INVESTIGATION OF THE RELATIVE SURFACE DOSE FROM LIPOWITZ-METAL TISSUE COMPENSATORS FOR 24-MV AND 6-MV PHOTON BEAMS

Our radiation therapy department has acquired a tissue compensator system for construction of patient-specific Lipowitz-metal tissue compensators. Since the arrival of this apparatus its use has been limited due to the observance of marked skin reactions located directly beneath the area of the compensator. Although there has been extensive literature on the dose distribution of these metal compensators, there is little data on the effects to the skin for energies greater than 10 MV. Determination of the relative surface dose from Lipowitz-metal tissue compensators is herein investigated for 24- and 6-MV x-ray beams. Effects of field size, source-to-skin distance and thickness of compensator are evaluated as well as the effect of the Lexan tray which supports the compensator during treatment.