Which expression correctly defines dose equivalent?

Which expression correctly defines dose equivalent?

• A. Gy
• B. Sv
• C. Gy × quality factor
• D. J/kg

Answer: (C)

Dose equivalent accounts for how different types of radiation cause different biological effects, not just the amount of energy deposited. To get this protection-relevant quantity, you start with the absorbed dose D (in Gy) and multiply by a radiation weighting factor w_R (historically called the quality factor). The product D × w_R gives the dose equivalent, and its value is expressed in sieverts (Sv) because w_R converts the physical energy deposited into a biologically weighted measure. So Gy × quality factor is the correct way to define dose equivalent. The other options describe absorbed dose (Gy or J/kg) without the quality adjustment, or the unit without applying the weighting.

Dose equivalent accounts for how different types of radiation cause different biological effects, not just the amount of energy deposited. To get this protection-relevant quantity, you start with the absorbed dose D (in Gy) and multiply by a radiation weighting factor w_R (historically called the quality factor). The product D × w_R gives the dose equivalent, and its value is expressed in sieverts (Sv) because w_R converts the physical energy deposited into a biologically weighted measure. So Gy × quality factor is the correct way to define dose equivalent. The other options describe absorbed dose (Gy or J/kg) without the quality adjustment, or the unit without applying the weighting.