Definition and implication of the operational quantities in the National Regulation of Radiation Protection

The principle concept of radiation protection became clear by 1977 recommendation. The biological effects of radiation on human organism were classified three factors, exposure, stochastic effects and nonstochastic effects. The radiation control system was established by justification of radiation use, optimization of radiation protection and radiation limits. 'The effective dose equivalent' was introduced as the fundamental limits for the stochastic effects, and each dose equivalent of skin, lens eye and other organs and tissues for nonstochastic effects. There are three kinds of operational quantities for ICRP, ICRU radiation protection such as ambient dose equivalent H*(d), directional dose equivalent H'(d, Ω) and individual dose equivalent Hp(d). Some differences between 1 cm dose conversion factor and the dose conversion factors in ICRU Reports were observed. The future problems may be improvement and clear definition of the dose conversion factors. (S.Y.)