Analysis of Mutation Induction By Low Dose Rate Tritium Radiation Using Hyper Sensitive Detection System

Abstract

An exposure condition of tritium radiation from nuclear fusion reactor could be a long-term exposure with low dose rate. The biological effects of low dose (rate) radiation are not clear because any suitable detection system has not been established. Regarding to mutation induction by high LET radiation such as neutrons, the reversed dose rate effect has been reported when the dose rate is lower than a certain value. This might be caused by hypersensitivity of G2/M phase population to mutation induction by high LET radiation. However, it is not clear whether this phenomenon could be seen in the case of tritium radiation. To examine the low dose rate effect of tritium, we established a hypersensitive mutation detection system using hamster cells carrying a human X-chromosome. We have tested mutation induction by tritiated water at dose rate between 0.18 and 4.4 cGy/h. Our results suggest that mutation frequency seems to be slightly increased at lower dose rate. [J Radiat Res 44:391 (2003)]