Dynamic beam current control for improved dose accuracy in PBS proton therapy
| Autor: | M F Belosi, Christian Bula, David Meer, Michael Eichin, Jan Hrbacek |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Radiological and Ultrasound Technology business.industry Radiotherapy Planning Computer-Assisted Cyclotron Radiotherapy Dosage 030218 nuclear medicine & medical imaging law.invention 03 medical and health sciences 0302 clinical medicine Optics law 030220 oncology & carcinogenesis Control system Proton Therapy Humans Radiology Nuclear Medicine and imaging Current (fluid) Latency (engineering) Pencil-beam scanning Radiation treatment planning business Proton therapy Beam (structure) |
| Zdroj: | Physics in Medicine & Biology. 64:175003 |
| ISSN: | 1361-6560 |
| Popis: | The step-and-shoot method of pencil beam scanning delivers the dose on a 3D grid in the target volume, with one dimension defined by the proton energy. While the dose per pencil beam may vary substantially within an iso-energy layer, the beam current typically remains constant. In this static operation mode, the inherent latency of the beam switch-off mechanism results in a lower limit for the deliverable spot dose, which may prevent the application of some of the low-weighted spots prescribed by the treatment planning system. To overcome this limitation, we introduced dynamic beam current control at the PSI Gantry 2, an innovative new approach successfully commissioned and in clinical operation since fall 2017. The control system was enhanced with a direct link to the vertical deflector located at the centre of the cyclotron. This connection allows much faster beam current changes (~0.1 ms) and hence opens up the possibility of dynamically reducing the current for individual low-dose spots. We demonstrate that with this new dynamic operation mode, all spots are delivered as planned without compromising treatment time. We show by two independent and complementary methods that the delivered dose distribution is improved. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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