ABUTMENT OF HIGH-ENERGY ELECTRON FIELDS

The problem of positioning multiple electron fields on the skin surface is complicated by the fact that the scattering properties of electrons result in constriction of the higher value isodoses and bulging out of the lower value isodoses. We have studied the dose distributions in the junction region for adjacent electron fields using our 3-dimensional radiation treatment planning system by investigating the effects of field separation for several field size, air gap, and beam energy combinations. Film dosimetry was used to measure specific test cases. Using our 3-dimensional radiation treatment planning system, we are able to display the calculated dose distribution, calculate dose-volume histograms, and compare calculations with the film dosimetry measurements. Results of our study are presented.