CMD Radiation Safety & Protection 2

Question 1

What is the annual occupational effective dose limit for radiation workers in the United States?

Accepted Answer

50 mSv

Answer

The NRC sets the annual occupational effective dose limit at 50 mSv (5 rem) per year for radiation workers.

Question 2

Which radiation quantity accounts for both the absorbed dose and the biological effectiveness of different radiation types?

Accepted Answer

Equivalent dose (Sievert)

Answer

Equivalent dose in Sieverts equals absorbed dose multiplied by the radiation weighting factor, reflecting biological effectiveness.

Question 3

A dosimetrist is planning a high-dose-rate brachytherapy procedure. What is the minimum recommended shielding material thickness for a dedicated HDR vault with Ir-192?

Accepted Answer

24 inches of concrete or equivalent

Answer

HDR Ir-192 vaults typically require approximately 24 inches (60 cm) of concrete or equivalent shielding to meet dose rate limits in adjacent areas.

Question 4

Which principle of radiation protection requires that doses be kept as low as reasonably achievable?

Accepted Answer

ALARA

Answer

ALARA (As Low As Reasonably Achievable) is the guiding principle requiring radiation doses to be minimized beyond regulatory limits when practical.

Question 5

When using a survey meter to check for contamination after a brachytherapy seed implant procedure, which meter type is most appropriate?

Accepted Answer

Geiger-Müller detector

Answer

A Geiger-Müller detector is the most appropriate survey instrument for contamination checks due to its high sensitivity for detecting small amounts of radioactivity.

(CMD) Certified Medical Dosimetrist Practice Test

(CMD) Certified Medical Dosimetrist Practice Test

CMD Radiation Safety & Protection 2