The essentials of radiation protection

This article reviews the basis of radiation protection. First, the definitions of specific terms such as absorbed radiation dose, equivalent radiation dose, effective dose, committed effective dose, total effective dose are given. Then the biological effects of radiations: stochastic and deterministic effects are described briefly. Radiation metrology in the medical sector and dosimetry are presented. Simulations with mathematical models and anthropomorphic phantoms allow physicists to deduce the the real dose received in the body from measured data. It is recalled that it is the linear no-threshold dose-response that has been adopted by the ICRP (International Commission on Radiological Protection) for ionizing radiation. It is also recalled that radiation protection rests on the application of 3 principles. First, the principle of justification: no action must be made unless it brings a global benefit. Secondly, the principle of optimization: the radiation exposure must be maintained at the lowest level possible in light of economic and social factors. And thirdly, the principle of dose limitation: the radiation dose received by a worker must be below a limit value that has been set at 20 mSv annually. The principle of dose limitation requires the implementation of a traceability system for recording the radiation doses received by workers annually. (A.C.)