an x-ray unit, it is calibrated to produce receptor exposures as required by the radiologist. Once the part being radiographed has been exposed to produce the proper receptor exposure, the AEC automatically terminates the exposure. The manual timer should be used as a backup timer should the photo timer fail to terminate the exposure, thus protecting the patient from overexposure and the x-ray tube from excessive heat load. Circuit breakers and fuses are circuit devices used to protect circuit elements from overload. In case of current surge, the circuit will be broken, thus preventing equipment damage. A rheostat is a type of variable resistor.]

Which of the following functions to protect the x-ray tube and the patient from overexposure in the event that the AEC fails to terminate an exposure? (A) Circuit breaker (B) Fuse (C) Backup timer (D) Rheostat

(D) 25mA, 7/10s, 70kV [In the RAO position, the sternum must be visualized through the thorax and heart. Prominent pulmonary vascular markings can hinder good visualization. A method frequently used to overcome this problem is to use a milliampere-seconds value with a long exposure time. The patient is permitted to breathe normally during the (extended) exposure and by so doing blurs out the prominent vascularities.]

Which of the following groups of exposure factors would be most effective in eliminating prominent pulmonary vascular markings in the RAO position of the sternum? (A) 500 mA, 1/30 s, 70 kV (B) 200 mA, 0.04 second, 80 kV (C) 300 mA, 1/10 s, 80 kV (D) 25mA, 7/10s, 70kV

(D) 25 mA, 7/10 s, 70 kV [In the RAO position, the sternum must be visualized through the thorax and heart. Prominent pulmonary vascular markings can hinder good visualization. A method frequently used to overcome this problem is to use a milliampere-seconds value with a long exposure time. The patient is permitted to breathe normally during the (extended) exposure and by so doing blurs out the prominent vascularities.]

Which of the following groups of exposure factors would be most effective in eliminating prominent pulmonary vascular markings in the RAO position of the sternum? (A) 500 mA, 1/30 s, 70 kV (B) 200 mA, 0.04 second, 80 kV (C) 300 mA, 1/10 s, 80 kV (D) 25 mA, 7/10 s, 70 kV

(A) 2.5 mAs, 100 kVp [Because patient dose is regulated by the quantity of x-ray photons delivered to the patient, the milliampere-seconds value regulates patient dose. Highly energetic x-ray photons (high kilovoltage) are more likely to penetrate the patient rather than be absorbed by biologic tissue. Consequently, the use of high-kilovoltage and low-milliampere-seconds exposure factors is preferred in an effort to reduce patient dose.]

Which of the following groups of exposure factors would deliver the lowest patient dose? (A) 2.5 mAs, 100 kVp (B) 5 mAs, 90 kVp (C) 10 mAs, 80 kVp (D) 20 mAs, 70 kVp

(D) 1, 2, and 3 [All the factors listed influence the effect of radiation on tissue. Larger quantities, of course, increase radiation's effect on tissue. The energy (i.e., quality and penetration) of the radiation determines whether the effects will be superficial (erythema) or deep (organ dose). Certain tissues (such as blood-forming organs, the lens, and the gonads) are more radiosensitive than others (such as muscle and nerve). The length of time over which the exposure is spread (fractionation) is important; the longer the period of time, the less are the tissue effects.]

Which of the following has (have) an effect on the amount and type of radiation-induced tissue damage? 1. Quality of radiation 2. Type of tissue being irradiated 3. Fractionation (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only [Because minerals in rocks and the earth can emanate radioactivity, high levels of radon gas inside homes have been of recent concern. Another source of radon gas is from burning cigarettes, whether as a smoker or as passive exposure. Uranium miners have been identified with a much higher incidence of lung cancer; many of these individuals also were smokers. Radiology departments are not known as a source of radon gas exposure.]

Which of the following has(have) been identified as source(s) of radon exposure? 1. Indoors, in houses 2. Smoking cigarettes 3. Radiology departments (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) K [The radiograph illustrates an AP projection of the scapula; abduction of the arm moves the scapula away from the rib cage, revealing a greater portion of the scapula than would be visualized with the arm at the side. A number of bony structures are identified: the acromion process (A), the humeral head (B), glenoid fossa (C), scapular spine (D), clavicle (E), supraspinatus fossa (F), acromioclavicular joint (G), scapular notch (H), coracoid process (I), inferior angle/apex (j), body/costal surface (K), lateral/axillary border (L), axillary part upper rib (M).]

Which of the following indicates the scapular costal surface seen in the figure below? (A) D (B) H (C) K (D) M

(B) 1 and 2 only [Radiologic interventional procedures function to treat pathologic conditions as well as provide diagnostic information. Percutaneous transluminal angioplasty (PTA) uses an inflatable balloon catheter under fluoroscopic guidance to increase the diameter of a plaquestenosed vessel. A stent is a cage-like metal device that can be placed in the vessel to provide support to the vessel wall. A peripherally inserted central catheter (PICC) is also placed under fluoroscopic control. It is simply a venous access catheter that can be left in place for several months. It provides convenient venous access for patients requiring frequent blood tests, chemotherapy, or large amounts of antibiotics.]

Which of the following interventional procedures can be used to increase the diameter of a stenosed vessel? 1. Percutaneous transluminal angioplasty (PTA) 2. Stent placement 3. Peripherally inserted central catheter (PICC line) (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(C) Diagnostic x-rays [LET increases with the ionizing potential of the radiation; for example, alpha particles are more ionizing than x-radiation, and, therefore, they have a higher LET. As ionizations and LET increase, there is greater possibility of an effect on living tissue; therefore, the RBE increases. The RBE [sometimes called quality factor (QF)] of diagnostic x-rays is 1, the RBE of fast neutrons is 10, the RBE of 5-MeV alpha particles is 20, and the RBE of 10-MeV protons is 5.0.]

Which of the following ionizing radiations is described as having an RBE of 1.0? (A) 10 MeV protons (B) 5 MeV alpha particles (C) Diagnostic x-rays (D) Fast neutrons

(B) 1 and 2 only [Anemia is a blood condition characterized by a decreased number of circulating red blood cells and decreased hemoglobin; it has many causes. Adequate hemoglobin is required to provide oxygen to the body. Anemia is treated according to its cause. Hematuria is the term used to describe blood in the urine and is unrelated to anemia.]

Which of the following is (are) characteristic(s) of anemia? 1. Decreased number of circulating red blood cells 2. Decreased hemoglobin 3. Hematuria (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3 [All the tissues listed are considered especially radiosensitive. The intestinal crypt cells of Lieberkühn are responsible for the absorption of nutrients into the bloodstream. Because these cells are continually being cast off, new cells must continually arise. Being highly mitotic undifferentiated stem cells, they are very radiosensitive. Excessive radiation to the blood-forming organs (such as bone marrow) can cause leukemia or life-span shortening. Young, immature embryonic cells such as erythroblasts are listed among the most radiosensitive. Lymphocytes are the most radiosensitive cells in the body.]

Which of the following is (are) considered especially radiosensitive tissues? 1. Bone marrow 2. Intestinal crypt cells 3. Erythroblasts (A) 1 and 2 only (B) 1 and 3 only (C) 2 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3 [Follow-up studies have been done on individuals receiving accidental exposure to radiation (e.g., medical personnel, uranium miners, and children irradiated in vivo). Pioneer radiation workers developed leukemia and other cancers, their vision was clouded by the formation of cataracts, and their lives were shorter than those of their colleagues. With today's sophisticated equipment and knowledge of radiation protection, none of these situations should occur.]

Which of the following is (are) considered long-term somatic effect(s) of exposure to ionizing radiation? 1. Life-span shortening 2. Carcinogenesis 3. Cataractogenesis (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) 1 only [Kilovoltage is the qualitative regulating factor; it has a direct effect on photon energy. That is, as kilovoltage is increased, photon energy increases. Photon energy is inversely related to wavelength. That is, as photon energy increases, wavelength decreases. Photon energy is unrelated to milliamperage.]

Which of the following is (are) directly related to photon energy? 1. Kilovoltage 2. Milliamperes 3. Wavelength (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3 [Breast tissue has very low subject contrast, but it is imperative to visualize micro-calcifications and subtle tissue density differences. Fine detail is necessary to visualize any micro-calcifications; therefore, a small-focal-spot tube is essential. High, short-scale contrast (and, therefore, low kilovoltage) is needed to accentuate minute differences in tissue density. A compression device serves to even out differences in tissue thickness (thicker at the chest wall, thinner at the nipple) and decrease OID and helps to decrease the production of scattered radiation.]

Which of the following is (are) essential to high-quality mammographic examinations? 1. Small-focal-spot x-ray tube 2. Short-scale contrast 3. Use of a compression device (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(A) 1 only [The cervical intervertebral foramina form a 45-degree angle with the MSP and, therefore, are well visualized in a 45-degree oblique position. Zygapophyseal joints are formed by articulating surfaces of the inferior articular facet of one vertebra with the superior articular facet of the vertebra below; they are well demonstrated in the lateral position of the cervical spine. The intervertebral disk spaces are best demonstrated in the lateral position.]

Which of the following is (are) well demonstrated in the oblique position of the cervical vertebrae? 1. Intervertebral foramina 2. Disk spaces 3. Zygapophyseal joints (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(B) Vidicon

Which of the following is a type of television camera tube that converts a visible image on the output phosphor of the image intensifier into an electronic signal? (A) Ionization chamber (B) Vidicon (C) Charge-coupled device (D) Cathode ray tube

(A) 0.1 mGy [Patients will occasionally question the radiographer regarding the amount of radiation they are receiving during their examination. Most of these patients are merely curious because they have heard a recent news report about x-rays, or have perhaps studied about x-rays in school recently. It is a good idea for radiographers to have some knowledge of average exposure doses for patients who desire this information. The curious patient can also be referred to the medical physicist for more detailed information. The average PA chest delivers an ESE of 0.1 mGy; AP supine lumbar spine radiograph delivers about 3 mGy. The average AP supine abdomen delivers about 4.0 mGy; the AP cervical spine is about 1.5 mGy. The AP pelvis also delivers about 1.5 mGy. The average skull about 2 mGy and the average extremity about 0.5 mGy.]

Which of the following is an acceptable approximate entrance skin exposure (ESE) for a PA chest radiograph? (A) 0.1 mGy (B) 0.5 mGy (C) 1.5 mGy (D) 3 mGy

(A) Patient AP with 30- to 35-degree angle cephalad [The routine AP projection of the lumbar spine demonstrates the intervertebral disk spaces between the first four lumbar vertebrae. The space between L5 and S1, however, is angled with respect to the other disk spaces. Therefore, the CR must be directed 30 to 35 degrees cephalad to parallel the disk space and thus project it open onto the IR.]

Which of the following positions will provide an AP projection of the L5-S1 interspace? (A) Patient AP with 30- to 35-degree angle cephalad (B) Patient AP with 30- to 35-degree angle caudad (C) Patient AP with 0-degree angle (D) Patient lateral, coned to L5

(C) Exposure field recognition errors may occur [If the X-ray exposure field is improperly collimated, positioned, and sized, exposure field recognition errors can occur (C). These can lead to histogram analysis errors due to signals generated from outside of the exposure field. This may result in dark, light, or noisy images. The MTF, or modulation transfer function (A) is a mathematical function that measures the ability of a digital detector to transfer its spatial resolution characteristics of the image. If a radiographic grid has a frequency that approximates the CR scan frequency and the grid strips are oriented in the same direction as the scan, the Moiré artifact may be observed (B). The appearance of ghost artifacts can be seen when CR image plates are incompletely erased. If an image plate has not been used for 24 hours, it should be erased again before using it for a diagnostic radiographic exposure (A).]

Which of the following may occur if the X-ray exposure field is not properly collimated, positioned, and sized? (A) Modulation transfer function failure (B) Moiré artifact (C) Exposure field recognition errors may occur (D) Ghost artifact

(B) 1 and 2 only

Which of the following methods can be used effectively to decrease differential absorption, providing a longer scale of contrast in the diagnostic range? 1. Using high peak kilovoltage and low milliampere-seconds factors 2. Using compensating filtration 3. Using factors that increase the photoelectric effect (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) 1 and 2 only [When differences in absorption characteristics are decreased, body tissues absorb radiation more uniformly, and as a result, more grays are seen on the radiographic image. A longer scale of contrast is produced. High-kilovoltage and low-milliamperage factors achieve this. Compensating filtration is also used to "even out" densities in uneven anatomic parts, such as the thoracic spine. The photoelectric effect is the interaction between x-ray photons and matter that occurs at low-peak kilovoltage levels—levels that tend to produce short-scale contrast.]

Which of the following methods can be used effectively to decrease differential absorption, providing a longer scale of contrast in the diagnostic range? 1. Using high peak kilovoltage and low milliampere-seconds factors 2. Using compensating filtration 3. Using factors that increase the photoelectric effect (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) erect PA, chin extended, OML 15 degree from horizontal [The radiograph shown is a PA projection (Caldwell method) of the frontal and anterior ethmoidal sinuses. The frontal sinuses are seen centrally in the vertical plate of the frontal bone behind the glabella and extending laterally over the superciliary arches. The ethmoidal sinuses are seen adjacent and inferior to the medial aspect of the orbits. The patient is positioned PA erect with the chin extended so that the OML is elevated 15 degrees from the horizontal. If the OML were perpendicular to the IR, the petrous pyramids would fill the orbits (true PA). In the PA position with chin extended (choice A) and OML 37 degrees to the IR (parietoacanthial projection, Waters method), the petrous pyramids are projected below the maxillary sinuses.]

Which of the following methods was used to obtain the image seen in Figure 2-6? (A) erect PA, chin extended, OML forming 37 degrees to IR (B) erect PA, OML, and CR perpendicular to IR (C) erect PA, chin extended, OML 15 degree from horizontal (D) erect PA, chin extended, OML 30 degree from horizontal

(C) OSL dosimeter [Ionization is the fundamental principle of operation of both the film badge and the pocket dosimeter. In the film badge, the film's silver halide emulsion is ionized by x-ray photons. The pocket dosimeter contains an ionization chamber, and the number of ionizations taking place may be equated to exposure dose; it is accurate, but it is used only to detect larger amounts of radiation exposure. Is not commonly used in diagnostic radiography. The TLD can measure exposures as low as 5 mrem, whereas film badges will measure a minimum exposure only as low as 10 mrem. TLDs contain lithium fluoride crystals that undergo characteristic changes on irradiation. When the crystals are subsequently heated, they emit a quantity of visible (thermo) luminescence/light in proportion to the amount of radiation absorbed. The relatively new OSL dosimeters contain aluminum oxide crystals that also undergo characteristic changes on irradiation. When the Al 2 O 3 crystals are stimulated by a laser, they emit (optically stimulated) luminescence/light in proportion to the amount of radiation absorbed. OSL dosimeters can measure exposures as low as 1 mrem.]

Which of the following personnel monitoring devices is commonly used in diagnostic radiography and considered to be most sensitive and accurate? (A) TLD (B) Film badge (C) OSL dosimeter (D) Pocket dosimeter

(C) Lateral [The parietoacanthial (Waters' method) projection demonstrates the maxillary sinuses. The PA axial with a caudal central ray (Caldwell) demonstrates the frontal and ethmoidal sinus groups. The lateral projection, with the central ray entering 1 inch posterior to the outer canthus, demonstrates all the paranasal sinuses. X-ray examinations of the sinuses should always be performed erect, to demonstrate leveling of any fluid present.]

Which of the following positions demonstrates all the paranasal sinuses? (A) Parietoacanthial (B) PA axial (C) Lateral (D) True PA

(B) 1 and 2 only [The parietoacanthal (Waters method) projection demonstrates the maxillary sinuses. The modified Waters position, with the CR directed through the open mouth, will demonstrate the sphenoid sinuses through the open mouth. The PA axial projection demonstrates the frontal and ethmoidal sinus groups. The lateral projection, with the CR entering 1 inch posterior to the outer canthus, demonstrates all the paranasal sinuses. X-ray examinations of the sinuses always should be performed erect to demonstrate leveling of any fluid present.]

Which of the following positions is/are most frequently used to demonstrate the sphenoid sinuses? 1. Modified Waters (mouth open) 2. Lateral 3. PA axial (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 30-degree RPO [The articular facets (zygapophyseal joints) of the L5-S1 articulation form a 30-degree angle with the MSP; they are, therefore, well demonstrated in a 30-degree oblique position. The 45-degree oblique position demonstrates the zygapophyseal joints of L1-4.]

Which of the following positions will demonstrate the lumbosacral zygapophyseal articulation? (A) AP (B) Lateral (C) 30-degree RPO (D) 45-degree LPO

(C) 30-degree RPO [The articular facets (zygapophyseal joints) of the L5-S1 articulation form a 30-degree angle with the MSP; they are, therefore, well demonstrated in a 30-degree oblique position. The 45-degree oblique position demonstrates the zygapophyseal joints of L1-4.]

Which of the following positions will demonstrate the lumbosacral zygapophyseal articulation? (A) AP (B) Lateral (C) 30-degree RPO (D) 45-degree LPO

(B) Upper-limb venogram [The cephalic, basilic, and subclavian veins should be demonstrated on an upper limb venogram. Venography of the upper limb usually is performed to rule out venous obstruction or thrombosis. The injection site is usually in the hand or wrist, and images should be obtained up to the area of the superior vena cava.]

Which of the following procedures will best demonstrate the cephalic, basilic, and subclavian veins? (A) Aortofemoral arteriogram (B) Upper-limb venogram (C) Lower-limb venogram (D) Renal venogram

(D) 1, 2, and 3 [The stochastic effects of radiation are plotted on a linear dose-response curve. The linear dose-response curve has no threshold; that is, there is no dose below which radiation is absolutely safe. The nonlinear/sigmoidal dose-response curve has a threshold and is thought to be generally correct for most deterministic effects—such as skin erythema, hematologic depression, and radiation lethality (death).]

Which of the following radiation exposure responses exhibit a nonlinear threshold dose-response relationship? 1. Skin erythema 2. Hematologic depression 3. Lethality (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) Retrograde urography [Retrograde urography requires ureteral catheterization so that a contrast medium can be introduced directly into the pelvicalyceal system. This procedure provides excellent opacification and structural information but does not demonstrate the function of these structures. IV studies such as the IVU demonstrate function. Cystourethrography is an examination of the bladder and urethra, frequently performed during voiding. Nephrotomography is performed after IV administration of a contrast agent; it may be used to evaluate small intrarenal lesions and renal hypertension.]

Which of the following radiologic procedures requires that a contrast medium be injected into the renal pelvis via a catheter placed within the ureter? (A) Nephrotomography (B) Retrograde urography (C) Cystourethrography (D) IVU

(B) Internal rotation position [The internal rotation position places the humeral epicondyles perpendicular to the IR, the humerus in a true lateral position, and the lesser tubercle in profile. The external rotation position places the humeral epicondyles parallel to the IR, the humerus in a true AP position, and the greater tubercle in profile. The neutral position is used often for the evaluation of calcium deposits in the shoulder joint.]

Which of the following shoulder projections can be used to evaluate the lesser tubercle in profile? (A) External rotation position (B) Internal rotation position (C) Neutral rotation position (D) Inferosuperior axial position

(C) 2 and 3 only

Which of the following statements is (are) true regarding Figure 7-10? 1. Excessive kilovoltage was used. 2. High contrast is demonstrated. 3. Insufficient penetration is evident. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(D) 1, 2, and 3 [All fluoroscopic equipment must provide at least 30 cm (12 inches), and preferably 38 cm, (15 inches) between the xray source (focal spot) and the xray tabletop (patient), according to NCRP Report No. 102. The tabletop intensity of the fluoroscopic beam must not exceed 100 mGya/min (10 R/min,) or 21 mGya/min/mA (2.1 R/min/mA). The tabletop intensity of high level control fluoroscopy must not exceed 200 mGya/min (20 R/min) With undertable fluoroscopic tubes, a Buckyslot cover having at least the equivalent of 0.25-mm Pb must be available to attenuate scattered radiation. Fluoroscopic milliamperes must not exceed 5, although image intensified fluoroscopy usually operates between 1 and 3 mA.]

Which of the following statements is (are) true with respect to radiation safety in fluoroscopy? 1. Tabletop radiation intensity must not exceed 100 mGya/min. 2. Tabletop radiation intensity must not exceed 21 mGya/min/mA. 3. In high-level fluoroscopy, tabletop intensity up to 200 mGya/min is permitted. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 1 and 3 only

Which of the following statements regarding dual x-ray absorptiometry is (are) true? 1. Radiation dose is low. 2. Only low-energy photons are used. 3. Photon attenuation by bone is calculated. (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(C) 1 and 3 only [Dual x-ray absorptiometry (DXA) imaging is used to evaluate bone mineral density (BMD). It is the most widely used method of bone densitometry—it is low-dose, precise, and uncomplicated to use/perform. DXA uses two photon energies—one for soft tissue and one for bone. Since bone is denser and attenuates x-ray photons more readily, photon attenuation is calculated to represent the degree of bone density. Bone densitometry DXA can be used to evaluate bone mineral content of the body, or part of it, to diagnose osteoporosis or to evaluate the effectiveness of treatments for osteoporosis.]

Which of the following statements regarding dual x-ray absorptiometry is (are) true? 1. Radiation dose is low. 2. Only low-energy photons are used. 3. Photon attenuation by bone is calculated. (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 1, 2, and 3

(C) 2 and 3 only [The scapular Y projection requires that the coronal plane be about 60 degrees to the IR (MSP is about 30 degrees), thus resulting in an oblique projection of the shoulder. The vertebral and axillary borders of the scapula are superimposed on the humeral shaft, and the resulting relationship between the glenoid fossa and humeral head will demonstrate anterior or posterior dislocation. Lateral or medial dislocation is evaluated on the AP projection.]

Which of the following statements regarding the PA oblique scapular Y projection of the shoulder is (are) true? 1. The midsagittal plane should be about 60 degrees to the IR. 2. The scapular borders should be superimposed on the humeral shaft. 3. An oblique projection of the shoulder is obtained. (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(C) 1 and 3 only [The pictured radiograph is an AP projection of the knee with the knee extended. The tibial intercondylar eminences are well demonstrated on the tibial plateau, and the femorotibial joint is well visualized. The intercondyloid fossa is not demonstrated here. A "tunnel" view of the knee is required to demonstrate the intercondyloid fossa.]

Which of the following statements regarding the radiograph in Figure A is (are) true? 1. The tibial eminences are well visualized. 2. The intercondyloid fossa is demonstrated between the femoral condyles. 3. The femorotibial articulation is well demonstrated. (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 2 and 3 only

(B) 1 and 2 only [The gallbladder is located on the posterior surface of the liver in the right upper quadrant (RUQ). The hepatic (right colic) flexure, so named because of its close proximity to the liver, is also in the RUQ. The cecum, located in the right lower quadrant (RLQ), is continuous with the terminal ileum—forming the ileocecal valve.]

Which of the following structures is (are) located in the right upper quadrant (RUQ)? 1. Hepatic flexure 2. Gallbladder 3. Ileocecal valve (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(D) Gastric fundus The stomach is normally angled with the fundus lying posteriorly and the body, pylorus, and duodenum inferior to the fundus and angling anteriorly. Therefore, when the patient ingests barium and lies AP recumbent, the heavy barium gravitates easily to the fundus and fills it. With the patient PA recumbent, barium gravitates inferiorly to the body, pylorus, and duodenum, displacing air into the fundus.

Which of the following structures will be filled with barium in the AP recumbent position of a sthenic patient during an upper GI examination? (A) Duodenal bulb (B) Descending duodenum (C) Pyloric vestibule (D) Gastric fundus

(D) Gastric fundus [The stomach is normally angled with the fundus lying posteriorly and the body, pylorus, and duodenum inferior to the fundus and angling anteriorly. Therefore, when the patient ingests barium and lies AP recumbent, the heavy barium gravitates easily to the fundus and fills it. With the patient PA recumbent, barium gravitates inferiorly to the body, pylorus, and duodenum, displacing air into the fundus.]

Which of the following structures will usually contain air, in the PA recumbent position on a sthenic patient, during a double-contrast upper GI (UGI) examination? (A) Duodenal bulb (B) Descending duodenum (C) Pyloric vestibule (D) Gastric fundus

(C) High-kilovoltage exposure factors [When tissue densities within a part are very dissimilar (e.g., the chest), the radiographic result (especially analog) can be unacceptably high contrast. To "even out" these exposure values and produce a more appropriate scale of grays, exposure factors using high kilovoltage should be employed. The higher the grid ratio, the higher is the resulting contrast. Use of short exposure time is always encouraged to reduce the possibility of motion unsharpness but has no impact on varying tissue densities. Exposure factors using high milliampere-seconds generally result in excessive receptor exposure, frequently obliterating much of the gray scale.]

Which of the following technical changes would best serve to remedy the effect of very dissimilar tissue densities? (A) Use of short exposure time (B) Use of a high-ratio grid (C) High-kilovoltage exposure factors (D) High milliampere-seconds exposure factors

(C) Angle the CR 35 to 45 degrees cephalad. [In the PA position, portions of the barium-filled hypersthenic stomach superimpose on themselves. Thus, patients with a hypersthenic body habitus usually present a high transverse stomach with poorly defined curvatures. If the PA stomach is projected with a 35- to 45-degree cephalad CR, the stomach "opens up." That is, the curvatures, the antral portion, and the duodenal bulb all appear as a sthenic habitus stomach would appear. A 35-to 40-degree RAO position is used to demonstrate many of these structures in the average, or sthenic, body habitus. A lateral position is used to demonstrate the anterior and posterior gastric surfaces and retrogastric space.]

Which of the following techniques would provide a posteroanterior (PA) projection of the gastroduodenal surfaces of a barium-filled high and transverse stomach? (A) Place the patient in a 35- to 40-degree right anterior oblique (RAO) position. (B) Place the patient in a lateral position. (C) Angle the CR 35 to 45 degrees cephalad. (D) Angle the CR 35 to 45 degrees caudad.

(C) Angle the CR 35 to 45 degrees cephalad. [In the PA position, portions of the barium-filled hypersthenic stomach superimpose on themselves. Thus, patients with a hypersthenic body habitus usually present a high transverse stomach with poorly defined curvatures. If the PA stomach is projected with a 35- to 45-degree cephalad CR, the stomach "opens up." That is, the curvatures, the antral portion, and the duodenal bulb all appear as a sthenic habitus stomach would appear. A 35-to 40-degree RAO position is used to demonstrate many of these structures in the average, or sthenic, body habitus. A lateral position is used to demonstrate the anterior and posterior gastric surfaces and retrogastric space.]

Which of the following techniques would provide a posteroanterior (PA) projection of the gastroduodenal surfaces of a barium-filled high and transverse stomach? (A) Place the patient in a 35- to 40-degree right anterior oblique (RAO) position. (B) Place the patient in a lateral position. (C) Angle the CR 35 to 45 degrees cephalad. (D) Angle the CR 35 to 45 degrees caudad.

(B) 1 and 2 only [Resolution describes how closely fine details may be associated and still be recognized as separate details before seeming to blend into each other and appear "as one." The degree of resolution transferred to the IR is a function of the resolving power of each of the system components and can be expressed in line pairs per millimeter (lp/mm), line-spread function (LSP), or modulation transfer function (MTF). Lp/mm can be measured using a resolution test pattern; a number of resolution test tools are available. LSP is measured using a 10-μm x-ray beam; MTF measures the amount of information lost between the object and the IR. The effective focal spot is the foreshortened size of the actual focal spot as it is projected down toward the IR, that is, as it would be seen looking up into the emerging x-ray beam. This is called the line-focus principle and is not a unit used to express resolution.]

Which of the following units is (are) used to express resolution? 1. Line-spread function 2. Line pairs per millimeter 3. Line-focus principle (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) 1 only

Which of the following voltage ripples is (are) produced by single-phase equipment 1. 100% voltage ripple 2. 13% voltage ripple 3. 3.5% voltage ripple (A) 1 only (B) 2 only (C) 2 and 3 only (D) 1, 2, and 3

(B) Left axillary ribs [The axillary portions of ribs are demonstrated in a 45-degree oblique position. In order to place the axillary portions parallel to the image receptor (IR), the affected side is away from the IR in the PA oblique (RAO and LAO) positions and toward the IR in the AP oblique (RPO and LPO) positions. Radiography of the sternum, in the slight RAO position, requires greater obliquity for thinner patients and lesser obliquity for thicker patients. The scapular Y position of the shoulder is performed to demonstrate dislocation and requires a rotation of 45-60 degrees, with the affected side closest to the IR.]

Which of the following will be demonstrated best in the 45-degree right anterior oblique (RAO) position? (A) Right axillary ribs (B) Left axillary ribs (C) Sternum in the heart shadow (D) Left scapular Y

(B) Decreased SID [One of the most important ways to decrease exposure to ionizing radiation is to increase the distance between the source and the individual exposed. As the distance between the radiation source and the irradiated individual decreases, tissue exposure increases dramatically according to the Inverse Square Law of radiation. An increase in mAs will increase patient dose proportionally. An increase in filtration will decrease patient skin dose, as low energy photons are removed from the x-ray beam. An increase in kVp will increase the number of high energy photons, thereby increasing patient dose. However, when accompanied by an appropriate decrease in mAs, increased kVp serves to decrease patient dose.]

Which of the following will produce the most significant increase in patient dose? (A) Decreased mAs (B) Decreased SID (C) Increased filtration (D) Increased kVp

(B) Decreased SID [One of the most important ways to decrease exposure to ionizing radiation is to increase the distance between the source and the individual exposed. As the distance between the radiation source and the irradiated individual decreases, tissue exposure increases dramatically according to the Inverse Square Law of radiation. An increase in mAs will increase patient dose proportionally. An increase in filtration will decrease patient skin dose, as low energy photons are removed from the x-ray beam. An increase in kVp will increase the number of high energy photons, thereby increasing patient dose. However, when accompanied by an appropriate decrease in mAs, increased kVp serves to decrease patient dose.]

Which of the following will produce the most significant increase in patient dose? (A) Decreased mAs (B) Decreased SID (C) Increased filtration (D) Increased kVp

(C) 2 and 3 only

Which of the following would be appropriate IP front material(s)? 1. Tungsten 2. Magnesium 3. Bakelite (A) 1 only (B) 1 and 2 only (C) 2 and 3 only (D) 1, 2, and 3

(A) Short SID [The shorter the SID, the greater is the skin dose (ESE). This is why there are specific SSD restrictions in fluoroscopy. X-ray beam quality has a significant effect on patient skin dose. The use of high kilovoltage produces more high-energy penetrating photons, thereby decreasing skin dose. Filtration is used to remove the low-energy photons that contribute to skin dose from the primary beam. Although milliamperage regulates the number of x-ray photons produced, it does not affect photon quality.]

Which of the following would be most likely to cause the greatest skin dose (ESE)? (A) Short SID (B) High kilovoltage (C) Increased filtration (D) Decreased milliamperage

(A) Number 1 [Four positions for the lumbar spine are illustrated. Number 1 is an RPO, and number 2 an LAO. The posterior oblique positions (LPO and RPO) demonstrate the zygapophyseal joints closer to the IR, while the anterior oblique positions (LAO and RAO) demonstrate the zygapophyseal joints further from the IR (Fig. B). Number 3 is the AP projection, which demonstrates the lumbar bodies and disk spaces and the transverse and spinous processes. Number 4 is the lateral position, which provides the best demonstration of the lumbar bodies, intervertebral disk spaces, spinous processes, pedicles, and intervertebral foramina.]

Which of the positions illustrated in the figure below will best demonstrate the lumbar zygapophyseal joints closest to the IR? (A) Number 1 (B) Number 2 (C) Number 3 (D) Number 4

(A) Number 1

Which of the x-ray circuit devices shown in Figure 6-5 operates on the principle of self-induction? (A) Number 1 (B) Number 3 (C) Number 5 (D) Number 7

(C) Internal rotation [The external rotation position is the true AP position and places the greater tubercle in profile laterally and places the lesser tubercle anteriorly. The internal rotation position demonstrates the lesser tubercle in profile medially and places the humerus in a true lateral position; the greater tubercle is seen superimposed on the humeral head. The epicondyles should be superimposed and perpendicular to the IR. The neutral position places the epicondyles about 45 degrees to the IR and places the greater tubercle anteriorly but still lateral to the lesser tubercle.]

Which position of the shoulder demonstrates the lesser tubercle in profile medially? (A) AP (B) External rotation (C) Internal rotation (D) Neutral position

(D) Ionization chamber [The pocket dosimeter, or pocket ionization chamber, resembles a penlight. Within the dosimeter is a thimble ionization chamber. In the presence of ionizing radiation, a particular quantity of air will be ionized and cause the fiber indicator to register radiation quantity in milliroentgen (mR). The self- reading type may be "read" by holding the dosimeter up to the light and, looking through the eyepiece, observing the fiber indicator, which indicates a quantity of 0 to 200 mR. Although it provides an immediate reading while other personnel monitors require "processing," the disadvantage of the pocket dosimeter is that it does not provide a permanent legal record of exposure.]

Which type of personnel radiation monitor can provide an immediate reading? (A) Thermoluminescent dosimeter (TLD) (B) Optically stimulated luminescence (OSL) (C) Film badge (D) Ionization chamber

(B) Emphysema [Chest radiographs demonstrating emphysema will show the characteristic irreversible trapping of air that increases gradually and overexpands the lungs. This produces the characteristic "flattening" of the hemidiaphragms and widening of the intercostal spaces. The increased air content of the lungs requires a compensating decrease in technical factors. Pneumonia is inflammation of the lungs, usually caused by bacteria, virus, or chemical irritant. Pneumothorax is a collection of air or gas in the pleural cavity (outside the lungs), with an accompanying collapse of the lung. Pleural effusion is excessive fluid between the parietal and visceral layers of pleura.]

Widening of the intercostal spaces is characteristic of which of the following conditions? (A) Pneumothorax (B) Emphysema (C) Pleural effusion (D) Pneumonia

(B) There is greater patient dose with three-phase equipment than with single-phase equipment. [If the same kilovoltage is used with single-phase and three-phase equipment, the three-phase unit will require about 50% fewer milliampere-seconds to produce similar radiographs. Because three-phase equipment has much higher effective voltage than single-phase equipment, the three-phase radiograph will have lower contrast. A lower milliampere-seconds value can be used with three-phase equipment, so heat units are not built up as quickly. When technical factors are adjusted to obtain the same receptor exposure and contrast, there is no difference in patient dose.]

With milliamperage adjusted to produce equal exposures, all the following statements are true except (A) a single-phase examination done at 10 mAs can be duplicated with three-phase, 12-pulse at 5 mAs. (B) There is greater patient dose with three-phase equipment than with single-phase equipment. (C) Three-phase equipment can produce comparable radiographs with less heat unit (HU) buildup. (D) Three-phase equipment produces lower-contrast radiographs than single-phase equipment.

(B) The ESE decreases. [Because of the divergent quality of the x-ray beam, as source-to-skin distance (SSD) increases, entrance skin exposure (ESE) decreases for the necessary exit dose. SSD must be at least 30 cm on mobile fluoroscopic equipment, and at least 38 cm on fixed fluoroscopic equipment.]

With milliamperes (mA) increased to maintain fluoroscopic output intensity, how is the ESE affected as the source-to-skin distance (SSD) is increased? (A) The ESE increases. (B) The ESE decreases. (C) The ESE remains unchanged. (D) ESE is unrelated to SSD.

(B) Rami [With the patient in the PA position, the rami are well visualized with a perpendicular ray or with 20 to 25 degrees of cephalad angulation. A portion of the mandibular body is demonstrated in this position, but most of it is superimposed over the cervical spine.]

With the patient's head in a PA position and the CR directed 20 degrees cephalad, which part of the mandible will be best visualized? (A) Symphysis (B) Rami (C) Body (D) Angle

(D) 2 and 3 only [With single-phase, full-wave-rectified equipment, the voltage is constantly changing from 0% to 100% of its maximum value. It drops to 0 every 180 degrees (of the AC waveform); that is, there is 100% voltage ripple. With three-phase equipment, the voltage ripple is significantly smaller. Three-phase, six-pulse equipment has a 13% voltage ripple, and three-phase, 12-pulse equipment has a 3.5% ripple. Therefore, the voltage never falls below 87% to 96.5% of its maximum value with three-phase equipment, and it closely approaches constant potential [direct current (DC)].]

With three-phase equipment, the voltage across the x-ray tube 1. drops to zero every 180 degrees 2. is 87% to 96% of the maximum value 3. is at nearly constant potential (A) 1 only (B) 2 only (C) 1 and 2 only (D) 2 and 3 only