The linear no‐threshold dose‐effect relation: Is it relevant to radiation protection regulation?

Abstract

Official radiogenic cancer risk estimates for low-dose, protracted exposure conditions have been based on linear, no-threshold downward extrapolation from medium and high-dose effects among a population of A-bomb survivors, with the application of a downward correction for an assumed reduced biological effectiveness at low doses and low dose rates (DDREF correction). Neither in the follow-up of populations exposed to the high-dose A-bomb flash, nor from epidemiological data after low-dose occupational or medical irradiation is there any convincing evidence for this DDREF hypothesis--even less for a zero-effect threshold dose. To the contrary, for external low-dose exposures of nuclear workers or general populations, cancer risks per unit dose have been found to be about 1 order of magnitude larger than those derived from the Japanese survivors, with larger discrepancies for persons above 50 years of age, and for x-rayed fetuses. This may be due to a dose and dose-rate effect exactly opposite from that postulated by the DDREF assumption, and a dose-dependent bias due to selection for exceptionally high immune competence among the > 5 years A-bomb survivor cohort. Excess cancer mortality following occupational exposures to ingested fission products and radiation-associated teratogenic, genetic, and cancer detriment among diverse populations who had ingested small amounts of radioactivity after the precipitation of fallout at great distances from the Chernobyl nuclear explosion, suggest discrepancies of as much as 2 orders of magnitude with official risk estimates. Contrary to widely publicized statements, claiming that current regulations of population exposures are far too restrictive, thus unnecessarily costly for the radiation industries, the aggregate of radiation epidemiological evidence suggests that current standards are inadequate to protect public health.

Weight-Based, Low-Dose Pediatric Whole-Body PET/CT Protocols

“…This model assumes that the risk of solid cancer incidence at low levels can be extrapolated from linear fits to the risk of cancer incidence at high levels. Although this remains an active area of debate (27,28), several sources have argued that this is a prudent working assumption given the current, limited knowledge of the risks associated with low levels of radiation (29). The risk of cancer incidence is a function of effective dose, sex, and age.…”

Objectivity and ethics in environmental health science.

“…Although peer review may catch obvious flaws or poor writing, it cannot ensure that findings are correct, or even that research is not fraudulent (Broad and Wade 1982). In areas where scientific research, professional meetings, fellowships, and journals are funded through organizations with interests in an established perspective, peer review by orthodox scientists may lead to rejection of studies whose results challenge established assumptions, even if their methodology is appropriate (Nussbaum 1998;Nussbaum and Köhnlein 1994).…”

Childhood Leukemia and Cancers Near German Nuclear Reactors: Significance, Context, and Ramifications of Recent Studies

“…Observations of excess cancers, neonatal mortalities, spontaneous abortions, and other diseases have continued to clash with claims by the International Atomic Energy Agency (IAEA), speaking for the United Nations World Health Organization (WHO), that exposures from Chernobyl fallout were orders of magnitude too low to be causally associated with these reported health effects. 16,[31][32][33][34] This contention is based on population dose estimates by UNSCEAR, 6 combined with radiation risk factors for low-dose external exposures adopted by that organization and the ICRP. 8 However, numerous "authoritative" reports on the health legacy of the Chernobyl catastrophe have ignored evidence of serious flaws and gaps in knowledge on which the currently accepted models for population exposure and radiation risk estimates are based.…”