Which unit is used for expressing an effective radiation dose?

Which unit is used for expressing an effective radiation dose?

• A. Sieverts (Sv)
• B. Gray (Gy)
• C. Coulombs per kilogram
• D. Joules per kilogram

Answer: (A)

Expressing an effective radiation dose uses a unit that reflects both how much energy is deposited and how that energy affects different tissues. The sievert is that unit because it incorporates tissue-specific weighting factors to represent biological risk, not just physical energy delivered. Absorbed dose, measured in gray (joules per kilogram), tells you how much energy is deposited but doesn’t account for how damaging that energy is to particular tissues. Exposure, expressed in coulombs per kilogram, relates to ionization in air rather than dose to tissue. Joules per kilogram is the same as gray, an energy-based measure of dose, not a risk-based quantity. So, the appropriate unit for expressing an effective dose is the sievert.

Expressing an effective radiation dose uses a unit that reflects both how much energy is deposited and how that energy affects different tissues. The sievert is that unit because it incorporates tissue-specific weighting factors to represent biological risk, not just physical energy delivered.

Absorbed dose, measured in gray (joules per kilogram), tells you how much energy is deposited but doesn’t account for how damaging that energy is to particular tissues. Exposure, expressed in coulombs per kilogram, relates to ionization in air rather than dose to tissue. Joules per kilogram is the same as gray, an energy-based measure of dose, not a risk-based quantity.

So, the appropriate unit for expressing an effective dose is the sievert.