Changes

Stochastic effect (somatic or heritable) increases with radiation dose and is probably proportional to dose at low doses and low dose rates.<ref name="Pub099">[[ICRP Publication 99]] Low-dose Extrapolation of Radiation-related Cancer Risk. Ann. ICRP 35(4), 2005.</ref> ([[ICRP Publication 99]] Low-dose Extrapolation of Radiation-related Cancer Risk). At higher doses and dose rates, the probability often increases with dose more markedly than simple proportion. At even higher doses, close to the thresholds of tissue reactions, the probability increases more slowly, and may begin to decrease as a result of the competing effect of cell killing. It is not feasible to determine on epidemiological grounds alone that there is, or is not, an increased risk of cancer for members of the public associated with absorbed doses of the order of 100 mGy or below. The linear non-threshold model remains a prudent basis for the practical purposes of radiological protection at low doses and low dose rates.