Control of low-level radiation exposure: time for a change?

The carcinogenic risks of exposure to low-level ionising radiation used by the ICRP have been challenged as being, at the same time, both too high and too low. This paper explains that the epidemiological evidence will always be limited at low doses, so that understanding the cellular mechanisms of carcinogenesis is increasingly important to assess the biological risks. An analysis is then given of the reasons why the challenges to the ICRP, especially about the linear non-threshold response model, have arisen. As a result of considering the issues, the Main Commission of the ICRP is now proposing a revised, simpler, approach based on the concept of what is being called 'controllable dose'. This is an individual-based philosophy and represents a shift in emphasis by the Commission from societal-oriented criteria using Collective Dose. Finally the paper speculates on the consequences for radiological protection of such a change in policy. The Commission wishes its ideas to be discussed as part of its reconsideration of its recommendations.