The equivalent dose H_T accounts for radiation type through which factor?

• A. The tissue weighting w_T.
• B. The total dose over time.
• C. The radiation type via w_R.
• D. The dose rate.

Answer: (C)

The main idea is that the equivalent dose H_T accounts for how different radiation types affect biology by using a radiation weighting factor, w_R. This factor scales the absorbed dose in tissue T to reflect the greater or lesser damage caused by the type of radiation. So, H_T is essentially the absorbed dose in tissue T multiplied by w_R (and summed over radiation types if needed). The result is in sieverts, since w_R is dimensionless. For example, alpha particles, being more biologically damaging, have a higher w_R than gamma rays, so the same absorbed energy from alpha radiation contributes more to H_T than from gamma radiation. The tissue weighting factor w_T is used later to get the effective dose across tissues, not to compute H_T itself.