STUDIES ON THE CORRECTION FACTOR FOR THE HOLLOW OUT IRRADIATION TECHNIQUE

Abstract

The correction factor for the hollow out irradiation technique is usually calculated as a magnitude of dose reduction at the center of rotation with respect to primary radiation. This correction factor, which had taken account of scattered radiation, was calculated from the ratio of two average TARs with and without the hollow out absorber, and its scattered radiation component was distinguished from its primary radiation component to be analyzed. The magnitude of dose reduction rate with respect to the scattered radiation component was much the same to that with respect to the primary radiation component. Consequntly, the correction factor, which had taken account of scattered radiation, showed good agreement with the correction factor with respect to primary radiation only.