Special Issue Article
Antone L. Brooks
Abstract
Abstract This presentation evaluates the role of dose and dose rate on the induction of cancer. It is important to realize that high doses of radiation produce cancer. The level estimated by the National Academy of Science is 5% per Sievert. Since most environmental exposures result in exposures in the mSv range and dose rates protracted over months or years the extrapolation of the data from high doses to low doses results in uncertainty. The DOE funded a research program to study the biological changes induced by low doses of radiation using modern cell and molecular techniques combined advances in technology. These studies determined that there is a need for basic paradigm changes in radiation biology and suggested that mutations and chromosome damage may not play the major role in the induction of cancer by ionizing radiation. At high doses of radiation where increases in cancer can be easily detected in both humans and experimental animals there is extensive cell killing, tissue disorganization and tissue damage. Dose rates that result in large doses per cell turnover also produce extensive cell killing, tissue disorganization, immune suppression, induction of chronic inflammatory disease, fibrosis and pneumonitis and changes in metabolic pathways. Such research suggests that cell killing and tissue damage and the physiological responses to that damage are the major mechanisms for radiation induced lung cancer, not mutations or chromosome damage. This presentation will discuss paradigm changes and the need for a serious rethinking of radiation standards and the implementation of protective action following low doses and low dose rate exposures to human populations.