Program Information
Small Field Electron Beam Dose Calculation Using VirtuaLinac Monte Carlo Simulation Platform
X Wang1*, A Rodrigues1 , D Sawkey2 , Q Wu1 , (1) Duke University Medical Center, Durham, NC, (2) Varian Medical Systems, Palo Alto, CA
Presentations
TU-RPM-GePD-T-6 (Tuesday, August 1, 2017) 3:45 PM - 4:15 PM Room: Therapy ePoster Lounge
Purpose: Dynamic Electron Arc Radiotherapy (DEAR) is a novel electron radiation therapy technique and its feasibility to produce conformal dose distribution over large and curved target has been demonstrated. The accuracy of small field dosimetry is essential and challenging for DEAR. VirtuaLinac is a cloud-based Monte Carlo simulation platform for radiotherapy research, its recent development includes a unique feature to simulate dynamic beam delivery on patient CT. The purpose of this work is to validate VirtuaLinac calculation accuracy on small electron field.
Methods: First, the electron beam dose calculation of VirtuaLinac is commissioned on standard electron fields using the commissioning data measured in water phantom with standard applicators from 6x6 to 25x25 cm2 for energies of 6, 9, 12, and 16 MeV. Then, small fields with cutout in the shape of square (1x1, 2x2, 3x3 cm2), circular (1, 2, 3 cm diameters) and slit (1x10, 3x10 cm2) cutouts were studied. The PDDs and profiles at representative depths were compared with those from Eclipse eMC, EGSnrc and measurements.
Results: For the standard fields, very good agreement is observed between the VirtuaLinac and measurement data. The root mean square deviation (RMSD) is < 1% or the distance-to-agreement (DTA) is < 1 mm for PDDs in buildup, fall-off and Bremsstrahlung regions, and for profiles in in-field, out-field and penumbra regions. For the fields with small cutout, the PDDs deviate from the standard field but there were still good agreements between measurement and VirtualLinac and EGSnrc calculations. However, observable discrepancies exist in the eMC calculations.
Conclusion: We have validated the use of VituaLinac in electron beam dose calculation for standard static field. The small field calculation agrees reasonably well, therefore it can be a useful tool for DEAR development. Its web interface is easy to use and has advantages over other Monte Carlo systems.
Funding Support, Disclosures, and Conflict of Interest: Research is partially supported by Varian Medical System.
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