Regulatory implementation of the occupational equivalent dose limit for the lens of the eye and underlying relevant efforts in Japan

Yokoyama, Sumi*; Hamada, Nobuyuki*; Tsujimura, Norio; Kunugita, Naoki*; Nishida, Kazutaka*; Ezaki, Iwao*; Kato, Masahiro*; Okubo, Hideki*

International Journal of Radiation Biology, 99(4), p.604 - 619, 2023/04

https://doi.org/10.1080/09553002.2022.2115160

In April 2011, the International Commission on Radiological Protection recommended reducing the occupational equivalent dose limit for the lens. Such a new occupational lens dose limit has thus far been implemented in many countries, and there are extensive discussions toward its regulatory implementation in other countries. In Japan, discussions in the Japan Health Physics Society (JHPS) began in April 2013 and in Radiation Council in July 2017, and the new occupational lens dose limit was implemented into regulation in April 2021. To share our experience, we have published a series of papers summarizing situations in Japan: the first paper based on information available by early 2017, and the second paper by early 2019. This paper (our third paper of this series) aims to review updated information available by mid-2022, such as regarding regulatory implementation of the new occupational lens dose limit, recent discussions by relevant ministries based on the opinion from the council, establishment process of safety and health management systems, the JHPS guidelines on lens dose monitoring and radiation safety, voluntary countermeasures of the licensees, development of lens dose calibration method, and recent studies on exposure of the lens in nuclear workers and biological effect on the lens.

Detection of DNA damage induced by heavy ion irradiation in the individual cells with comet assay

Wada, Seiichi; Natsuhori, Masahiro*; Ito, Nobuhiko*; Funayama, Tomoo; Kobayashi, Yasuhiko

Nuclear Instruments and Methods in Physics Research B, 206, p.553 - 556, 2003/05

https://doi.org/10.1016/S0168-583X(03)00820-6

Determining the biological effects of a very low number of charged particles crossing the cell nucleus is interest for estimating the risk due to environmental exposure to charged particles. Especially it is necessary to detect the radiation damage induced by a precise number of charged particles in the individual cells. To compare the number of ions traversing the cell and the DNA damage produced by the hit ions, we applied comet assay. Cells attached on the ion track detector CR-39 were irradiated with 17.3 MeV/u 12C, 15.7 MeV/u, 10.4 MeV/u 20Ne and 6.9 MeV/u 40Ar ion beams at TIARA, JAERI-Takasaki. After irradiation, CR-39 was covered with 1 % agarose. After electrophoresis the CR-39 was taken off from the slide glass. The agarose gel on the CR-39 was stained with ethidium bromide and the opposite side of the CR-39 was etched with KOH-ethanol solution at 37 . We observed that the ion particles with higher LET value induced the heavier DNA damage, even by the same number of ion-hits within the irradiated cells.

None

JNC TN1400 99-019, 117 Pages, 1999/10

JNC-TN1400-99-019.pdf:5.25MB

no abstracts in English

None

Mihara, Morihiro; Yoshikawa, Hideki; Yui, Mikazu

PNC TN8410 94-241, 53 Pages, 1994/07

PNC-TN8410-94-241.pdf:1.34MB

None

The Japanese nuclear energy encyclopedia edited and computerized to promote public acceptance, Chapter 11; Radiation

Shimooke, Takanori; *; Kobayashi, Kensuke;

Proc. of the Int. Conf. on Radiation Effects and Protection, p.496 - 499, 1992/00

no abstracts in English