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Stasinou D, Patatoukas G, Kollaros N, Diamantopoulos S, Kypraiou E, Kougioumtzopoulou A, Kouloulias V, Efstathopoulos E, Platoni K. Implementation of TG-218 for patient specific QA Tolerance and Action Limits determination: Gamma passing rates evaluation using 3DVH software. Med Phys 2022; 49:4322-4334. [PMID: 35560362 DOI: 10.1002/mp.15703] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 03/18/2022] [Accepted: 04/26/2022] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To determine the tolerance (TL) and action limits (AL) of gamma passing rates (%GP) for Volumetric-Modulated Arc Therapy (VMAT) patient-specific quality assurance (PSQA), according to the AAPM TG-218 recommendations, and to evaluate comparatively the clinical relevance of 2D%GP and 3D%GP. MATERIALS AND METHODS PSQA was performed for 100 head and neck (H&N) and 73 prostate cancer VMAT treatment plans. Measurements were acquired using a cylindrical water equivalent phantom, hollow in the center, allowing measurements with homogeneous or heterogeneous inserts. LINAC delivered dose distributions were compared to the ones calculated from the treatment planning system (TPS) through gamma index. TL and AL were determined through the computation of 2D%GP, using the recommended acceptance criteria. Dose-volume histograms (DVH) were reconstructed from the measurements using a commercially available software, to detect the dosimetric differences (%DE) between the compared dose distributions. Utilizing the estimated dose on the patient anatomy, structure specific %GP (3D%GP) were calculated. The 3D%GP were compared to the 2D%GP ones, based on their correlation with the %DE. Each metric's sensitivity was determined through receiver operator characteristic (ROC) analysis. RESULTS TL and AL were in concordance with the universal ones, regarding the prostate cancer cases, but were lower for the H&N cases. Evaluation of %DE did not deem the plans unacceptable. The 2D%GP and the 3D%GP did not differ significantly regarding their correlation with %DE. For prostate plans, %GP sensitivity was higher than for H&N cases. CONCLUSIONS Determination of institutional specific TL and AL allow the monitoring of the PSQA procedure, yet for plans close to the limits clinically relevant metrics should be used before they are deemed unacceptable, for the process to be of higher sensitivity and efficiency. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Despoina Stasinou
- Medical Physics Unit, 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, University General Hospital 'Attikon', 1 Rimini Street, Haidari, Athens, 124 62, Greece
| | - George Patatoukas
- Medical Physics Unit, 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, University General Hospital 'Attikon', 1 Rimini Street, Haidari, Athens, 124 62, Greece
| | - Nikos Kollaros
- Medical Physics Unit, 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, University General Hospital 'Attikon', 1 Rimini Street, Haidari, Athens, 124 62, Greece
| | - Stefanos Diamantopoulos
- Medical Physics Unit, 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, University General Hospital 'Attikon', 1 Rimini Street, Haidari, Athens, 124 62, Greece
| | - Efrosyni Kypraiou
- Radiation Therapy Unit, 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, University General Hospital 'Attikon', 1 Rimini Street, Haidari, Athens, 124 62, Greece
| | - Andromachi Kougioumtzopoulou
- Radiation Therapy Unit, 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, University General Hospital 'Attikon', 1 Rimini Street, Haidari, Athens, 124 62, Greece
| | - Vasilios Kouloulias
- Radiation Therapy Unit, 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, University General Hospital 'Attikon', 1 Rimini Street, Haidari, Athens, 124 62, Greece
| | - Efstathios Efstathopoulos
- Medical Physics Unit, 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, University General Hospital 'Attikon', 1 Rimini Street, Haidari, Athens, 124 62, Greece
| | - Kalliopi Platoni
- Medical Physics Unit, 2nd Department of Radiology, Medical School, National and Kapodistrian University of Athens, University General Hospital 'Attikon', 1 Rimini Street, Haidari, Athens, 124 62, Greece
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