Ядерна фізика та енергетика Nuclear Physics and Atomic Energy   ISSN: 1818-331X (Print), 2074-0565 (Online)   Publisher: Institute for Nuclear Research of the National Academy of Sciences of Ukraine   Languages: Ukrainian, English   Periodicity: 4 times per year   Open access peer reviewed journal

Full text (en)

K. Vilchynska¹, O. Bezshyyko², V. Vashchyshyn¹, L. Golinka-Bezshyyko^2,*, R. Zelinskyi<sup>3

1</sup> Radiotherapy Department, Universal Clinic "Oberig", Kyiv, Ukraine
² Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
³ Radiotherapy Department, Medical Center of Yuriy Spizhenko LLC, Kyiv, Ukraine

^*Corresponding author. E-mail address: lyalkagb@gmail.com

Abstract: Modern radiotherapy techniques involve the use of high-modulated radiation fields. Intensity Modulated Radiation Therapy and Volumetric Modulated Arc Therapy require careful quality control to ensure that the planned dose distributions can be delivered by the treatment system. Quality assurance of the patient-specific treatment plan is often performed prior to treatment, when beams are delivered to the phantom and radiation doses are checked compared to the doses provided in the treatment planning system. In this study, myQA SRS measurements were compared to the EBT3 film measurements. The resolution of the film is 25 µm. The sufficiently high resolution of the stereotactic radiosurgery (SRS) detector (0.4 mm) makes it a potential alternative to film for real-time dosimetry. Irradiation was performed on a Varian TrueBeam linear accelerator. The gamma index criteria were 3 %/3 mm, the threshold dose was 10 %, and gamma index normalization was performed using the global maximum dose. The gamma index results obtained on film and on myQA SRS gave comparable results. The passing rate of film measurements based on gamma evaluation was 89.92 % and the passing rate of myQA SRS was 82.6 %. The average gamma values for the 3 %/3 mm global gamma analysis were 0.48 for the film and 0.594 for myQA SRS. In this study, film was chosen as the reference clinical detector with the highest resolution available today. myQA SRS, designed for verification of stereotactic plans, qualitatively and quantitatively identified areas of dose mismatch.

Keywords: radiation therapy, quality assurance, detectors, radiochromic film, linear accelerator, treatment planning system, dose distribution.

1. T. Pócza et al. Comparison of three film analysis software using EBT2 and EBT3 films in radiotherapy. Radiology and Oncology 54(4) (2020) 505. https://doi.org/10.2478/raon-2020-0049

2. P.C.Y. Yeh et al. Monte Carlo evaluation of Acuros XB dose calculation Algorithm for intensity modulated radiation therapy of nasopharyngeal carcinoma. Radiation Physics and Chemistry 140 (2017) 419. https://doi.org/10.1016/j.radphyschem.2017.02.025

3. Y. Zhou et al. Commissioning and clinical evaluation of a novel high-resolution quality assurance digital detector array for SRS and SBRT. Journal of Applied Clinical Medical Physics 25(4) (2024) e14258. https://doi.org/10.1002/acm2.14258

4. J.M. Park et al. Reliability of the gamma index analysis as a verification method of volumetric modulated arc therapy plans. Radiation Oncology 13 (2018) 175. https://doi.org/10.1186/s13014-018-1123-x

5. M. Miften et al. Tolerance limits and methodologies for IMRT measurement-based verification QA: Recommendations of AAPM Task Group No. 218. Medical Physics 45(4) (2018) e53. https://doi.org/10.1002/mp.12810

6. S. James et al. Evaluation of commercial devices for patient specific QA of stereotactic radiotherapy plans. Journal of Applied Clinical Medical Physics 24(8) (2023) e14009. https://doi.org/10.1002/acm2.14009