Measurements and treatment planning calculations of electron dose distributions below bolus edges.

Electron dose distributions below bolus edges of various thicknesses and angles were measured using a diode in a water phantom. The measurements were compared with treatment planning calculations using the gamma method. Below 5 mm boluses, the dose variations were acceptable for all angles, while for boluses thicker than 5 mm, the lowest edge gave the smallest dose variations. The calculated dose distributions agreed well with the measured dose distributions.