Radiation and Radiological Disasters. (Animation) The product of absorbed dose to a given organ or tissue multiplied by a quality factor (also known as a weighting factor [WF]), and then sometimes multiplied by other necessary modifying factors, to account for the potential for a biological effect resulting from the absorbed dose. (See: Quality factor). It is expressed numerically in rem (traditional units) or sieverts (SI units). (Radiation Terms, Health Physics Society)