Mortality risk coefficients for radiation-induced cancer at high doses and dose-rates, and extrapolation to the low dose domain.
Risk coefficients for life-long excessive mortality due to radiation-induced cancers are presented, as derived in 1988 by the U.N. Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), principally on the basis of follow-up from A-bomb survivors in Japan, over the period from 1950 through 1985. The data are based on the new, revised dosimetry (DS 86) in the two cities, and reflect the effects of high and intermediate doses of basically low LET radiation delivered instantaneously. The author presents arguments relevant to the extrapolation of the risk to the low dose (dose rate) domain, as outlined by UNSCEAR in its 1986, and the NCRP (USA) in its 1980, (no 64), reports. The arguments are based on models and dose-response relationships for radiation action, derived from data on cellular radiobiology, animal experiments on radiation-induced cancers and life shortening, as well as the available limited human epidemiological evidence. The available information points to the lower effectiveness of sparsely ionizing radiation at low doses and low dose-rates, as compared with that observed for high, acutely delivered doses. The possible range of the reduction values (DREF) is presented. For high LET radiations, the evidence is less extensive and sometimes contradictory; however, it does not point to a reduction of the effectiveness at low doses/dose-rates, relative to the high dose domain. Practical consequences of these facts are considered.
Liniecki
J
J
D000328:Adult; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009381:Neoplasms, Radiation-Induced / Q000401:mortality*; D011829:Radiation Dosage; D012307:Risk Factors