[Radiation protection in medicine]

Medical uses of radiation became by far the greatest man-made source of doses to the population at large. As technology and health care improved there has been an increase in the usage of radiation, measured by the frequency of procedures per caput and by the levels of individual and collective dose. From the early 1920's there has been the gradually developing pressure to eliminate unnecessary exposures and to reduce individual doses. Justification of practices and optimization of protection became the leading principles for keeping individual doses and the number of patients exposed As Low As Reasonably Achievable. However, less attention has been given to optimization in medical applications than in most other radiological fields. The range of doses associated with the same procedure is often extremely large, which implies that there is considerable scope for dose reduction. The first important factor is to increase awareness of the relative ease with which doses can be reduced. This requires familiarity with the levels of dose connected with the various procedures and with techniques of quality control. A new and potentially very strong tool is provided by dose constraints, which should be selected by appropriate professional bodies and which should be used in practice as a quantitative guide to good practice. The key elements of optimization of protection, based on the ICRP recommendations were discussed.