Room: AAPM ePoster Library
Purpose: new-type linear accelerator with its unique treatment planning system (TPS) from United Imaging Healthcare (UIH) was introduced into clinical use in 2019. To evaluate its plan optimization performance of the new TPS (uRT-TPS), a dosimetry study was designed and its results was compared with the Varian Eclipse TPS.
Methods: rectum patient plans were enrolled in this study. These plans were randomly selected from our clinical database. All ROIs were delineated as clinical required. The treatment plans in Eclipse system were designed by a dosimetrist with more than 5 years treatment planning experience. The treatment plans in uRT-TPS were designed by the same dosimetrist with the instruction from vendor. The same objective functions for PTV and OARs were used as much as possible during the optimization in both TPS. Meanwhile, the uRT-TPS has developed an auto planning function in its uRT-TPS. This function was also tested in this study. After the optimization was completed, we normalized D95 (dose for 95% volume coverage) to the same level for comparison.
Results: these plans were clinical acceptable. For the manual plans in eclipse, the manual plans in uRT-TPS and the auto plans in uRT-TPS, the PTV Dmean was 51.7, 51.2 and 51.4Gy. The homogeneity index (HI) for PTV was 0.071, 0.059 and 0.064. The conformity index (CI) for PTV was 0.984, 1.014 and 1.029. The bladder Dmean was 36.1, 32.1 and 31.5Gy. The left femoral head Dmean was 23.0, 19.7 and 19.2Gy. The right femoral head Dmean was 22.4, 19.9 and 19.4Gy. The uRT-TPS manual plans have best performce in HI and CI, which were better than its auto planning.
Conclusion: this preliminary study, UIH treatment planning system has provided a similarly performance with the eclipse TPS. Further study is required to analysis its performance in more scenarios.