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Evaluation of a New Commercially Available Water Phantom: Evaluation of Mechanical Performance

S Stathakis

N Papanikolaou , A Alexandrian , N Kirby , K Rasmussen , D Saenz , D Defoor , S Stathakis*, University of Texas HSC SA, San Antonio, TX


SU-E-108-8 (Sunday, July 30, 2017) 1:00 PM - 1:55 PM Room: 108

Purpose: To evaluate features and mechanical properties of PTW BeamScan, a new commercially available water phantom for beam data acquisition.

Methods: Mechanical testing on the automatic level adjustment, automatic water leveling, beam centering and field rotation adjustment tools in the BeamScan software were tested in correspondence to measurements in actual tank performance. In addition to testing features, precision and accuracy of the detector arm were measured. Assessment on stepwise time continuous data acquisition modes were made by collecting beam profile data. A PTW SemiFlex 3D was used for beam profile measurements on multiple field sizes. To test the field rotation adjustment tool, a 1° and 0.5° rotations in gantry angle were introduced to see how well the software could account for deviations in a 20x20 field size.

Results: Repeated measurements of the tools of BeamScan consistently yield precise outcomes with low uncertainty. Mechanical testing of the detector arm yielded precision within 0.2 mm. Profiles acquired in step-wise and time data acquisition modes were agreeable for multiple field sizes; however, the time elapsed for data acquisition was high dependent on the field size. In a 20x20 field size, step-wise data mode took 7 minutes and 44 seconds to acquire profile data while in the same set up the time data mode only took 4 minutes and 50 seconds. The auto level tool effectively determined offsets in the phantom’s physical level with no detriment to acquired beam data.

Conclusion: Mechanical evaluation of the PTW BeamScan water phantom were performed. Integrated features of the water phantom performed with high precision. Speed and accuracy of the continuous mode acquisition allows users to speed up acquisition of quality assurance measurements without loss of beam data quality.

Funding Support, Disclosures, and Conflict of Interest: PTW Research grant

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