4.1 Image Acquisition and Technical Evaluation (285)
Which of the following focal-spot sizes should be employed for magnification radiography? A 0.2 mm B 0.6 mm C 1.2 mm D 2.0 mm
(A) 0.2 mm
What pixel size has a 2,048 × 2,048 matrix with a 60-cm FOV? A 0.3 mm B 0.5 mm C 0.15 mm D 0.03 mm
(A) 0.3 mm
A part whose width is 6 inches will be imaged at 44 inches SID. The part to be imaged lies 9 inches from the IR. What will be the magnification factor? A 1.25 B 1.86 C 4.9 D 7.3
(A) 1.25
A satisfactory radiograph was made without a grid, using a 72-inch SID and 8 mAs. If the distance is changed to 40 inches and an 8:1 ratio grid is added, what should be the new mAs? A 10 mAs B 18 mAs C 20 mAs D 32 mAs
(A) 10 mAs old mAs / new mAs = old dis squared / new dis squared answer X 8:1 (4)
If the required technique is 10 mAs, 70 kVp, and the mA station is 500 mA, which of the following exposure times would be needed? A 20 ms B 33 ms C 50 ms D 100 ms
(A) 20 ms
If 85 kVp, 400 mA, and ⅛ s were used for a particular exposure using single-phase equipment, which of the following milliamperage or time values would be required, all other factors being constant, to produce a similar receptor exposure using high frequency multiphase equipment? A 200 mA B 800 mA C 0.125 s D 0.25 s
(A) 200 mA When changing from single-phase to high frequency multi phase equipment, a conversion factor of 0.5 is used. In this case, we were using 50 mAs. Therefore, 50 mAs x 0.5 = 25 mAs. Choice A provides us with the correct mA - 200 mA x 1/8 sec = 25 mAs.
Which of the following groups of exposure factors will produce the shortest scale of contrast? A 200 mA, 0.25 s, 70 kVp, 12:1 grid B 500 mA, 0.10 s, 90 kVp, 8:1 grid C 400 mA, 0.125 s, 80 kVp, 12:1 grid D 300 mA, 0.16 s, 70 kVp, 8:1 grid
(A) 200 mA, 0.25 s, 70 kVp, 12:1 grid
Which of the following fluoroscopic modes delivers the smallest patient dose? A 30 cm field B 25 cm field C 12 cm field D 9 cm field
(A) 30 cm field
Which of the following groups of exposure factors would be most appropriate for a sthenic adult IVU? A 300 mA, 0.02 s, 72 kVp B 300 mA, 0.01 s, 82 kVp C 150 mA, 0.01 s, 94 kVp D 100 mA, 0.03 s, 82 kVp
(A) 300 mA, 0.02 s, 72 kVp
The exposure factors of 300 mA, 0.017 second, and 72 kVp produce an mAs value of A 5. B 50. C 500. D 5000.
(A) 5
Of the following groups of analog exposure factors, which is likely to produce the shortest scale of image contrast? A 500 mA, 0.040 second, 70 kV B 100 mA, 0.100 second, 80 kV C 200 mA, 0.025 second, 92 kV D 700 mA, 0.014 second, 80 kV
(A) 500 mA, 0.040 second, 70 kV The lower the kilovoltage, the shorter is the scale of contrast.
A part whose width is 6 inches will be imaged at 44 inches SID. The part to be imaged lies 9 inches from the IR. What will be the projected image width of the part? A 8 inches B 10 inches C 12 inches D 20 inches
(A) 8 inches iw / ow = SID / SOD
Which of the following absorbers has the highest attenuation coefficient? A Bone B Muscle C Fat D Air
(A) Bone
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
How would the introduction of a 6-in. OID affect analog 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.
If a lateral projection of the chest is being performed on an asthenic patient and the outer photocells are selected, what is likely to be the outcome? A Decreased receptor exposure B Increased receptor exposure C Scattered radiation fog D Motion blur
(A) Decreased receptor exposure
Which of the following techniques is used to evaluate the dynamics of a part? A Fluoroscopy B Stereoscopy C Tomography D Phototiming
(A) Fluoroscopy The dynamics, or motion, of a part must be studied during a "real-time" examination such as fluoroscopy affords.
Regardless of pixel size, which of the following factors influence spatial resolution? (select the two that apply) A Focal spot selection B kVp selection C Adding a grid, with a compensating change in mAs D Increasing collimation E Changing SID
(A) Focal spot selection (E) Changing SID
Which of the following is most likely to produce a radiograph with a long scale of contrast? A Increased photon energy B Increased OID C Increased mAs D Increased SID
(A) Increased photon energy
Which of the following terms/units is used to express the resolution of a diagnostic image? A Line pairs per millimeter (lp/mm) B Speed C Latitude D Kiloelectronvolts (keV)
(A) Line pairs per millimeter (lp/mm)
Which of the following factors are considered geometric factors that affect radiographic image quality? (select the three that apply) A Magnification B Kilovoltage C Contrast resolution D Distortion E Focal-spot blur F Exposure time
(A) Magnification (D) Distortion (E) Focal-spot blur There are three geometric factors that affect radiographic quality: magnification, distortion, and focal-spot blur. Focal-spot blur (also called geometric unsharpness, or penumbra) is caused by undercutting of the edges of anatomical structures by x-rays emanating from various portions of the anode focal spot (x-rays do not emanate from a single point source in the anode).
Which three of the following six pathologies require a reduction in technique during a radiographic examination: A Osteoarthritis B Pneumonia C Osteopetrosis D Emphysema E Osteomalacia F Atelectasis
(A) Osteoarthritis (D) Emphysema (E) Osteomalacia Osteoarthritis and Osteomalacia both remove the mineral Calcium from the bones. In doing so, the average atomic number of the calcium depleted bony tissue is lower, and it takes less energy to penetrate than healthy bone tissue. Emphysema manifests as an over inflation of the alveoli of the lungs.
A technologist prepares to perform an exam on an x-ray machine they have never used before. Which of the following three patient factors should be considered in the selection of appropriate kVp and mAs for an optimal image of the projections involved? A Patient habitus B SID C Estimated part thickness D Part composition E Voltage waveform of the equipment F Measured part thickness G Beam filtration
(A) Patient habitus (C) Estimated part thickness (F) Measured part thickness
Which of the following are methods to prolong x-ray tube life? (select the three that apply) A Perform the x-ray tube warm-up procedure when the anode is cold B Use long exposure time settings C Limit exposure prep time D Avoid performing certain projections in the department's exam protocol E Reduce repeat radiographs F Keep the kVp setting constant for all exams
(A) Perform the x-ray tube warm-up procedure when the anode is cold (C) Limit exposure prep time (E) Reduce repeat radiographs
A radiograph exposed using a 12:1 ratio focused grid may exhibit a loss of receptor exposure at its lateral edges because the A SID was too great. B grid failed to move during the exposure. C x-ray tube was angled in the direction of the lead strips. D CR was off-center.
(A) SID was to great If the SID is above or below the recommended focusing distance, the primary beam at the lateral edges will not coincide with the angled lead strips
If a radiograph exposed using a 12:1 ratio grid exhibits a loss of receptor exposure at its lateral edges, it is probably because the A SID was too great B grid failed to move during the exposure C x-ray tube was angled in the direction of the lead strips D central ray was off-center
(A) SID was too great
SID affects spatial resolution in which of the following way A Spatial resolution is directly related to SID. B Spatial resolution is inversely related to SID. C As SID increases, spatial resolution decreases. D SID is not a spatial resolution factor.
(A) Spatial resolution is directly related to SID. As the distance from focal spot to IR (SID) increases, so does spatial resolution. Because the part is being exposed by more perpendicular (less divergent) rays, less magnification and blur are produced.
When performing an axial projection, which of the following is NOT true? A The amount of elongation distortion is affected by focal spot size. B The amount of elongation distortion is affected by the alignment of the long axis of the object to the direction of the angle. C The amount of elongation distortion is proportional to the size of the angle. D The amount of elongation distortion is proportional to the object's OID.
(A) The amount of elongation distortion is affected by focal spot size.
When an exposure is made using AEC but positioning is suboptimal, such that a portion of an active cell is struck by the primary beam, which of the following will occur? A The exposure will terminate prematurely and the displayed image will have mottle in the regions where the anatomy is thickest. B The exposure duration will be longer and the patient will receive excessive dose. C The exposure will terminate as expected and the displayed image will show no adverse effects. D The exposure duration will be longer and the displayed image will have mottle in the regions where the anatomy is thickest.
(A) The exposure will terminate prematurely and the displayed image will have mottle in the regions where the anatomy is thickest.
Decreasing field size from 14 × 17 in. to 8 × 10 in., with no other changes, will A decrease receptor exposure and decrease the amount of scattered radiation generated within the part B decrease receptor exposure and increase the amount of scattered radiation generated within the part C increase receptor exposure and increase the amount of scattered radiation generated within the part D increase receptor exposure and decrease the amount of scattered radiation generated within the part
(A) decrease receptor exposure and decrease the amount of scattered radiation generated within the part
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
(A) decrease the millamperage
A 15% increase in kVp accompanied by a 50% decrease in mAs will result in A decreased patient dose B increase in contrast. C increased brightness. D spatial resolution.
(A) decreased patient dose
Exposure values arising from excessive kV, insufficient collimation, or thick anatomic structures are termed A fog. B matrix. C artifact. D resolution.
(A) fog Scattered radiation produces fog, which can add unwanted exposure values to the x-ray image and impair its diagnostic value
Better resolution is obtained with A high SNR. B low SNR. C windowing. D smaller matrix.
(A) high SNR
A 15% decrease in kilovoltage accompanied by doubling the milliampere-seconds will result in a(n) A increase in patient dose B increase in exposure latitude C decrease in receptor exposure D decrease in spatial resolution
(A) increase in patient dose
X-ray energy is directly controlled by which of the following factors? A kVp B mAs C SID D OID
(A) kVp
To produce a just perceptible increase in receptor exposure in analog imaging, the radiographer should increase the A mAs by 30% B mAs by 15% C kV by 15% D kV by 30%
(A) mAs by 30% An increase or decrease in milliampere-seconds of at least 30% is necessary to produce a perceptible effect. Increasing the kilovoltage by 15% will have about the same effect as doubling the milliampere-seconds
All the following are related to spatial resolution except A milliamperage B focal-spot size C source-to-object distance D OID
(A) milliamperage The milliamperage is unrelated to spatial resolution; it affects the quantity of x-ray photons produced and thus receptor exposure and patient dose.
An increase in kilovoltage in analog imaging is most likely to A produce a longer scale of contrast B produce a shorter scale of contrast C decrease the receptor exposure D decrease the production of scattered radiation
(A) produce a longer scale of contrast
The relationship between the height of a grid's lead strips and the distance between them is referred to as grid A ratio B radius C frequency D focusing distance
(A) ratio
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
Misalignment of the tube-part-IR relationship results in A shape distortion B size distortion C magnification D blur
(A) shape distortion
As grid ratio is decreased, A the scale of contrast becomes longer B the scale of contrast becomes shorter C receptor exposure decreases D radiographic distortion decreases
(A) the scale of contrast becomes longer Because lead content decreases when grid ratio decreases, a smaller amount of scattered radiation is trapped before reaching the IR. More grays, therefore, are recorded, and a longer scale of contrast results. Receptor exposure would increase with a decrease in grid ratio.
An exposure was made at 40-in. SID using 5 mAs and 105 kVp with an 8:1 grid. In an effort to improve image contrast, the image is repeated using a 12:1 grid and 90 kVp. Which of the following exposure times will be most appropriate, using 400 mA, to maintain the original receptor exposure? A 0.01 s B 0.03 s C 0.1 s D 0.3 s
(B) 0.03 s
A satisfactory radiograph of the abdomen was made at a 42-inch SID using 300 mA, 0.06-second exposure, and 80 kVp. If the distance is changed to 38 inches, what new exposure time would be required? A 0.02 second B 0.05 second C 0.12 second D 0.15 second
(B) 0.05 second
What pixel size has a 1024 × 1024 matrix with a 35-cm FOV? A 30 mm B 0.35 mm C 0.15 mm D 0.03 mm
(B) 0.35 mm
An increase in the kilovoltage applied to the x-ray tube increases the 1. percentage of high-energy photons produced. 2. beam intensity. 3. patient absorption. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2, and 3
(B) 1 and 2 only
Exposure factors of 100 kVp and 6 mAs are used with a 6:1 grid for a particular exposure. What should be the new milliampere-seconds value if a 12:1 grid is substituted? A 7.5 mAs B 10 mAs C 13 mAs D 18 mAs
(B) 10 mAs
Of the following groups of technical factors, which will produce the greatest receptor exposure? A 10 mAs, 74 kV, 44-in. SID B 10 mAs, 74 kV, 36-in. SID C 5 mAs, 85 kV, 48-in. SID D 5 mAs, 85 kV, 40-in. SID
(B) 10 mAs, 74 kV, 36-in. SID
Suppose a radiographer would normally use 5 mAs and 65 kVp on a neonate mobile AP abdomen radiograph using a non-grid DR detector array. However, upon arriving to the NICU, it is discovered that the neonate's abdomen is significantly distended due to ascites. The radiographer decides to use an 8:1 slip-on grid to reduce the amount of scatter radiation reaching the IR. Based on the condition of the patient and the use of an 8:1 grid, which of the following would be the best selection of technical factors the radiographer should use to maintain the desired exposure to the IR? A 20 mAs, 65 kVp B 10 mAs, 75 kVp C 10 mAs, 65 kVp D 12.5 mAs, 65 kVp
(B) 10 mAs, 75 kVp
In a PA projection of the chest being used for cardiac evaluation, the heart measures 15.2 cm between its widest points. If the magnification factor is known to be 1.3, what is the actual diameter of the heart? A 9.7 cm B 11.7 cm C 19.7 cm D 20.3 cm
(B) 11.7 cm MF = image size / object size
A satisfactory radiograph was made without a grid using a 72-in. SID and 8 mAs. If the distance is changed to 40 in. and an 12:1 ratio grid is added, what should be the new milliampere-seconds value? A 9.5 mAs B 12 mAs C 21 mAs D 26 mAs
(B) 12 mAs
In a posteroanterior (PA) projection of the chest being used for cardiac evaluation, the heart measures 14.7 cm between its widest points. If the magnification factor is known to be 1.2, what is the actual diameter of the heart? A 10.4 cm B 12.25 cm C 13.5 cm D 17.64 cm
(B) 12.25 cm The formula for magnification factor (MF) = image size/object size. When the magnification factor is known, the formula used to determine actual size of an object is Object size = Image size / Magnification Factor
While using a digital radiography system, suppose a radiographer uses exposure factors of 10 mAs and 70 kVp with an 8:1 grid for an AP shoulder radiograph with acceptable anatomical part penetration and detector element (DEL) exposure. If the radiographer desires to increase scatter absorption using a 12:1 grid, what new exposure factors should be used to maintain the same DEL exposure? A 15 mAs, 70 kVp B 12.5 mAs, 70 kVp C 7.5 mAs, 70 kVp D 2.5 mAs, 70 kVp
(B) 12.5 mAs, 70 kVp
The exposure factors of 400 mA, 70 ms, and 78 kV were used to produce a particular receptor exposure. A similar radiograph can be produced using 500 mA, 90 kV, and A 14 ms B 28 ms C 56 ms D 70 ms
(B) 28 ms
A 3-inch object to be radiographed at a 36-inch SID lies 4 inches from the image recorder. What will be the image width? A 2.6 inches B 3.3 inches C 26 inches D 33 inches
(B) 3.3 inches
A radiograph made using 300 mA, 0.1 second, and 75 kV exhibits motion unsharpness but otherwise satisfactory technical quality. The radiograph will be repeated using a shorter exposure time. Using 86 kV and 400 mA, what should be the new exposure time? A 25 ms B 37 ms C 50 ms D 75 ms
(B) 37 ms
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
1, 2, and 3 Differential absorption refers to the x-ray absorption characteristics of neighboring anatomic structures. The radiographic representation of these structures is referred to as radiographic contrast; it may be enhanced with high-contrast technical factors, especially using low kilovoltage levels. At low-kilovoltage levels, the photoelectric effect predominates and differential absorption is emphasized
Which of the following pathologic conditions require(s) a decrease in exposure factors? 1. Pneumothorax 2. Emphysema 3. Multiple myeloma
1, 2, and 3 Pneumothorax is a collection of air or gas in the pleural cavity. Emphysema is a chronic pulmonary disease characterized by an increase in the size of the air-containing terminal bronchioles. These two conditions add air to the tissues, making them more easily penetrated. Multiple myeloma is a condition characterized by infiltration and destruction of bone and marrow.
Shape distortion is influenced by the relationship between the 1. x-ray tube and the part to be imaged. 2. body part to be imaged and the IR. 3. IR and the x-ray tube.
1, 2, and 3 Shape distortion is caused by misalignment of the x-ray tube, the body part to be radiographed, and the IR. An object can be falsely imaged (foreshortened or elongated) as a result of incorrect placement of the tube, the part, or the IR. Only one of the three need be misaligned for distortion to occur
The exposure factors used for a particular nongrid x-ray image were 300 mA, 4 ms, and 90 kV. Another image, using an 8:1 grid, is requested. Which of the following groups of factors is most appropriate? A 400 mA, 3 ms, 110 kV B 400 mA, 12 ms, 90 kV C 300 mA, 8 ms, 100 kV D 200 mA, 240 ms, 90 kV
(B) 400 mA, 12 ms, 90 kV The original milliampere-seconds value is 1.2. The ideal adjustment, therefore, requires a 4.8 mAs at 90 kV. Although 2.4 mAs with 100 kV (choice C), or 1.2 mAs with 110 kV (choice A), also might seem workable, an increase in kilovoltage would further compromise contrast, nullifying the effect of the grid. Additionally, kilovoltage exceeding 100 should not be used with an 8:1 grid.
What is the spatial frequency of a digital system with a pixel pitch of 100 um? A 10.0 lp/mm B 5.0 lp/mm C 0.05 lp/mm D 0.01 lp/mm
(B) 5.0 lp/mm Change 100um to 0.1 mm. If pixel pitch is 0.1 mm, a line pair is 0.2 mm wide. Therefore, there are 5 line pairs in 1 mm
A 5-in. object to be radiographed at a 44-in. SID lies 6 in. from the IR. What will be the image width? A 5.1 in. B 5.8 in. C 6.1 in. D 6.7 in.
(B) 5.8 in.
Which of the following groups of analog exposure factors is most likely to produce the longest scale of contrast? A 200 mA, 0.25 second, 70 kVp, 12:1 grid B 500 mA, 0.10 second, 90 kVp, 8:1 grid C 400 mA, 0.125 second, 80 kVp, 12:1 grid D 300 mA, 0.16 second, 70 kVp, 8:1 grid
(B) 500 mA, 0.10 second, 90 kVp, 8:1 grid
A satisfactory radiograph was made using a 36-in. SID, 12 mAs, and a 12:1 grid. If the examination will be repeated at a distance of 42 in. and using a 5:1 grid, what should be the new milliampere-seconds value to maintain the original receptor exposure? A 5.6 B 6.5 C 9.7 D 13
(B) 6.5
The exposure factors of 400 mA, 17 ms, and 82 kV produce a milliampere-seconds value of A 2.35 B 6.8 C 23.5 D 68
(B) 6.8
If 300 mA has been selected for a particular exposure, what exposure time should be selected to produce 18 mAs? A 40 ms B 60 ms C 400 ms D 600 ms
(B) 60 ms
If a duration of 0.05 second was selected for a particular exposure, what milliamperage would be necessary to produce 30 mAs? A 900 B 600 C 500 D 300
(B) 600
In an AP abdomen taken at 105-cm SID during an IV urography series, one renal shadow measures 9 cm in width. If the OID is 18 cm, what is the actual width of the kidney? A 5 cm B 7.5 cm C 11 cm D 18 cm
(B) 7.5 cm
In an AP abdomen radiograph taken at 105-cm SID during an IVU series, one renal shadow measures 9 cm in width. If the OID is 18 cm, what is the actual width of the kidney? A 5 cm B 7.5 cm C 11 cm D 18 cm
(B) 7.5 cm Image size / Object size = SID / SOD
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
When describing the overall efficiency of CR photostimulabe phosphor plates converting x-ray signals into a useful image, which of the following terms best fit this definition? A Modulation transfer function B Detective quantum efficiency C Absorption efficiency D Conversion efficiency
(B) Detective quantum efficiency
Which of the following is most likely to produce a high-quality image? A Small image matrix B High signal-to-noise ratio (SNR) C Large pixel size D Low resolution
(B) High signal-to-noise ratio (SNR)
From the following list, select the effective methods of reducing scatter radiation production in the patient (select the two that apply). A Using an air-gap technique B Increasing collimation C Using a high ratio grid D Using a direct conversion digital system E Placing a lead apron over the anatomy of interest F Using anatomical part compression
(B) Increasing collimation (F) Using anatomical part compression
Grids improve the radiographic image by reducing the amount of scattered radiation fog. How does the use of grids impact exposure factors? A It has no effect on exposure factors B It increases exposure factors C It decreases exposure factors D It doubles exposure factors
(B) It increases exposure factors
For which of the following examinations might the use of a grid not be necessary in an adult patient? A Hip B Knee C Abdomen D Lumbar spine
(B) Knee The knee is frequently small enough to be imaged without a grid. The general rule is that structures measuring more than 10 cm should be imaged with a grid.
The anode heel effect results in variation of the intensity of the beam across the field of view. Select four items from the list that will reduce the appearance of this variation on the displayed image. A Smaller anode target angle B Larger anode target angle C Longer SID D Automatic rescaling E Flat fielding F Aligning a tapering body part so that the thicker portion is on the anode side of the beam G Aligning a tapering body part so that the thicker portion is on the cathode side of the beam
(B) Larger anode target angle (C) Longer SID (E) Flat fielding (G) Aligning a tapering body part so that the thicker portion is on the cathode side of the beam A larger anode target angle, longer SID, flat fielding, and aligning a tapering body part so that the thicker portion is on the cathode side of the beam will all reduce the appearance of the variation of beam intensity caused by the heel effect (B, C, E, and G).
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
(B) Magnification radiography
Which of the following terms is used to express spatial resolution? A Kiloelectronvolts (keV) B Modulation transfer function (MTF) C Relative speed D Latitude
(B) Modulation transfer function (MTF)
Which of the following pathologic conditions would require a decrease in exposure factors? A Empyema B Osteoporosis C Pleural effusion D Hemothorax
(B) Osteoporosis
Which of the following pathologies would justify a decrease in technique? A Ascites B Pneumothorax C Hydrocephalus D Atelectasis
(B) Pneumothorax
Which of the following is most likely to occur as a result of using a 30-in. SID with a 14 × 17 in. IR to radiograph a fairly homogeneous structure? A Production of quantum mottle B Receptor exposure variation between opposite ends of the IR C Production of scatter radiation fog D Excessively short-scale contrast
(B) Receptor exposure variation between opposite ends of the IR
Receptor exposure decreases with an increase in (select the three that apply): A kV B SID C focal spot size D mAs E part thickness F grid ratio G field size
(B) SID (E) part thickness (F) grid ratio Because grids remove many x-ray photons that would have contributed to receptor exposure, the addition of a grid requires a significant increase in mAs.
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.
(B) Spatial resolution is inversely related to OID.
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) There is greater patient dose with three-phase equipment than with single-phase equipment.
If an acceptable image is obtained utilizing 20 mAs, 75 kVp at a 40-in. SID, what adjustment must be made to mAs with a 35-in. SID to maintain image receptor exposure? A Use 25 mAs, 75 kVp B Use 15 mAs, 75 kVp C Use 18 mAs, 75 kVp D Use 5 mAs, 75 kVp
(B) Use 15 mAs, 75 kVp
In digital radiography, patient information is displayed in the corners of the monitor for an exam. The 3 steps a technologist must take to ensure that the information is accurate are: A Verify the patient's Identity by confirming their name and date of birth after the exam is complete. B Verify the patient's Identity by confirming their name and date of birth before beginning the exam. C Match the exam images to the Technologist Image number. D Match the exam images to the exam accession number, either via query of the RIS worklist or manual entry. E Verify the exam details with the patient. Confirm type of exam, body part to be examined, and side of the body are correct.
(B) Verify the patient's Identity by confirming their name and date of birth before beginning the exam. (D) Match the exam images to the exam accession number, either via query of the RIS worklist or manual entry. (E) Verify the exam details with the patient. Confirm type of exam, body part to be examined, and side of the body are correct.
Which of the following best allows optimal visualization of both soft tissue and bony structures in a given image? A Narrow dynamic range B Wide dynamic range C Brightness gain D Structures recorded
(B) Wide dynamic range
The best way to control voluntary motion is A immobilization of the part. B careful explanation of the procedure. C short exposure time. D physical restraint.
(B) careful explanation of the procedure.
In amorphous selenium flat-panel detectors, the term amorphous refers to a A crystalline material having typical crystalline structure. B crystalline material lacking typical crystalline structure. C toxic crystalline material. D homogeneous crystalline material.
(B) crystalline material lacking typical crystalline structure.
Radiographic contrast is the result of A transmitted electrons B differential absorption C absorbed photons D milliampere-seconds selection
(B) differential absorption
Using a short (25-30 in.) SID with a large (14 × 17 in.) IR is likely to A increase the scale of contrast B increase the anode heel effect C cause malfunction of the AEC D cause premature termination of the exposure
(B) increase the anode heel effect Use of a short SID with a large-size IR (and also with anode angles of 10 degrees or less) causes the anode heel effect to be much more apparent. The x-ray beam needs to diverge more to cover a large-size IR, and it needs to diverge even more for coverage as the SID decreases.
When involuntary motion must be considered, the exposure time may be cut in half if the kilovoltage is A doubled B increased by 15% C increased by 25% D increased by 35%
(B) increased by 15%
If a 4-inch collimated field is changed to a 14-inch collimated field, with no other changes, the image receptor will experience A decreased receptor exposure. B increased receptor exposure. C more spatial resolution. D less spatial resolution.
(B) increased receptor exposure
How are mAs and receptor exposure related in the process of image formation? A mAs and receptor exposure are inversely proportional B mAs and receptor exposure are directly proportional C mAs and receptor exposure are related to image unsharpness D mAs and receptor exposure are unrelated
(B) mAs and receptor exposure are directly proportional
A focal-spot size of 0.3 mm or smaller is essential for A small-bone radiography B magnification radiography C long SID techniques D fluoroscopy
(B) magnification radiography
Radiation spreads from a source in an expanding sphere, the area given by 4/3πr34/3πr3. So long as the rate of emission is constant, the intensity of the radiation will reduce by a factor squared as an observer moves away from the source. This describes A ALARA B the inverse square law C the line focus principle D the half value layer
(B) the inverse square law
Compensating filters are radiographically useful in that A they prevent unnecessary characteristic radiation from being produced. B they provide more uniform exposure to anatomical parts having unequal thicknesses. C they eliminate the need for internal and external filtration in the x-ray tube housing and collimator. D they eliminate scatter production in the patient, thereby reducing image noise.
(B) they provide more uniform exposure to anatomical parts having unequal thicknesses.
Compton scatter production and photoelectric absorption within the patient both increase at the same rate as A beam filtration increases. B tissue thickness increases. C kVp increases. D OID increases.
(B) tissue thickness increases
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
A radiograph made using 300 mA, 0.1 second, and 75 kVp exhibits motion unsharpness, but otherwise satisfactory technical quality. The radiograph will be repeated using a shorter exposure time. Using 86 kV and 500 mA, what should be the new exposure time? A 0.12 second B 0.06 second C 0.03 second D 0.01 second
(C) 0.03 second
The exposure factors of 300 mA, 0.07 second, and 95 kVp were used to deliver a particular analog receptor exposure and contrast. A similar analog x-ray image can be produced using 500 mA, 80 kVp, and A 0.01 second. B 0.04 second. C 0.08 second. D 0.16 second.
(C) 0.08 second.
An exposure was made using 300 mA, 40 ms exposure, and 85 kV. Each of the following changes will cut the receptor exposure in half except a change to A 1/50 sec exposure B 72 kV C 10 mAs D 150 mA
(C) 10 mAs
A lateral radiograph of the cervical spine was made at 40 in. using 300 mA and 0.03 second exposure. If it is desired to increase the distance to 72 in., what should be the new milliampere (mA) setting, all other factors remaining constant? A 400 mA B 800 mA C 1000 mA D 1200 mA
(C) 1000 mA
A satisfactory radiograph was made using a 40-inch SID, 10 mAs, and a 12:1 grid. If the examination will be repeated at a distance of 48 inches and using an 8:1 grid, what should be the new mAs to maintain the original receptor exposure? A 5.6 B 8.8 C 11.5 D 14.4
(C) 11.5
Exposure factors of 110 kVp and 12 mAs are used with an 8:1 grid for a particular exposure. What should be the new mAs if a 12:1 grid is substituted? A 3 B 9 C 15 D 18
(C) 15
In order to double the x-ray quantity to the image receptor (IR) using kilovoltage-peak (kVp), the radiographer would need to raise the kVp by ______ percent. A 5 B 10 C 15 D 20
(C) 15
Exposure factors of 90 kVp and 4 mAs are used for a particular nongrid exposure. What should be the new mAs if an 8:1 grid is added? A 8 B 12 C 16 D 20
(C) 16
An exposure was made using 600 mA, 0.04 sec exposure, and 85 kVp. Each of the following changes will serve to reduce the receptor exposure by one-half except change to A 1/50 sec exposure B 72 kVp C 18 mAs D 300 mA
(C) 18 mAs
Of the following groups of exposure factors, which will produce the greatest receptor exposure? A 400 mA, 30 ms, 72-in. SID B 200 mA, 30 ms, 36-in. SID C 200 mA, 60 ms, 36-in. SID D 400 mA, 60 ms , 72-in. SID
(C) 200 mA, 60 ms, 36-in. SID
An exposure was made using 600 mA and 18 ms. If the mA is changed to 400, which of the following exposure times would most closely approximate the original receptor exposure? A 16 ms B 0.16 second C 27 ms D 0.27 second
(C) 27 ms
Exposure factors of 80 kVp and 8 mAs are used for a particular nongrid exposure. What should be the new milliampere-seconds value if an 8:1 grid is added? A 16 mAs B 24 mAs C 32 mAs D 40 mAs
(C) 32 mAs
Which of the following will produce the greatest distortion? A AP projection of the skull B PA projection of the skull C 37° AP axial of the skull D 20° PA axial of the skull
(C) 37° AP axial of the skull The 37° (caudad) AP axial projection of the skull, for example, projects the facial bones inferiorly so that the occipital bone can be visualized to better advantage.
If 92 kV and 12 mAs were used for a particular abdominal exposure with single-phase equipment, what mAs would be required to produce a similar radiograph with three-phase equipment? A 36 B 24 C 6 D 3
(C) 6
Which of the following groups of exposure factors would be most appropriate to control involuntary motion? A 400 mA, 0.03 second B 200 mA, 0.06 second C 600 mA, 0.02 second D 100 mA, 0.12 second
(C) 600 mA, 0.02 second
A satisfactory radiograph of the abdomen was made at a 38-in. SID using 400 mA, 60-ms exposure, and 80 kV. If the distance is changed to 42 in., what new exposure time would be required? A 25 ms B 50 ms C 73 ms D 93 ms
(C) 73 ms old mAs / new mAs = old distance squared / new distance squared
A particular radiograph was produced using 6 mAs and 110 kVp with an 8:1 ratio grid. The radiograph is to be repeated using a 16:1 ratio grid. What should be the new mAs? A 3 B 6 C 9 D 12
(C) 9 old mAs / new mAs = old grid / new grid
Which of the following terms is used to describe unsharp edges of tiny radiographic details? A Diffusion B Mottle C Blur D Umbra
(C) Blur
Which of the following measures the percentage of x-rays absorbed by the detector? A FPD B PPI C DQE D DXR
(C) DQE
What is the best way to reduce magnification distortion? A Use a small focal spot. B Increase the SID. C Decrease the OID. D Avoid tube angle techniques.
(C) Decrease the OID
Which of the following combinations is most likely to be associated with quantum mottle? A Decreased milliampere-seconds, decreased SID B Increased milliampere-seconds, decreased kilovoltage C Decreased milliampere-seconds, increased kilovoltage D Increased milliampere-seconds, increased SID
(C) Decreased milliampere-seconds, increased kilovoltage Fast imaging systems using low-milliampere-seconds and high-kilovoltage factors are most likely to be the cause of quantum mottle
Breast tissue is compressed in mammographic procedures to improve contrast resolution by reducing the production of Compton scatter. Which of the following also reduces Compton scatter production? A Using a grid B Increasing kVp C Decreasing tissue density (mass/volume) D Increasing average atomic number of tissue irradiated
(C) Decreasing tissue density (mass/volume)
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) High-kilovoltage exposure factors
All the following statements regarding CR IPs are true except A IPs have a thin lead foil backing. B IPs can be placed in the Bucky tray. C IPs must exclude all white light. D IPs function to protect the PSP.
(C) IPs must exclude all white light. IPs do not contain a light sensitive material and, therefore, do not need to be light-tight. The photostimulable PSP is not affected by light
Which of the following is most likely to result from the introduction of a grid with appropriate technical factor change? A Increased patient dose and increased scattered radiation fog B Decreased patient dose and decreased scattered radiation fog C Increased patient dose and decreased scattered radiation fog D Decreased patient dose and increased scattered radiation fog
(C) Increased patient dose and decreased scattered radiation fog
In which of the following examinations should 70 kV not be exceeded? A Upper GI (UGI) B Barium enema (BE) C Intravenous urogram (IVU) D Chest
(C) Intravenous urogram (IVU)
In which of the following examinations would a IR front with very low absorption properties be especially desirable? A Extremity radiography B Abdominal radiography C Mammography D Angiography
(C) Mammography
Which of the following best describes the distance from the center of one pixel to the center of the adjacent pixel? A Pixel density B Pixel size C Pixel pitch D Pixel wide
(C) Pixel pitch
For a radiographic exposure of the femur, how should the anode heel effect be properly applied? A Place the anode end of the x-ray tube over the proximal femur. B Place the cathode end of the x-ray tube over the distal femur. C Place the cathode end of the x-ray tube over the proximal femur. D Either the anode or cathode end of the x-ray tube could be placed over either end of the femur.
(C) Place the cathode end of the x-ray tube over the proximal femur.
Which of the following has the greatest effect on receptor exposure? A Aluminum filtration B Kilovoltage C SID D Scattered radiation
(C) SID
The radiographer receives an x-ray order for a 1-year-old child. Without adequate immobilization techniques or accessories such as a Pigg-O-Stat™, which of the following image qualities could be affected? A Receptor exposure B Contrast C Spatial resolution D Distortion
(C) Spatial resolution
In which of the following ways might higher image contrast be obtained in abdominal radiography? 1. By using lower kilovoltage 2. By using a contrast medium 3. By limiting the field size
1, 2, and 3 The abdomen has low tissue contrast, and abdominal radiographs can exhibit very low contrast unless technical factors are selected to increase contrast. To produce higher contrast in abdominal radiography, lower kVp can be used. To better demonstrate high contrast within a viscus, a contrast medium such as barium, iodine, or air can be used. Restricting the size of the field will also function to increase contrast because less scattered radiation will be generated
How is SID related to exposure rate and receptor exposure? A As SID increases, exposure rate increases and radiographic receptor exposure increases. B As SID increases, exposure rate increases and radiographic receptor exposure decreases. C As SID increases, exposure rate decreases and radiographic receptor exposure increases. D As SID increases, exposure rate decreases and radiographic receptor exposure decreases.
(D) As SID increases, exposure rate decreases and radiographic receptor exposure decreases.
How is source-to-image distance (SID) related to exposure rate and receptor exposure? A As SID increases, exposure rate increases and receptor exposure increases. B As SID increases, exposure rate increases and receptor exposure decreases. C As SID increases, exposure rate decreases and receptor exposure increases. D As SID increases, exposure rate decreases and receptor exposure decreases.
(D) As SID increases, exposure rate decreases and receptor exposure decreases.
Which of the following conditions will require an increase in x-ray photon energy/penetration? A Fibrosarcoma B Osteomalacia C Paralytic ileus D Ascites
(D) Ascites
Which of the following pathologies would justify an increase in technique? A Multiple myeloma B Pneumothorax C Emphysema D Atelectasis
(D) Atelectasis Multiple myeloma (A), Pneumothorax (B), and Emphysema (C) are all destructive conditions that require a decrease in technique. Atelectasis makes the area of interest more difficult to penetrate.
Which of the following is not considered a radiographic geometric factor? A Magnification B Focal spot size C OID D Beam filtration
(D) Beam filtration
Which of the following represents the image acquisition contrast resolution? A Pixel B Pixel size C Pixel pitch D Bit depth
(D) Bit depth Pixel bit depth is known as the number of bits within a pixel which presents the number of gray tones that pixel can produce
Which of the following is NOT true of spatial resolution, FOV, and matrix size as they relate to each other? A Increasing matrix size with no change to FOV will improve spatial resolution. B Changing FOV has no effect on matrix size. C Decreasing FOV with no other changes will improve spatial resolution. D Changing matrix size has no effect on spatial resolution.
(D) Changing matrix size has no effect on spatial resolution.
Each manufacturer's software system determines the gray scale available for when the x-ray image is displayed. Which of the following terms best describes this definition? A Modulation transfer function B Detective quantum efficiency C Exposure latitude D Dynamic range
(D) Dynamic range
A patient is being positioned for a particular radiographic examination. The x-ray tube, image recorder, and grid are properly aligned, but the body part is angled. Which of the following will result? A Grid cutoff at the periphery of the image B Grid cutoff along the center of the image C Increased receptor exposure at the periphery D Image distortion
(D) Image distortion
A technologist is about to perform a trauma cross-table cervical spine on a hypersthenic patient who is short of breath. As the technologist is setting up for the projection, it becomes clear that the patient will not be able to hold their breath through the exposure. How should the technologist adjust technique to preserve image quality? A Change to a grid with a lower grid ratio. B Use a shorter SID. C Increase kVp by 15% and divided mA by 2. D Increase kVp by 15% and divide exposure time by 2.
(D) Increase kVp by 15% and divide exposure time by 2.
What is the single most important factor controlling size distortion? A Tube, part, IR alignment B IR dimensions C SID D OID
(D) OID
When an imaging department installs new radiographic equipment with higher DQE (Detective Quantum Efficiency) than previous equipment, the most important/valuable advantage is: A Image quality improves. B Repeat rates reduce. C Exam throughput increases. D Patient dose is reduced.
(D) Patient dose is reduced When an imaging system has a higher DQE, which means it captures a greater percentage of the remnant beam, and therefore, lower mAs techniques can be applied with these machines while still yielding a diagnostic image. Improvements in image quality, reduction in repeat rate, and workflow efficiencies are all beneficial, however, they are better influenced by high quality technologists, not high quality equipment
Which of the following best describes the number of pixels per unit area? A Pixel size B Pixel pitch C Pixel wide D Pixel density
(D) Pixel density Pixels are measured per inch; a higher pixel density per inch allows for more sharpness and clarity for the image
If insufficient x-ray quantity is supplied to a digital image receptor, which of the following will be seen on the final radiographic image? A Decreased image brightness B Increased contrast (shorter grayscale) C Decreased spatial resolution D Quantum mottle (noise)
(D) Quantum mottle (noise)
Underexposure of a radiograph can be caused by all the following except insufficient A milliamperage (mA) B exposure time C Kilovoltage D SID
(D) SID
Which digital imaging characteristic is defined as the "sharpness of the structural edges recorded in an image"? (Carroll, Quinn B., 2nd ed., p.225) A Contrast resolution B Subject contrast C Short-scale contrast D Spatial resolution
(D) Spatial resolution
If a 6-in. OID is introduced during a particular radiographic examination, what change in SID will be necessary to overcome objectionable magnification? A The SID must be increased by 6 in.. B The SID must be increased by 18 in.. C The SID must be decreased by 6 in.. D The SID must be increased by 42 in..
(D) The SID must be increased by 42 in..
A technologist setting a manual technique on a DR imaging system is contemplating changing mA from 300 down to 150, with no other changes to other factors. Which of the following effects will happen as a result of this change? A The patient dose will double. B The image will have increased brightness. C The image will have a shorter scale of contrast. D The signal-to-noise ratio will decrease.
(D) The signal-to-noise ratio will decrease.
When the collimated field must extend past the edge of the body, allowing primary radiation to strike the tabletop, as in a lateral lumbar spine radiograph, what may be done to prevent excessive receptor exposure owing to undercutting? A Reduce the milliampere-seconds. B Reduce the kilovoltage. C Use a shorter SID. D Use lead rubber to absorb tabletop primary radiation.
(D) Use lead rubber to absorb tabletop primary radiation.
Quantum mottle manifests within an image because A there was not enough filtration of the primary beam. B too much scatter radiation was produced. C a grid was not employed to effectively clean up the scatter. D a poor signal was captured by the image receptor.
(D) a poor signal was captured by the image receptor
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.
Decreasing field size from 14 × 17 into 8 × 10 inches will A decrease receptor exposure and increase the amount of scattered radiation generated within the part. B increase receptor exposure and increase the amount of scattered radiation generated within the part. C increase receptor exposure and decrease the amount of scattered radiation generated within the part. D decrease receptor exposure and decrease the amount of scattered radiation generated within the part.
(D) decrease receptor exposure and decrease the amount of scattered radiation generated within the part.
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
(D) decreased SID
All the following affect the exposure rate of the primary beam except A milliamperage B kilovoltage C distance D field size
(D) field size
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 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.
In preparing to use Automatic Exposure Control in combination with a PSP image receptor for an AP lumbar spine projection on a patient with a hypersthenic habitus, an optimal image can best be produced with which of the following changes to technical factors? A kVp is decreased to compensate for decreased patient size. B The outer cells of the AEC are active. C The AEC calibration is adjusted via the "+" density controls on the control panel, creating a longer exposure. D kVp is increased to compensate for increased part thickness.
(D) kVp is increased to compensate for increased part thickness.
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. 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
Misrepresentation of the true size of an anatomical structure is called A elongation B foreshortening C geometric unsharpness D magnification
(D) magnification
Changes in milliampere-seconds can affect all the following except A quantity of x-ray photons produced B exposure rate C receptor exposure D spatial resolution
(D) spatial resolution
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.
1 and 2 only
Cassette-front material can be made of which of the following? 1. Carbon fiber 2. Magnesium 3. Lead
1 and 2 only
Compared to a low ratio grid, a high ratio grid will 1.absorb more of the useful beam. 2.absorb more scattered radiation. 3.allow more centering latitude.
1 and 2 only
Exposure rate increases with an increase in 1. mA. 2. kVp. 3. SID.
1 and 2 only
For which of the following examinations can the anode heel effect be an important consideration? 1. Lateral thoracic spine 2. AP femur 3. Right anterior oblique (RAO) sternum
1 and 2 only
Higher kVp settings can provide which of the following benefits? 1. Improved penetration 2. Patient dose reduction 3. Increased spatial resolution
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
1 and 2 only
Low-kilovoltage exposure factors usually are indicated for radiographic examinations using 1. water-soluble, iodinated media 2. a negative contrast agent 3. barium sulfate
1 and 2 only
The effect that differential absorption has on radiographic contrast of a high-subject-contrast part can be minimized by 1. using a compensating filter. 2. using high-kilovoltage exposure factors. 3. increased collimation.
1 and 2 only
Which of the following can have an effect on radiographic contrast? 1. Beam restriction 2. Grids 3. Focal spot size
1 and 2 only
Which of the following is (are) classified as rare earth phosphors? 1. Lanthanum oxybromide 2. Gadolinium oxysulfide 3. Cesium iodide
1 and 2 only
Which of the following units is (are) used to express resolution? 1. Line-spread function 2. Line pairs per millimeter 3. Line-focus principle
1 and 2 only
Which one of the following is (are) used to control the production of scattered radiation? 1. Collimators 2. Optimal kV 3. Use of grids
1 and 2 only
With all other factors constant, as digital image matrix size increases, 1. pixel size decreases. 2. resolution increases. 3. pixel size increases.
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
1 and 2 only 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 will improve the spatial resolution of image-intensified images? 1. A very thin coating of cesium iodide on the input phosphor 2. A smaller-diameter input screen/phosphor 3. Increased total brightness gain
1 and 2 only An image's spatial resolution refers to the sharpness of its image details. As the input screen/phosphor layer is made thinner, spatial resolution increases. Also, the smaller the input phosphor diameter, the greater is the spatial resolution. A brighter image is easier to see but does not affect resolution.
Disadvantages of using lower kilovoltage technical factors, with mAs compensated to maintain receptor exposure, include 1. insufficient penetration 2. increased patient dose 3. diminished resolution
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.
Greater latitude is available to the radiographer in which of the following circumstances? 1. Using high-kV technical factors 2. Using a low-ratio grid 3. Using low-kV technical factors
1 and 2 only High-kilovolt technical factors offer much greater margin for error; in the high-kV ranges, an error of a few kV makes little/no difference in the resulting image. Lower-ratio grids offer more tube-centering latitude than high-ratio grids.
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
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.
Phosphors classified as rare earth include 1. lanthanum oxybromide. 2. gadolinium oxysulfide. 3. cesium iodide.
1 and 2 only Rare earth phosphors have a greater conversion efficiency than do other phosphors. Lanthanum oxybromide is a blue-emitting phosphor, and gadolinium oxysulfide is a green-emitting phosphor.
The sharpness of image details depends on all the following except 1. quantity of filtration. 2. anode angle. 3. OIDs.
1 and 2 only The factors that affect the sharpness of image details are focal-spot size, source-to-image receptor distance (SID), object-to-image distance (OID), and motion. Detail sharpness is improved using a small focal spot size, largest practical SID, shortest possible OID, and avoiding motion of the part being imaged.
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.
1 and 2 only These scattered photons carry no useful information and contribute to radiation fog, thus potentially decreasing radiographic contrast, especially in analog imaging.
Disadvantages of moving grids over stationary grids include which of the following? 1. They can prohibit the use of very short exposure times. 2. They increase patient radiation dose. 3. They can cause phantom images when anatomic parts parallel their motion.
1 and 2 only patient dose is increased with moving grids. Since the central ray is not always centered to the grid because it is in motion, lateral decentering occurs (resulting in diminished density), and consequently, an increase in exposure is needed to compensate (either manually or via AEC).
Which two (2) of the following statements are true regarding image distortion? 1. The least amount of image distortion occurs along the path of the CR 2. CR alignment has little/no impact on image distortion 3. X-ray tube angle impacts shape distortion 4. The least amount of image distortion occurs at the periphery of the x-ray beam 5. SID impacts shape distortion as well as size distortion
1 and 3 are correct
A grid usually is employed in which of the following circumstances? 1. When radiographing a large or dense body part 2. When using high kilovoltage 3. When a lower patient dose is required
1 and 3 only
An anatomical part calls for a kilovoltage (kVp) setting necessary to penetrate the part. If a lower than acceptable kVp were selected using a fixed milliampere-seconds (mAs) setting, this would result in which of the following? 1. Increased patient dose 2. Increased exposure to the image receptor 3. Decreased penetration of the anatomical part
1 and 3 only
An increase in the milliamperage (mA) setting increases 1. X-ray beam quantity 2. X-ray beam quality 3. Image receptor exposure
1 and 3 only
Filtration of the radiographic x-ray beam functions to do which of the following? 1. Reduce patient skin dose 2. Decrease average beam energy 3. Provide uniform exposure of an anatomical part with different thicknesses
1 and 3 only
If a radiograph exhibits insufficient receptor exposure, this might be attributed to 1. insufficient kVp. 2. insufficient SID. 3. grid cutoff.
1 and 3 only
If the x-ray image exhibits insufficient receptor exposure, this might be attributed to 1. Insufficient kilovoltage 2. Insufficient SID 3. grid cutoff
1 and 3 only
If x-ray beam filtration were not present, which of the following would be considered a negative effect? 1. Increased patient dose 2. Overexposure of the IR 3. Average energy of the x-ray beam would decrease
1 and 3 only
The factors that impact spatial resolution include 1. Focal spot size 2. Type of rectification 3. SID
1 and 3 only
Which of the following imaging procedures do not require the use of ionizing radiation to produce an image? 1. Ultrasound 2. Computed axial tomography 3. MRI
1 and 3 only
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.
1 and 3 only
Which of the following is affected by the size of the x-ray field? 1. Amount of scattered radiation produced 2. Motion unsharpness 3. Patient dose
1 and 3 only
Which of the following pathologic conditions would require an increase in exposure factors? 1. Empyema 2. Osteoporosis 3. Pleural effusion
1 and 3 only
Which of the following will improve the sharpness of the edges of small anatomical parts? 1. Small focal spot size 2. Increased OID 3. Increased SID
1 and 3 only
Which of the following will contribute to the production of longer-scale radiographic contrast? 1. An increase in kV 2. An increase in grid ratio 3. An increase in photon energy
1 and 3 only Increased photon energy is caused by an increase in kVp, resulting in more penetration of the part and a longer scale of contrast.
Which of the following function(s) to reduce the amount of scattered radiation reaching the IR? 1. Grid devices 2. Restricted focal spot size 3. Beam restrictors
1 and 3 only There are several ways to reduce the amount of scattered radiation reaching the IR. First, the use of optimum kVp is essential; excessive kVp will increase the production of scattered radiation. Second, conscientious use of the beam restrictor (collimator) will reduce scattered radiation; the smaller the volume of irradiated tissue, the less scattered radiation is produced
A decrease from 90 to 77 kVp will result in an increase in 1. wavelength 2. gray scale 3. scattered radiation
1 only
A positive contrast agent 1. absorbs x-ray photons 2. results in a dark area on the radiograph 3. is composed of elements having low atomic number
1 only
An increase in kilovoltage with appropriate compensation of milliampere-seconds will result in 1. increased part penetration. 2. higher contrast. 3. increased receptor exposure.
1 only
In radiography of a large abdomen, which of the following is (are) effective way(s) to minimize the amount of scattered radiation reaching the image receptor (IR)? 1. Use of optimal collimation 2. Use of low mAs 3. Use of a low-ratio rather than high-ratio grid
1 only
Which of the following examinations might require the use of 70 kV? 1. AP abdomen 2. Chest radiograph 3. Barium-filled stomach
1 only
Which of the following is (are) characteristic(s) of a 5:1 grid? 1. It allows some positioning latitude. 2. It is used with high-kilovoltage exposures. 3. It absorbs a high percentage of scattered radiation.
1 only
Which of the following is (are) directly related to photon energy? 1. Kilovoltage 2. Milliamperes 3. Wavelength
1 only
There is direct relationship between spatial resolution and 1. SID. 2. tube current. 3. focal-spot size.
1 only As SID increases, spatial resolution increases because magnification is decreased - a direct relationship.
The functions of automatic beam limitation devices include 1. reducing the production of scattered radiation 2. increasing the absorption of scattered radiation 3. changing the quality of the x-ray beam
1 only Beam restrictors function to limit the size of the irradiated field. In so doing, they limit the volume of tissue irradiated (thereby decreasing the percentage of scattered radiation generated in the part) and help to reduce patient dose.
What are the effects of scattered radiation on a radiographic image? 1. It produces fog. 2. It increases contrast. 3. It increases grid cutoff.
1 only If these scattered rays are energetic enough to exit the body, they will strike the IR from all different angles. They, therefore, do not carry useful information and merely produce a flat, gray (low-contrast) fog over the image. Grid cutoff increases contrast and is caused by an improper relationship between the x-ray tube and the grid, resulting in absorption of some of the useful/primary beam
According to the line-focus principle, an anode with a small angle provides 1. improved spatial resolution. 2. improved heat capacity. 3. less heel effect.
1 only The line-focus principle states that as the target/focal track angle gets larger, the effective focal spot is larger. When the effective focal spot is larger, focal spot blur increases, and spatial resolution is decreased.
Spatial resolution is directly related to 1. source-image distance (SID). 2. tube current. 3. focal spot size.
1 only As SID increases, spatial resolution increases (a direct relationship) because magnification decreases. So SID is directly related to spatial resolution
A technique chart should be prepared for each AEC x-ray unit and should contain which of the following information for each type of examination? 1. Photocell(s) used 2. Optimum kilovoltage 3. Backup time
1, 2, and 3
Acceptable method(s) of minimizing motion unsharpness is (are) 1. suspended respiration 2. short exposure time 3. patient instruction
1, 2, and 3
Acceptable method(s) of minimizing motion unsharpness is (are) 1. suspended respiration. 2. short exposure time. 3. patient instruction.
1, 2, and 3
Factor(s) that impact receptor exposure include 1. milliamperage. 2. exposure time. 3. kilovoltage
1, 2, and 3
For which of the following procedures must the radiographer carefully consider exposure time? 1. Patients who are unable to cooperate 2. UGI radiography 3. Lateral thoracic spine radiography
1, 2, and 3
Geometric unsharpness is influenced by 1. OID 2. SOD 3. SID
1, 2, and 3
Geometric unsharpness is influenced by which of the following? 1. Distance from object to image 2. Distance from source to object 3. Distance from source to image
1, 2, and 3
Geometric unsharpness will be least obvious 1. at long SIDs. 2. with small focal spots. 3. at the anode end of the image.
1, 2, and 3
The advantage(s) of high-kilovoltage chest radiography is (are) that 1. exposure latitude is increased 2. it produces long-scale contrast 3. it reduces patient dose
1, 2, and 3
Which of the following are potential undesirable effect(s) of scattered radiation? 1. Image fog 2. Increased patient dose 3. Increased radiographer dose
1, 2, and 3
Which of the following can affect histogram appearance? 1. Centering accuracy 2. Positioning accuracy 3. Processing algorithm accuracy
1, 2, and 3
Which of the following can contribute to the image contrast? 1. Tissue density 2. Pathology 3. Muscle development
1, 2, and 3
Which of the following can minimize magnification seen in a radiographic image? 1. Long SID 2. Short OID 3. Compression
1, 2, and 3
Which of the following factors impact(s) spatial resolution? 1. Focal spot size 2. Subject motion 3. SOD
1, 2, and 3
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
1, 2, and 3
Which of the following is (are) associated with subject contrast? 1. Patient thickness 2. Tissue density 3. Kilovoltage
1, 2, and 3
Which of the following is (are) characteristic(s) of a 16:1 grid? 1. It absorbs a high percentage of scattered radiation. 2. It has little positioning latitude. 3. It is used with high-kVp exposures.
1, 2, and 3
Which of the following is likely to contribute to the radiographic contrast present on an analog x-ray image? 1. Atomic number of tissues radiographed 2. Any pathologic processes 3. Degree of muscle development
1, 2, and 3
Which of the following may be used to reduce the effect of scattered radiation on the radiographic image? 1. Grids 2. Collimators 3. Compression bands
1, 2, and 3
Which of the following pathologic conditions are considered additive conditions with respect to selection of exposure factors? 1. Osteoma 2. Bronchiectasis 3. Pneumonia
1, 2, and 3
Which of the following can affect radiographic contrast? 1. LUT 2. Pathology 3. OID
1, 2, and 3 All three factors can affect radiographic contrast. The look up table (LUT) can alter the contrast. Since pathology can alter the degree of attenuation of the x-ray beam, it can affect contrast. OID can affect contrast when it is used as an air gap.
The average frequency of photons contained within the x-ray beam can be increased by 1. Increasing mAs 2. Increasing kVp 3. Increasing filtration 4. Decreasing kVp
2 and 3
A decrease from 80 mAs to 40 mAs will result in a decrease in which of the following? 1. Wavelength 2. Exposure rate 3. Beam intensity
2 and 3 only
Characteristics of high-ratio focused grids, compared with lower-ratio grids, include which of the following? 1. They allow more positioning latitude. 2. They are more efficient in collecting SR. 3. They absorb more of the useful beam.
2 and 3 only
For an AP projection of the knee, if the patient is unable to fully extend the lower extremity, what could the radiographer do to minimize magnification distortion? 1. Use a compression band to extend the lower extremity 2. Increase the SID 3. Perform a PA projection
2 and 3 only
Spatial resolution can be improved by decreasing 1. the SID 2. the OID 3. patient/part motion
2 and 3 only
Which of the following decrease attenuation of the x-ray beam? 1. Positive contrast agents 2. Air 3. Negative contrast agents
2 and 3 only
Which of the following refers to anatomical shape distortion? 1. Magnification 2. Elongation 3. Foreshortening
2 and 3 only
The term differential absorption is closely related to 1. beam intensity 2. subject contrast 3. pathology
2 and 3 only This differential absorption contributes to the various shades of gray in the x-ray image, as does the energy/penetration characteristic of the beam as regulated by the kV. Beam intensity/quantity/mAs is not related to differential absorption.
Spatial resolution is inversely related to 1. SID 2. OID 3. grid ratio
2 only
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
2 only
A lateral (analog) radiograph of the lumbar spine was made using 200 mA, 1/2 second exposure, and 90 kV. If the exposure factors were changed to 200 mA, 0.25 second, and 104 kV, there would be an obvious change in which of the following? 1. Receptor exposure 2. Scale of grays/contrast 3. Distortion
2 only The original milliampere-seconds value (regulating receptor exposure) was 100. The original kilovoltage (impacting contrast) was 90. The milliampere-seconds value was cut in half, to 50. The kilovoltage was increased (by 15%) to compensate for the receptor exposure loss and thereby increase the scale of grays.
Occasionally, it is difficult for the radiographer to obtain a diagnostic image of the odontoid (dens) process using the open-mouth technique. An alternative method, called the Fuchs's method, may be used where the patient extends their head to place the mental and mastoid plane perpendicular to the image receptor. However, if the patient is unable to obtain the full extension needed, a cephalic angulation of the x-ray tube may be warranted. What would be the potential disadvantage(s) of such an angulation of the tube? A The chin would be projected cephalically to prevent superimposition over the odontoid process. B The odontoid process would appear within the opening of the foramen magnum. C The tube angulation would foreshorten the odontoid process and therefore may superimpose the borders of a fracture gap in such a way that the fracture may go undetected. D The thyroid dose would significantly increase.
(C) The tube angulation would foreshorten the odontoid process and therefore may superimpose the borders of a fracture gap in such a way that the fracture may go undetected.
Which of the following combinations will result in the most scattered radiation reaching the image receptor? A Using more mAs and compressing the part B Using more mAs and a higher ratio grid C Using less mAs and more kVp D Using less mAs and compressing the part
(C) Using less mAs and more kVp
The reduction in x-ray photon intensity as the photon passes through material is termed A absorption B scattering C attenuation D divergence
(C) attenuation
The absorption of useful radiation by a grid is called A grid selectivity. B grid cleanup. C grid cutoff. D latitude.
(C) grid cutoff.
A graphic diagram of signal values representing various absorption properties within the part being imaged is called a A processing algorithm B DICOM C histogram D window
(C) histogram
Causes of overexposure using AEC include (select the three that apply) A insufficient backup time selected B selected photocell is under tissue less dense than area of interest C plus density control incorrectly selected D required exposure time more than minimum response time E selection of incorrect Bucky F selected photocell is under a radiopaque appliance/prosthesis
(C) plus density control incorrectly selected (E) selection of incorrect Bucky (F) selected photocell is under a radiopaque appliance/prosthesis If wall Bucky is selected for tabletop exposure overexposure will result, as exposure continues because wall photocells are not activated by tabletop exposure (E).
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
Combinations of milliamperage and exposure time that produce a particular milliampere-seconds value will produce identical receptor exposure. This statement is an expression of the A inverse-square law B line-focus principle C reciprocity law D D log E curve
(C) reciprocity law
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
(C) signal-to-noise ratio
If 100 mA were selected for a radiographic exposure, what exposure time would be required to produce 5 mAs? A 0.005 sec B 0.02 sec C 0.5 sec D 0.05 sec
(D) 0.05 sec
What pixel size has a 2048 × 2048 matrix with an 80-cm FOV? A 0.04 mm B 0.08 mm C 0.2 mm D 0.4 mm
(D) 0.4 mm In this case the FOV is 80 cm; since the answer is expressed in mm, first change 80 cm to 800 mm. Then 800 divided by 2048 equals 0.4 mm.
If 300 mA has been selected for a particular exposure, what exposure time would be required to produce 60 mAs? A 1/60 second B 1/30 second C 1/10 second D 1/5 second
(D) 1/5 second
If a particular grid has lead strips 0.40 mm thick, 4.0 mm high, and 0.25 mm apart, what is its grid ratio? A 8:1 B 10:1 C 12:1 D 16:1
(D) 16:1
Which of the following matrix sizes is most likely to produce the best image resolution? A 128 × 128 B 512 × 512 C 1,024 × 1,024 D 2,048 × 2,048
(D) 2,048 × 2,048
Using a 48-in. SID, how much OID must be introduced to magnify an object two times? A 8-in. OID B 12-in. OID C 16-in. OID D 24-in. OID
(D) 24-in. OID To magnify an object to twice its actual size, the part must be placed midway between the focal spot and the IR.
If 0.05 second was selected for a particular exposure, what mA would be necessary to produce 15 mAs? A 900 B 600 C 500 D 300
(D) 300
If exposure factors of 85 kVp, 400 mA, and 12 ms yield an output exposure of 150 mR, what is the milliroentgens per milliampere-seconds (mR/mAs)? A 0.32 B 3.1 C 17.6 D 31
(D) 31
If 84 kV and 8 mAs were used for a particular abdominal exposure with single-phase equipment, what milliampere-seconds value would be required to produce a similar radiograph with three-phase, 12-pulse equipment? A 24 mAs B 16 mAs C 8 mAs D 4 mAs
(D) 4 mAs
An x-ray image of the ankle was made at 40-SID, 200 mA, 50 ms, 70 kV, 0.6 mm focal spot, and minimal OID. Which of the following modifications would result in the greatest increase in magnification? A 1.2 mm focal spot B 36-in. SID C 44-in. SID D 4-in. OID
(D) 4-in. OID
If 92 kV and 12 mAs were used for a particular abdominal exposure with single-phase equipment, what mAs would be required to produce a similar radiograph with three-phase equipment? A 36 B 24 C 8 D 6
(D) 6
An exposure was made using 300 mA and 50 ms. If the exposure time is changed to 22 ms, which of the following milliamperage selections would most closely approximate the original receptor exposure? A 300 mA B 400 mA C 600 mA D 700 mA
(D) 700
Which of the following radiographic examinations can use the anode heel effect to best advantage? A AP foot B AP knee C PA skull D AP thoracic spine
(D) AP thoracic spine
