Chapter 9

A radiograph is produced using 4 mAs and 70 kVp. The resulting receptor exposure is 0.001 mGy. If technical factors are changed to 8 mAs and the same kVp, the next radiograph will have a receptor exposure of: a) 0.002 mGy b) 0.0005 mGy c) 0.0012 mGy d) 0.01 mGy

a) 0.002 mGy

A new x-ray machine is installed in your department with 3.0 mm of aluminum filtration. What would be the effect of increasing the filtration to 3.5 mm of aluminum? 1. decreased patient skin dose 2. increased receptor exposure 3. increased distortion a) 1 only b) 2 only c) 3 only d) 1 and 2 only

a) 1 only

If 80 kVp, 400 mA, and 0.025 sec. produce a satisfactory radiograph, what mAs was used? a) 10 b) 5 c) 100 d) 1

a) 10

If a satisfactory density is obtained with 40 mAs at 72 in., what mAs is required to maintain the same exposure at 40 in.? a) 12 mAs b) 40 mAs c) 100 mAs d) 130 mAs

a) 12 mAs

After completing a radiograph using 27 mAs at 90 kVp, the image demonstrates adequate overall density but an area that is underpenetrated. In order to produce an optimum image in terms of contrast and penetration, the repeat image should be taken at a) 27 mAs and 100 kVp. b) 54 mAs and 77 kVp. c) 13 mAs and 94 kVp. d) 27 mAs and 94 kVp.

a) 27 mAs and 100 kVp.

A radiograph of the forearm is acquired using 25 mA at 60 kVp. What new kVp would be required to double the exposure? a) 69 kVp b) 9.6 kVp c) 51 kVp d) 119 kVp

a) 69 kVp

Assuming all other factors are constant, what field size will produce the lowest receptor exposure? a) 8 in x 10 in b) 10 in x 12 in c) 14 in x 17 in d) field size does affect receptor exposure

a) 8 in x 10 in

Which examination does not exhibit an inherently large OID? a) AP Lumbar Spine b) Lateral Cervical Spine c) Lateral chest d) Lateral sternum

a) AP Lumbar Spine

When the anatomy being imaged is parallel to the image receptor, and the X-ray beam is angled, what type of shape distortion will result? a) Elongation b) Foreshortening c) magnification d) none of the above

a) Elongation

The major controlling factor of contrast is a) Kvp b) mAs c) focal spot size d) OID

a) Kvp

Which factor influences the average energy of photons reaching the IR? a) Kvp b) mAs c) Focal spot size d) mA

a) Kvp

Which of these factors allow for the best visualization of small parts in a radiograph? a) Pixel pitch = 0.1 mm b) Pixel pitch = 0.2 mm c) Pixel pitch = 0.3 mm d) Pixel pitch = 0.4 mm

a) Pixel pitch = 0.1 mm

Which of these variables affect the spatial resolution recorded in the radiographic image? a) SID b) Kvp c) mAs d) anode heel effect

a) SID

As Compton scatter increases, contrast decreases. a) True b) False

a) True

As OID decreases, contrast decreases a) True b) False

a) True

As SID increases, IR exposure decreases. a) True b) False

a) True

As grid ratio increases, contrast increases. a) True b) False

a) True

As kVp increases, contrast decreases. a) True b) False

a) True

Kilovoltage controls the relationship between photoelectric versus Compton interactions. a) True b) False

a) True

additive pathology causes an increases in brightness of the image a) True b) False

a) True

barium will cause an increase in brightness in IR a) True b) False

a) True

Motion damages _______. a) detail b) magnification c) distortion d) nothing

a) detail

The window width controls a) dynamic range b) brightness c) speed d) depth

a) dynamic range

A radiograph that has densities that are very different from each other a) has high contrast b) has low contrast c) has long-scale contrast d) B and C

a) has high contrast

A radiograph of the pelvis is produced with excellent contrast but low receptor exposure. The initial technique was 16 mAs, 80 kVp, 40 inch SID, and no grid. What is the ideal way to increase the receptor exposure? a) increase mAs b) increase kVp c) decrease mAs d) decrease kVp

a) increase mAs

When imaging a patient with severe osteoporosis, failing to adjust the exposure factors could have what effect on the receptor exposure? a) increased receptor exposure b) decreased receptor exposure c) no effect on receptor exposure

a) increased receptor exposure

As kVp ____, a ____ range of photon energies is produced. a) increases, wider b) increases, narrower c) decreases, wider d) none of the above

a) increases, wider

Changes to the mA or exposure time are known to affect what aspect of the x-ray beam? a) intensity b) beam hardness c) penetrability d) beam energy

a) intensity

Resolution is typically measured in a) line pairs per millimeter b) line pairs per meter c) line pairs per inch d) line pairs per foot

a) line pairs per millimeter

Digital receptor systems with a large DEL pitch will have: a) low spatial resolution b) High spatial resolution c) Pitch does not affect spatial resolution d) decrease in receptor exposure

a) low spatial resolution

All of the following are related to recorded detail except a) mA b) focal spot size c) IR speed d) OID

a) mA

During a series of portable chest x-rays, the technologist fails to adjust the kVp for an especially large patient. This is likely to result in which of the following? a) quantum mottle b) saturation c) excessive receptor exposure d) penumbra

a) quantum mottle

Receptor exposure is defined as: a) the amount of radiation striking the IR b) the amount of radiation absorbed by the patient c) the visible difference in brightness levels in the image d) the amount of magnification in the digital image

a) the amount of radiation striking the IR

High contrast is directly related to a) the number of photoelectric interactions. b) high kVp. c) an increase in the amount of Compton scatter. d) mAs

a) the number of photoelectric interactions.

A radiograph that demonstrates considerable differences between densities is called 1. high contrast 2. long scale of contrast 3. short scale of contrast 4. low scale of contrast a) 1 and 2 only b) 1 and 3 c) 1, 2, and 4 d) all of the above

b) 1 and 3

Calculate the magnification factor for an image taken at a 40 inch distance (SID), and an OID of 2 in a) 0.95 b) 1.05 c) 20 d) 1.5

b) 1.05

A pixel that has an eight-bit depth displays _______ shades of gray. a) 126 b) 256 c) 512 d) 1024

b) 256

The window level controls a) Contrast b) Brightness c) speed d) resolution

b) Brightness

Additive pathology would result in an increase of IR exposure a) True b) False

b) False

As OID increases, IR exposure increases. a) True b) False

b) False

As OID increases, contrast decreases . a) True b) False

b) False

As focal spot size increases, contrast increases. a) True b) False

b) False

Milliampere-seconds influences contrast. a) True b) False

b) False

Restricting the primary beam increases exposures. a) True b) False

b) False

Which of the following can also be referred to as size distortion? a) Elongation b) Magnification

b) Magnification

Resolution is improved when a) OID increases b) OID decreases c) SID decreases d) All of the above

b) OID decreases

Which of the following situations regarding SID is correct as it relates to size distortion? a) Size distortion increases with a longer SID b) Size distortion decreases with a longer SID c) Size distortion is independent of SID d) None of the above

b) Size distortion decreases with a longer SID

A severely underexposed film image will a) demonstrate adequate image detail but low contrast b) be unable to visualize recorded detail c) darken when placed on an illuminator. d) demonstrate high radiographic density.

b) be unable to visualize recorded detail

A severely underexposed image receptor will a) demonstrate adequate image detail b) be unable to visualize recorded detail. c) darken when placed on an illuminator. d) demonstrate high radiographic density.

b) be unable to visualize recorded detail.

The window level controls a) contrast b) brightness c) dynamic range d) speed

b) brightness

The window width controls a) brightness b) contrast c) speed d) resolution

b) contrast

A portable chest x-ray is required on a very small patient. The mAs and kVp are set as low as possible, but you still expect the receptor exposure to be too high. Another way to decrease the receptor exposure would be to: a) decrease the diagnostic filtration b) increase the SID c) decrease the grid ratio

b) increase the SID

In a direct capture radiography system, a decreased detector element (DEL) size results in a) Decreased spatial resolution b) increased spatial resolution c) No change in spatial resolution d) No answer text provided.

b) increased spatial resolution

The controlling factor of exposure is a) Kvp b) mAs c) OID d) SID e) None of the above

b) mAs

Which factor influences the number (quantity) of photons reaching the IR? a) Kvp b) mAs c) focal spot selection d) exposure time

b) mAs

Computerized digital images consist of a ________ of picture elements, each with a video display value or gray shade a) row b) matrix c) column d) pixels

b) matrix

Which technical factor should the technologist use to control the receptor exposure? a) kilovoltage potential (kVp) b) milliamperage-seconds (mAs) c) Source-to-image distance (SID) d) Protective shielding

b) milliamperage-seconds (mAs)

A fluoroscopic examination that uses barium as a contrast material would typically produce images with a) long scale contrast. b) short scale contrast. c) low contrast. d) both a and c

b) short scale contrast.

When matrix size is increased and pixel size goes down, a) spatial resolution decreases. b) spatial resolution increases. c) contrast increases. d) both A and C

b) spatial resolution increases.

An increase in tube potential would increase receptor exposure by: 1. increasing the number of photons in the beam 2. increasing the penetrating ability of the beam 3. increasing the attenuation of the beam a) 1 only b) 2 only c) 1 and 2 only d) 1, 2, and 3

c) 1 and 2 only

An under-exposed image might have an image artifact called: 1. Noise 2. Mottle 3. Saturation a) 1 only b) 2 only c) 1 and 2 only d) 1, 2, and 3

c) 1 and 2 only

Image distortion can best be described as which of the following?1. Enlargement of the size of the anatomy being imaged2. Misrepresentation of the shape of the anatomy being imaged3. Blurriness of structural lines of the anatomy being imaged a) 1 only b) 2 only c) 1 and 2 only d) 1, 2, and 3

c) 1 and 2 only

A radiograph with few shades of gray exhibits 1. high contrast 2. low contrast 3. long scale of contrast 4. short scale of contrast a) 1 and 2 only b) 2 and 3 only c) 1 and 4 only d) all of the above

c) 1 and 4 only

Optimum recorded detail may be caused by which of the following factors? 1. Long SID 2. Long OID 3. Short SID 4. Short OID 5. Large focal spot 6. Small focal spot 7. Patient motion 8. Magnification 9. High speed image receptor 10. Low speed image receptor 11. X-ray tube motion a) 2, 3, 5, 7, 8, 9, 11 b) 1, 4, 6, 8, 11 c) 1, 4, 6, 10 d) 3, 5, 9

c) 1, 4, 6, 10

A matrix of size 2048x1536 would have _______ pixels. a) 512 b) 3584 c) 3,145,728 d) none of the above

c) 3,145,728

Shape distortion includes which specific types of distortion? a) Magnification and minification b) Magnification, elongation, and foreshortening c) Elongation and foreshortening d) Foreshortening and compression

c) Elongation and foreshortening

An image with high spatial resolution would also be described as having a) High blur b) High mottle c) High sharpness d) High distortion

c) High sharpness

Distortion is a misrepresentation of a) Size only b) Shape only c) Size and shape d) detail

c) Size and shape

All of the following factors would affect radiographic contrast EXCEPT a) field size b) OID c) focal spot selection. d) Kvp

c) focal spot selection.

As kVp increases, the percentage of Compton interactions _______ and contrast_______. a) decreases; decreases b) decreases; increases c) increases; decreases d) increases; increases

c) increases; decreases

As kVp increases, the percentage of Compton interactions _______ and photoelectric interactions _______. a) decreases; decreases b) decreases; increases c) increases; decreases d) increases; increases

c) increases; decreases

Poor receptor exposure in a digital image is most likely to result in: a) excessive darkness of the image b) excessive contrast in the image c) information lost in the image d) anatomic distortion

c) information lost in the image

The space between detector elements is called the: a) matrix size b) bit depth c) pitch d) exposure latitude

c) pitch

Spatial resolution is controlled by a) bit depth b) contrast resolution c) pixel size d) byte size

c) pixel size

The difference between two adjacent densities is a) recorded detail b) Quantum mottle c) radiographic contrast d) distortion

c) radiographic contrast

Receptor exposure is affected by: 1. mAs 2. collimation 3. filtration a) 1 only b) 2 only c) 3 only d) 1, 2, and 3

d) 1, 2, and 3

Shape distortion is related to a misalignment of, or angle present on which of the following? 1. X-ray tube 2. Anatomy being imaged 3. Image receptor a) 1 only b) 1 and 3 only c) 2 and 3 only d) 1, 2, and 3

d) 1, 2, and 3

If all other exposure variables remain constant, which of these object-to-image distances (OID) will produce a radiograph with the LEAST amount of image blur? a) 72 inches b) 40 inches c) 12 inches d) 4 inches

d) 4 inches

A line pair is made up of a) a line b) two lines c) a space d) A and C

d) A and C

As focal spot decreases, a) Umbra is improved b) resolution decreases c) resolution increases d) A and C only

d) A and C only

Which statement is FALSE? a) As mAs increases, exposure increases. b) As mAs decreases, density decreases. c) As mAs increases, density increases. d) As mAs decreases, exposure increases.

d) As mAs decreases, exposure increases.

A radiograph that has densities that are very similar to each other a) has high contrast b) has low contrast c) has long-scale contrast d) Band C

d) Band C

A patient presents to the radiology department for a foot radiograph and upon assessment of the patient, the technologist sees that the patient has stepped on a nail and the nail is still sticking out of the plantar surface of the foot approximately two inches. This nail will create OID that cannot be avoided on an AP foot radiograph. What steps should the radiographer take to prevent the size distortion that would be created by the long OID? a) The technologist should remove the nail so that OID can be reduced. b) The technologist should use a shorter SOD to reduce the magnification. c) The technologist should reduce the usual 40-inch SID to reduce the magnification. d) The technologist should increase the SID beyond the standard 40 inches to reduce the magnification.

d) The technologist should increase the SID beyond the standard 40 inches to reduce the magnification.

Which of the following projections of the skull would result in elongation of the anatomy being imaged? a) PA (no tube angle) b) lateral c) Parietoacanthial Waters (with skull extended so OML is at 37 degree angle to IR) d) Towne's (37 degree angle on the X-ray tube)

d) Towne's (37 degree angle on the X-ray tube)

Which of the following situations will result in the greatest amount of shape distortion? a) X-ray beam perpendicular to the object, which is parallel to the image receptor b) X-ray beam angled 20 degrees to anatomy that is parallel to the image receptor c) Anatomy that is angled 10 degrees in relation to the beam and image receptor d) X-ray beam angled 45 degrees to anatomy that is parallel to the image receptor

d) X-ray beam angled 45 degrees to anatomy that is parallel to the image receptor

Recorded detail is a) The degree of geometric sharpness b) definition c) The accuracy of the structural lines actually recorded in the radiographic image d) all of the above

d) all of the above

Size distortion can be controlled by a) SID b) Radiographic distance c) OID d) all of the above

d) all of the above

The overall quality of the radiographic image is determined by a) sharpness b) visibility of anatomic structures c) accuracy of structural lines d) all of the above

d) all of the above

Which of these equipment factors can influence spatial resolution in radiography? Choose multiple 1. DEL size 2. DEL pitch 3. Matrix size 4. Pixel size a) 1 only b) 1 and 2 only c) 1, 2, and 3 only d) all of the above

d) all of the above

A technologist can identify an image produced with excessively high mAs based on which of the following? a) the appearance of quantum mottle b) the appearance of excessive image contrast c) the appearance of vertical streaks in the image d) an exposure outside of the acceptable range

d) an exposure outside of the acceptable range

All of the following impact digital image spatial resolution EXCEPT a) pixel pitch b) pixel size c) matrix size d) bit depth

d) bit depth

The relationship between digital image resolution a) is direct with matrix size. b) is indirect with pixel size. c) is direct with pixel bit depth. d) both A and B

d) both A and B

An AP chest x-ray was obtained at 40 inches, 3.5 mAs, 110 kVp, with a 12:1 grid. Which variable change would increase the receptor exposure? a) increase SID b) decrease mAs c) decrease kVp d) decrease grid ratio

d) decrease grid ratio

Which of the choices below does not increase contrast? a) increasing grid ratio b) increase in OID c) decrease in Kvp d) increase in Kvp

d) increase in Kvp

The relationship between IR exposure and SID is (hint the best answer) a) directly proportional . b) inversely proportional. c) directly proportional to the square of the distance. d) inversely proportional to the square of the distance. e) None of the above

d) inversely proportional to the square of the distance.

Optimum radiographic image quality is a function of proper exposure technique selection. Given the three sets of mAs calculations that follow, all three should yield the same degree of radiographic exposure to a detector. Exposure 1: 200 mA × 0.05 ms Exposure 2: 100 mA × 0.10 ms Exposure 3: 400 mA × 0.025 ms This is known as a) the inverse square law. b) the kVp/mAs ratio. c) mA/mAs proportionality. d) mAs reciprocity

d) mAs reciprocity

Select which set of technical factors listed below that will yield the least radiographic density mA OID Grid ratio Seconds SID KVP A. 200 4 8:1 0.15 150 86 B. 300 8 8:1 0.15 150 94 C. 300 2 8:1 0.20 200 82 D. 100 10 8:1 0.05 100 84 a) the answer is A b) the answer is B c) the answer is C d) the answer is D

d) the answer is D

A radiograph that is too light has ________________ to visualize the anatomic structures. a) excessive brightness b) excessive IR exposure c) insufficient IIR exposure d) A and B e) A and C

e) A and C