Abstract
TDF (time-dose factor values for both low (radium) and high dose-rate (Co60, Cathetron) intracavitary regimes in the treatment of cervical and endometrial carcinoma were calculated. Although some statistical differences were found between the TDF values of patients with and without complications, individualization of the treatment is of utmost importance in preventing radiation-induced complications. Patients treated by the Cathetron with single fractions of 10 Gy each had statistically more complications and higher TDF values than patients treated with fractions of 7.5 Gy each. Optimum TDF values for low and high dose-rate treatments are given although it is shown that the TDF system overestimates the required dose at high dose-rate by approximately 33%. Therefore a new normalizing constant of 1.18, instead of 1.57 as used so far, is proposed.