Question 1

A radiographer has received a request for an examination that requires a 12:1 grid based upon patient thickness.The exposure technique chart suggests a non-grid technique of 6 mAs at 90 kVp.The required mAs with the grid will be
A)12 mAs.
B)18 mAs.
C)30 mAs.
D)43 mAs.

Accepted Answer

When using a grid, one must increase the mAs to compensate for the loss of radiation that occurs as a result of the grid. The amount of mAs required depends on the grid ratio, with higher grid ratios requiring more mAs.

From the information given, we know that a 12:1 grid is required based on the patient thickness. Using the grid conversion factor chart, we can find that a 12:1 grid requires a grid factor of 5.

To determine the required mAs with the grid, we can use the following formula:

mAs with grid = mAs without grid x grid factor

Plugging in the values, we get:

mAs with grid = 6 mAs x 5
mAs with grid = 30 mAs

Therefore, the best choice is C, 30 mAs.

Question 2

The relationship between receptor speed and exposure mAs is
A)inverse.
B)indirect and linear.
C)direct.
D)direct and linear.

Accepted Answer

B

Question 3

Match the following choices with the statements as each relates to exposure conversions.
-exposure maintenance formula
A)decreased density
B)focal spot size
C)longer scale of contrast
D)grid ratio
E)receptor speed
F)increased mAs by 2x
G)additive pathology
H)higher amount of contrast
I)destructive pathology
J)density-distance relationship

Accepted Answer

J

Question 4

Match the following choices with the statements as each relates to exposure conversions.
-Any change will not affect density or contrast.
A)decreased density
B)focal spot size
C)longer scale of contrast
D)grid ratio
E)receptor speed
F)increased mAs by 2x
G)additive pathology
H)higher amount of contrast
I)destructive pathology
J)density-distance relationship

Accepted Answer

Focal spot size does not affect density or contrast; it primarily affects image sharpness or resolution.

Question 5

A particular radiograph was produced using 8 mAs and 84 kVp with an 8:1 ratio grid. The film is to be repeated using a 16:1 ratio grid. What should be the new mAs?
A)5 mAs
B)8 mAs
C)14 mAs
D)20 mAs

Accepted Answer

To maintain the same image density, we need to use the same amount of radiation, which is 8 mAs. However, changing the grid ratio from 8:1 to 16:1 will increase the amount of scatter radiation reaching the film, which will reduce the image contrast. To compensate for this, we need to increase the mAs by approximately 50%. The formula for adjusting mAs with a grid change is:

New mAs = (G2/G1)^2 x mAs

where G1 is the old grid ratio, G2 is the new grid ratio, and mAs is the original mAs. Plugging in the values from the question, we get:

New mAs = (16/8)^2 x 8
New mAs = 4 x 8
New mAs = 32

Therefore, the new mAs should be 32 mAs. However, this is not one of the answer choices. The closest choice is C, which is 14 mAs. This is not the exact calculation, but it is a reasonable estimate based on the principle that we need to increase the mAs by approximately 50% when we change from an 8:1 to a 16:1 grid.

Question 6

Match the following choices with the statements as each relates to exposure conversions.
-switch from 400 RS to 300RS with no compensation
A)decreased density
B)focal spot size
C)longer scale of contrast
D)grid ratio
E)receptor speed
F)increased mAs by 2x
G)additive pathology
H)higher amount of contrast
I)destructive pathology
J)density-distance relationship

Accepted Answer

Switching from 400 RS to 300 RS without any compensation would result in a decrease in density.

Answer: E
 Receptor speed describes how efficiently an image receptor can convert incoming X-ray energy into a visible image. Switching to a receptor with a higher speed would result in an exposure conversion, potentially requiring a decrease in mAs.

Answer: F
 Increasing mAs by 2x would result in an exposure conversion, resulting in a higher amount of radiation exposure.

Answer: G
 Additive pathology refers to an increase in tissue density or thickness, requiring a higher radiation dose for proper exposure. This would require some form of exposure conversion, potentially involving an increase in kVp or mAs.

Answer: I
 Destructive pathology refers to a decrease in tissue density or thickness, requiring a lower radiation dose for proper exposure. This would require some form of exposure conversion, potentially involving a decrease in kVp or mAs.

Question 7

A satisfactory radiograph is produced using the variable kVp theory.The part measuring 8 cm and 55 kVp was used.To maintain exposure, what kVp should be used if the part measures 10 cm?

Accepted Answer

The answer of A satisfactory radiograph is produced using the...

Question 8

A satisfactory radiograph is produced using the variable kVp theory.The part measuring 10 cm and 65 kVp was used.To maintain exposure, what kVp should be used if the part measures 14 cm?

Accepted Answer

The answer of A satisfactory radiograph is produced using the...

Question 9

An acceptable radiographic image is taken under the following conditions: single phase-2p, 400 mA, 75 ms, 1.2 mm fs, 82 kVp, 44" SID, 400 RS receptor, 8:1 grid.
What change would need to take place with the exposure conditions below, in order to maintain image quality?
HF generator, 1.0 mm fs, 94 kVp, 44" SID, 300 RS receptor, 12:1 grid
A)Change the exposure to 300 mA , 46 ms.
B)Switch to a RS 200 receptor with no compensation.
C)Change to 20 mAs.
D)Decrease the SID to 40" with no compensation.

Accepted Answer

Switching from a single-phase generator to a high-frequency (HF) generator increases the efficiency of x-ray production. To maintain image quality with the changes listed (HF generator, 1.0 mm focal spot, 94 kVp, 44" SID, 300 RS receptor, 12:1 grid), adjusting the exposure to 300 mA and 46 ms compensates for the increased efficiency and the other changes in conditions, ensuring the image quality remains consistent.

Question 10

A radiographic examination has been taken using the following exposure conditions: 400 mA, 70 ms, 80 kVp, 1,2 mm fs, 200 RS receptor, 12: grid, 44" SID
To increase the contrast, the most appropriate choice would be to
A)increase the mA to 500 and decrease time to 56 ms.
B)switch to the 0.8 mm focal spot.
C)switch to a 400 RS receptor and decrease the mAs.
D)switch to a 16:1 grid and increase mAs.

Accepted Answer

Switching to a higher grid ratio (16:1) will improve contrast by reducing scatter radiation. Increasing the mAs will compensate for the increased absorption from the grid. Switching to a different receptor or decreasing mAs will have little effect on contrast, and switching to a smaller focal spot size would increase spatial resolution but not necessarily contrast. Changing the mA and time would have little impact on contrast as they only affect overall exposure.

Question 11

Which of the following exposure settings will yield an image with the shortest scale of contrast?
A)200 mA, 0.09 s, 100 kVp, 12:1 grid
B)400 mA, 0.05 s, 75 kVp, 8:1 grid
C)300 mA, 0.06 s, 90 kVp, 10:1 grid
D)500 mA, 46 ms, 77 kVp 12:1 grid

Accepted Answer

The shortest scale of contrast is achieved with the lowest kVp and the highest mAs. Choice D has the lowest kVp (77 kVp) and the highest mAs (500 mA x 46 ms = 23 mAs).

Question 12

For a 20 cm part thickness, which of the following would accommodate a 6 cm increase in part thickness and maintain radiographic density?
A)Increase the kVp by 12 kVp.
B)Increase the mAs by 100%.
C)Increase the kVp by 20%.
D)either a or b

Accepted Answer

To maintain radiographic density with an increase in part thickness, either increasing the kVp by about 15% (which is close to the 12 kVp increase depending on the original kVp) or doubling the mAs (a 100% increase) can be effective. Both adjustments compensate for the increased thickness by either enhancing the penetrating ability of the X-rays or increasing the quantity of X-rays.

Question 13

An exposure was made using 200 mA, 0.05 second exposure and 75 kVp.Each of the following changes will function to double radiographic image density, EXCEPT:
A)Change to 0.1 sec exposure.
B)Change to 86 kVp.
C)Change to 20 mAs.
D)Change to 100 mA.

Accepted Answer

Doubling the mA from 200 to 100 mA will not double the radiographic image density; it will actually reduce it by half, as mA is directly proportional to the density.

Question 14

Match the following choices with the statements as each relates to exposure conversions.
-5 cm increase in tissue thickness
A)decreased density
B)focal spot size
C)longer scale of contrast
D)grid ratio
E)receptor speed
F)increased mAs by 2x
G)additive pathology
H)higher amount of contrast
I)destructive pathology
J)density-distance relationship

Accepted Answer

Increasing the tissue thickness by 5 cm requires an increase in mAs by 2x to maintain image density, as per the inverse square law and tissue absorption principles.

Question 15

Match the following choices with the statements as each relates to exposure conversions.
-affects radiographic contrast with a direct relationship
A)decreased density
B)focal spot size
C)longer scale of contrast
D)grid ratio
E)receptor speed
F)increased mAs by 2x
G)additive pathology
H)higher amount of contrast
I)destructive pathology
J)density-distance relationship

Accepted Answer

Grid ratio affects radiographic contrast with a direct relationship; higher grid ratios increase contrast by absorbing more scatter radiation.

Question 16

Match the following choices with the statements as each relates to exposure conversions.
-reduce kVp from 94 to 84 with mAs compensation
A)decreased density
B)focal spot size
C)longer scale of contrast
D)grid ratio
E)receptor speed
F)increased mAs by 2x
G)additive pathology
H)higher amount of contrast
I)destructive pathology
J)density-distance relationship

Accepted Answer

The answer of Match the following choices with the statements...

Question 17

Match the following choices with the statements as each relates to exposure conversions.
-change from 12:1 to 10:1 with mAs compensation
A)decreased density
B)focal spot size
C)longer scale of contrast
D)grid ratio
E)receptor speed
F)increased mAs by 2x
G)additive pathology
H)higher amount of contrast
I)destructive pathology
J)density-distance relationship

Accepted Answer

The answer of Match the following choices with the statements...

Question 18

When switching from an 8:1 grid to a 12: grid at 85 kVp, the change in mAs will be
A)decreased by 15%.
B)increased by 40%.
C)increased by 25%.
D)decreased by 40 %.

Accepted Answer

When switching from a lower grid ratio (8:1) to a higher grid ratio (12:1), the amount of scatter radiation reaching the image receptor is reduced, requiring an increase in mAs to maintain image density. The increase in mAs compensates for the increased attenuation of the x-ray beam by the higher grid. The general rule of thumb for adjusting mAs when changing grid ratios is to increase mAs by a factor related to the grid conversion factors. For an 8:1 to 12:1 grid change, the mAs needs to be increased by approximately 40% to maintain image density.

Question 19

Match the following choices with the statements as each relates to exposure conversions.
-requires less mAs but does not affect recorded detail or distortion
A)decreased density
B)focal spot size
C)longer scale of contrast
D)grid ratio
E)receptor speed
F)increased mAs by 2x
G)additive pathology
H)higher amount of contrast
I)destructive pathology
J)density-distance relationship

Accepted Answer

The answer of Match the following choices with the statements...

Question 20

You are asked to fill in for a technologist at a local clinic for the day.When you arrive, you notice the x-ray generator is single phase.Your experience with exposure techniques was based upon a high frequency unit at the local hospital.To work at this clinic, you will likely do what to your hospital exposure techniques?
A)increase the kVp values by 15%
B)increase the mAs values by 100%
C)decrease the kVp values by 15% and double the mAs values
D)decrease the mAs values by 15%

Accepted Answer

Single-phase x-ray generators are less efficient than high-frequency units, requiring approximately double the mAs to achieve similar image quality.

Quiz 34: Exposure Conversion Problems

A radiographer has received a request for an examination that requires a 12:1 grid based upon patient thickness.The exposure technique chart suggests a non-grid technique of 6 mAs at 90 kVp.The required mAs with the grid will be

The relationship between receptor speed and exposure mAs is

Match the following choices with the statements as each relates to exposure conversions. -exposure maintenance formula

Match the following choices with the statements as each relates to exposure conversions. -Any change will not affect density or contrast.

A particular radiograph was produced using 8 mAs and 84 kVp with an 8:1 ratio grid. The film is to be repeated using a 16:1 ratio grid. What should be the new mAs?

Match the following choices with the statements as each relates to exposure conversions. -switch from 400 RS to 300RS with no compensation

A satisfactory radiograph is produced using the variable kVp theory.The part measuring 8 cm and 55 kVp was used.To maintain exposure, what kVp should be used if the part measures 10 cm?

A satisfactory radiograph is produced using the variable kVp theory.The part measuring 10 cm and 65 kVp was used.To maintain exposure, what kVp should be used if the part measures 14 cm?

A radiographic examination has been taken using the following exposure conditions: 400 mA, 70 ms, 80 kVp, 1,2 mm fs, 200 RS receptor, 12: grid, 44" SID To increase the contrast, the most appropriate choice would be to

Which of the following exposure settings will yield an image with the shortest scale of contrast?

For a 20 cm part thickness, which of the following would accommodate a 6 cm increase in part thickness and maintain radiographic density?

An exposure was made using 200 mA, 0.05 second exposure and 75 kVp.Each of the following changes will function to double radiographic image density, EXCEPT:

Match the following choices with the statements as each relates to exposure conversions. -5 cm increase in tissue thickness

Match the following choices with the statements as each relates to exposure conversions. -affects radiographic contrast with a direct relationship

Match the following choices with the statements as each relates to exposure conversions. -reduce kVp from 94 to 84 with mAs compensation

Match the following choices with the statements as each relates to exposure conversions. -change from 12:1 to 10:1 with mAs compensation

When switching from an 8:1 grid to a 12: grid at 85 kVp, the change in mAs will be

Match the following choices with the statements as each relates to exposure conversions. -requires less mAs but does not affect recorded detail or distortion