To construct a -radiation dose–response calibration curve by use of the CBMN assay, we pooled the data from the 16 donors to take into account the variability between individuals, since itis known that the micronucleus frequency is affected by factors such as age, gender, diet and exposure to chemical agents
[20]. The results obtained from the 16 donors were also divided by age And gender and the corresponding calibration curves were constructed. The spontaneous level of micronuclei assessed from the 16 healthy donors ranged from 7 to 18 (data not shown), with a mean Value of 12 micronuclei per 1000 binucleated cells, in good agreement with baseline values obtained in other laboratories [39,40] and with what was expected since baseline values ranging from 0 to 40 micronuclei per 1000 binucleated cells have been reported [6].