This report considers the evidence relating to cancer risk associated with exposure to low doses of low linear energy transfer radiation, and particularly doses below current recommended limits for protection of radiation workers and the general public. The focus is on evidence regarding linearity of the dose-response relationship for all cancers considered as a group, but not necessarily individually, at low doses [the so-called linear, non-threshold (LNT) hypothesis]. It looks at the possibility of establishing a universal threshold dose below which there is no risk of radiation-related cancer. The report is organised by scientific discipline, beginning with epidemiological studies of exposed human populations.
ABSTRACT GUEST EDITORIAL PREFACE EXECUTIVE SUMMARY INTRODUCTION EPIDEMIOLOGICAL CONSIDERATION Introduction Inferences based on acute doses in the moderate-to-high dose range Estimation of risk at low doses and low dose rates Thresholds vs. the linear, no-threshold theory Conclusion: Implications for low-dose cancer risk LOW-DOSE RISK BIOLOGY Introduction Damage caused by radiation Damage Response Pathways Fidelity of DSB repair Impact of defects in DNA repair, checkpoint control and apoptosis Conclusions CELLULAR CONSEQUENCES OF RADIATION-INDUCED DAMAGE Radiation- induced Chromosome Aberrations Radiation-Induced Somatic Cell Mutations Adaptive Response, Genomic Instability and Bystander Effect Conclusions: Implications for Risk Assessment CARCINOGENIC EFFECTS OF IONIZING RADIATION Mechanisms of radiation-induced cancer Tissue Modifying Factors Radiation-induced Cancer in Animals Life Shortening Summary Conclusions: Implications for radiation-related cancer at low doses QUANTITATIVE UNCERTAINTY ANALYSIS Overview Sources of uncertainty Allowing for the uncertain possibility of a threshold Conclusions CONCLUSIONS REFERENCES