Impact of proton PBS machine operating parameters on the effectiveness of layer rescanning for interplay effect mitigation in lung SBRT treatment.

Autor: Liang X; Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida, USA., Liu C; Department of Radiation Oncology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China., Shen J; Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona, USA., Flampouri S; Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, USA., Park JC; Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida, USA., Lu B; Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida, USA., Yaddanapudi S; Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida, USA., Tan J; Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida, USA., Furutani KM; Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida, USA., Beltran CJ; Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida, USA.
Jazyk: angličtina
Zdroj: Journal of applied clinical medical physics [J Appl Clin Med Phys] 2024 Jul; Vol. 25 (7), pp. e14342. Date of Electronic Publication: 2024 Apr 08.
DOI: 10.1002/acm2.14342
Abstrakt: Background: Rescanning is a common technique used in proton pencil beam scanning to mitigate the interplay effect. Advances in machine operating parameters across different generations of particle therapy systems have led to improvements in beam delivery time (BDT). However, the potential impact of these improvements on the effectiveness of rescanning remains an underexplored area in the existing research.
Methods: We systematically investigated the impact of proton machine operating parameters on the effectiveness of layer rescanning in mitigating interplay effect during lung SBRT treatment, using the CIRS phantom. Focused on the Hitachi synchrotron particle therapy system, we explored machine operating parameters from our institution's current (2015) and upcoming systems (2025A and 2025B). Accumulated dynamic 4D dose were reconstructed to assess the interplay effect and layer rescanning effectiveness.
Results: Achieving target coverage and dose homogeneity within 2% deviation required 6, 6, and 20 times layer rescanning for the 2015, 2025A, and 2025B machine parameters, respectively. Beyond this point, further increasing the number of layer rescanning did not further improve the dose distribution. BDTs without rescanning were 50.4, 24.4, and 11.4 s for 2015, 2025A, and 2025B, respectively. However, after incorporating proper number of layer rescanning (six for 2015 and 2025A, 20 for 2025B), BDTs increased to 67.0, 39.6, and 42.3 s for 2015, 2025A, and 2025B machine parameters. Our data also demonstrated the potential problem of false negative and false positive if the randomness of the respiratory phase at which the beam is initiated is not considered in the evaluation of interplay effect.
Conclusion: The effectiveness of layer rescanning for mitigating interplay effect is affected by machine operating parameters. Therefore, past clinical experiences may not be applicable to modern machines.
(© 2024 The Authors. Journal of Applied Clinical Medical Physics is published by Wiley Periodicals, Inc. on behalf of The American Association of Physicists in Medicine.)
Databáze: MEDLINE
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