A Study on Time- and Radiation-dependent Changes in the Frequency of Lymphocytes with Chromosome Aberrations in the Circulation, Following Multiple Exposures of the Pelvis to γ-Irradiation

Unstable chromosome aberrations of peripheral lymphocytes were observed during the course of radiotherapy in patients with cervical cancer. They did not increase monotonously with repeated exposures, but a plateau was observed around the second week of treatment. Similar tendencies were observed in both 72-hour and 50-hour culture experiments, although the number of abberrations was lower in the former. The distribution of numbers of dicentrics per cell fitted well the Poisson pattern throughout the period of observation. Peripheral lymphocyte counts reached a low plateau before the fifth exposure, and dropped again in the third week. It was speculated that the "member exchange" and/or mobilization of lymphocytes caused the nonlinear increase in chromosome aberrations.