Planar dose calculation of electron therapy.

The aim of this study is to determine the planar dose distribution of irregularly-shaped electron beams at their maximum dose depth () using the modied lateral build-up ratio (LBR) and curve-fitting methods.Circular and irregular cutouts were created using Cerrobend alloy for a 14 × 14 cmapplicator. Percentage depth dose (PDD) at the standard source-surface-distance (SSD = 100 cm) and point dose at different SSD were measured for each cutout.