Evaluation of a Novel Independent Secondary Dose Calculation Software for Brain SRS, Lung SBRT, and MR-Guided Adaptive Pancreatic SBRT
Abstract
Purpose
Due to the dose engine algorithm, there is a gap between Independent secondary dose calculation (ISDC) and the treatment planning system algorithm for small fields, inhomogeneity environment correction, and online adaptive plan QA using the same vendor tool. In this study, we evaluated the feasibility and accuracy of ArcherQA, a Monte-Carlo based independent dose calculation software, in brain SRS, lung SBRT and MR-guided adaptive pancreatic SBRT.
Methods
10 brain SRS plans with totally 59 brain lesions and 10 lung SBRT plans planned in Varian Eclipse treatment planning system (TPS), 5 adaptive pancreatic SBRT plans with totally 25 fractions planned in MRIdian TPS are evaluated by comparing ISDC results between Varian Mobius3D, ViewRay online adaptation QA tool and ArcherQA. Gamma passing rate (TPS vs. ISDC: 3%/3mm, 10% threshold), percentage differences (TPS vs. ISDC) of target coverage (mean dose and D90) and OAR max doses are calculated.
Results
For brain SRS, ArcherQA has same gamma passing rate (100%) compared with Mobius3D (100%), but significantly improves the percentage differences in GTV Dmean , GTV D90, PTV Dmean and PTV D90. For lung SBRT, ArcherQA has better results compared with Mobius3D but not significantly in gamma passing rate, percentage differences in GTV D90, Dmax in bronchus, esophagus, and heart. However, ArcherQA significantly improves the percentage differences in PTV Dmean and D90. For online adaptive pancreatic SBRT, ViewRay online adaptation QA tool has significantly better gamma passing rate, percentage differences in GTV Dmean, PTV Dmean, Dmax in duodenum, stomach and small bowel compared with ArcherQA.
Conclusion
ArcherQA has similar gamma passing rate compared with Mobius3D in brain SRS and lung SBRT but has significantly closer target coverage results to TPS than Mobius3D. ArcherQA is feasible in clinical application in online adaptive QA with good gamma passing rate as a 3rd party QA tool.