QUANTITIES AND UNITS IN RADIATION PROTECTION

In its Publication No. 60, the International Commission on Radiologica l Protection (ICRP) introduced a new quantity, the equivalent dose in tissue, [GRAPHICS] where D-T.R is the absorbed dose averaged over the tissue or organ, T, and W-R, is the radiation weighting factor. The la tter depends on the incident radiation, i.e., the type and energy, but is independent of the tissue. On the other hand, a customarily define d quantity, the 'dose equivalent' is maintained (in particular the ope rational dose-equivalent quantities introduced in ICRU Report 39), but the relationship between the quality factor Q(L) and the linear energ y transfer, L, has been redefined. In the case of neutrons, this proce dure gives rise to an increase of the corresponding fluence to dose-eq uivalent conversion factors. The reason for introducing these and the new tissue-weighting factor changes are discussed.