Radiation Weighting Factor
a) The radiation weighting (Wt) factor is the factor by which the absorbed dose (rad or gray) must be multiplied to obtain a quantity that expresses, on a common scale for all ionizing radiation, the biological damage (rem or Sievert) to the exposed tissue. It is used because some types of radiation, such as alpha particles, are more biologically damaging to live tissue than other types of radiation when the absorbed dose from both is equal. This replaces the term quality factor in the latest system of recommendations for radiation protection. For example, the gonads have a Wt of 0.20; whereas the skin has a Wt of 0.01 as the gonads are more sensitive to radiation than the skin.