From scientific evidence to radiation protection

The long-term effects on health from radiation at low dose rates depend on so many biological variables that simple generalizations are unlikely to be valid for any specific individual at any specific time. Increased incidence of cancers can be observed from moderate doses at high dose rates. At lower doses and lower dose rates evidence is less clear. Advances in molecular biology in the last decade are enabling striking progress to be made in understanding the cellular mechanisms that determine the responses to radiation and their underlying genetic control. Enough is known now to conclude that any response will depend on an individual's genetic makeup and may be varied in time for a given individual, depending, inter alia on the pattern of dose in time. Faced with this uncertainty, the pragmatic approach for protection remains that of basing the level of protection simply on the magnitude of the radiation dose, albeit not with the underlying idea that with every radiation event there is a fixed probability of causing cancer. (author)