Which unit is used to express effective dose in radiation protection?

Which unit is used to express effective dose in radiation protection?

• A. Gray
• B. Sievert
• C. Joule
• D. Rad

Answer: (B)

Effective dose is a risk-oriented quantity in radiation protection. It reflects not just how much energy is deposited, but how that energy will affect health across different tissues and types of radiation. To capture this, absorbed dose (energy per mass) is adjusted by factors that account for the radiation’s biological effectiveness and the varying sensitivity of tissues, and then combined into a single value that represents overall harm to a person. That single value is expressed in sieverts. The gray is the unit for absorbed dose, which measures energy deposited per kilogram but does not account for how damaging the radiation is or which tissues are affected. The joule is a basic unit of energy, not a dose measure. The rad is an older unit of absorbed dose, also not adjusted for biological impact. Since effective dose must reflect risk to the whole person, the sievert is the appropriate unit.

Effective dose is a risk-oriented quantity in radiation protection. It reflects not just how much energy is deposited, but how that energy will affect health across different tissues and types of radiation. To capture this, absorbed dose (energy per mass) is adjusted by factors that account for the radiation’s biological effectiveness and the varying sensitivity of tissues, and then combined into a single value that represents overall harm to a person. That single value is expressed in sieverts.

The gray is the unit for absorbed dose, which measures energy deposited per kilogram but does not account for how damaging the radiation is or which tissues are affected. The joule is a basic unit of energy, not a dose measure. The rad is an older unit of absorbed dose, also not adjusted for biological impact. Since effective dose must reflect risk to the whole person, the sievert is the appropriate unit.