Physical Aspects of Electron-Beam Arc Therapy

Abstract

The effect of different parameters on dose distribution in electron beam arc therapy for human tumors was studied to develop a technique for routine clinical use. A special diaphragm was designed to facilitate telecentric rotation. Dosimetry was performed with an ion chamber, film and LiF powder in cylindrical polystyrene phantoms and an Alderson Rando phantom. Dose distributions were evaluated with regard to dose homogeneity, and a method of sharpening the dose fall-off near the ends of the arc was proposed. Criteria for selection of isocenter depth and field size were developed. Methods of dose calculation, calibration and treatment planning are discussed.