Dosimetric Evaluation of a Computed Tomography Treatment System

Abstract

Pixel-by-pixel correction for tissue inhomogeneities was performed with a CT-interfaced treatment planning system. The CT number for each pixel was converted to a physical density. Comparison of the resulting data with dose measurements in a RANDO phantom shows that pixel calculation overestimates dose by 5--7% at locations adjoining the lung, where loss of scatter is not taken into account by the algorithm. However, the new system does have some advantages over conventional treatment planning systems.