Which unit is used to express effective dose?

Which unit is used to express effective dose?

• A. Coulombs per kilogram (C/kg)
• B. Gray (Gy)
• C. Sievert (Sv)
• D. Becquerel (Bq)

Answer: (C)

Effective dose uses the Sievert because it translates the amount of radiation energy deposited into a form that reflects actual health risk. The absorbed energy per unit mass, measured in Gray, tells you how much energy is deposited, but it doesn’t account for how dangerous that energy is for different tissues or for different kinds of radiation. The Sievert incorporates weighting factors for radiation type and tissue sensitivity, giving a risk-oriented dose. In practice, effective dose combines these factors so that it represents the overall potential harm to the body. By contrast, Gray measures only energy deposited (absorbed dose), Becquerel measures how many decays occur (radioactivity), and Coulombs per kilogram relates to exposure/air kerma. These do not directly express the risk to the body in the way the Sievert does, which is why effective dose is expressed in Sieverts.

Effective dose uses the Sievert because it translates the amount of radiation energy deposited into a form that reflects actual health risk. The absorbed energy per unit mass, measured in Gray, tells you how much energy is deposited, but it doesn’t account for how dangerous that energy is for different tissues or for different kinds of radiation. The Sievert incorporates weighting factors for radiation type and tissue sensitivity, giving a risk-oriented dose. In practice, effective dose combines these factors so that it represents the overall potential harm to the body.

By contrast, Gray measures only energy deposited (absorbed dose), Becquerel measures how many decays occur (radioactivity), and Coulombs per kilogram relates to exposure/air kerma. These do not directly express the risk to the body in the way the Sievert does, which is why effective dose is expressed in Sieverts.