The following issues are monitored by the IRPA Executive Council because of their potential impact on the practice of radiation protection. Major developments will be shared with the IRPA community through the IRPA news and other channels.
IRPA Associate Societies will be invited to suggest updates to this list. Please note the intention to maintain a relatively short list of the highest-priority issues.
Assessment of Dose to the Lens of the Eye
Dose to the lens of the eye has received increased attention in recent years with ICRP's new dose limits to the lens of the eye being adopted in the International and European Basic Safety Standards. In 2017, IRPA released Guidance on Implementation of Eye Dose Monitoring and Eye Protection of Workers. Practical dosimetry methods for measuring dose to the lens of the eye are emerging, but further work is required in this area and in establishing an appropriate regulatory framework and good practice.
Developments in Tissue Reactions and Related Science
Recent work of ICRP, especially in ICRP Publication 118, has shed light on the complexity of tissue reactions (deterministic effects) due to exposure to radiation. New scientific evidence on cataracts and circulatory disease suggesting effects at levels considerably lower than previously understood has raised the profile of tissue reactions. Continued research is necessary to improve the understanding of the risk and mechanisms of cataract induction and circulatory disease related to radiation exposure especially below 0.5 Gy.
Low-Dose and Low-Dose-Rate Risk, and LNT for Radiation Protection
NCRP Scientific Committee (SC) 1-25 on Recent Epidemiologic Studies and Implications for the Linear-Non threshold Model evaluated recent epidemiologic data relevant to the Linear-No-Threshold (LNT) model, primarily covering the past 10 to 15 years representing the time since the epidemiologic data used by the National Academies’ Health Risks from Exposure to Low Levels of Ionizing Radiation (BEIR VII) and the United Nations Scientific Committee on the Effects of Atomic Radiation 2006 reports were compiled.
SC 1-25 concluded that there was sufficient epidemiologic evidence consistent with the LNT model to continue to recommend it as a practical and prudent guide for radiation protection purposes. Ultimately, however, it will be necessary to base judgments on the complementary epidemiologic and animal LD/LDR data and to understand the causal and protective mechanisms for radiogenic cancer. The outcome of the SC 1-25 has been published as a NCRP commentary, Commentary No. 27 - Implications of Recent Epidemiologic Studies for the Linear-Non threshold Model and Radiation Protection (2018).
ICRP has embarked on an extensive review of the science in this area by establishing Task Group 91 Radiation Risk Inference at Low-dose and Low-dose Rate Exposure for Radiological Protection Purposes. A 2015 paper in Radiation and Environmental Biophysics presents progress on this topic.
Optimisation of Radiation Protection for (Paediatric) Patients
Several initiatives, like Image Gently and Image Wisely, have emerged in recent years to promote optimisation of radiation protection of patients. The focus is mostly but not exclusively on paediatric patients, and mostly but not exclusively in medical imaging. However, there are contrary views on the subject as well, for example a 2017 paper in the Journal of Nuclear Medicine. IRPA encourages continued debate on this subject, but also endorses initiatives that promote optimisation of radiation protection of patients, workers, and the public.
Practical Aspects of the Proposed Revision to ICRU Operational Quantities
Changes to operational quantities are proposed in a draft report of ICRU and ICRP that underwent public consultation in late 2017. Several comments raised the issue of potentially significant impacts on practical aspects including instrument calibration and design which could have significant cost implications. The draft report and consultation comments are available.
Practical Radiation Protection: Reasonableness, Conservatism and the Graded Approach
IRPA and some other international organisations have proposed that more attention should be given to encouraging a more proportionate approach to practical implementation of radiation protection, for example through avoiding inappropriate conservatisms in assessments, greater emphasis on ‘reasonableness’ in ALARA considerations and a more effective use of the graded approach in regulatory affairs. In interfaces with the international organisations IRPA will continue to encourage such approaches.
Revision of Radon Dose Coefficients
Revised radon dose coefficients have been published in ICRP Publication 137 Occupational Intakes of Radionuclides Part 3. A Summary of ICRP Recommendations on Radon is available in ICRPÆDIA. Although protection against radon is primarily based on measurement and control of levels of exposure, dose estimates are required in certain situations for workers. For buildings and underground mines, a dose coefficient of 3 mSv per mJ h m-3 (approximately 10 mSv per WLM) is recommended, i.e. approximately double the value of the previously recommended value. For indoor work involving substantial physical activity, and exposures in tourist caves, the recommended dose coefficient is 6 mSv per mJ h m-3 (approximately 20 mSv per WLM). This increase in dose coefficients will result in higher assessed doses to workers exposed to radon, possibly resulting in doses approaching regulatory limits in some cases. In addition, doses from natural background exposure will increase significantly. As these figures are used in communicating to the public about radiation exposures, careful consideration will be needed on how this change will be communicated.
ICRP Review of the System of Radiological Protection
ICRP has embarked on a review of the system of radiological protection. This review is at a very early stage. A first discussion with organisations in formal relations with ICRP (which includes IRPA) was the core of their annual meeting in Stockholm in October 2018. From the meeting notes: "ICRP ... has begun exploring areas of the system of radiological protection that might need further consideration. This is a precursor to deciding on priorities in preparation for a full review of the system of radiological protection, and the possibility of beginning an effort to develop a new set of fundamental recommendations. Similar efforts leading up to ICRP Publication 103 took about a decade."