Which statement correctly identifies the effective dose?

• A. The absorbed dose D.
• B. The effective dose E = Σ w_T H_T.
• C. The dose rate in air.
• D. The equivalent dose H_T = D × w_R.

Answer: (B)

Effective dose is a single quantity that estimates the overall risk of stochastic effects by combining tissue-specific doses with tissue and radiation weighting factors. For each tissue, the equivalent dose H_T is the absorbed dose D in that tissue multiplied by the radiation weighting factor w_R. The overall effective dose sums these contributions across all tissues: E = Σ_T w_T H_T. This makes the statement that effective dose equals the sum of tissue-weighted equivalent doses the correct description, because it captures both the different radiation types and the varying sensitivities of tissues. The absorbed dose alone doesn't account for tissue risk, dose rate in air is not a risk metric for the whole body, and an individual tissue’s equivalent dose doesn’t represent the total body risk.