Regulatory Implementation of the Equivalent Dose Limit for the Lens of the Eye for Occupational Exposures

Successes and Challenges to the Approaches Identified Through a Survey of Regulators

This report summarises the practical experiences of regulators and stakeholders worldwide in implementing the International Commission's on Radiological Protection (ICRP) recommended equivalent dose limit for the lens of the eye for occupational exposure, including successes and challenges to the approaches. It was produced by the NEA Expert Group on the Dose Limit for the Lens of the Eye (EGDLE) created in 2019 by the Committee on Radiological Protection and Public Health (CRPPH), with the objective of providing an opportunity for regulators and stakeholders to share lessons learned in the practical implementation of the ICRP’s recommended equivalent dose limit for the lens of the eye for occupational exposures. As several studies have suggested that the development of cataracts may occur following exposure to significantly lower doses of ionising radiation than previously considered, the ICRP recommended reducing the equivalent dose limit for the lens of the eye for occupational exposure to 20 millisieverts (mSv) in a year, averaged over defined five-year periods (100 mSv/5 years), with no single year exceeding 50 mSv.

This report is based on the analysis of a survey gathering information from member countries’ regulatory bodies and technical and scientific support organisations (TSO) on the implementation of the ICRP’s recommended equivalent dose limit for the lens of the eye for occupational exposures. A total of 24 organisations from 15 countries provided responses to the survey, representing 18 regulatory bodies and 3 TSOs.

Responding countries identified areas where they could benefit from sharing experiences and from a possible harmonisation in approaches. They include:

• Requirements for individual monitoring, and consensus on the use of eye lens dosimeters measuring personal dose equivalent Hp(3).
• Eye lens dosimetry, with the use of ISO and IEC standards to define accreditation and technical/performance specifications for Hp(3) eye lens dosimeters, with a need to address issues such as beta and neutron radiations, and mixed radiation fields (beta/photons), and intercomparisons.
• Dosimeter placement and taking account of personal protective equipment.
• Acceptability of the use of surrogate dosimeters and correction factors.

All the respondent countries identified opportunities for continued dialogue and information exchanges in the international fora, especially in the above-mentioned areas, where international harmonisation would be beneficial. They also identified areas of research that could contribute to advances in radiological protection aspects for the eye, in addition to improvements in eye lens dosimetry.