Dose-response relationship for radiation carcinogenesis in the low-dose region

Evidence that low-level radiation substantially enhances the effectiveness of repair mechanisms is summarized. This finding destroys the theoretical basis (there is no other basis) for use of a linear-no threshold dose-response relationship to estimate the cancer risk of exposure to low-level radiation. Such a methodology will exaggerate the risk. This conclusion is further supported by epidemiological evidence and by studies of the effects of radon exposure in the home, which are reviewed.