Radiation protection refers to all the actions and activities necessary to prevent the exposure of humans and the environment to ionising radiation, and if prevention of such exposure is not possible, these actions should endeavour to reduce the harmful inuence of this radiation on the health of future generations in the form of genetic consequences. With this in mind, the International Commission on Radiological Protection (ICRP) has formulated the following recommendation: No practice involving exposure to radiation should be adopted unless it produces

15.1 Introduction ..................................................................................................297 15.2 Basic Concepts, Values, and Units of Measure Applied in Radiation Protection .....................................................................................299