The importance of data from the atomic bomb survivors for international radiological protection.

Epidemiological studies using data from the lifetime experience of the survivors of the atomic bombings of Japan have been fundamental in shaping the international system of radiological protection since a clear excess risk of, first leukaemia and then other cancers, became apparent in the 1950s and 1960s. Cancer mortality and incidence data have been collected, collated and analysed by the Radiation Effects Research Foundation (RERF, and its predecessor, the Atomic Bomb Casualty Commission, ABCC) and the risk estimates so produced have been used subsequently by the International Commission on Radiological Protection (ICRP) to provide the main technical basis of its general recommendations, from its 1965 Recommendations to the latest 2007 Recommendations. As the database has grown with increasing follow-up of the survivors, together with continued refinement of the dosimetry system, ABCC/RERF analyses have become more sophisticated, permitting knowledge of the variation of risks for a growing number of specific types of cancer, as modified by sex, age-at-exposure and time-since-exposure/attained age. A growing database of non-cancer effects, such as diseases of the circulatory system and eye lens opacities, is also providing risk estimates. Even now, 80 years after the bombings, the survivors provide important information on risks decades after exposure at a young age. There is little doubt that recent RERF studies of cancer and non-cancer diseases in the survivors will continue to steer the ICRP in its progress towards the next Recommendations.