[en] During radiotherapy treatment with X rays or gamma rays blood receives -due to circulation - a different dose to that one received by tumor. Even more, an individual blood cell can circulate by a radiation field more or less times that the average cell, and then it is not sufficient to specify an average dose in blood, but it is necessary to determine a dose distribution. In this work the dose distribution in lymphocites of cervix-uterine cancer patients submited to radiotherapy with X rays of 6 to 15 Mv in the Instituto Nacional de Cancerologia (Oncology National Institute). The calculations are based in the formalism presented in Ref. 1 taking acount the break up or fractioning and the number of fields in each treatment manner. Our interest in the problem appears in the desire to 'calibrate' as biological dosemeter an evaluation technique of genetic damage using samples of peripheric blood of radiotherapy patients. (Author)