Repercussions for radiological protection of the recent revisions in Japanese A-bomb dosimetry

The recent re-evaluation of the dose data for the Japanese A-bomb survivors shows significant differences from the doses used by UNSCEAR, BEIR and ICRP. Detailed revision and application of the new dose estimates is an ongoing process, and it may take some time for definitive risk estimates to emerge. In the interim we consider it important to review and encourage risk estimation using data other than those from Japan. We give estimates of low LET risks, based on the data of UNSCEAR but specifically excluding the bomb data. We find a total cancer mortality risk figure which is within a factor of 2 of the value given in ICRP Publication 26, but in accord with estimates of BEIR and UNSCEAR before reduction to account for dose rate/response effects. The need to consider the revised dose estimates for Hiroshima and Nagasaki focuses attention on the paucity of data on which dose limits for high LET radiation can be based. The uncertainties inherent in the analysis of epidemiological data or animal experiments allow a wide range of radiation risk scenarios to be made. ICRP Publication 26 appears to represent a mid-range view. The temporary loss of the bomb dosimetry emphasizes the need for improved neutron dosimetry techniques and increased effort in human epidemiology and radiation biology. (author)