Ch. 6

Question 1

The product of milliamperage and exposure time is _______ to the quantity of x-rays produced.

Answer 1

directly proportional

Question 2

As mAs increases, the quantity of radiation reaching the IR

Answer 2

Increases

Question 3

If you were to select 250 mA and 0.5s on the control panel, how much mAs would be created?

Answer 3

125 mAs

mA x time = mAs

Question 4

The original exposure to the IR is 100mA at 125ms. Which of the following exposure techniques would decrease the IR exposure by about 1/2?

200 mA at 31ms
100 mA at 0.063.s
50 mA at 0.125 s
All the above

Answer 4

All the above

Question 5

The original technique is 300 mA at 50ms. If the mA is increased to 500, what exposure time will maintain the same exposure to the IR?

0.030 s
0.30 s
3 ms
15 ms

Answer 5

0.030 s

Question 6

The original technique is 50mA at 0.20s. Which of the following exposure techniques will maintain the same exposure to the IR?

100 mA at 0.10 s and 200 mA at 0.05 s
100 mA at 0.10 s and 400 mA at 25 ms
200 mA at 0.05 s and 400 mA at 25 m
All are correct

Answer 6

All are correct

Question 7

Which of the following is correct regarding the effect mAs has on the displayed digital image?
A. Increases brightness.
B. Decreases brightness.
C. Does not control brightness.
D. Increases contrast

Answer 7

Does not control brightness

Question 8

Increased quantum noise is seen in a digital image with:

Answer 8

severely lower-than-needed mAs

Question 9

If the exposure indicator value indicates too little radiation reaching the IR and the image displays increased quantum noise, what technique change would be best?

Answer 9

increase kVp by 15% and double mAs

Question 10

The numerical value that is displayed on the processed image to indicate the level of x-ray exposure received on the digital image receptor is the

Answer 10

Exposure indicator

Question 11

Which of the following technical factors affects the exposure to the IR by altering the amount and penetrating ability of the x-ray beam?

a. kVp
b. mA
c. Seconds
d. SID

Answer 11

kVp

Question 12

In order to reduce patient exposure, what exposure factors should be considered?

Answer 12

higher kVp, lower mAs

Question 13

A high kVp results in:

A less variation in the x-ray intensities exiting the patient.
B decrease interactions from Compton scattering.
C high-contrast image.

Answer 13

A) less variation in the x-ray intensities exiting the patient.

Question 14

How much change in kVp will change the radiation exposure to the IR by a factor of 2?

Answer 14

15%

The 15% rule states that increasing or decreasing the kVp by 15% has the same effect as doubling or halving the mAs

Question 15

The original technique is 80kVp at 20 mAs. If the kVp is increased to 92, what change in mAs will maintain the exposure to the IR?

Answer 15

10 mAs

A 15% increase in kVp, requires ½ the mAs to maintain a similar exposure to the IR.

Question 16

The original technique is 80 kVp at 20 mAs. If the kVp is decreased to 68, what change in mAs will maintain the exposure to the IR?

Answer 16

40 mAs

Double your mAs

Question 17

During the selection of the focal spot size, the radiographer is really determining the:

Answer 17

Actual size of the filament used

Question 18

The distance between the radiation source and the image receptor is the:

Answer 18

SID

Question 19

The relationship between distance and x-ray beam intensity, specifically that the intensity of the x-ray beam is inversely proportional to the square of the distance from the source, is the:

Answer 19

Inverse square law

Question 20

If a person stands 3 feet from the source of exposure, receives an exposure of 160 mR, and then moves to 6 feet from the source of exposure, what would be the new exposure according to the ISL?

Answer 20

40 mR

Question 21

If a person stands 12 feet from the source of exposure, receives an exposure of 60 mR, and then moves to 3 feet from the source of exposure, what would be the new exposure according to the ISL?

Answer 21

960 mR

According to the inverse square law, decreasing the distance from the x-ray source from 12 to 3 feet (factor of four) will result in an increase of exposure from 60 to 960 mR.

Question 22

The distance between the object being imaged and the IR is the:

Answer 22

OID

Question 23

When the SID is divided by the SOD, what is the result called?

Answer 23

Magnification Factor

Question 24

If the first image of a chest is done using 72 in and 12 mAs, and a second image is done using 40 in, how much mAs should be used to maintain exposure to the IR?

Answer 24

4 mAs

Question 25

A quality radiographic image is done using 10 mAs, 70 kVp, and a 12:1 ratio grid. How much mAs is needed to produce an image with the same exposure to the IR when the grid is removed?

Answer 25

2 mAs

Question 26

The original technique is 80 kVp at 20 mAs using an 8:1 grid ratio. What change is mAs is needed if changing to a 16:1 grid ratio?

Answer 26

30 mAs

Question 27

The misrepresentation of the size of an object is:

Answer 27

Magnification

Question 28

In order to image a structure that is located anteriorly in the body, it is best radiographed to minimize magnification by doing a(n) _______ projection

Answer 28

posterior-anterior (PA)

Question 29

Magnification is affected by:

Answer 29

SID

Question 30

If the image size measures 4.6 in, and the magnification factor is 1.42, what is the size of the object?

Answer 30

3.24 in image size divided by magnification factor SID OVER SOD

Question 31

Shape distortion can be created by:

Answer 31

decreasing SOD angling the central ray

Question 32

The SOD can be determined by:

Answer 32

subtracting the OID from SID

Question 33

What effect will increasing SID have on spatial resolution?

Answer 33

increasing spatial resolution

Question 34

For every ______ of part thickness, the radiographer should adjust the mAs by a factor of two.

Answer 34

4-5 cm

Question 35

If the first radiograph of a foot is done using 4 mAs at 40 in, and a second radiograph is done using 50 in, how much mAs should be used to maintain exposure to the IR?

Answer 35

6 mAs (New SID)² = 50² (Old SID)² = 40² New mAs = (50²/40²) * 4 mAs = 6.4 mAs

Question 36

Assuming all produce appropriate diagnostic images, which of the following would be the best exposure technique choice when performing a chest radiograph on an infant? A. Use 40 ms exposure time. B. Use 60 ms exposure time. C. Use 200 ms exposure time. D. Use at least 80 kVp.

Answer 36

A. Use 40 ms exposure time. Shortest possible exposure time

Question 37

With all other factors remaining the same, a patient with which body habitus would require the highest exposure factors?

Answer 37

hypersthenic

Question 38

The property of the x-ray beam that impacts the unsharpness on the image is the beam:

Answer 38

divergence

Question 39

Once the part has been penetrated, a doubling of the mAs results in _______ the exposure to the IR.

Answer 39

two times

Question 40

Which of the following mA and exposure time combinations does not produce 12 mAs? A. 200 mA at 0.06 s B. 400 mA at 0.03 s C. 600 mA at 20 ms D. 800 mA at 0.15 s

Answer 40

D. 800 mA at 0.15 s mA x time 800 mA at 0.15 s results in 120 mAs

Question 41

If lower than needed kVp is selected, the digital image will have:

Answer 41

higher subject contrast and increased quantum noise

Question 42

Using twice as much mAs as needed will result in

Answer 42

adequate image brightness and unnecessary patient radiation exposure

Question 43

Knowing that 6 mAs is appropriate for a knee examination done at 40 in SID, how much mAs should be used at 56 in SID?

Answer 43

12 mS

Question 44

Which of the following is not affected by a change in SID? A. Spatial resolution B. Image contrast C. Amount of radiation reaching the IR D. Magnification

Answer 44

Image contrast

Question 45

The radiographic grid is located

Answer 45

between the patient and the IR

Question 46

Decreasing collimation results in: A. increased fog and lower image contrast B. increased fog and increased patient exposure C. lower image contrast and increased patient exposure D. all options are correct

Answer 46

ALL

Question 47

Decreasing collimation results in

Answer 47

increased fog, lower image contrast, increased patient exposure

Question 48

Increasing tube filtration results in an x-ray beam with:

Answer 48

fewer photons and higher energy

Question 49

As compared to a patient with a 24 cm thick abdomen, imaging a patient with a 20 cm thick abdomen will result in: A. less scatter and increased spatial resolution B. less scatter and higher contrast C. increased spatial resolution and higher contrast D. all options are correct

Answer 49

D. all options are correct

Question 50

Increasing part thickness decreases image contrast: true or false?

Answer 50

True

Question 51

Kilovoltage does not affect the quantity of exit radiation until adequate penetration is reached T or F

Answer 51

True

Question 52

The amount of mAs used controls image brightness T or F

Answer 52

False mAs does not control brightness!

Question 53

Changes in kVp do not affect the exposure indicator value T or F

Answer 53

False

Question 54

Any increase in magnification results in a decrease in spatial resolution T or F

Answer 54

True

Question 55

When choosing a grid for an examination, the grid with the highest grid ratio should always be selected in order to most improve image contrast. T or F

Answer 55

False

Question 56

As compared to a three-phase x-ray unit, a single-phase unit requires higher exposure techniques to produce a comparable image. T or F

Answer 56

True

Question 57

The same mAs and kVp should be used for an AP lumbar spine and a lateral lumbar spine. T or F

Answer 57

False

Question 58

To reduce patient radiation exposure, is it best to use a lower kVp and higher mAs.

Answer 58

False You want to use high kVp and low mAs!

Question 58

OID affects magnification, spatial resolution, contrast, and exposure to the IR.

Answer 58

True

Question 59

KNOW GRID CONVERSIONS

Question 60

no grid, conversion?

Answer 60

1

Question 61

5:1 grid conversion?

Answer 61

2

Question 62

6:1 gird conversion is?

Answer 62

3

Question 63

8:1 grid conversion?

Answer 63

4

Question 64

12:1 grid conversion?

Answer 64

5

Question 65

16:1 grid conversion?

Answer 65

6