Model of Total Skin Electron Treatment Using the 'Six-Dual–Field' Technique

During implementation of the total skin electron treatment, using six-dual-field tech-nique, at radiotherapy department a large number of measurements are needed. To as-sess depth dose curve required by clinicians and dose uniformity over a whole treatment plane, combinations of different irradiation parameters are used (electron energy, beam angle, scatterers). Measurements for each combination must be performed. One possible way to reduce number of measurements is to model the treatment using the Monte Carlo simulation of electron transport. We made a simplified multiple-source Monte Carlo model of electron beam and tested it by comparing calculations and experimental re-sults. Calculated data differs less than 5 percent from measurements in the treatment plane. During the treatment patient can be approximated using cylinders with different diameters and orientations. We tried to model the depth dose variations in the total skin electron treatment not just around the body cross-section (simplified to cylinders of dif-ferent diameters), but also along the body to account for the variations in body curva-ture longitudinally. This effect comes down to the problem of modeling distribution in different cylinders, but varying the longitudinal orientation of those cylinders. We com-pared Monte Carlo calculations and film measurements of depth dose curves for two ori-entations of the cylindrical phantom, which were the simplest for experimental arrange-ment. Comparison of the results proved accuracy of the model and we used it to calcu-late depth dose curves for a number of other cylinder orientations