Dose and dose-rate effectiveness of radiation: first objectivity then conclusions -

Abstract

This letter comments on the ongoing re-evaluation of the dose and dose rate effectiveness factor (DDREF) equal to 2.0, currently recommended by the International Commission on Radiological Protection. The topics of DDREF and threshold are related to the linear no-threshold theory (LNT), which does not take into account that DNA damage and repair are in dynamic equilibrium probably reached in a long term. Living organisms must have been adapted by natural selection to the today’s background level of radiation or to some average from the past, when the radiation background was higher. Dosedependent self-selection of exposed people and other biases common in epidemiological studies, cited in support of the DDREF lowering, are discussed here. In conclusion, the LNT and under-estimation of DDREF tend to exaggerate radiationrelated health risks at low dose and dose rates exposures. Future risk estimates should be based on direct comparisons of experimental data from acute and protracted exposures.