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Comparison of Two Commercially Available EPID QA Systems Tested On Two Different EPID Systems

A Alexandrian

A Alexandrian*, K McConnell , S Stathakis , University of Texas HSC SA, San Antonio, TX


SU-I-GPD-T-456 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall

Purpose: To determine if QA performance between two EPID QA systems is agreeable and to see if it depends on the EPID imaging system being used.

Methods: Two EPID QA systems were used for the study. The first system is the PTW EPID QA phantom with epidsoft software. The other system is LinaTech QA Phantom with LinaTech IVS software for QA analysis. The LinaTech IVS imager and Varian asi1000 EPID devices were used for acquiring images. 20 images acquired daily for both phantoms on each system were acquired and analyzed using each systems respective QA software. Both systems use overlapping QA tools to gauge performance of EPID panels; however, they report them in different manners.

Results: Both QA systems performed within reasonable agreement regardless of the EPID imaging panel being analyzed. For image distortion, IVS reported shifts in horizontal, vertical, and diagonal coordinates while epidsoft reported distortion in terms of degree. Despite the different metrics, both systems passed uniformly in all images. For testing Low Contrast Resolution both systems could detect similar number of low contrast objects. Spatial frequency in terms of line pairs per mm was found to be around 0.6 lp/mm.

Conclusion: Although both EPID QA systems report results in slightly different styles, there is consistency between the results found in both systems in both EPID systems used in testing.

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