TH-AB-BRA-05: Infrastructure and Process for Model-Based Dose Calculation Software Commissioning in Brachytherapy

Purpose: To describe a new infrastructure and process that will enable end-users to commission model-based dose calculation (MBDC) software for brachytherapy planning, and to invite end-users to participate in the beta testing phase of this process. Methods: The AAPM working groups on model-based dose calculation algorithms in brachytherapy (WGDCAB) and brachytherapy source registry (WGBSR) collaboratively implemented the basic MBDC software commissioning workflow described in the AAPM+ESTRO TG-186 report. For a small number of initial test cases virtual CT image, anatomical structure set, treatment plan, and associated 3D dose data for a single dwell position occupied by a WGDCAB generic high-dose-rate Ir-192 virtual source, with or without a generic shielded applicator, were generated. Dose distributions were calculated using Monte Carlo (MC) code MCNP6, Elekta’s Advanced Collapsed cone Algorithm (ACE™), and Varian’s Acuros™ BV module. All data were saved in DICOM RT format and uploaded to a provisional, web-accessible repository in the joint AAPM—IROC Houston brachytherapy source registry. It is envisioned that end-users will download data for a test case from the repository, verify its correctness, calculate 3D dose locally, and then compare with MCNP6 and MBDC doses obtained from the repository using TPS-based comparison tools. User guides in preparation for each TPS will facilitate the process. Results: Initial evaluations of DICOM data download, TPS import, MBDC dose calculation, and reference dose comparison indicate that the infrastructure and process described above are both viable and practicable. Ancillary data including generic source and shielded applicator specifications, CAD drawings, and MC code definitions are also available in the repository. Conclusion: With further refinement and beta-test input from end-users, a practical MBDC software commissioning process for brachytherapy can be established. A procedure for adding new test cases submitted by end-users to the repository will be put in place by WGDCAB.