Estimation of dose in cancer patients treated with fractionated radiotherapy using translocation, dicentrics and micronuclei frequency in peripheral blood lymphocytes.

The frequency of translocation, dicentrics (DC) and micronuclei (MN) was studied in blood samples exposed in vitro to (60)Co gamma radiation and cervical cancer patients undergoing fractionated radiotherapy. The samples exposed under in vitro condition showed that the frequency of translocation and dicentric followed Poisson distribution ('u' varied between -0.04 and +1.41 for translocation and between -0.09 and +1.81 for DC) and that obtained with MN follow over dispersion ('u' varied between +2.04 and +9.28). However, the cervical cancer patients undergoing radiotherapy showed over dispersion for all these three aberrations (DC, MN and translocation). The frequencies of aberrations obtained in cancer patients were found to be lower than those obtained for in vitro exposure for doses more than 2 Gy equivalent whole body dose (EWBD). The dose-response curves were constructed using the frequencies of DC, MN and translocation as a function of EWBD. Doses as measured from the dose response curves were compared with the estimated dose in order to check whether the measured and estimated doses agree. The percent variation between the doses measured from aberration frequencies and that of the estimated dose was lower with translocation (10.8+/-7.41%) compared to those obtained with DC (38. 08+/-31.85%) and MN (47.19+/-31.80%).