Optimising multi-target multileaf collimator tracking using real-time dose for locally advanced prostate cancer patients
| Autor: | Emily A Hewson, Doan Trang Nguyen, Andrew Le, Jeremy T Booth, Paul J Keall, Lars Mejnertsen |
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| Rok vydání: | 2022 |
| Předmět: |
Male
Radiological and Ultrasound Technology 0299 Other Physical Sciences Radiotherapy Planning Computer-Assisted Prostate Prostatic Neoplasms Radiotherapy Dosage real-time adaptive radiotherapy Nuclear Medicine & Medical Imaging Motion motion management multi-target tracking 0299 Other Physical Sciences 0903 Biomedical Engineering 1103 Clinical Sciences Humans Radiology Nuclear Medicine and imaging MLC tracking Radiotherapy Intensity-Modulated Radiometry |
| Zdroj: | Physics in Medicine & Biology |
| ISSN: | 1361-6560 0031-9155 |
| DOI: | 10.1088/1361-6560/ac8967 |
| Popis: | Objective. The accuracy of radiotherapy for patients with locally advanced cancer is compromised by independent motion of multiple targets. To date, MLC tracking approaches have used 2D geometric optimisation where the MLC aperture shape is simply translated to correspond to the target’s motion, which results in sub-optimal delivered dose. To address this limitation, a dose-optimised multi-target MLC tracking method was developed and evaluated through simulated locally advanced prostate cancer treatments. Approach. A dose-optimised multi-target tracking algorithm that adapts the MLC aperture to minimise 3D dosimetric error was developed for moving prostate and static lymph node targets. A fast dose calculation algorithm accumulated the planned dose to the prostate and lymph node volumes during treatment in real time, and the MLC apertures were recalculated to minimise the difference between the delivered and planned dose with the included motion. Dose-optimised tracking was evaluated by simulating five locally advanced prostate plans and three prostate motion traces with a relative interfraction displacement. The same simulations were performed using geometric-optimised tracking and no tracking. The dose-optimised, geometric-optimised, and no tracking results were compared with the planned doses using a 2%/2 mm γ criterion. Main results. The mean dosimetric error was lowest for dose-optimised MLC tracking, with γ-failure rates of 12% ± 8.5% for the prostate and 2.2% ± 3.2% for the nodes. The γ-failure rates for geometric-optimised MLC tracking were 23% ± 12% for the prostate and 3.6% ± 2.5% for the nodes. When no tracking was used, the γ-failure rates were 37% ± 28% for the prostate and 24% ± 3.2% for the nodes. Significance. This study developed a dose-optimised multi-target MLC tracking method that minimises the difference between the planned and delivered doses in the presence of intrafraction motion. When applied to locally advanced prostate cancer, dose-optimised tracking showed smaller errors than geometric-optimised tracking and no tracking for both the prostate and nodes. |
| Databáze: | OpenAIRE |
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