[A study on over-centerable multi-axial conformation radiotherapy for prostatic carcinoma--analysis of the dose...

The over-centerable multi-axial conformation radiotherapy was studied for stage C carcinoma of the prostate and the dose distribution obtained by this method was compared with those of other radiation methods. It is clinically important to reduce volume irradiated to normal tissues as the radiation damage depends not only on the extent of overdose but also on the amount of the overdosed volume and for the analysis of dose distribution, the volume-dose histogram is an useful method. Using newly developed software of computer for radiation treatment planning system (CMS, Modulex), we studied the volume-dose histogram in the conformation radiotherapy of prostatic carcinoma. With regard to the volume-dose histogram, the conformation technique showed better dose distribution than other conventional methods. In two-axial conformation technique with over-centerable multi-leaf collimators, although that was slightly inferior in the dose homogeneity in the lesion, the doses irradiated to rectum and bladder were lowest. In conclusion, our conformation technique is the most suitable method for delivering better dose distribution to the carcinoma of the prostate with minimum dose to rectum and bladder.