Experimental evaluation of the accuracy of skin dose calculation for a commercial treatment planning system.

This work investigates the accuracy of skin dose calculations using the Eclipse treatment planning system. Skin dose was measured using micro-MOSFETs for a range of irradiation conditions (open fields, physical wedges, dynamic wedges, different SSDs) for 6MV and 10MV beams, and compared with the mean dose calculated to a 2mm thick "skin" structure for semi-cylindrical phantoms (representative of a neck or breast). Agreement between the calculated and measured skin dose values was better than +/-20% for 95% of all measured points (both 6MV and 10MV x-ray spectra). For a fixed geometry, the TPS correctly calculated relative changes in dose, showing that minimization of skin dose in IMRT will be effective in Eclipse.