Keywords: ambient radiation, cancer, deficiency, essential agents, human health, nurture, optimum levels, safe levels, ionising radiation, dose-response curve, radiation safety, radiation threshold, low radiation
Documented optimum and threshold for ionising radiation
A concept of the complete dose-response curve of ionising radiation will allow us to live in harmony with this ubiquitous agent. Convincing data show ionising radiation is essential for life. Ambient levels of ionising radiation (about 2 mSv/y without medical and cosmic radiation) are adequate for life but insufficient for abundant health. We live with a partial deficiency of ionising radiation. Thousands of people have lived for generations with 2?20 times the ambient levels of radiation without showing ill health. A conservative threshold, the maximum safe level of radiation, was estimated from abundant rodent data to be about 8000 mSv/y. When human and rodent data were collated, a conservative optimum of 60 mSv/y was obtained. Radiation levels greater than the threshold are harmful. The facts suggest that radiobiologists and governments should abandon the 'linear no threshold' (LNT) paradigm and accept natural and industrial low level sources of ionising radiation in order to promote abundant health.