Radiation safety

Question 1

What is the main source of physician radiation exposure?

Answer 1

scatter

Question 2

Acronym ALARA means?

Answer 2

As Low As Reasonably Achievable

Question 3

What 3 major principles of radiation safety help to minimize radiation exposure

Answer 3

1. Time: reduce exposure time
2. Distance: double distance from radiation decreases exposure by factor of 4 (inverse square law)
3. Shielding: wear lead apron, thyroid shield, eye glasses

Question 4

Permissible annual dose for occupational exposures in rems for whole body and ocular:

Answer 4

Whole body: 5 rems

Ocular: 15 rems

Question 5

Absorption Dose

Rad = conventional unit. Gray or Gy = standard international unit.

What is the conversion factor?

Answer 5

100 rad = 1 Gy

Question 6

Biologic risk of radiation exposure

Rem = conventional unit. Sievert or Sv = standard international.

Conversion factor?

Answer 6

100 rem = 1 Sv

Question 7

What is the typical radiation exposure of a KUB?

Compare to CT abdomen.

Answer 7

0.25 mSv for KUB

CT abdomen > 12.5 mSv (at least 50x greater)