In calculating the sievert, the radiation weighting factor takes into account which of the following?

In calculating the sievert, the radiation weighting factor takes into account which of the following?

• A. The age of the exposed person
• B. The energy of the original photons only
• C. The time since exposure
• D. The type of radiation and LET

Answer: (D)

The key idea is that the radiation weighting factor represents how biologically damaging energy deposited by different radiation types is, so it depends on both the type of radiation and its LET (linear energy transfer). When calculating the sievert, you multiply the absorbed dose (in grays) by this weighting factor to convert to a dose that reflects biological effect. High-LET radiations, like alpha particles, deposit energy densely along their tracks and cause more biological damage per unit energy than low-LET radiations such as many photons, so their weighting factors are larger. This is why the same amount of energy from different radiation types does not produce the same biological risk, which the sievert accounts for through w_R. In contrast, the age of the person, the time since exposure, or the energy of photons alone aren’t what determine the weighting factor; those aspects don’t alter the inherent per-energy biological effectiveness captured by the type and LET.

The key idea is that the radiation weighting factor represents how biologically damaging energy deposited by different radiation types is, so it depends on both the type of radiation and its LET (linear energy transfer). When calculating the sievert, you multiply the absorbed dose (in grays) by this weighting factor to convert to a dose that reflects biological effect. High-LET radiations, like alpha particles, deposit energy densely along their tracks and cause more biological damage per unit energy than low-LET radiations such as many photons, so their weighting factors are larger. This is why the same amount of energy from different radiation types does not produce the same biological risk, which the sievert accounts for through w_R. In contrast, the age of the person, the time since exposure, or the energy of photons alone aren’t what determine the weighting factor; those aspects don’t alter the inherent per-energy biological effectiveness captured by the type and LET.