Radiation Physicist Question:

Effective dose is a calculated quantity developed by the ICRP (1991) for purposes of radiation protection. The effective dose is assumed to be related to the risk of a radiation-induced cancer or a severe hereditary effect. It takes into account: the absorbed doses that will be delivered to the separate organs or tissues of the body during the lifetime of an individual due to intakes of radioactive materials; the absorbed doses due to irradiation by external sources; the relative effectiveness of different radiation types in inducing cancers or severe hereditary effects; the susceptibility of individual organs to develop a radiation-related cancer or severe hereditary effect; considerations of the relative importance of fatal and non-fatal effects; and, the average years of life lost from a fatal health effect. (HPS 005-3) Thus, the effective dose is a quantity calculated by multiplying the equivalent dose received by every significantly irradiated tissue in the body by a respective tissue weighting factor (this factor reflects the risk of radiation-induced cancer to that tissue) and summing together the individual tissue results to obtain the effective dose. Such a dose, in theory, carries with it the same risk of cancer as would an equal equivalent dose delivered uniformly to the whole body.