An 11 year follow-up of individual radiation responses as assessed by micronuclei induction in peripheral blood lymphocytes.

In this short note we describe the results of a unique 11 year follow-up of the induction of micronuclei by radiation in three individuals. These individuals were all part of two larger studies carried out in 1987 and 1998 respectively, each having similar population characteristics. No significant differences in the average radiation response of these two populations were observed, nor were there any apparent differences in the 1987 and 1998 responses of two of the three individuals reassessed. Data from the third individual (and from a wider study reported elsewhere) do, however, provide some evidence for an age dependence. It is concluded that significant individual variations in the age-dependent responses to radiation may exist, and that while for some individuals there is no increase in radiosensitivity with age, for others there is. Such age dependences may be diluted by studying age-related responses in whole populations of limited size rather than by following individuals over a long period of time. The results reported here are from a limited data set and it is important that further studies are carried out to provide evidence for or against the existence of an age-dependent response to radiation in some individuals.