"Maximum dose" points in cervical and endometrial cancer medium dose rate brachytherapy

Background. Best dose distribution in target volume and control of Organ at Risk (OAR) dose are the two main goals in brachytherapy. Materials and Methods: In this study in vivo dosimetry in 4 rectal points was performed by Transillumination Dosimeter (TLD) s and the measured doses were compared in different patients. One point was reported to have the maximum dose in each patient and the very dose was considered as rectal dose according to ICRU-38 prescription; however, the next higher dose was also considered the same as the highest point when the difference was not more than 10% of the highest value. Results: In more than 50% of the cases the 1(st) and 2(nd) highest points were in the same range with less than 10% variation. There were 3 points in approximately equal dose in 7% of cases. Conclusion: These findings are challenging with the ICRU-38 recommendations reporting the existence of a sole maximum rectal dose. So it seems wise to consider an isodose plate of maximum doses instead of one point only. Iran. J. Radiat. Res., 2009; 6 (4): 189-194