2017 年 52 巻 2 号 p. 77-87
In April 2011, the International Commission on Radiological Protection recommended reducing the occupational equivalent dose limit for the lens of the eye. Since then, discussions toward implementation of such a revised dose limit into national law have been made in various countries. In the United States of America (US), the National Council on Radiation Protection and Measurements (NCRP) established Scientific Committee 1-23 (SC 1-23) in January 2014 to provide guidance on whether existing dose limits for the ocular lens should be changed in the US, to which the author of this paper served as Consultant. In January 2017, NCRP published Commentary No. 26 “Guidance on radiation dose limits for the lens of the eye” which was prepared by SC 1-23. With this Commentary, NCRP now recommends reducing the occupational dose limit for the lens from equivalent dose of 150 mSv/year to absorbed dose of 50 mGy/year along with the use of relative biological effectiveness value for high linear energy transfer radiation. This review provides an outline of this Commentary.