The LNT model is the best we can do - today

The form of the dose-response curve for radiation-induced cancers, particularly at low doses, is the subject of an ongoing and spirited debate. The present review describes the current database and basis for establishing a low dose, linear no threshold (LNT) model. The requirement for a dose-response model to be used for risk assessment purposes is that it fits the great majority of data derived from epidemiological and experimental tumour studies. Such is the case for the LNT model as opposed to other nonlinear models. This view is supported by data developed for radiation-induced mutations and chromosome aberrations. Potential modifiers of low dose cellular responses to radiation (such as adaptive response, bystander effects and genomic instability) have not been shown to be associated with tumour development. Such modifiers tend to influence the slope of the dose-response curve for cellular responses at low doses and not the shape-thereby resulting in a quantitative modification rather than a qualitative one. Additional data pertinent to addressing the shape of the tumour dose-response relationship at low doses are needed.