Chromosome aberrations in peripheral lymphocytes of patients irradiated with 15-MeV-photons for Morbus Hodgkin.

Chromosome aberrations in peripheral lymphocytes of two Morbus Hodgkin patients were analyzed before and during the ongoing radiotherapy. Venous blood was taken 5 min after and before a successive irradiation in order to examine the dose dependence as well as the influence of mixed unirradiated and irradiated lymphocytes on the aberration rate. Both patients showed an overdispersed distribution of dicentric chromosomes and acentric fragment from the outset of therapy and independent of the time blood was taken. The dose-effect relationship established for both types of aberrations by the Maximum-Likelihood approach may best be described as being linear. The dose effect curves 5 min after a fraction did not differ from those calculated for a time thereafter. However, after the first two irradiations, the rate of dicentric chromosomes in the blood samples taken at a later time was about twice as high as that in the samples taken 5 min after irradiation. Dicentric chromosomes were twice more frequent during the entire radiotherapy than acentric fragments and about 30 times more frequent than centric ring chromosomes.