FRCR FRCR Physics and Radiation Safety

Question 1

What is the unit of absorbed radiation dose in the SI system?

Accepted Answer

Gray (Gy)

Answer

Sievert (Sv)

Answer

Becquerel (Bq)

Answer

Roentgen (R)

Question 2

Which interaction between X-rays and matter is most important for diagnostic imaging in soft tissue at typical diagnostic energies?

Accepted Answer

Compton scattering

Answer

Photoelectric effect

Answer

Pair production

Answer

Coherent scattering

Question 3

What does the term 'half-value layer' (HVL) describe in radiology?

Accepted Answer

Thickness of material reducing beam intensity by 50%

Answer

Half-life of a radionuclide

Answer

Depth at which dose is halved in a patient

Answer

Distance at which dose rate halves

Question 4

Which type of radiation has the highest linear energy transfer (LET)?

Accepted Answer

Alpha particles

Answer

Beta particles

Answer

X-rays

Answer

Gamma rays

Question 5

In CT dosimetry, what does CTDI (Computed Tomography Dose Index) measure?

Accepted Answer

Average dose delivered along the scan axis

Answer

Effective dose to the whole body

Answer

Organ dose to a specific structure

Answer

Surface entrance dose

Question 6

Which legislation governs radiation protection in medical exposures in the US?

Accepted Answer

NRC regulations (10 CFR)

Answer

ALARA directive

Answer

ICRP Publication 103

Answer

EURATOM BSS Directive