EXPERIMENTAL VERIFICATION FOR ELECTRON BEAM DOSE ALGORITHMS

Abstract

The goal of radiotherapy is to deliver a high and uniform dose over the target volume and to minimize dose elsewhere. In order to avoid serious complications, (e.g. necrosis), the ICRU 50, 1993, recommended that the dose to the target volume should be delivered homogeneously and the deviation should not exceed ± 5% and recently± 3% between any two points inside the target volume.

One of sources of error in dose delivered to the tumor is due to the method used in its calculation. A significant error was found due to the presence of non regular tissues in shape and composition such as internal or external tissue inhomogeneities. It may also found as a result of extending the source surface distance, shaping the electron field and the obliquity beam incident. For these reasons the pencil beam algorithm inside the computer planning system should be verified.