Automatic 3D Monte-Carlo-based secondary dose calculation for online verification of 1.5 T magnetic resonance imaging guided radiotherapy
| Autor: | Melissa Friedlein, Daniela Thorwarth, M. Nachbar, O. Dohm, David Mönnich, Daniel Zips |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
MR-Linac
Radiation medicine.diagnostic_test Dose calculation Computer science medicine.medical_treatment Monte Carlo method R895-920 Neoplasms. Tumors. Oncology. Including cancer and carcinogens Magnetic resonance imaging MR-guided radiotherapy Imaging phantom Linear particle accelerator Radiation therapy Medical physics. Medical radiology. Nuclear medicine Adaptive radiotherapy Online plan quality assurance Head model Online secondary dose calculation medicine Radiology Nuclear Medicine and imaging Original Research Article RC254-282 Simulation |
| Zdroj: | Physics and Imaging in Radiation Oncology Physics and Imaging in Radiation Oncology, Vol 19, Iss, Pp 6-12 (2021) |
| ISSN: | 2405-6316 |
| DOI: | 10.1016/j.phro.2021.05.002 |
| Popis: | Highlights • First implementation of an independent 3D-secondary dose calculation (3D-SDC). • Validation of the 3D-SDC solution using patient plans and experimental plan QA. • Online SDC of central targets is feasible with a median calculation time of 1:23 min. • Peripheral targets with small beam numbers need alternative validation strategies. Background and purpose Hybrid magnetic resonance linear accelerator (MR-Linac) systems represent a novel technology for online adaptive radiotherapy. 3D secondary dose calculation (SDC) of online adapted plans is required to assure patient safety. Currently, no 3D-SDC solution is available for 1.5T MR-Linac systems. Therefore, the aim of this project was to develop and validate a method for online automatic 3D-SDC for adaptive MR-Linac treatments. Materials and methods An accelerator head model was designed for an 1.5T MR-Linac system, neglecting the magnetic field. The use of this model for online 3D-SDC of MR-Linac plans was validated in a three-step process: (1) comparison to measured beam data, (2) investigation of performance and limitations in a planning phantom and (3) clinical validation using n = 100 patient plans from different tumor entities, comparing the developed 3D-SDC with experimental plan QA. Results The developed model showed median gamma passing rates compared to MR-Linac base data of 84.7%, 100% and 99.1% for crossplane, inplane and depth-dose-profiles, respectively. Comparison of 3D-SDC and full dose calculation in a planning phantom revealed that with ⩾5 beams gamma passing rates >95% can be achieved for central target locations. With a median calculation time of 1:23 min, 3D-SDC of online adapted clinical MR-Linac plans demonstrated a median gamma passing rate of 98.9% compared to full dose calculation, whereas experimental plan QA reached 99.5%. Conclusion Here, we describe the first technical 3D-SDC solution for online adaptive MR-guided radiotherapy. For clinical situations with peripheral targets and a small number of beams additional verification appears necessary. Further improvement may include 3D-SDC with consideration of the magnetic field. |
| Databáze: | OpenAIRE |
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