Cellular and molecular changes induced by low- versus high-dose radiation

摘要

The shape of the dose-effect curve of biological parameters depends on a number of factors, among which, the radiosensitivity of the target under study, the dose spacing and dose rate are important ones. When one goes down to the lower dose range, especially with doses below 0.2 Gy, changes of many biological parameters in the opposite direction to those observed with doses higher than 0.5 Gy are often documented, thus resulting in a U- or J-shaped or an inverted U- or J-shaped curve. In the present paper, such a phenomenon is reviewed by giving data from the author's laboratory demonstrating the difference in nature of effects induced by low versus high-dose X-rays at molecular and cellular levels as well as their implications in the intact organism. A hypothetical dose-effect model is suggested to summarize the observations.