Dose optimization with computer-controlled gantry rotation, collimator motion and dose-rate variation.

ABSTRACT

The applications of a computer-controlled radiation therapy system to optimize dose distributions in two dimensions are explored. This study is limited to a target volume with constant cross-section along an axis parallel to the long axis of the patient. The machine components that are continuously varied during treatment are the dose rate, the gantry angle, and the four independent collimator jaws, two of which can cross the beam centerline. Basic control strategies, treatment planning and delivery techniques are illustrated with clinical examples. We conclude that the computer-controlled radiation therapy system can easily and reliably deliver dose distributions which are significantly better than those produced by conventional multiple-field techniques.