The biological background to the recommendations of the ICRP

An account is given of the historical origins of the International Commission on Radiological Protection. The Commission's most recent recommendations issued in 1977 are based on a philosophy of avoiding unnecessary radiation exposure and justifying such exposures as do occur. In addition, annual individual levels of exposure are set which the Commission recommend should not be exceeded. These levels are derived from information on the effects of radiation obtained from fundamental radiobiological studies but mainly from epidemiological data on human subjects irradiated accidentally or for medical reasons. These data are reviewed in the article. The Commission use these to make numerical estimations of the risk incurred in receiving doses of radiation. In setting the levels the Commission have attempted to establish degrees of risk for workers and the public at large which will compare favourable with risks generally regarded as acceptable. Although there are still considerable uncertainties about radiation effects, particularly at very low doses, it is unlikely that the Commission's estimates of risk from radiation are misleadingly optimistic