A comprehensive pre-clinical treatment quality assurance program using unique spot patterns for proton pencil beam scanning FLASH radiotherapy Journal Article
| Authors: | Tsai, P.; Yang, Y.; Wu, M.; Chen, C. C.; Yu, F.; Simone, C. B. 2nd; Choi, J. I.; Tomé, W. A.; Lin, H. |
| Article Title: | A comprehensive pre-clinical treatment quality assurance program using unique spot patterns for proton pencil beam scanning FLASH radiotherapy |
| Abstract: | Background: Quality assurance (QA) for ultra-high dose rate (UHDR) irradiation is a crucial aspect in the emerging field of FLASH radiotherapy (FLASH-RT). This innovative treatment approach delivers radiation at UHDR, demanding careful adoption of QA protocols and procedures. A comprehensive understanding of beam properties and dosimetry consistency is vital to ensure the safe and effective delivery of FLASH-RT. Purpose: To develop a comprehensive pre-treatment QA program for cyclotron-based proton pencil beam scanning (PBS) FLASH-RT. Establish appropriate tolerances for QA items based on this study's outcomes and TG-224 recommendations. Methods: A 250 MeV proton spot pattern was designed and implemented using UHDR with a 215nA nozzle beam current. The QA pattern that covers a central uniform field area, various spot spacings, spot delivery modes and scanning directions, and enabling the assessment of absolute, relative and temporal dosimetry QA parameters. A strip ionization chamber array (SICA) and an Advanced Markus chamber were utilized in conjunction with a 2 cm polyethylene slab and a range (R80) verification wedge. The data have been monitored for over 3 months. Results: The relative dosimetries were compliant with TG-224. The variations of temporal dosimetry for scanning speed, spot dwell time, and spot transition time were within ± 1 mm/ms, ± 0.2 ms, and ± 0.2 ms, respectively. While the beam-to-beam absolute output on the same day reached up to 2.14%, the day-to-day variation was as high as 9.69%. High correlation between the absolute dose and dose rate fluctuations were identified. The dose rate of the central 5 × 5 cm2 field exhibited variations within 5% of the baseline value (155 Gy/s) during an experimental session. Conclusions: A comprehensive QA program for FLASH-RT was developed and effectively assesses the performance of a UHDR delivery system. Establishing tolerances to unify standards and offering direction for future advancements in the evolving FLASH-RT field. © 2024 The Author(s). Journal of Applied Clinical Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine. |
| Keywords: | intensity modulated radiation therapy; neoplasm; neoplasms; radiotherapy dosage; radiotherapy; radiation response; health care quality; radiotherapy, intensity-modulated; quality assurance; quality assurance, health care; radiometry; radiotherapy planning, computer-assisted; phantoms, imaging; proton; proton therapy; procedures; organs at risk; imaging phantom; humans; human; radiotherapy planning system; ultra-high dose rate |
| Journal Title: | Journal of Applied Clinical Medical Physics |
| Volume: | 25 |
| Issue: | 8 |
| ISSN: | 1526-9914 |
| Publisher: | American College of Medical Physics |
| Date Published: | 2024-08-01 |
| Start Page: | e14400 |
| Language: | English |
| DOI: | 10.1002/acm2.14400 |
| PUBMED: | 38831639 |
| PROVIDER: | scopus |
| PMCID: | PMC11302823 |
| DOI/URL: | |
| Notes: | Article -- Source: Scopus |
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