Preliminary evaluation of the clinical use of a system for intraoperative radiotherapy with electrons (IORT)

: The preliminary evaluation of the dosimetric characteristics of a dedicated intraoperative electron beam therapy system is described (Bionix Corporation). The linear accelerator is the Varian 2100 C with electron beam energies of 6, 9, 12, 16 e 20 MeV. The isodose distribution for each of 15 available applicators (5 plane and 10 beveled) has been studied with a water phantom. The problems of the homogeneity of dose distribution, scattered and leakage radiation outside the applicators and X-ray contamination of the electron beams have been addressed, at the nominal 20 MeV energy for exemplification. The accurate knowledge of such physical and dosimetric properties are necessary for the implementation of the IORT techniques in terms of choice of the applicator size and electron beam energy for tumor coverage and dose sparing of critical organs.