MONTE CARLO MODELING OF THE GAMMA KNIFE PERFEXION^TM

Abstract

The Gamma Knife Perfexion^TM is a radiosurgical treatment device used to irradiate targets in the head such as tumors, blood vessel defects, and malfunctioning nerves. It uses 192 high activity Cobalt-60 sources collimated to a common focus to impart radiological damage to the target structure while minimizing dose to adjacent healthy tissue a few millimeters away. Tungsten collimators are organized into eight sectors of 24 sources each, and can independently choose one of three collimation sizes for each sector. The largest collimator size is designed to produce a sphere of dose 16 mm in diameter at the focus. The smaller collimators produce dose spheres 8 mm and 4 mm in diameter.