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CANCER RISKS ATTRIBUTABLE TO LOW DOSES OF IONIZING RADIATION - ASSESSING WHAT WE REALLY KNOW?
Brenner, D. J., R. Doll, D. T. Goodhead, E. J. Hall, C. E. Land, J. B. Little, J. H. Lubin, D. L. Preston, R J. Preston, J. S. Puskin, E. Ron, R. K. Sachs, J. M. Samet, R. B. Setlow, AND M. Zaider. CANCER RISKS ATTRIBUTABLE TO LOW DOSES OF IONIZING RADIATION - ASSESSING WHAT WE REALLY KNOW? PNAS (PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES) 100(24):13761-13766, (2003).
Cancer Risks Attributable to Low Doses of Ionizing Radiation - What Do We Really Know?
High doses of ionizing radiation clearly produce deleterious consequences in humans including, but not exclusively, cancer induction. At very low radiation doses the situation is much less clear, but low-dose radiation risks are of societal importance in relation to issues as varied as screening tests for cancer, the future of nuclear power, occupational radiation exposure, frequent flyer risks, manned space exploration, and radiological terrorism. We review the difficulties involved in quantifying low-dose radiation risks, and address two specific questions: First, what is the lowest dose of x or gamma rays for which there is good evidence of increased cancer risks in humans? The epidemiological data suggest that it is about 10 to 50 mSv for an acute exposure, and about 50 to 100 mSv for a protracted exposure. Second, what is the most appropriate way to extrapolate such cancer risk estimates to still lower doses? Given that it is supported by experimentally grounded, quantifiable, biophysical arguments, a linear extrapolation of cancer risks from intermediate to very low doses appears currently to be the most appropriate methodology. This linear assumption is not necessarily the most conservative approach, and it is likely that it will result in an underestimate of some radiation-induced cancer risks and an overestimate of others.