Comparison of measured and calculated doses in a Rando phantom with a realistic lung radiotherapy treatment plan including heterogeneities

Abstract

In this work, dose measurements were performed to evaluate an external radiotherapy treatment plan and, particularly, to validate dose calculations for a lung lesion case. Doses were calculated by the Varian Eclipse treatment planning system using the AAA anisotropic analytical algorithm. The measurements were performed using a Rando anthropomorphic phantom and TLD700 thermoluminescent dosimeters. The comparison between doses calculated and doses measured by means of thermoluminescence (TL) shows compatibility except for a few points, due to the limitations in the heterogeneity correction used for the case studied here. The deviation between the calculated and measured doses is about 6.5% for low (< 0.5Gy) doses and about 1% for higher doses (> 0.5Gy).The deviation between AAA-calculated and TL-measured doses was also found to be higher in proximity to heterogeneous tissue interfaces.