Radiation Protection Principles Flashcards

Which quantity is used to express the effective dose received by a radiation worker and accounts for tissue sensitivity?

Answer: Effective dose (Sv)

Effective dose (Sv) weights equivalent doses by tissue weighting factors to reflect overall biological risk to the whole body.

A radiographer doubles the distance from a fluoroscopy unit. By what factor does the radiation intensity change?

Answer: Decreases by one-fourth

According to the inverse square law, doubling the distance reduces intensity to 1/4 of the original value.

Which type of radiation interaction is primarily responsible for photoelectric absorption in diagnostic radiology?

Answer: Photoelectric effect

The photoelectric effect dominates at lower kVp ranges used in diagnostic radiology, where the photon is completely absorbed by an inner-shell electron.

What is the recommended annual occupational effective dose limit for radiation workers in the US according to NCRP?

Answer: 50 mSv

NCRP Report No. 116 sets the annual occupational effective dose limit at 50 mSv (5 rem).

Which material provides the most effective shielding against scatter radiation in a radiographic suite?

Answer: Concrete or lead

Lead and concrete are used for primary and secondary barriers because of their high atomic number and density, which attenuate X-rays effectively.

A pregnant technologist should limit fetal dose to no more than how much over the entire gestational period, per NCRP?

Answer: 5 mSv (0.5 rem)

NCRP recommends the fetal dose not exceed 5 mSv (0.5 rem) over the entire gestation once pregnancy is declared.

Which beam-limiting device is most effective at reducing patient dose and improving image contrast?

Answer: Collimator

Collimation restricts the primary beam to the area of clinical interest, reducing scatter production and patient dose.