TG 91: Radiation Risk Inference at Low-Dose and Low-Dose Rate Exposure for Radiological Protection Purposes

<p>The detriment-adjusted nominal risk coefficients recommended by ICRP have been based, to a large extent, on data obtained from the atomic bomb survivors in Japan. ICRP introduced a Dose and Dose-Rate Effectiveness Factor (DDREF) of 2 to include in calculations of these risk coefficients for application at the low doses and low-dose rate exposures typical in radiological protection. The DDREF was included to account for the survivors&rsquo; single acute exposure, and because a linear quadratic instead of a linear risk to dose response was thought to be the most plausible biological model.</p> <p>This paper summarizes the recent work of ICRP Task Group 91 on this topic. Task Group activities have included reviews of the history of low-dose and low-dose-rate effects, various exposure scenarios and their doses and dose rates, radiation-induced effects at the molecular, cellular, animal, and human level, and biologically-based mechanistic models of carcinogenesis. The Task Group performed a meta-analysis of low-dose-rate epidemiological studies, and re-analyses of published results on radiation-induced effects among animal models and among Japanese atomic bomb survivors.</p>