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Which of the following is a principle component of PACS? A. Image Acquisition B. Film Digitizer C. Teleradiology D. Spatial Resolution

Correct answer: (A) Image Acquisition. Explanation: The principle components of PACS are Image Acquisition, Display Workstations, Network, and Storage Systems. These components all work together to allow diagnostic images to be sent to the radiologist for dictation, sent to medical records, and stored for possible future use.

When performing radiographs on patient's with prosthetics, the AEC will expose ________ and soft tissues may be _________ on the radiograph. A. Longer; overexposed B. Shorter; overexposed C. Longer; underexposed D. Shorter; underexposed

Correct answer: (A) Longer; overexposed. Explanation: Because prosthetics are additive to the overall density of the part being radiographed, the AEC will expose longer than the same part without a prosthetic present. This can caused burnout of the soft tissues surrounding the bone and prosthetic decreasing the diagnostic quality of the image.

___________ is the process of converting alternating current (AC) to direct current (DC). A. Rectification B. Step up transformation C. Step down transformation D. Photoemission

Correct answer: (A) Rectification. Explanation: X-ray imaging systems require direct current (DC). Since standard wall outlets run with alternating current (AC), a rectifier is necessary to convert this type of current to direct current.

Which of the following is located in the anode assembly of the x-ray tube? A. Rotor B. Filament C. Focusing cup D. Wiring

Correct answer: (A) Rotor. Explanation: The anode assembly contains the anode, stator, and rotor. The rotor is a hollow copper cylinder that is attached to the anode and is located inside the stator. The rotor is affected by the electromagnetic field causing the stator to rotate. (B) The filament is located in the cathode assembly of the x-ray tube. (C) Focusing cup is located in the cathode assembly of the x-ray tube. (D) Wiring is located in the cathode assembly of the x-ray tube.

What turns the anode in the xray tube? A. Rotor B. Stator C. Focal track D. Focal spot

Correct answer: (A) Rotor. Explanation: The rotor turns the anode itself. of an induction motor electromagnet. The stator supplies electromagnetic induction to the rotor. The stator is the only part of the cathode or anode located outside of the vacuum glass envelope. The rotor is inside the stator and inside the glass envelope. The rotor needs to be engaged prior to exposure to send current to the stator. The focal track represents the circular path on the anode target that is hit with the electron beam. The focal spot is the area on the focal track impacted by electron beam.

What is the equation for the total resistance in a series circuit? A. Rt=R1+ R2 + R3 B. 1/Rt= 1/R1+ 1/R2+ 1/R3 C. Rt=R1- R2 - R3 D. 1/Rt= 1/R1- 1/R2- 1/R3

Correct answer: (A) Rt=R1+ R2 + R3. Explanation: The equation for the total resistance in a series circuit is Rt=R1+ R2 + R3. Which is the sum of all the elements equaling the circuit. Resistance of a series is measured in ohms. (B) 1/Rt= 1/R1+ 1/R2+ 1/R3 is the equation of total resistance in a parallel circuit. Which is the sum of the reciprocal of each element is inversely proportional to the total. Parallel circuit supply a greater total current from the power source.

What letter indicates the reflective layer of the intensifying screen? A. A B. B C. C D. D

Correct answer: (B) Explanation: The reflective layer of intensifying screens is located between the base and the phosphor layer. Reflective layer intercepts the light that is emitted isotropically when x-rays hit the phosphor and redirects it back to the screen.

Which ionizing chamber should be used when performing KUB radiographs? A. Center B. All three chambers or both outer chambers C. Right outer chamber D. Left outer chamber

Correct answer: (B) All three chambers or both outer chambers. Explanation: When selecting which ionization chamber to use for a KUB, it could be the technologists' first instinct to choose the center chamber. The reason for not choosing the center chamber is the location of the spinal column. By choosing the right and left outer chambers or all three chambers, the focus of the AEC is the soft tissues as opposed to the spine.

Which of the following is the lowest frequency generator? A. Single phase B. Three phase C. High frequency D. Capacitor discharge

Correct answer: (A) Single phase. Explanation: Single phase generators produce a voltage ripple of 120 pulses per second which produces 2 usable pulses per cycle. (B) Three phase generators produce a voltage ripple of 360 pulses per cycle. (C) High frequency generators convert AC to DC power to change incoming voltage frequency to 6,000 Hertz range. (D) Capacitor discharge mobile units operate with the power from the discharge of the high voltage capacitor. May continue to discharge after exposure is made.

What is the smallest percentage of mAs increase needed to produce a noticeable increase in density? A. 20-25% B. 25-30% C. 30-35% D. 35-40%

Correct answer: (C) 30-35%. Explanation: mAs and optical density have a direct relationship, in that as mAs increases, optical density increases. Optical density can be controlled by two major factors: mAs and SID. Several problems would arise if SID was continuously changed from exam to exam, therefore, mAs would be the more controlling factor.

The most important characteristics of radiographic quality are: I. Contrast resolution II. Spatial resolution III. Noise IV. Artifacts A. I only B. II and IV C. I, II, and III D. I, II, III, and IV

Correct answer: (D) I, II, III, and IV. Explanation: Contrast resolution, spatial resolution, noise, and artifacts all contribute to the diagnostic quality of a radiographic image. Whether or not these factors negatively or positively contribute to the radiographic image depends on not only their presence or absence but also the level at which they are present.

The acronym PACS stands for: A. Picture Activation and Communication Systems B. Picture Arriving and Communication Systems C. Picture Attenuation and Communication Systems D. Picture Archiving and Communication Systems

Correct answer: (D) Picture Archiving and Communication Systems. Explanation: The acronym PACS stands for Picture Archiving and Communication System. When in full use, PACS allows the acquisition, interpretation, and storage of medical images in its digital format without having to use the hard copy (film). By using PACS, Radiology departments are able to lower costs and improve time efficiencies in patient diagnosis.

Leakage radiation from the housing of the xray tube should not exceed. A. 100 mR/hr at 1 meter B. 100 mR/hr at 2 meter C. 200 mR/hr at 1 meter D. 200 mR/hr at 2 meter

Correct answer: (A) 100 mR/hr at 1 meter. Explanation: The xray tube is surrounding by a protective housing which controls leakage and scatter radiation. Leakage radiation should not exceed 100 mR/hr at 1 meter. The protective housing is composed of cast steel and is lined with lead to absorb any radiation that was not part of the primary beam being emitted through the window of the protective housing.

Thermionic emission is the release of electrons from a heated ______. A. Autotransformer B. Rectifier C. Filament D. Inverter

Correct answer: (C) Filament. Explanation: In the process of thermionic emission, electrons are discharged from a heated filament on the cathode side of the x-ray tube. As the filament gets hotter, more and more electrons are "shed" from the filament. The type of material that composes the filament, the temperature of the filament, and the size of the filament all affect the quantity of electrons released.

What would be the effect of use of the outer photocells for a lateral projection of the chest when making an exposure of an asthenic patient? A. Increased density B. Motion blur C. Decreased density D. Fog

Correct answer: (C) Decreased density. Explanation: When performing an examination on an asthenic patient, who is thin, selection of the lateral photocells will probably result in underexposure. This will occur because the exposure will be terminated as soon as the lateral photocells detect radiation. Since there will be no tissue overlying the lateral photocells, the exposure will be terminated immediately.

__________ is the process of remote transmission and viewing of images. A. Teleradiology B. Telecommunications C. Mobile Radiology D. Mobile communications

Correct answer: (A) Teleradiology. Explanation: The process of remote transmission and viewing of images is called teleradiology. Teleradiology allows Radiologic Technologists to send radiographic images through a remote transmission to Radiologists in virtually any location. DICOM was produced as a standard of imaging and interface formatting to make Teleradiology efficient.

The quantity of the electron stream as it travels through the x-ray tube from the cathode to the anode is controlled by -------? A. mAs B. kvp C. contrast D. density

Correct answer: (A) mAs. Explanation: As the tube current milliamperage is increased the number of electrons traveling through xray tube that will strike the target will increase. The quantity of xrays produces increases or decreases in direct proportion to quantity of milliamperage. 100mA tube current will produce 100 units of radiation.

Misrepresentation of the size and/or shape on a radiographic image compared to the actual size of the structure being imaged is? A. Recorded detail B. Distortion C. Degree of unsharpness D. Image misrepresentation

Correct answer: (B) Distortion. Explanation: Recorded detail and distortion are geometric properties of a radiographic image. Distortion is image misrepresentation of the size and shape of the structures of interest. Distortion can be either size (magnification) or shape (elongation or foreshortening).

Which of the following will occur on a digital image as a result of inadequate mAs? A. B B. E C. C D. F

Correct answer: (B) E. Explanation: The x-ray tube is a vacuum that contains two electrodes. Those electrodes are the cathode and the anode. The anode is the positive side of the x-ray tube. There are two different types of anodes: either stationary or rotating. General x-ray uses a rotating anode because it is able to produce high intensity x-ray beams in a short period. The target on the anode is the area that is stuck by the electrons from the cathode.

The _______________ initiates the spinning of the anode and thermionic emission at the cathode. A. Step down transformer B. Exposure switch C. Step up transformer D. Diode

Correct answer: (B) Exposure switch. Explanation: When the exposure switch pushed, one of the first things that occurs is that the anode begins to spin. Often this is referred to as "rotor" or "revving" up the tube. As the anode begins to spin, simultaneously, thermionic emission is occurring at the cathode. The spinning of the anode increases the positive charge that attracts the negative electrons collecting in the electron cloud.

Which letter indicates a useful beam?

Correct answer: (D) Explanation: X-rays are emitted isotropically with equal intensity in all directions. The useful beam is emitted through the window of the x-ray tube. All other x-rays that escape from the tube housing are leakage radiation.

Water-soluble contrast studies require a kV range of between __ and __ kV. A. 80; 90 B. 90; 100 C. 100; 125 D. 125; 150

Correct answer: (A) 80; 90. Explanation: Iodinated water-soluble contrast studies require a kV range of 80-90. This type of contrast is not as dense as barium, and is not as difficult to penetrate. Because of the iodine component of the contrast, however, an increase is necessary and 80-90 kV is a sufficient change.

Which of the following transforms the luminescent light from the PSP into the image seen on the CRT? A. ADC B. helium neon laser C. photostimulable phosphor D. scanner-reader

Correct answer: (A) ADC. Explanation: The ADC is the analog-to-digital converter, which digitizes the analog image that is generated by conversion of the luminescent light emitted by the PSP. This digital signal becomes a digital image for display on a high-resolution monitor or for printing by a laser printer.

The grainy appearance of this image is a result of __________________. A. Quantum mottle B. Chemical fog C. Dirty screens D. Guide shoe markers

Correct answer: (A) Quantum mottle. Explanation: Quantum mottle shows up on a radiograph as a "salt and pepper" appearance. Quantum mottle is caused by an insufficient amount of x-ray photons penetrating the patient. The only way to eliminate quantum mottle is to increase the mAs value at the control panel. (B) Chemical fog causes a "curtain effect" on the radiograph. (C) Dirty screens can cause a number of artifacts from static to image fog. (D) Guide shoe marks appear as white marks parallel to the direction of the traveling film.

____________ is the fidelity in which the anatomical structure that is being examined is demonstrated on the radiograph. A. Radiographic quality B. Radiographic resolution C. Radiographic noise D. Contrast resolution

Correct answer: (A) Radiographic quality. Explanation: One of the most important aspects of a radiograph is to demonstrate the anatomical part as accurately as possible. When a radiograph truly reproduces the part being x-rayed it is described as a high-quality radiograph. There are many factors that affect radiographic quality, and there is not a universally accepted way to measure it.

____________ refers to the accuracy to which the anatomical structure that is being x-rayed is imaged on the radiograph. A. Radiographic quality B. Spatial resolution C. Contrast resolution D. Noise

Correct answer: (A) Radiographic quality. Explanation: When radiographing a part, the most important thing is to visualize the part as true as possible. Radiographic quality, otherwise known as image quality, is crucial in the accurate diagnosis of patient pathology. It is the role of the RT to achieve the greatest radiographic quality achievable.

What method is used to assess the adequacy of development parameters? A. Sensitometry B. Densitometry C. Wisconsin test D. Pinhole camera

Correct answer: (A) Sensitometry. Explanation: The automatic film processor can be monitored daily for quality control using a sensitometer. Densitometry is used to measure optical density. The Wisconsin kVp test is performed using a digital kVp meter. The effective focal spot size is monitored by measurement with a pinhole camera, star test pattern, or a slit camera.

Which of the following minimizes involuntary motion unsharpness? A. Shorter exposure times B. Small focal spot C. Increased SID D. Decreased OID

Correct answer: (A) Shorter exposure times. Explanation: Choosing a small focal spot size, increasing the SID, and decreasing the OID are all selections that can be made in order to reduce geometric unsharpness and improve resolution. Minimizing motion unsharpness due to involuntary motion can only be achieved by lowering the overall exposure time.

If a heart measures 13.6 cm at its maximum width, and its image on a chest radiograph measures 15.9 cm, what is the MF (magnification factor)? A. 216.24 B. 1.169 C. 0.855 D. 2.162

Correct answer: (B) 1.169. Explanation: Magnification factor is calculated by taking the image size and dividing it by the object size. In this problem, the image size is 15.9 cm and the object size is 13.6 cm. The equation used to solve this problem is: MF= 15.9 cm/ 13.6 cm

What is the milliampere-seconds value with exposure factors of 17 ms, 200 mA and 70 kVp? A. 34 B. 3.4 C. 1.19 D. 11.9

Correct answer: (B) 3.4. Explanation: The milliampere-seconds value can be calculated by multiplication of the mA and the time. 17 ms = 0.017 second 0.017 xx 200 = 3.4 mAs This problem illustrates the importance of familiarity with decimals to avoid common mathematical errors.

What is the correct mAs value when using exposure factors of 200 mA, 90 kV, 22 ms? A. 2.4 B. 4.4 C. 22 D. 44

Correct answer: (B) 4.4. Explanation: The milliamperage-seconds value is the product of the milliamperes (mA) and the exposure time. When performing this calculation, pay attention to the decimal places. 22 ms = 0.022 s.

Which of the following exposure factor groups will result in the shortest scale of contrast? A. 700 mA, 0.015 s, 80 kV B. 500 mA, 0.450 s, 70 kV C. 200 mA, 0.025s, 90 kV D. 100 mA, 0.1 s, 80 kV

Correct answer: (B) 500 mA, 0.450 s, 70 kV. Explanation: Kilovoltage is the primary factor that regulates radiographic contrast. As kilovoltage decreases, the scale of contrast becomes shorter. Milliamperage-seconds values can be adjusted to maintain density. Of the choices given, choice B will result in the shortest scale of contrast.

An 8-inch object that is 6 inches from the IR will be radiographed with an SID of 40 inches. What will be the width of the image? A. 9.0 B. 9.4 C. 10. 0 D. 10.4

Correct answer: (B) 9.4. Explanation: The formula to determine the amount of image magnification is: Image size/object size = SID/SOD, where SOD = SID-OID So: x/8 = 40/40-6 x/8 = 40/34 x = 9.4

Distortion depends on: I. Object thickness II. Object position III. Object shape IV. Object material A. I only B. I and II only C. I, II, and III D. I, II, III, and IV

Correct answer: (C) I, II, and III. Explanation: The thickness position and shape of an object affect distortion. Thicker objects are more distorted than thin objects. The object plane must lie parallel to the IR plane or distortion will occur. Object shape plays an important part in distortion as well. If an object has two sides with very different shapes, the distortion will be a lot greater than a symmetrical object.

Which of the following is a cause of foreshortening in a radiographic image? A. Excessive distance between focus and IR B. Excessive distance between object and IR C. Object at angle to IR D. Inadequate distance between focus and IR

Correct answer: (C) Object at angle to IR. Explanation: Foreshortening is a form of shape distortion that occurs when the long axis of the part is angulated with respect to the IR. Angulation of the x-ray tube results in elongation of the part. The x-ray tube, anatomic part, and IR should be aligned parallel to reduce shape distortion. Size distortion is inversely proportional to the SID and directly proportional to the OID.

Protective aprons usually contain ___ mm Pb, and reduce occupational exposure by ___%. A. 0.5; 50 B. 1.5; 25 C. 1.5; 50 D. 0.5; 25

Correct answer: (D) 0.5; 25. Explanation: It is standard that protective aprons contain 0.5 mm Pb at a minimum to aide in the protection of the Radiologic Technologist, and other healthcare members alike. Protective aprons can reduce occupational exposure by 25%, which is significant over a long period of time.

Which of the following is located in the cathode assembly of the x-ray tube? A. Stator B. Tungsten anode C. Bearing D. Focusing cup

Correct answer: (D) Focusing cup. Explanation: The cathode assembly contains the filament, focusing cup and wiring. The focusing cup is a shallow depression in the cathode that houses the filament. (A) Stator is located in the anode assembly of the x-ray tube. (B) Anode is located in the anode assembly of the x-ray tube. (C) Bearings are located in the anode assembly of the x-ray tube.

The effectiveness of the focusing cup is determined by which of the following principles? I. Focusing cup size II. Focusing cup shape III. Filament size IV. Filament shape V. Position of filament within focusing cup A. I, II, and III B. II, III, and IV C. IV and V D. I, II, III, IV, and V

Correct answer: (D) I, II, III, IV, and V. Explanation: There are many characteristics that affect how well a focusing cup functions inside the x-ray tube. These characteristics are the size and shape of the focusing cup, the size and shape of the filament, and the position of the filament inside of the focusing cup. All of these aspects cohesively function to allow the focusing cup to reduce divergence of the electron stream as it travels from the cathode to the anode.

The four principal components of a PACS are the ______ system, the ______ system, the ________ system, and the _______ system. A. Image acquisition, distortion, network, storage B. Image acquisition, display, highlighting, sizing C. Image acquisition, display, network, storage D. Image acquisition, distortion, highlighting, sizing

Correct answer: (C) Image acquisition, display, network, storage. Explanation: PACS is composed of four principal components: the image acquisition system, the display system, the network system, and the storage system. These system components separate the functions of PACS, as a whole, and allows the use of these functions to be performed quickly and more efficiently.

What change in SID is required to overcome magnification when an 8 inch OID is introduced? A. Increase SID by 8 inches B. Increase SID by 16 inches C. Increase SID by 56 inches D. Increase SID by 64 inches

Correct answer: (C) Increase SID by 56 inches. Explanation: OID is directly related to magnification, which results in loss of recorded detail. To compensate for an increase in OID, the SID, which has an inverse relationship to magnification, must be increased. However, the SID must be increased 7" to compensate for every inch increase in the OID. In this case, the OID of 8 inches will require an increase in SID of 56 inches.

An image of the wrist is made using 400 mA, 25 ms, 70 kV, a focal spot of 0.4 mm, minimum OID, and a 30 inch SID. Which of the following changes will result in the largest increase in magnification? A. Increase the focal spot size to 0.6 mm B. Increase the SID to 32 inches C. Increase the OID to 3 inches D. Decrease the SID to 25 inches

Correct answer: (C) Increase the OID to 3 inches. Explanation: Changes in the OID are directly related to changes in magnification, but changes in the SID are inversely related to magnification. A change in focal spot size will not affect the magnification. Magnification is decreased with an increase in the SID. The decrease in SID required to compensate for an increase of an inch of OID is 7", so the greatest increase in magnification will result from the increase in the OID to 3 inches.

___________ are inserted into the x-ray tube housing below the x-ray window to absorb low energy x-rays. A. Collimators B. Intensifying filters C. Metal filters D. Protective barriers

Correct answer: (C) Metal filters. Explanation: Metal filters are installed inside the x-ray tube and absorb the low energy photons that are created during x-ray production. Low energy x-rays are not diagnostically valuable and can be harmful to the patient because of their shallow penetrability.

Which of the following is demonstrated in the radiographic image below?

Correct answer: (C) Motion artifact. Explanation: Motion artifact can be caused by both voluntary and involuntary motion. Good communication with the patient can reduce voluntary movement during the exposure, but use of a short exposure time can also be used to reduce motion artifact. Motion artifact is characterized by blurring of moving parts. Fog is characterized by regional or global increase in blackness. Double exposure reveals superimposition of parts. Overexposure results in increased blackness throughout the image.

Which of the following represents the direction of travel of electrons in the x-ray tube? A. anode to cathode B. anode to focus C. cathode to anode D. filament to cathode

Correct answer: (C) Cathode to anode. Explanation: A diode tube with a negative and a positive electrode, the x-ray tube is designed for travel of high speed electrons produced at the cathode end to a target at the anode. The incident electrons are released by the cathode filament after it has been heated to incandescence, a process known as thermionic emission. With the application of kilovoltage, the electrons are driven through the tube to the anode target's focal spot. They suddenly decelerate there and this produces x-rays.

Which of the following AEC chambers would be appropriate to use for an AP knee? A. Right outer B. Left outer C. Center D. None of the above

Correct answer: (C) Center. Explanation: When performing an AP view of the knee, the center ionizing chamber is the correct chamber to select. Choosing any other chamber could lead to over or underexposure of the radiographic image. Choosing the correct ionizing chamber is key when utilizing AEC in radiographic imaging.

The acronym DICOM stands for: A. Digital Information and Communication in Medicine B. Digital Imaging and Communities in Medicine C. Digital Imaging and Communications in Medicine D. Digital Information and Communities in Medicine

Correct answer: (C) Digital Imaging and Communications in Medicine. Explanation: The acronym DICOM stands for Digital Imaging and Communications in Medicine. DICOM is a standard way in healthcare for handling, storing, printing, and transmitting information in regards to medical imaging and information.

What is the cause of the artifact on the image below? A. Light leak B. Angulation of the grid C. Dust on the light guide in the CR reader D. Static

Correct answer: (C) Dust on the light guide in the CR reader. Explanation: The white line seen on the image is the result of dust on the light guide in the CR reader. Light leak results in overexposed areas and increased density. Angulation of the grid results in grid cutoff. Static creates a "dark lightening" artifact.

The focusing cup surrounds the _____ and is most commonly made of _____. A. Filament; Tungsten or nickel B. Anode; Molybdenum or nickel C. Filament; Molybdenum or nickel D. Anode; Tungsten or nickel

Correct answer: (C) Filament; Molybdenum or nickel. Explanation: The focusing cup surrounds the filament of the cathode and is most commonly composed of molybdenum or nickel. The focusing cup's purpose is to reduce divergence of the electron beam as it travels from the cathode to the anode. By reducing this divergence, more of the electrons will strike the anode target, producing more x-rays.

All of the following are types of technique charts except: A. Fixed kVp-variable mAs B. Variable kVp-fixed mAs C. Fixed mAs-fixed kVp D. All of the above are types of technique charts.

Correct answer: (C) Fixed mAs-fixed kVp. Explanation: Technique charts provide information to allow more consistent image quality and radiation protection through decreased need for repeat exposures. Fixed kVp-variable mAs technique charts assume the optimal kVp for the part that is being radiographed. Variable kVp-fixed mAs charts are based on the assumption that beams with shorter, more penetrating rays are required for thicker parts. The kVp is varied according to the thickness of the part, which should be measured using calipers. The third type of technique chart is the variable technique chart, with variable kVp and variable mAs, used for alteration of routine techniques under conditions that include various pathologies, age of the patient and ability to cooperate, contrast media, and casts.

______ is the data exchange standard that integrates hospital information systems such as RIS and HIS. A. HL6 B. HL5 C. HL7 D. HL8

Correct answer: (C) HL7. Explanation: HL7 stands for Health Level-7. HL7 is a standard of data exchange that is used in many information systems and is vital to the smooth transfer of information between HIS, RIS, and PACS. HL5, HL6, and HL8 are not formats of data exchange.

The use of ___ mAs, ___ kVp, and ________ image receptors reduces quantum mottle. A. Low; low; slower B. Low; high; faster C. High; low; slower D. High; high; faster

Correct answer: (C) High; low; slower. Explanation: Quantum mottle is often caused by an insufficient amount of x-ray photons, which is controlled by the mAs value selected by the technologist. The best combination of factors to reduce quantum mottle is high mAs values, low kVp values, and the use of a slower image receptor. The use of these factors will increase the overall diagnostic quality of the radiographic image. Quantum mottle is radiographic noise that often manifests as a "salt and pepper" appearance on the radiograph, and is referred to by many technologists as graininess.

The acronym HIS stands for ____________. A. Human Infrastructure Systems B. Human Information Systems C. Hospital Information Systems D. Hospital Infrastructure Systems

Correct answer: (C) Hospital Information Systems. Explanation: HIS stands for Hospital Information Systems and is responsible for gathering patient information. This information is used in many departments other than the radiology department. Some of these departments are billing, admissions, and accounting.

The stated focal spot size is the result of measurement directly under the actual focal spot, but it varies along the length of the beam. At which portion of the x-ray beam is the effective focal spot smallest? A. Anode end B. Cathode end C. Outer edge D. Along the path of the beam

Correct answer: (A) Anode end. Explanation: The focal spot is smallest at the anode end, due to the anode heel effect. The line-focus principle guides construction of x-ray tube targets, so they are angled, usually between 12 to 17 degrees to the vertical. This causes foreshortening of the actual focal spot as it is projected downward, and it is invariably smaller than the actual focal spot. As the focal spot is projected towards the cathode end, it becomes larger, but due to the anode heel effect, it is smaller at the anode end.

What part of the x-ray circuit controls the initial kVp? A. Autotransformer B. Exposure switch C. Timer circuit D. Stator

Correct answer: (A) Autotransformer. Explanation: There are two parts to the basic x-ray circuit: The main circuit and the filament circuit. The main circuit contains the main breaker, exposure switch, autotransformer, timer circuit, high voltage step-up transformer, four diode rectification circuit, x-ray tube, and rotor stator. The Filament circuit contains the filament circuit variable resistance and filament step-down transformer. The autotransformer of the main circuit controls the voltage on the low voltage side of the circuit before the voltage is increased on the high voltage side. (B) The exposure switch activates the rotating anode. (C) The timer circuit ends the exposure. (D) The stator turns on the anode.

The two types of RIS systems are __________ and ___________. A. Broker; Brokerless B. Paper; Paperless C. Broker; Paperless D. Paper; and Brokerless

Correct answer: (A) Broker; Brokerless. Explanation: The two types of RIS systems are broker and brokerless systems. In a broker system, patient and exam information is sent to a PACS broker in order to be "translated" before it reaches the PACS system. If the PACS system that coordinates with the RIS system does not support HL7, a PACS broker is necessary. HL7 is a communication protocol used in several information systems. Brokerless systems do not have to use a PACS broker because the PACS systems that these RIS systems work with are able to support the HL7 protocol.

You receive an order for a two view forearm radiograph on a patient with extensive osteoporosis. When normally performing a forearm radiograph, an AP view would be obtained using 62 kVp and 6 mAs. Because of the patient's pathology, which of the following adjustments in technical factors should be made? A. Decrease B. Increase C. No adjustment

Correct answer: (A) Decrease. Explanation:Osteoporosis is a disease in which the bone progressively loses density, causing it to become brittle and fragile overtime. In an averaged sized patient without osteoporosis, 62 kVp and 6 mAs would be a sufficient selection in technical factors; however, due to the destructive nature of the pathology, a decrease must be made. The level of reduction in technical factors will vary depending on the severity of the osteoporosis, but the factors must decrease in order prevent over exposure.

What is the most likely cause of decreased density on the lateral edges of an x-ray when using a parallel grid? A. Decreased SID B. Static electrical discharge C. Off-centering D. Wrong tube angle

Correct answer: (A) Decreased SID. Explanation: The x-ray beam is not parallel to the strips of the grid, which are parallel to each other. The x-rays diverge and as they diverge at an increased angle, cutoff or decreased density are evident at the lateral edges. If the SID is decreased, the effect is more pronounced. Of the other choices, , centering and angulation, would result in a variation in density between the two edges. Static electricity can leave a black "lightening" imprint on the film.

Quantity and mAs have a/an ___________ relationship, and quality and kVp have a/an ____________ relationship. A. direct; direct B. direct; indirect C. indirect; indirect D. indirect; direct

Correct answer: (A) Direct; direct. Explanation: As the mAs value is increased at the operating console, the number, or quantity, of x-ray photons emitted is increased. Likewise, as the kVp value is increased, the quality, or penetrability of the x-ray photons produced increases as well.

What type of artifact is present in the below radiograph? A. Exposure artifact B. Storage and handling artifact C. Machine artifact D. Processing artifact

Correct answer: (A) Exposure artifact. Explanation: The suspender clips shown in the radiograph is classified as an exposure artifact. Proper exam explanation to the patient, gathering of patient history, and physical visualization can all reduce these types of artifacts from occurring. Specifically asking the patient if they have any metal objects, or any other objects in the area of interest is a good practice to keep.

You are performing a PA chest radiograph on a patient who is experiencing severe anxiety. The patient is hyperventilating and is finding it difficult to follow your breathing instructions. You are using the following technical factors: 110 kVp, 12 mAs, and 72" SID. What adjustments can be made to compensate for the patient's inability to fully suspend respiration? A. Increase kVp and decrease mAs B. Decrease kVp and decrease mAs C. Increase kVp and increase mAs D. Decrease kVp and increase mAs

Correct answer: (A) Increase kVp and decrease mAs. Explanation: Hyperventilation is shallow, rapid respiration, and can cause motion on a radiographic image. One of the ways to decrease this distortion is by decreasing the exposure time. The mAs factor determines exposure time in that mAs stands for (milliamps x seconds). To decrease the exposure time without compromising the diagnostic quality of the image, the kVp must be increased and the mAs decreased.

What is elongation? A. Object appears to be longer B. Object appears to be shorter C. Object appears to be wider D. Object appears to be smaller

Correct answer: (A) Object appears to be longer. Explanation: Elongation is when the object imaged appears to be longer than in reality. This occurs when the tube or image receptor is improperly aligned.

The current along a conductor is proportional to the potential difference is the definition of? A. Ohm's law B. Potential difference C. Electrodynamics D. Power loss formula

Correct answer: (A) Ohm's law. Explanation: Ohm's law is a mathematical relationship for resistance circuits between factor of current, potential difference, and resistance. Ohm's law is written as V= IR where V= potential difference in volts, I= current in amperage, and R= resistance in ohms. (B) Potential difference describes force which is the difference between the number of electrons at one end of the circuit versus the other end of the circuit. (C) Electrodynamics is the movement of electrons. (D) The power loss formula is changes in resistance to heat output.

The ____________ is achieved by placing the patient 8-12 inches from the image receptor to reduce scatter radiation at the IR. A. Inverse Square Law B. Air gap technique C. Grid ratio D. Automatic Exposure Control

Correct answer: (B) Air gap technique. Explanation: The air gap technique is used to help aide in the reduction of scatter radiation that reaches the image receptor. Scatter radiation does not add any diagnostic quality to the radiographic image. One major advantage of using the air gap technique is that it leads to less radiation dose to the patient. Due to the fact that a grid is not being utilized, technical factors do not have to be increased to compensate, therefore, lowering overall patient dose.

What type of timer for the x-ray unit is mostly used today? A. Synchronous B. Electronic C. Milliampere-second D. Automatic exposure control

Correct answer: (B) Electronic. Explanation: The most commonly used timer in x-ray today is the electronic timer. Electronic timers can accurate expose as short as 0.001 second with only a 1 msec delay. Electronic timers charge a silicon controlled rectifier which trigger the exposure. (A) Synchronous timer is a simple motor that turns at the same rate as the generator. (C) Milliampere-second timers are mainly used in falling load generators and some capacitor discharge units. When the desired mAs (mA and time) level is reached the timer interrupt the circuit and stop the exposure. (D) Automatic exposure control timers are programmed to stop exposure time. It measures a preset quantity of radiation and stops the timer circuit when that dose is hit to produce a desired film density.

When adjusting mA what factor is affected? A. kVp level B. Filament current C. Moment of exposure D. Speed of rotating anode

Correct answer: (B) Filament current. Explanation: When adjustments are made to the mA the filament current is adjusted as well. (A) To change the kVp level, the kVp is to be adjusted. (C) The moment of exposure is controlled by the exposure switch. (D) In order to change the speed of the rotating anode the rotator switch must be adjusted.

What aspect of the x-ray tube is responsible for reducing the spread of electrons that tends to occur as electrons travel from the cathode to the anode? A. Filament B. Focusing Cup C. Rectifier D. Glass envelope

Correct answer: (B) Focusing Cup. Explanation: The focusing cup envelopes the cathode filament and is negatively charged. Because the focusing cup and the electrons both hold a negative charge, they repel each other. This repelling action allows the focusing cup to form a barrier around the electron field and helps to reduce inaccurate anode strikes.

Which of the following will not result in underexposure of a radiograph? A. Inadequate kVp B. Inadequate SID C. Inadequate milliamperage D. Inadequate exposure time

Correct answer: (B) Inadequate SID. Explanation: Inadequate SID results in increased exposure rate and can cause overexposure of a radiograph. Insufficient kilovoltage results in underpenetration and excessive contrast. Insufficient milliamperage or exposure time decrease the radiographic density.

What change in kilovoltage is required to compensate for 2 centimeters of increased patient thickness when mAs is fixed and kV is variable? A. increase 2 kV B. increase 4 kV C. decrease 2 kV D. decrease 4 kV

Correct answer: (B) Increase 4 kV. Explanation: The body part that is radiographed must be carefully measure with calipers. If the variable kilovoltage method is used, the technique chart will display a specific mAs value to each body part. As the part becomes thicker, 2 kV should be added to the exposure for every centimeter increase in thickness. In this case, 4 kV should be added.

What happens to scatter as kVp is increased? A. Decreases B. Increases C. Remains the same D. Halved

Correct answer: (B) Increases. Explanation: When kVp is increased scatter is increased. Scatter radiation is the production from Compton interaction. Compton interaction is when a photon interacts with an outer shell electron and then changes direction. When kVp is increased more photons interact with matter and more photons will also undergo scatter. (A) When kVp is decreased scatter radiation is decreased.

Which of the following characterizes a transformer? A. It changes one form of energy to another. B. It converts electric potential and current to higher or lower intensity. C. It restricts the primary beam. D. It absorbs low-energy radiation that does not contribute to the image.

Correct answer: (B) It converts electric potential and current to higher or lower intensity. Explanation: The transformer is a device that uses interacting magnetic fields produced by changing electric currents. Although the transformer does not convert one form of energy to another, it transforms electric potential and current into higher or lower intensity. Transformers operate only with AC current, which is a changing electric current. A collimator restricts the primary beam. Filters absorb low-energy radiation that increases the patient dose without contributing to the image.

Which of the following can occur when the planes of the x-ray tube are angled against the lead strips of a grid during an exposure? A. Off-center errors B. Off-level error C. Off-focus error D. Upside down error

Correct answer: (B) Off-level error. Explanation: An off-level error can occur when the planes of the x-ray tube and grid surface are not parallel, resulting in grid cutoff and off-level errors. This occurs if the grid cassette is tilted under the patient, particularly during mobile radiography, or if the x-ray tube is angled against the lead strips of the grid. The grid surface must be perpendicular to the central ray to avoid cutoff. If CR angulation is necessary, then the tube angle should be parallel with the direction of the lead strips. Off-center errors occur when the x-ray beam is shifted laterally to the grid, causing lateral decentering characterized by uniform loss of density across the image. Off-focus errors occur when the SID is out of the specified focal range, resulting in peripheral loss of density. If the focused gird is upside down, the lead strips will be angled opposite the path of the beam, causing significant grid cut-off.

What type of circuit does the diagram depict? A. Series B. Parallel C. Continuous D. Electric

Correct answer: (B) Parallel. Explanation: The diagram above depicts a parallel circuit. This can be identified because each part of the circuit has its own individual branch. (A) Series circuits have devices linked together one after the other. (D) Electric circuit are both series and parallel circuits.

If the body part is improperly aligned that will cause? A. Elongation B. Foreshortening C. Both A & B D. Neither A or B

Correct answer: (C) Both. Explanation: When the body part being imaged is improperly aligned that will cause a shape distortion either as elongation or foreshortening on the image.

Which of the following types of maintenance programs should be included in the QC program for an automatic processor? A. Bucky alignment maintenance B. Preventative maintenance C. Chemical tank maintenance D. Fluoro tower maintenance

Correct answer: (B) Preventative maintenance. Explanation: Performing maintenance on automatic processors is crucial in maintaining a consistent workflow. In order to keep the processor at full functioning capacity, it is important to perform scheduled maintenance, preventative maintenance, and nonscheduled maintenance. Performing preventative maintenance reduces the chance that large issues will occur. Also by performing nonscheduled maintenance, along with scheduled maintenance, small problems that occur can be caught before they become extreme. Bucky alignment, chemical tank, and fluoro tower maintenance are not tests associated with the automatic processor.

Which of the following will occur on a digital image as a result of inadequate mAs? A. Loss of brightness B. Quantum noise C. Loss of contrast D. Shape distortion

Correct answer: (B) Quantum noise. Explanation: Noise is dependent upon the number of x-ray photons that reach the detector. An underexposed image will result in quantum noise and should be repeated if the exposure meter indicates the exposure is 50% less than desirable. In plain radiography, noise can be decreased by increasing the dose to the patient. An increase of "N" will result in a decrease of noise that is equal to the square root of N. In a CT image, noise can be decreased by increasing the mAs, increasing the tube current, or by changing the filters.

The acronym RIS stands for _______________ and is a computer software that sends requests for images to be delivered to the appropriate PACS archive area. A. Radiology Infrastructure System B. Radiology Information System C. Radiology Information Structure D. Radiology Instruction System

Correct answer: (B) Radiology Information System. Explanation: The acronym RIS stands for Radiology Information Systems. The RIS system is sometimes referred to as the "nervous system" of the radiology department because every part of the radiology department relies on the RIS system in some way. The RIS system provides the modalities with a worklist of patients and their accompanying exam(s).

Which of the following factors has the largest effect on the radiographic exposure of an image? A. Kilovoltage B. SID C. Scatter D. Aluminum filtration

Correct answer: (B) SID. Explanation: Although kilovoltage, scattered radiation, and aluminum filtration all have an effect on density, changes in SID have a more significant effect that is expressed by the inverse square law of radiation, which states that exposure rate and radiographic exposure decrease as distance from the source of radiation increases. The exposure rate is inversely proportional to the square of the SID.

Which coil of the transformer is where the x-ray current is induced? A. Primary B. Secondary C. Alternating D. Step up

Correct answer: (B) Secondary. Explanation: The transformer is composed of 2 coils close to each other but they do not have an electrical connection. The primary coil is supplied with the current while the secondary current is induced with the current. (A) When the current is applied to the primary coil lines of force which induce through the secondary coil and start flow of electrons. (D) A step up transformer is when the voltage is increased from primary to secondary.

________ is when the drive mechanism moves the IP at a consistent, decreased pace along the long axis of the IP. A. Diagonal scan B. Slow scan C. Fast scan D. Reciprocating scan

Correct answer: (B) Slow scan. Explanation: Slow scan is when the drive mechanism carries the IP at a slow pace along its long axis. This is not considered one of the more efficient scan methods, due to the absolute necessity of the motor driving equipment to work constantly at 100% functionality.

The target on the anode of the x-ray tube is noted by which letter?

Correct answer: (B) T. Explanation: The x-ray tube is a vacuum that contains two electrodes. Those electrodes are the cathode and the anode. The anode is the positive side of the x-ray tube. There are two different types of anodes: either stationary or rotating. General x-ray uses a rotating anode because it is able to produce high intensity x-ray beams in a short period. The target on the anode is the area that is stuck by the electrons from the cathode.

Which of the following density settings will increase the exposure by 25%? A. -2 B. -1 C. +1 D. +2

Correct answer: (C) +1. Explanation: Density settings, in most systems, fall on the following scale (-3,-2,-1,0,+1,+2,+3). Each increment change affects the density by 25% either positively, or negatively. In order to increase the exposure by 25%, a density setting of +1 must be chosen.

The following technical factors are selected at the operating console: 70 kVp and 32 mAs. In what kinetic energy range will any Bremsstrahlung radiation produced fall? A. 0-140 keV B. 70-140 keV C. 0-70 keV D. None of the above

Correct answer: (C) 0-70 keV. Explanation: Bremsstrahlung radiation produced during x-ray production can have kinetic energies as high as the kVp value chosen by the Radiologic Technologist at the operating console, but not higher.

A kV value of __-__ is required to adequately penetrate and visualize barium filled structures. A. 80-90 B. 90-110 C. 100-125 D. 125-150

Correct answer: (C) 100-125. Explanation: Because of the chemical component of Barium, kV values of 100-125 are required in order to penetrate the barium filled substances. Anything lower than that will not demonstrate the part properly and will decrease the overall diagnostic quality of the image.

When magnifying an object two times with an SID of 50 inches, which of the following represents the correct OID? A. 10 inches B. 15 inches C. 25 inches D. 40 inches

Correct answer: (C) 25 inches. Explanation: To magnify an object to twice its actual size, it must be placed halfway between the focal spot and the IR. Magnification is useful in mammography, for enlargement and visualization of tiny blood vessels filled with contrast medium and for detection of hairline fractures.

Which device found within the operator's console is adjusted by the radiographer when selecting a KV? A. Step-up transformer B. Rectifier C. Autotransformer D. Step-down transformer

Correct answer: (C) Autotransformer. Explanation: The kilovoltage control adjusts the autotransformer in the high-voltage circuit. The actual kilovoltage changes, depending upon the type of equipment, so it is measured as a peak value attained during the cycle. Changes in kilovoltage increase or decrease the speed of electrons emitted from the filament.

What is geometric unsharpness around the edge of an image? A. Collimation B. Diaphragm C. Penumbra D. Cone field size

Correct answer: (C) Penumbra. Explanation: Penumbra is the geometric unsharpness around the edge of an image. Penumbra is when x-ray photons are created in all areas instead of a focused spot. This occurs when an aperture diaphragm is in close proximity to the tube port. Image sharpness is improved when penumbra is reduced. (A) Collimation is a type of beam restrictor that is composed of a set of led shutters at right angles to each other. (B) A diaphragm is a flat sheet of metal with a hole in the center which is attached to the x-ray tube as a beam restrictor. (D) Cone field size is the field of view for a cone or cylinder diaphragm.

The central ray is to be_________ to the anatomical part being imaged. A. Dorsal B. Parallel C. Perpendicular D. Tangential

Correct answer: (C) Perpendicular. Explanation: The central ray will be perpendicular to both the anatomy being imaged and the image receptor. If the central ray is not perpendicular, some degree of distortion will be noted.

_____________ collimators are devices that automatically sense the size of the image receptor and adjust the collimating shutters to that size. A. Automatic Exposure Control (AEC) B. Half-Value Layer (HVL) C. Positive Beam Limiting (PBL) D. Focal-Spot Size

Correct answer: (C) Positive Beam Limiting (PBL). Explanation: Most imaging systems today are equipped with PBL collimators, decreasing the chance of collimating errors by the Radiologic Technologist. Because there are several different image receptor sizes, the PBL function must be evaluated to ensure that all IR sizes used by the facility are accounted for. Furthermore, the distance and centering sensors must be within 1%-2% accurate of the SID.

What is the cause of the artifact demonstrated in the image below?

Correct answer: (C) Reversal of the imaging plate and cassette in the cassette holder. Explanation: The artifacts seen on the image are patterns from the plastic support structures of the CR cassette that are superimposed on the anatomy when the tube side of the cassette was mistakenly pointed toward the patient and away from the x-ray tube.

On the diagram below, what is the stator?

Correct answer: (C) S. Explanation: The stator of an x-ray tube is what turns on the anode from the induction motor electromagnets. It is also the only part of the cathode that is outside of the glass envelope. The rotor must be activated at exposure to cause a current to go to the stator which then causes the rotor to turn the anode. (A) A is the anode. (B) C is the cathode. (D) R is the rotor.

How is magnification calculated? A. Image size/ magnification factor B. SOD+ OID C. SID/ SOD D. Image size/ SID

Correct answer: (C) SID/ SOD. Explanation: In order to calculate magnification you must use SID (source to image receptor distance) and SOD (source to object distance). Magnification= SID/SOD. If you do not know the SOD you can calculate it by subtracting the OID from the SID.

Which of the following refers to the ability of a digital system to display details? A. Contrast B. Pixel size C. Spatial resolution D. Intensity

Correct answer: (C) Spatial resolution. Explanation: The ability of a digital imaging system to display details is known as the spatial resolution. It is a function of pixel size and is expressed as the number of line pairs per millimeter. It is determined by the detector element size in the flat panel detector.

What transformer is located in the filament circuit? A. Four-diode rectification B. Two-diode rectification C. Step-down D. Step-up

Correct answer: (C) Step-down. Explanation: The filament circuit is composed of the step-down transformer and the filament circuit variable resistance. The filament circuit takes incoming line power and produces thermionic emission from the filament wire. This can be adjusted by the technologist by adjusting the mA.

What is the most likely effect of using a large IR (14 x 17 inches) with a short SID (24")? A. The exposure will terminate early. B. The scale of contrast will be increased. C. There will be an increased anode heel effect. D. The radiograph will be underexposed.

Correct answer: (C) There will be an increased anode heel effect. Explanation: The anode heel effect will be more pronounced when using a short SID with a large-size IR or with an anode angle less than 10 degrees. Both the large IR and the short SID make it necessary for the beam to diverge. At the anode end, the beam is stopped by the anode as photons are absorbed, resulting in a decrease in the intensity of the beam at the anode end.

What part of the x-ray circuit ends the exposure? A. Autotransformer B. Exposure switch C. Timer circuit D. Stator

Correct answer: (C) Timer circuit. Explanation: The timer circuit ends the exposure. There are two parts to the basic x-ray circuit: The main circuit and the filament circuit. The main circuit contains the main breaker, exposure switch, autotransformer, timer circuit,, high voltage step-up transformer, four diode rectification circuit, x-ray tube, and rotor stator. The Filament circuit contains the filament circuit variable resistance and filament step-down transformer. (A) The autotransformer of the main circuit controls the voltage on the low voltage side of the circuit before the voltage is increased on the high voltage side. (B) The exposure switch activates the rotating anode. (D) The stator turns on the anode.

Which of the following characterizes the radiographic image below?

Correct answer: (C) Underexposure. Explanation: The radiographic image demonstrates underexposure, characterized by lack of detail and a mottled appearance. Underexposure may occur from use of inadequate mAs or as the result of a malfunction of the AEC. A properly exposed CR image of the same patient reveals significantly more diagnostic and anatomic information. (See picture below)

When the structure of a body part prevents use of a short OID, which of the following can be adjusted to compensate for magnification distortion? A. Use of a low-ratio grid B. Use of a smaller focal spot size C. Use of a long SID D. Use of a fast intensifying screen

Correct answer: (C) Use of a long SID. Explanation: The OID is directly proportional to the magnification and the SID is inversely proportional. In general, it requires an adjustment of 7" of SID to compensate for a change of 1" in OID. Increasing the SID will decrease the magnification effect of the OID, although this may require a large increase in exposure factors, particularly when larger body parts are being irradiated. Grid ratio, focal spot size, and intensifying screen are all unrelated to magnification.

Which generation CT scanner uses a fixed ring of 4800 detectors that completely surrounds the patient with the full circle of the gantry? A. 1st B. 2nd C. 3rd D. 4th

Correct answer: (D) 4th. Explanation: Fourth-generation scanners were developed during the 1980s, at the same time as the third-generation scanners. They possess a fixed ring of 4800 or more detectors, which completely surround the patient in a full circle within the gantry. A single x-ray tube rotates through a 360° arc during data collection. Throughout the continuous rotary motion, short bursts of radiation are provided by a pulsed, rotating-anode x-ray tube, providing shorter scan times of as little as 1 minute for an entire exam (similar to a third-generation scanner). It is important to note that fourth-generation technology is not more advanced or more desirable than third-generation technology; it is simply different.

Voluntary motion that causes distortion on a radiographic image can be decreased in which of the following ways? A. High mA values along with shorter exposure times B. Careful explanation of procedure and breathing instructions to the patient C. None of the above D. A and B

Correct answer: (D) A and B. Explanation: Voluntary motions are movements of the body that the patient can control. Often this voluntary motion is due to a lack of proper communication between the technologist and the patient. More times than not, voluntary motion can be minimized if the technologist will take the time to thoroughly explain the procedure steps and what exactly is expected of the patient. If this method does not prove successful, increasing the mA values and lowering the exposure time will reduce the overall length of the exposure, giving the patient less time to perform unwanted movements.

Which of the following will result in increased CR resolution? A. Decrease in PSP crystal size B. Decrease in laser beam size C. Decrease in size of the monitor matrix D. A and B E. B and C F. All of the above

Correct answer: (D) A and B. Decrease in PSP crystal size and decrease in laser beam size. Explanation: Factors that impact the spatial resolution in CR include the size of the scanning laser beam, the size of the PSP, and the size of the monitor matrix. As the monitor matrix increases in size, there are more and smaller pixels. Since spatial resolution is measured in line pairs per millimeter, this results in improved spatial resolution. A decrease in monitor size will result in decreased spatial resolution, since there will be fewer pixels. As the PSP becomes smaller, there is less light diffusion that could result in a decrease in resolution, similar to the effect seen in intensifying screens. The laser beam should be the correct size and intensity and a narrow beam will produce optimal resolution.

What is the function of the lead-foil layer behind the rear screen of the IR? A. Increase screen speed B. Improve resolution C. Improve penetration D. Absorption of backscatter

Correct answer: (D) Absorption of backscatter. Explanation: The function of the lead foil layer behind the rear IR screen is to absorb backscatter, which occurs when radiation exits the rear screen, striking the metal back and bouncing to create image fog. This can result in imaging of the metal hinges or straps of the IR when high kilovoltage is used. Lead foil absorbs this backscatter before it fogs the film.

Which of the following is how resolution measured? A. Line pairs per millimeter B. Line spread function C. Modulation transfer function D. All of the above

Correct answer: (D) All of the above. Explanation: Image resolution is measured as line pairs per millimeter, line spread function, and modulation transfer function. Line pairs per millimeter measure the minimum size and space between objects that can be seen on the image. Line spread function measures the ability of film to measure the boundaries of the image. Modulation transfer function measures the resolving ability of a film/screen combination.

What affects shape distortion? A. OID B. SID C. Image receptor D. Angulation

Correct answer: (D) Angulation. Explanation: Shape distortion is affected by both part alignment and tube angulation. Angulation can be used to avoid superimposition of parts. Proper positioning is achieved when the part is parallel and the beam is perpendicular to the part and the image receptor. (A) OID affects size distortion. (B) SID affects size distortion. (C) Image receptor can affect alignment if not aligned perpendicular with the central ray.

All of the following characteristics affect radiographic quality. Which of the following characteristics can be avoided if proper examination of the patient and explanation of expectations occurs? A. Spatial Resolution B. Contrast Resolution C. Noise D. Artifacts

Correct answer: (D) Artifacts. Explanation: Artifacts are objects on the radiograph that negatively affect the overall radiographic image. When explaining the procedure to your patient, it is crucial to make sure that all artifacts are removed from the area of interest. Often explaining to your patient that the part being radiographed must be free of foreign objects can help you in the removal of artifacts.

Which of the following chambers gets the most exposure from radiation due to cumulative radiology imaging of the chest? A. Right outer chamber B. Left outer chamber C. Center chamber D. Both outer chambers

Correct answer: (D) Both outer chambers. Explanation: Due to the different attenuating qualities of the tissues of the body, the outside chambers receive the most exposure. Being that there are two outer chambers, it makes sense that these two chambers would receive more exposure than the center chamber.

The artifacts shown in the chest radiograph above are examples of __________ artifacts.

Correct answer: (D) Exposure. Explanation: The chest piercings displayed in the radiograph are examples of exposure artifacts. Artifacts that are associated with the manner in which an exam is conducted are called exposure artifacts. With proper questioning by the technologist, the piercings could have potentially been removed before the exposure, increasing the diagnostic quality of the image.

Which of the following is considered a geometric factors? A. subject contrast B. kVp C. patient thickness D. focal-spot blur

Correct answer: (D) Focal-spot blur. Explanation: Geometric factors that affect the radiographic image are magnification, distortion, and focal-spot blur. Focal-spot blur can distort the sharpness of an object on the radiograph. Patient thickness, subject contrast, and kVp are subject factors, and are not related to geometric factors.

Which of the following characterizes dual x-ray absorptiometry? A. Photon attenuation is calculated to represent the degree of soft-tissue attenuation. B. Only high energy photons are used. C. Radiation dose is high. D. It is uncomplicated to perform.

Correct answer: (D) It is uncomplicated to perform. Explanation:Dual x-ray absorptiometry (DXA) imaging is the most widely used method to evaluate bone mineral density. It requires use of two photon energies, one for bone and one for soft tissue. The photon attenuation is calculated to represent the degree of bone density, since bone density is higher than soft tissue and attenuates photons more readily. Patient dose is low. It provides a precise and uncomplicated method for evaluation of bone mineral content. DXA is used in diagnosis of osteoporosis and can be used to measure treatment efficacy.

Which of the following terms refers to the continued emission of light by a phosphor after the activating source is terminated? A. Image intensification B. Quantum mottle C. Fluorescence D. Phosphorescence

Correct answer: (D) Phosphorescence. Explanation: Phosphorescence occurs when an intensifying screen continues to emit light after the energizing source is terminated. Fluorescence is the emission of light when an intensifying screen absorbs x-ray photons, but fluorescent light stops when the energizing source is terminated. Image intensification is the amplification of brightness of a fluoroscopic image through an image intensifier. Quantum mottle is a speckled artifact on radiographic images that are performed using a rapid imaging system.

The information management and database portion of PACS is called ______. A. AMLCD B. ACR C. NEMA D. RIS

Correct answer: (D) RIS. Explanation: The information management and database portion of PACS is called RIS. The acronym RIS stands for Radiology Information Systems. The RIS system is able to perform many functions such as sending messages, calendar reporting, and storage of text data. Also, this system allows this information to be retrieved from many different locations at one time.

If an exposure is made using 400 mA, 20 ms, and 105 kV, which of the following adjustments will not reduce the density by one half? A. Reduction of the kV to 90kV B. Reduction of mA to 200 mA C. Reduction of exposure time to 10 ms D. Reduction of mAs to 6 mAs

Correct answer: (D) Reduction of mAs to 6 mAs. Explanation: The radiographic density changes in direct proportion to the milliampere-seconds. The mAs can be halved by halving the exposure time to 10 ms or by halving the mA to 200 mA. The relationship between kilovoltage and radiographic density is described by the 15% rule. For every 15% decrease in kV, the radiographic density is halved. The mAs in this example should be reduced to 4 mAs, which is ½ of the original mAs (400 x 0.020 s).

What type of magnetic attraction is the image below? A. Natural B. Artificial C. Attraction D. Repulsion

Correct answer: (D) Repulsion. Explanation: The image aboves show the repulsion in magnets. Lines of force from a magnet that flow in the same direction will repel from one another. The like poles of a magnet repel while the opposite poles attract when placed in each others force field. (C) Unlike poles of a magnet attract.

What is represented by the letter R?

Correct answer: (D) Rotor. Explanation: R indicates the rotor of the xray tube. The rotor is located both inside the stator and the glass envelope and it needs to be activated prior to exposure to send current to the stator. The stator is indicated by letter S. The stator is the only part of the cathode anode assembly located outside of the glass envelope. The stator turns the anode. The anode is indicated by letter A and is the positive part of the xray tube that receives the electrons from the cathode. The cathode is indicated by the letter C.

An example of size distortion on an image is? Show Explanation A. Alignment B. Angulation C. Direction D. SID

Correct answer: (D) SID. Explanation: Both OID and SID are examples of size distortion on the image. OID stands for object-to image receptor distance and SID stands for source to image receptor distance. As SID increases, magnification gets smaller, but as OID increases, magnification gets larger.

Which of the following is the standard way to measure focal spot size in most radiographic systems? A. Pinhole camera B. Star pattern C. Penny test D. Slit camera

Correct answer: (D) Slit camera. Explanation: The standard way to measure focal spot size for most systems is the slit camera The pinhole camera and the star pattern are other methods used to measure focal-spot size. The pinhole camera is difficult to use, whereas the star pattern is very simple to use. It is important to evaluate focal-spot size yearly and every time the x-ray tube is replaced.

What part of the xray tube is located outside the glass envelope? A. Anode B. Cathode C. Rotor D. Stator

Correct answer: (D) Stator. Explanation: The stator is the only part of the cathode anode assembly located outside of the glass envelope. The stator turns the anode. The rotor is located both inside the stator and the glass envelope and it needs to be activated prior to exposure to send current to the stator. The cathode is located within the glass envelope and propels the electrons to the anode. The anode is the positive side of the xray tube which receives the electrons.

The _______ modifies current before it reaches the cathode filament. A. Step up transformer B. Rectifier C. Filament transformer D. Step down transformer

Correct answer: (D) Step down transformer. Explanation: The step down transformer modifies the current before it reaches the cathode filament. It is referred to as the step down transformer because it has less turns on the secondary coil than that of the primary coil. The step down transformer is necessary in modifying the current before it reaches the cathode tube so thermionic emission can occur correctly.

Which of the following statements is incorrect about the IP in computed radiography? A. The IP does not have an intensifying screen. B. The IP does not contain radiographic film. C. The IP serves to protect the PSP. D. The IP should exclude all white light.

Correct answer: (D) The IP should exclude all white light. Explanation: Image plates (IPs) used in computer radiography appear similar the traditional film-screen cassette, but the IP's primary function is support and protection of the PSP that is placed inside the IR. The IR doesn't have an intensifying screen or film, so they do not have to be in a light tight lock box. Light has no effect on the PSP.

Which of the following represents the relationship between the SID and recorded detail? A. Recorded detail increases as the SID decreases. B. There is no relationship. C. There is an inverse relationship between recorded detail and SID. D. There is a direct relationship between recorded detail and SID.

Correct answer: (D) There is a direct relationship between recorded detail and SID. Explanation: SID is the distance from the focal spot to the IR. There is a direct relationship, so as the SID increases, the recorded detail also increases. Since increased SID results in less divergent rays, less magnification and blur are produced, so a long SID results in the best recorded detail. However, when the SID is increased, exposure factors will also need to be increased to maintain optimal density. This results in an increased patient dose. Most radiography is performed with a 40-inch SID, except for chest examinations.

Direct digital radiography differs from computed radiography in which of the following ways? A. Resolution is coarse. B. Flat panel detectors communicate directly with a computer workstation. C. Patient throughput is higher with DR compared to CR. D. A and B E. B and C F. All of the above

Correct answer: (E) B and C. Explanation: Both CR and DR have wider exposure latitude and better visualization of soft tissue and bone compared to film radiography. Resolution is finer with DR than with CR because there is less conversion of the information. Direct digital radiography uses a flat panel detector to communicate directly with a computer workstation. The detector may be direct or indirect. The CR image is stored on an imaging plate until it is scanned by a laser, which results in blue light energy that is amplified and converted from analog to digital form before it is sent to a computer for processing. Image production is more rapid with DR, allowing higher patient throughput.

Which of the following should be used when performing a radiologic examination on a patient with a Parkinsonian tremor? A. Compensating filter B. High-speed intensifying screen C. Short exposure time D. A and B E. B and C F. All of the above

Correct answer: (E) B and C. High-speed intensifying screen and short exposure time. Explanation: Use of a short exposure time is always preferable in radiography, but it can be exceptionally useful when imaging a patient with a tremor. Motion artifact can result in unsharpness, so a high-speed intensifying screen should be used to reduce the exposure time. Use of a compensating filter is not indicated.

The differential attenuation of tissue (or the Linear attenuation coefficient), and the corresponding shade of grey that is to be associated with that tissue on a CT image, is denoted by? A. The attenuation factor B. The Hounsfield number C. The attenuation number D. The CT number E. B and D F. A and C

Correct answer: (E) B and D. The Hounsfield number and the CT number. Explanation: After the CT computer (through thousands of mathematic calculations) determines the degree of attenuation (called the linear attenuation coefficient) for each voxel, these values are converted to another numeric scale called CT numbers, which are used in the display matrix. Originally, these CT numbers were called Hounsfield units, after Godfrey Hounsfield, * an English scientist who in 1970 produced the first head CT scan.

Which of the following will occur when using 72 kV in comparison to 60 kV, with all other things equal? A. Increased scatter radiation B. Shorter scale contrast C. Exposure latitude will be greater D. A and B E. B and C F. A and C

Correct answer: (F) A and C. Increased scatter radiation and exposure latitude will be greater. Explanation: As kilovoltage increases, there is a greater percentage of scatter radiation. The exposure latitude also increases. An increase in kilovoltage produces higher-energy photons with greater penetration. This results in a longer scale of contrast from production of more gray values on the image.

Which of the following can occur during post processing steps of a digital image? A. Edge enhancement B. Subtraction of superimposed images C. Contrast enhancement D. A and B E. A and C F. A, B and C

Correct answer: (F) A, B and C. Explanation: Digital images can be manipulated in a variety of ways, including subtraction, which refers to removal of superimposed or unwanted structures from the image. Contrast enhancement is also possible by altering the image to display a variety of brightnesses. Edge enhancement in digital imaging post processing improves the visibility of small high-contrast areas.

Which of the following is a characteristic of digital radiographic imaging? A. Rapid display of the image B. Solid state detector plates C. Direct-capture imaging system D. A and B E. B and C F. All of the above

Correct answer: (F) All of the above. Explanation: Digital radiography is a direct imaging system that uses solid state detectors that convert exit radiation into electrical charges (direct) or into visible light that is converted to electrical charges (indirect.) These signals are converted from analog to digital and the images are viewed immediately on a computer monitor.

Which of the following affect the geometry of the radiologic image? A. Tube angle B. OID C. SID D. A and B E. B and C F. All of the above

Correct answer: (F) All of the above. Explanation: The degree of magnification is determined by the OID and SID and it determines the size distortion. The OID should preferably be as short as possible with the SID as long as possible. To avoid shape distortion, the anatomic part should be accurately positioned parallel to the IR as well as possible. If the part is angled within the body and not parallel to the IR, foreshortening will occur, but if the x-ray tube is angled , elongation may occur.