Measurement of physical parameters for total skin electron therapy with a medical linear accelerator

A few physical measurements relevant to TSET are presented in this paper. 6 MeV electron beam with 1 cm perspex degrader placed at 20 cm in front of the phantom was used. The longitudinal profile was measured in air using 0.6 cm3 farmer type thimble chamber. The depth ionization and the absolute dose measurements were carried out with a PTW parallel plate chamber. It is observed that electron beams angled at 8 deg above and below horizontal gives a longitudinal homogeneity of ± 6% over 210 cm. The relative surface dose over the anterior surface of the humanoid phantom estimated by TLD shows a dose variation between 93% and 104% with respect to 100% at the umbilical level (calibration point). (author)