The 2023 Bo Lindell Laureate Lecture: Assessing and managing radiological risk

At low dose and low dose rate, the system of radiological protection developed by ICRP is based on the linear non-threshold (LNT) relationship between dose and risk. In ICRP Publication 9, the Commission stated 'As the existence of a threshold dose in unknown, it has been assumed that even the smallest doses involve a proportionately small risk of malignancies […]. The Commission is aware that the assumptions of no threshold and of complete additivity of all doses may be incorrect but is satisfied that they are unlikely to lead to the underestimation of risks'. ICRP Publication 26 laid down the basis of the current system of radiological protection and established a clear rationale between radiological risk assessment and radiological risk management. The effective dose concept was introduced in ICRP Publication 26 along with w_T based on the relative contribution of organs to radiological detriment. Dose limits values were directly supported by quantitative risk criteria. This rationale is less apparent in ICRP Publication 60, which introduced a somehow less quantitative approach for radiological risk management, based on detriment, tolerability of risk, reasonableness of the optimisation process and acceptable level of risk. Over the last two decades, several scientific results have raised questions related to radiological risk assessment and consequences for risk management. This article investigates some of these questions and potential consequences to be considered for the future of the system of radiological protection.