ICRP task group 123: classification of harmful radiation-induced effects on human health for radiological protection purposes

In the current system of radiological protection, radiation effects are classified as either tissue reactions (also known as deterministic effects) or stochastic effects. The objectives of the system are to manage and control exposures to ionising radiation so that harmful tissue reactions are prevented, and the risks of stochastic effects are reduced to the extent reasonably achievable. Thus, the classification of health effects is a very important pillar of the system of radiological protection. In recent years, there has been debate regarding the adequacy of the current scheme for classifying health effects. Recent publications, including those from ICRP, have highlighted the need for a review of the ICRP scheme for health effects classification. This article outlines the basis for the establishment of ICRP Task Group (TG) 123 and the outlined tasks, the key sources of uncertainties for consideration, the agreed approach and timeline to tackle the above tasks, as well as the links with and dependencies on the other ongoing developments to the system being considered by the other ICRP task groups.