A Boria*, Z Su, P Sabouri, G Narayanasamy, F Kalantari, University of Arkansas for Medical Sci, Little Rock, AR

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  A Boria

PO-GePV-T-229 (Sunday, 7/10/2022)   [Eastern Time (GMT-4)]

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Purpose: This study is intended to perform a comprehensive comparison between iBA’s MatriXX Resolution and Sun Nuclear’s ArcCHECK to assess the performance of both devices for routine patient specific IMRT QA procedures.

Methods: Fifteen patients’ IMRT plans that were previously verified using a Sun Nuclear ArcCHECK detector were delivered on a MatriXX Resolution device. The plans consisted of five lung, five head and neck, and five breast treatments with a mix of 6X and 6X-FFF energies. Uncertainties in device setup measurements were corrected by aligning the data to give the best 1%/1mm DTA criterion prior to data analysis. A gantry angle correction lookup table was generated by measuring data with 10x10 cm² fields for each energy with this correction table automatically applied to correct data during acquisition. Pass rates with gamma criteria (1%/1mm, 2%/1mm, 3%/1mm, 1%/2mm, 2%/2mm, 3%/2mm, 1%/3mm, 2%/3mm, and 3%/3mm) were analyzed for the two devices. A paired two-tailed t-test was used with p≤0.05 to compare the gamma pass rates of all the plans together and separately as three individual treatment sites.

Results: Statistically significant differences were not observed when analyzing the fifteen sets of plans measured together by a MatriXX Resolution and a ArcCHECK (respectively) based on gamma criteria of 2%/2mm (92.1%±12.6% vs 94.6%±5.6%; p=0.37), 3%/2mm (97.5%±6.4% vs 97.5%±2.4%; p=0.99), and 3%/3mm (98.3%±5.2% vs 98.6%±1.3%; p=0.84). Statistically significant differences were not observed when using gamma criteria of 3%/3mm for lungs plans (100%±0% vs 98.7%±1.4%; p=0.10), head and neck plans (99.1%±1.3% vs 98.8%±1.5%; p=0.53), or breast plans (95.9%±9.1% vs 98.3%±1.3%; p=0.55).

Conclusion: Both devices had clinically acceptable passing rates for lung, head and neck, and breast IMRT plans. The MatriXX Resolution with an automatically applied angular correction table can be used for performing routine IMRT QA in clinical practice.

Keywords

Quality Assurance, Treatment Verification, Radiation Detectors

Taxonomy

TH- External Beam- Photons: Quality Assurance - IMRT/VMAT

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