Abstract
The concept of radiation detriment is central to the System of Radiological Protection (hereafter, ‘the System’). It is a measure of harm to human health due to cancer and heritable effects from low-dose and/or low-dose-rate exposures to ionising radiation. This helps set dose limits and allows comparisons with other harms and benefits when considering justification and optimisation of protection.
Radiation detriment was updated in the 2007 Recommendations of the International Commission on Radiological Protection (ICRP, 2007), and revisited more recently while preparing for the review of the System. Although considerable detail on the development of radiation detriment was included in the 2007 Recommendations, attempts to reproduce the calculations did not, in some cases, result in the same figures as those published by ICRP.
Recognising the need for clarity, the first aim of the present publication is to reproduce, in complete detail, the calculation of radiation detriment for the purposes of radiological protection, and address any differences from the previous calculations. This transparency allows others to review the methodology in detail, and all the factors that went into the analysis. It is also a firm basis for possible future changes to the concept and calculation of radiation detriment.
In addition, a selected sensitivity analysis was performed to determine which factors have the most influence on the calculation of radiation detriment. This will help ICRP and others focus research efforts on those factors that matter most.
During the review of the calculations for the 2007 Recommendations (ICRP, 2007), a few programming errors were found. Although these resulted in miscalculations of nominal risk coefficients for the working-age population for some organs and tissues, the overall results were not greatly impacted. Fortunately, this means there is no impact on the System. Nonetheless, these errors are clearly discussed, assessed, and corrected in the present publication to ensure full transparency and accountability. These are two of the five principles in ICRP’s Code of Ethics (ICRP, 2014) which demands that ICRP:
acts to protect humans and the environment from the harmful effects of radiation (commitment to public benefit); acts independently of governments and organisations, including industry and other users of radiation (independence); acts impartially in its development of recommendations and guidance (impartiality); engages stakeholders and strives to be transparent in its actions and judgements (transparency); and is accountable to the framework that governs the activities of a charity (accountability).
ICRP recognises that it is the steward of the System, with a responsibility to keep it fit for purpose, but is not the owner, user, or benefactor. Therefore, in the continuing review and revision of the System, further practical ethical principles emerge. Inclusiveness and accessibility are central among them, to ensure that everyone who wants to weigh in on the review and revision of the System can do so. It is with these principles in mind that ICRP widely launched the review and revision with two open access papers (Clement et al., 2021; Laurier et al., 2021), which are available through the ICRP website, and organised the Workshop on the Future of Radiological Protection in October 2021. The Workshop was held online and included a no-cost registration option, so that anyone with an internet connection could join with no financial barrier to participation, fostering inclusiveness and accessibility. With transparency in mind, all materials from the Workshop will be openly available on the ICRP website for the foreseeable future.
There is further work to be done on radiation detriment in the framework of the review and revision of the System. For example, the work of ICRP Task Group 91 on radiation risk inference at low-dose and low-dose-rate exposure for radiological protection purposes will be an important input for future radiation detriment calculations. Whether and how other effects might be included will need to be considered, such as individual response to radiation, and diseases of the circulatory system now being addressed by ICRP Task Groups 111 and 119, respectively. ICRP has more recently launched Task Group 121 Effects of Exposure in Offspring and Next Generations, and Task Group 122 Update on Detriment Calculation of Cancer. It is not difficult to imagine another ICRP publication on radiation detriment taking all of this into account before the successor to the 2007 Recommendations (ICRP, 2007) is completed.
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