Program Information
Evaluating the Performance of Two Commercially Available Daily QA Phantoms
D Nicewonger*, N Papanikolaou , S Stathakis , University of Texas HSC SA, San Antonio, TX
Presentations
SU-I-GPD-T-459 (Sunday, July 30, 2017) 3:00 PM - 6:00 PM Room: Exhibit Hall
Purpose: The Daily QA3 phantom from SunNuclear Corporation has been a popular daily quality assurance tool for many institutions. PTW has recently introduced the Quickcheck phantom as an alternative. The goal of this study is to compare these two commercially available devices for daily quality assurance measurements of linear accelerator dose output and assess their overall performance.
Methods: Two daily QA phantoms (PTW QuickCheck and Sun Nuclear Corporation Daily QA3) were measured over a 4 month period using a 20x20cm² field size, and 150 MU using 6 and 18 MV on a daily basis and 6, 9, 12, 15, and 18 MeV electrons weekly on a 23EX Varian Linear Accelerator. Measurements with a 0.3cc thimble chamber were used as reference. Reproducibility and accuracy of the dose output were evaluated.
Results: The QuickCheck and Daily QA3 performed with maximum percent differences of 2.08% and 2.2% for output, 1.36% and .82% for flatness, -1.36% and-1.36% for inplane symmetry, 1.04% and -.66% for crossplane symmetry, and -.91% and .83% for beam quality respectively over all energies. The consistency of the output was within 2% for all energies when compared to the thimble chamber.
Conclusion: Consistent measurements over a four month period, easy user interface and wireless features prove the QuickCheck would be a suitable phantom for daily QA use. Future measurements include more consistency using an ion chamber as well as testing the sensitivity of the phantom by varying SSD, MU, dose rate and other factors.
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