抄録
In the Tokai-mura accident of September 1999, residents received not only gamma rays but also neutrons. For the estimation of the neutron doses, the quality factor proposed in ICRP 1977 Recommendation was used. Thereafter in October 2000, Japanese laws for radiation protection adopted the ICRP 1990 Recommendation, in which radiation-weighting factors were proposed for assessing stochastic effects of high LET radiation. However, for risk assessment, reexamination of the biological effects of low energy neutrons is considered. Although relative biological effectiveness (RBE) should be evaluated, it is hard to compile past data of experimental animals because of variations of experimental materials and methods in each experiment. It also needs to examine how to extrapolate the data from experimental animals to human.In this symposium, 1) suggestions from physical point of view, 2) present biological experiments in Japan, 3) problems for assessing neutron risks, will be presented, and then future researches and systems for promoting them will be discussed. [J Radiat Res 44:372-373 (2003)]
