Radiation Protection

  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
    • Image Upload 1
    •  
    • D
    •  
    • 1.48 mR 
    • inverse-square law of radiation. The formula is 
      Image Upload 2
    • Substituting known values:

    • Image Upload 3
    • 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
    • Image Upload 4
    •  
    • 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.
    • Image Upload 5
    •  
    • 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
    • Image Upload 6
    •  
    • A
    •  
    • 1 only
  5. If a patient received 2000 mrad during a 10-minute fluoroscopic examination, what was the dose rate?



    A
     
    0.02 rad/min 


    B
     
    0.2 rad/min 


    C
     
    2.0 rad/min 


    D
     
    20 rad/min
    • Image Upload 7
    •  
    • B
    •  
    • 0.2 rad/min 
    • 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
     
    100 rad 


    B
     
    200 rad 


    C
     
    300 rad 


    D
     
    400 rad
    • Image Upload 8
    •  
    • B
    •  
    • 200 rad
  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
    • Image Upload 9
    •  
    • 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
    • Image Upload 10
    •  
    • 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
    • Image Upload 11
    •  
    • 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
     
    200 rad/min 


    B
     
    5 rad/min 


    C
     
    2.0 rad/min 


    D
     
    0.2 rad/min
    • Image Upload 12
    •  
    • D
    •  
    • 0.2 rad/min 
    • 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: 
      Image Upload 13
  11. If a patient received 4,500 mrad during a 6-minute fluoroscopic examination, what was the dose rate?



    A
     
    0.75 rad/min 


    B
     
    2.7 rad/min 


    C
     
    7.5 rad/min 


    D
     
    27 rad/hr
    • Image Upload 14
    •  
    • A
    •  
    • 0.75 rad/min
    •  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: 
      Image Upload 15
    • 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
    • Image Upload 16
    •  
    • 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
    • Image Upload 17
    •  
    • 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
    • Image Upload 18
    •  
    • 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:
    • Image Upload 19
    • 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
    • Image Upload 20
    •  
    • B
    •  
    • FOV decreases
  16. If a patient received 2000 mrad during a 10-minute fluoroscopic examination, what was the dose rate?



    A
     
    0.2 rad/min 


    B
     
    2.0 rad/min 


    C
     
    5 rad/min 


    D
     
    200 rad/min
    • Image Upload 21
    •  
    • A
    •  
    • 0.2 rad/min
    • Image Upload 22
  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
    • Image Upload 23
    •  
    • C
    •  
    • 4.8 R 
    • Image Upload 24
    • 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.
    • Image Upload 25
    •  
    • 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?

    1. Less scattered radiation production

    2. Less patient hazard

    3. Less radiographic contrast





    A
     
    1 only 


    B
     
    1 and 2 only 


    C
     
    2 and 3 only 


    D
     
    1, 2, and 3
    • Image Upload 26
    •  
    • 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



    Image Upload 27





    A
     
    1 only 


    B
     
    1 and 2 only 


    C
     
    2 and 3 only 


    D
     
    1, 2, and 3
    • Image Upload 28
    •  
    • 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
     
    3 mrad/min 


    B
     
    30 mrad/min 


    C
     
    300 mrad/min 


    D
     
    3,000 mrad/min
    • Image Upload 29
    •  
    • C
    •  
    • 300 mrad/min 
    • 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
    • Image Upload 30
    •  
    • 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
    • Image Upload 31
    •  
    • 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
    • Image Upload 32
    •  
    • B
    •  
    • 1 and 2 only
Author
Anonymous
ID
302823
Card Set
Radiation Protection
Description
Minimizing patient exposure
Updated