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Rapid Commissioning of Varian TrueBeam Using Developer Mode and Beam Model Validation Using the Eclipse Scripting API

D Barbee

D Barbee*, NYU Langone Medical Center, New York, NY


MO-DE-FS1-9 (Monday, July 31, 2017) 1:45 PM - 3:45 PM Room: Four Seasons 1

Purpose: Linear accelerator commissioning requires numerous, repeated beam data measurements and quality assurance tests. Acquired data is then used to generate a beam model which requires validation against machine measurements. Both processes require point-by-point measurement and data transcription, which is inefficient and prone to transcription errors. This work utilizes Varian’s Developer Mode to automate commissioning tests and the Eclipse scripting API (ESAPI) to export data, resulting in significant efficiency increases and the eliminating transcription errors.

Methods: Three Truebeam accelerators equipped with Varian’s Developer (formerly Research) Mode were consecutively installed and commissioned over a 10 month period. Developer Mode XML files were generated to automate data acquisition and quality assurance tests. Point measurements including: symmetric/ asymmetric output factors, DLG, MLC transmission, MU linearity, and gantry angle dependence were performed using SNC’s PC Electrometer acquiring in logging mode. Logging mode results saved in Microsoft Excel format were processed to yield individual measurements through VBA macros. VMAT (dose rate, gantry speed, MLC speed), picket fence, Winston-Lutz, starshots (collimator X jaw, collimator Y jaw, MLC) QA tests were acquired using the portal imager via XML. Beam model validation was performed by generating test plans containing various field sizes, energies, geometries with multiple reference points, which were exported into Excel using ESAPI (v13).

Results: Automated Developer Mode measurement reduced measurement time by 50-75% in comparison to manual measurement techniques, with no decrease in acquisition speed or measurement accuracy and no transcription errors. Comparison to manual measurement, Varian’s Truebeam Representative Data, and published literature showed values were within 0.2-0.5%. Beam validation ESAPI scripts exported ~5000 dose reference points for open field and VMAT/IMRT QA point measurements.

Conclusion: Developer Mode allows for rapid data acquisition and automated QA testing resulting in significant time savings. ESAPI allows for rapid export of data for direct measurement against beam models.

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