In March 2019, the Nuclear Energy Agency (NEA) Committee on Radiological Protection and Public Health (CRPPH) created the Expert Group on the Dose Limit for the Lens of the Eye (EGDLE). The main objective is to give regulators and stakeholders (nuclear and non-nuclear entities) an opportunity to share lessons learned in the practical implementation of the equivalent dose limits for the lens of the eye for occupational exposures recommended by the International Commission on Radiological Protection (ICRP).

Background

NEA is an intergovernmental agency based in Paris, France, that facilitates cooperation among countries with advanced nuclear technology infrastructures to seek excellence in nuclear safety, technology, science, environment, and law. CRPPH is an NEA committee made up of regulators and radiation protection experts with a broad mission to assist NEA member countries in the implementation and enhancement of the system of radiological protection.

CRPPH has established a number of working parties and expert groups to support its work. Their mandates span nuclear and radiological emergency matters, legacy management, operational and analytical aspects of exposures at nuclear power plants, and implications of international recommendations on the system of radiological protection.

Brian Ahier, director of the Radiation Protection Bureau of Health Canada, and Christina Dodkin, radiation protection specialist with the Canadian Nuclear Safety Commission (CNSC), represent Canada on CRPPH.

Expert Group on the Dose Limit for the Lens of the Eye (EGDLE)

During their annual meeting in March 2019, CRPPH created the Expert Group on the Dose Limit for the Lens of the Eye (EGDLE). Christina Dodkin, CNSC, is the chair of the EGDLE. Marie-Claire Cantone, professor of applied physics, University of Milan, is vice-chair. Member countries represented on the EGDLE include Argentina, Canada, France, Germany, Ireland, Italy, Japan, Spain, United Kingdom, and United States.

The expert group’s objective is to provide an opportunity for regulators and stakeholders to share their experiences implementing ICRP’s recommended equivalent dose limits for the lens of the eye for occupational exposures. EGDLE’s deliverables include:

• A report that summarizes the practical experiences of regulators and stakeholders worldwide for implementing ICRP’s recommended equivalent dose limits for the lens of the eye for occupational exposures, including successes and challenges.
• Establishment of a network to maintain dialogue and information exchange.

EGDLE’s mandate was approved for a two-year term (until March 29, 2021).

EGDLE held their first meeting from July 25 to 26, 2019. During the meeting, the main results from several research projects were discussed.

• Representatives from the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) and Public Health England, presented the main results from various European Commission-funded projects. A series of projects have been devoted to optimization of radiological protection in working procedures in the non-nuclear (medical) fields, as well as to the development of improved eye dosimetry and recommendations for implementation, including guidance for calibration and testing. Other projects have dealt with epidemiological studies and dose assessments in order to quantify the dose-response relationship on occupational cataracts and lens opacities among cardiologists.
• A representative of the Fujita Health University School of Health Sciences presented an overview of the epidemiological studies conducted in Japan.
• A representative of the Electric Power Research Institute (EPRI) presented the main conclusions following a meta-analysis of approximately 300 epidemiological studies to inform a quantitative estimate of a dose threshold for radiation-induced lens opacities, as well as ongoing research with the CANDU Owners Group (COG) on phantoms for eye lens dosimetry and on protection factors for common protective equipment, including safety glasses and face shields.
• A representative of the Comisión Nacional de Energía Atómica, Argentina, briefly described two ongoing research projects. The first project, RELID, deals with Retrospective Evaluation of Lens Injuries and Dose in occupational exposure situations. The second project involves research on the mechanisms involved in lens injuries, using cell cultures of human lens samples from cadavers.

Each EGDLE member also presented their national experiences implementing ICRP’s recommended equivalent dose limits for the lens of the eye for occupational exposures, including successes and challenges to the approaches. Among the countries represented in the EGDLE, all have initiated at least the regulatory process to examine whether or not (and how) to implement new dose limits for the lens of the eye.

Japan and some of the European Commission member states are well advanced, the latter being driven by the deadline for adoption of the EURATOM Basic Safety and Standards Directive (BSSD). Among those countries, some have decided to enforce the new dose limits exactly as recommended by ICRP, while others have opted for a transitional phase with full implementation at a later time.

Other countries have not yet decided on the path forward for their regulatory framework, but all have launched actions of various types to engage stakeholders and/or elaborate on and disseminate guidance for practical implementation by stakeholders.

EGDLE members noted the overview of surveys conducted by the International Radiation Protection Association (IRPA) on the implementation of new lens-of-the-eye dose limits among their member countries. It was agreed that there is a wealth of information from the points of view of stakeholders, and more information is needed on the views of regulatory bodies. Therefore, next steps for the EGDLE will be to conduct a survey of nuclear and non-nuclear regulatory bodies through CRPPH member countries in early 2020. Priorities for the survey include:

• Understanding success factors for stakeholder engagement to ensure positive interactions when setting a substantial change in the dose limit to the lens of the eye
• Developing accreditation and approval processes for Hp(3) dosimetry
• Defining regulatory expectations for monitoring doses to the lens of the eye (protective equipment and correction factors, positioning of dosimetry, methods for indirect monitoring, etc.)

To learn more about the EGDLE, contact Christina Dodkin at [email protected].