Computer-assisted estimation of the dose distribution in intracavitary radiation therapy

A new version of a computer-assisted method for determination of the dose distribution in the pelvis of female patients treated with sealed radioactive radium or caesium sources is outlined. The position of the sources in a coordinate system centered on the symphysis is determined stereoradiographically. The dose values are calculated either for singular body points or for points situated on transversal, frontal and sagittal planes through the symphysis or for planes parallel to these. In consideration of the fact that for each patient the anatomical position of the calculation planes can be reproduced with sufficient precision, it is possible to cumulate on each plane the dose values obtained from treatment performed at different times. Experimental controls show good agreement between calculated and measured dose values. Some clinical examples of dose calculation for sagittal planes and of cumulated dose values for a frontal plane 7.4 cm underneath the symphysis are presented. (orig.)