1. If the exposure rate to an individual standing 4.0 m from a source of radiation is 10 mR/h, what will be the dose received after 20 minutes at a distance of 6 m from the source?

A

22.5 mR

B

7.5 mR

C

4.44 mR

D

1.48 mR
• •
• D
•
• 1.48 mR
• inverse-square law of radiation. The formula is • Substituting known values:

• • Thus, x = 4.44 mR in 60 minutes and, therefore, 1.48 mR in 20 minutes. Distance has a profound effect on dose received and, therefore, is one of the cardinal rules of radiation protection. As distance from the source increases, dose received decreases.
2. Moving the image intensifier closer to the patient during traditional fluoroscopy

1. decreases the SID

2. decreases patient dose

3. improves image quality

A

1 only

B

1 and 2 only

C

1 and 3 only

D

1, 2, and 3
• •
• D
•
• 1, 2, and 3
3. With milliamperes (mA) increased to maintain output intensity, how is the ESE affected as the source-to-skin distance (SSD) is increased?

A

The ESE increases.

B

The ESE decreases.

C

The ESE remains unchanged.

D

ESE is unrelated to SSD.
• •
• B
•
• The ESE decreases.
4. Which of the following will increase patient dose during fluoroscopy?

1. Decreasing the SSD

2. Using 2.5 mm Al filtration

3. Restricting tabletop intensity to less than 10 R/min

A

1 only

B

1 and 2 only

C

2 and 3 only

D

1, 2, and 3
• •
• A
•
• 1 only
5. If a patient received 2000 mrad during a 10-minute fluoroscopic examination, what was the dose rate?

A

B

C

D

• •
• B
•
• Two thousand mrad is equal to 2 rad. If 2 rad were delivered in 10 minutes, then the dose rate is 2 ÷ 10, or 0.2 rad/min.
6. What quantity of radiation exposure to the reproductive organs is required to cause temporary infertility?

A

B

C

D

• •
• B
•
7. Which of the following is (are) associated with Compton scattering?

 1 High-energy incident photons 2 Outer-shell electrons 3 Characteristic radiation

A

1 only

B

1 and 2 only

C

2 and 3 only

D

1, 2, and 3
• •
• B
•
• 1 and 2 only
8. Aluminum filtration has its greatest effect on

A

low-energy x-ray photons

B

high-energy x-ray photons

C

low-energy scattered photons

D

high-energy scattered photons
• •
• A
•
• low-energy x-ray photons
9. Patient exposure can be minimized by using which of the following?

 1 Accurate positioning 2 High-kV, low-mAs factors 3 Rare earth screens

A

1 only

B

1 and 2 only

C

1 and 3 only

D

1, 2, and 3
• •
• D
•
• 1, 2, and 3
10. If a patient received 1,400 mrad during a 7-minute fluoroscopic examination, what was the dose rate?

A

B

C

D

• •
• D
•
• A measure 1,400 mrad is equal to 1.4 rad. If 1.4 rad were delivered in 7 minutes, then the dose rate would be 0.2 rad/min: 11. If a patient received 4,500 mrad during a 6-minute fluoroscopic examination, what was the dose rate?

A

B

C

D

• •
• A
•
•  Since 4,500 mrad is equal to 4.5 rad, if 4.5 rad were delivered in 6 minutes, then the dose rate must be 0.75 rad/min: • Thus, x = 0.75 rad/min.
12. Which of the following most effectively minimizes radiation exposure to the patient?

A

Small focal spot

B

Low-ratio grids

C

Increased SID

D

High-speed intensifying screens
• •
• D
•
• High-speed intensifying screens
13. An increase of 1.0 mm added aluminum filtration of the x-ray beam would have which of the following effects?

1. Increase in average energy of the beam

2. Increase in patient skin dose

3. Increase in milliroentgen output

A

1 only

B

1 and 2 only

C

2 and 3 only

D

1, 2, and 3
• •
• A
•
• 1 only
14. A fluoroscopic examination requires 3 minutes of exposure on time. If the exposure rate for the examination is 250 mR/hr, what is the approximate exposure for the three minute procedure?

A

83.3 R

B

83.3 mR

C

12.5 R

D

12.5 mR
• •
• D
•
• 12.5 mR
• If the exposure rate for the examination is 250 mR/hour (60 minutes), then a 3-minute examination would be proportionally less—as the equation below illustrates:
• • 60 x = 750
•      x = 12.5 mR, dose in 3 minutes
15. Patient dose increases as fluoroscopic

A

FOV increases

B

FOV decreases

C

FSS increases

D

FSS decreases
• •
• B
•
• FOV decreases
16. If a patient received 2000 mrad during a 10-minute fluoroscopic examination, what was the dose rate?

A

B

C

D

• •
• A
•
• 17. If the exposure rate to an individual standing 2.0 m from a source of radiation is 15 R/min, what will be the dose received after 2 minutes at a distance of 5 m from the source?

A

1.2 R

B

2.4 R

C

4.8 R

D

9.6 R
• •
• C
•
• 4.8 R
• • 25 x = 60
• x = 2.4 R/minute at 2 m = 4.8 R after 2 minutes
18. If the entrance dose for a particular radiograph is 320 mR, the radiation exposure at 1 m from the patient will be approximately

A

32 mR.

B

3.2 mR.

C

0.32 mR.

D

0.032 mR.
• •
• C
•
• 0.32 mR.
•  Therefore, if the entrance dose for this image is 320 mR, the intensity of radiation at 1 m from the patient is 0.1% of that, or 0.32 mR (0.001 × 320 = 0.32).
19. Which of the following result(s) from restriction of the x-ray beam?

2. Less patient hazard

A

1 only

B

1 and 2 only

C

2 and 3 only

D

1, 2, and 3
• •
• B
•
• 1 and 2 only

1. can pose a safety hazard to personnel

2. can have a negative impact on image quality

3. occurs with low-energy incident photons A

1 only

B

1 and 2 only

C

2 and 3 only

D

1, 2, and 3
• •
• B
•
• 1 and 2 only
20. If a patient received 0.9 rad during a 3-minute fluoroscopic examination, what was the dose rate?

A

B

C

D

• •
• C
•
• If 0.9 rad were delivered in 3 minutes, then the dose rate would be 0.9/3, or 0.3 rad/min. Three-tenths rad is equal to 300 mrad.
21. Which of the following will reduce patient dose during fluoroscopy?

 1 Decreasing the source-skin distance (SSD) 2 Using 2.5 mm Al filtration 3 Restricting tabletop intensity to less than 10 R/min

A

1 only

B

1 and 2 only

C

2 and 3 only

D

1, 2, and 3
• •
• C
•
• 2 and 3 only
22. An increase in total filtration of the x-ray beam will increase

A

patient skin dose

B

beam HVL

C

image contrast

D

milliroentgen (mR) output
• •
• B
•
• beam HVL
23. Guidelines for the use of protective shielding state that gonadal shielding should be used

1. if the patient has reasonable reproductive potential

2. when the gonads are within 5 cm of the collimated field

3. when tight collimation is not possible

A

1 only

B

1 and 2 only

C

1 and 3 only

D

2 and 3 only
• •
• B
•
• 1 and 2 only
Author
Anonymous
ID
302823
Card Set