In EfD calculation, tissue weighting factor Wt represents:

In EfD calculation, tissue weighting factor Wt represents:

• A. The energy deposited per unit mass in tissue
• B. A factor that represents tissue sensitivity in EfD calculation
• C. The rate of energy absorption in tissue
• D. The energy required to cause a biological effect

Answer: (D)

The tissue weighting factor in EfD calculations measures how sensitive a tissue is to radiation-induced stochastic effects, and it’s used to scale a tissue’s dose so that overall risk can be summed across the body. It isn’t about how much energy is deposited in a tissue (that’s absorbed dose), nor about how fast energy is absorbed (dose rate), and it isn’t a quantity like “energy required to cause a biological effect.” Instead, Wt reflects the differing biological risk per unit of absorbed energy from one tissue to another, so tissues more prone to radiation-induced cancer or hereditary effects contribute more to the overall effective dose. In practice, the effective dose combines the dose to each tissue with its weighting factor and, for each tissue, uses the radiation type’s weighting factor to obtain the tissue’s equivalent dose. The sum across all tissues gives the EfD, capturing how risk varies with tissue type rather than just total energy absorbed.

The tissue weighting factor in EfD calculations measures how sensitive a tissue is to radiation-induced stochastic effects, and it’s used to scale a tissue’s dose so that overall risk can be summed across the body. It isn’t about how much energy is deposited in a tissue (that’s absorbed dose), nor about how fast energy is absorbed (dose rate), and it isn’t a quantity like “energy required to cause a biological effect.” Instead, Wt reflects the differing biological risk per unit of absorbed energy from one tissue to another, so tissues more prone to radiation-induced cancer or hereditary effects contribute more to the overall effective dose.

In practice, the effective dose combines the dose to each tissue with its weighting factor and, for each tissue, uses the radiation type’s weighting factor to obtain the tissue’s equivalent dose. The sum across all tissues gives the EfD, capturing how risk varies with tissue type rather than just total energy absorbed.