Program Information
Develop Methodology of Dose Calculation for Dynamic Electron Arc Radiotherapy (DEAR) Using VirtuaLinac Monte Carlo Simulation
X Wang1*, D Sawkey2 , Q Wu1 , (1) Duke University Medical Center, Durham, NC, (2) Varian Medical Systems, Palo Alto, CA
Presentations
SU-K-FS1-9 (Sunday, July 30, 2017) 4:00 PM - 6:00 PM Room: Four Seasons 1
Purpose: VirtuaLinac is a cloud-based Monte Carlo simulation platform for radiotherapy research. Recently it added support for non-isocentric dynamic beam delivery through the use of XML input, such feature is not yet available on commercial treatment planning systems (TPS), therefore is especially attractive for the development of Dynamic Electron Arc Radiotherapy (DEAR). The purpose of this study is to develop a framework interfacing to VirtualLinac for DEAR dose calculation.
Methods: CT images are first exported from Eclipse TPS in DICOM format and converted to phantom format for VirtualLinac which contains both density map and material table. Treatment plan in XML format is loaded to VirtualLinac through application programming interface (API) for the management of calculation tasks. The resulting dose matrix is exported and converted for evaluations. To visualize and compare dose distributions and other plan objects, the Computational Environment for Radiotherapy Research (CERR) was used. In the first example, a thorax rando phantom was used with static 6 MeV electron beam to validate the workflow. In the second example, a DEAR plan consisting of series of control points is used to irradiate a 17 cm long line target on the surface of cylindrical phantom, with 6MeV beam and 3x3 cm² cutout.
Results: For the static example, the dose distributions from VirtuaLinac agreed very well with those from Eclipse TPS using eMC. Gamma test with criterion of 2%/2mm shows 99.7% passing rate. For the DEAR plan, the VirtuaLinac dose is compared with the GafChromic film measurement and good agreement were observed in dose profiles, field size and penumbra along both directions.
Conclusion: We have developed and validated a framework to use VirtuaLinac in performing dose calculation for dynamic treatment delivery on patient CT images. It can be used for the future research in DEAR treatment planning.
Funding Support, Disclosures, and Conflict of Interest: The research is partially supported by Varian Medical System.
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