Micronucleus induction in peripheral blood lymphocytes of patients under radiotherapy treatment for cervical cancer or Hodgkin's disease.

The genetic damage present in peripheral blood lymphocytes of patients treated with fractionated partial-body radiation therapy for cervical cancer or Hodgkin's disease was followed during treatment by means of the cytokinesis-block micronucleus assay. For each patient a dose-response relationship with respect to the number of micronuclei after in vitro irradiation of blood samples pretreatment was also determined. Comparing the individual in vivo-in vitro data, the micronucleus yields after the equivalent whole-body dose during radiotherapy were found to differ substantially from the in vitro dose-response. Contrary to the linear-quadratic dose dependence after in vitro irradiation the initial increase in the micronucleus yield during radiotherapy levelled off at elevated doses. The observed differences cannot be attributed only to the effects of interphase death and the partial irradiation of the lymphocyte pool. The correlation between the micronucleus yield and the equivalent whole-body dose for values up to 2 Gy, observed for the pooled data of the first part of the radiotherapy treatment, demonstrates the suitability of the cytokinesis-block micronucleus assay as a biological dosemeter after accidents involving partial-body irradiation.