%A Michael C. Ferris
%A David M. Shepard
%T Optimization of Gamma Knife Radiosurgery
%D January 2000
%R 00-01
%I COMPUTER SCIENCES DEPARTMENT, UNIVERSITY OF WISCONSIN
%C MADISON, WI
%X
The Gamma Knife is a highly specialized treatment unit that provides
an advanced stereotactic approach to the treatment of tumors,
vascular malformations, and pain disorders within the head. Inside
a shielded treatment unit, beams from 201 radioactive sources are
focused so that they intersect at the same location in space,
resulting in a spherical region of high dose referred to as a shot
of radiation. The location and width of the shots can be adjusted
using focussing helmets. By properly combining a set of shots,
larger treatment volumes can be successfully treated with the Gamma
Knife.
The goal of this project is to automate the treatment planning
process. For each patient, an optimization seeks to produce a dose
distribution that conforms closely to the treatment volume. The
variables in the optimization can include the number of shots of
radiation along with the size, the location, and the weight assigned
to each. Formulation of such problems using a variety of
mathematical programming models is described, and the solution of
several test and real-patient examples is demonstrated.