Which statement correctly defines how effective dose relates to equivalent doses?

Which statement correctly defines how effective dose relates to equivalent doses?

• A. Effective dose equals the sum of tissue-weighted equivalent doses across tissues
• B. Effective dose equals the maximum tissue equivalent dose
• C. Effective dose equals absorbed dose for a single tissue
• D. Effective dose equals average ambient temperature

Answer: (A)

The key idea is that effective dose combines how much energy is deposited in each tissue with how sensitive that tissue is to radiation, and with the quality of the radiation. For each tissue, you convert the absorbed dose to an equivalent dose by accounting for the radiation type (the radiation weighting factor). Then you weight that tissue’s equivalent dose by the tissue weighting factor that reflects that tissue’s contribution to overall risk. Adding these tissue-weighted equivalent doses across all tissues gives the effective dose. This is exactly what the statement expresses. The other ideas don’t fit: focusing on a single tissue’s maximum dose ignores the distribution of dose and tissue sensitivities; using only the absorbed dose for one tissue ignores radiation quality and tissue risk weighting; and ambient temperature has no role in radiation dose calculations.

The key idea is that effective dose combines how much energy is deposited in each tissue with how sensitive that tissue is to radiation, and with the quality of the radiation. For each tissue, you convert the absorbed dose to an equivalent dose by accounting for the radiation type (the radiation weighting factor). Then you weight that tissue’s equivalent dose by the tissue weighting factor that reflects that tissue’s contribution to overall risk. Adding these tissue-weighted equivalent doses across all tissues gives the effective dose. This is exactly what the statement expresses.

The other ideas don’t fit: focusing on a single tissue’s maximum dose ignores the distribution of dose and tissue sensitivities; using only the absorbed dose for one tissue ignores radiation quality and tissue risk weighting; and ambient temperature has no role in radiation dose calculations.