A Solution for the Treatment of Small Lesions Using Electron Beams From a Saturne Linear Accelerator With Continuous Variable Trimmers; Dosimetrical Aspects

Abstract

For treatment of superficial lesions with ionizing radiation, a number of treatment techniques can be used. We use a standardized technique by applying electron beams from GE-MS Saturne-41 linear accelerators; this also works in cases where very small target areas have to be irradiated. In our institute linear accelerators of this type are equipped with continuous variable trimmer systems. Very small electron fields show specific dosimetric problems, which in general necessitates performing measurements for each individual patient. A solution is presented, using a specially designed set of 17 templates, which can be placed on the skin of a patient. The trimmers are set to a predefined field size. Output factors, profiles, percentage depth dose (PDD) and dose outside the template are determined for each combination of template and beam energy. Look-up tables are produced , which can be used by the radiation oncologist and in a monitor unit calculation program.