In radiological protection, what are the units for absorbed dose, dose equivalent, and effective dose respectively?

• A. Gy, Sv, Sv
• B. Gy, Gy, Sv
• C. Sv, Gy, Gy
• D. Bq, Gy, Sv

Answer: (A)

Absorbed dose quantifies how much energy is deposited in tissue per unit mass, so its unit is the gray (Gy), defined as joules per kilogram. Dose equivalent adjusts that energy deposition for the potential biological effect by applying radiation weighting factors, and the resulting quantity is expressed in sieverts (Sv). Effective dose goes a step further by incorporating tissue-specific sensitivity through tissue weighting factors, and it is also expressed in sieverts. So the correct sequence is Gy for absorbed dose, and Sv for both dose equivalent and effective dose. The other options mix units that don’t represent dose or ignore the biological weighting needed for dose equivalent and effective dose.