Biological effects of low doses of ionizing radiation: A fuller picture

hen the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) submitted its 1994 report to the United Nations General Assembly this year, the international community received a fuller picture of the biological effects of low doses of ionizing radiation. The 272-page 1994 report specifically addresses epidemiological studies of radiation carcinogenesis and adaptive responses to radiation in cells and organisms. The report is designed to supplement the more extensive 928-page report that UNSCEAR presented to the UN in 1993.* That report addressed global levels of radiation as well as major issues of radiation effects, including the mechanisms of radiation oncogenesis; the influence of level of dose and dose rate on stochastic effects of radiation; hereditary effects of radiation; radiation effects on the developing human brain; and late deterministic effects in children. Taken together, these two reports provide an impressive account of current knowledge on the biological effects of ionizing radiation. This article — though by no means an account of all essential information — summarizes the highlights of UNSCEAR's assessment of the effects of low doses of ionizing radiation, hereinafter called " low radiation doses" (see box, page 39) in the context of available radiobiological evidence.