Recent discussions toward regulatory implementation of the new occupational equivalent dose limit for the lens of the eye and related studies in Japan

日本における眼の水晶体の新しい職業線量限度の規制導入および関連研究への最近の議論

横山 須美*; 浜田 信之*; 辻村 憲雄   

Yokoyama, Sumi*; Hamada, Nobuyuki*; Tsujimura, Norio

In 2011, the ICRP recommended reducing an occupational equivalent dose limit for the lens of the eye. Since then, there have been extensive discussions toward regulatory implementation of such new occupational dose limit. In Japan, the Radiation Council established a Subcommittee in July 2017 to discuss the feasibility of implementing the new occupational lens dose limit. In March 2018, the Radiation Council requested all relevant government ministries and agencies to take necessary actions toward implementation of the new occupational dose limit, considering a series of discussions made by the Subcommittee. According to the currently available information, the new occupational lens dose limit will be implemented into regulations in Japan, most likely in April 2021. Epidemiological and biological studies on radiation effects on the lens and studies on lens dose measurements have been conducted in Japan, some of which have been funded by the Japanese Nuclear Regulation Authority. This paper provides an overview of the recent discussions toward regulatory implementation and the current status of the studies related to radiation exposure of the lens and its effect in Japan.