|TUB04||On-Line Dynamic Beam Intensity Control in a Proton Therapy Cyclotron||controls, cyclotron, proton, operation||148|
Modern proton therapy facilities use the pencil beam scanning (PBS) technique for the treatment of tumours: the beam is scanned through the tumour volume sequentially, i.e. stopping the beam at each position in the tumour for the amount of time necessary to deliver the prescribed dose for that position, and then moving to the next position (dose-driven delivery). This technique is robust against fluctuations in the beam current. Modern cyclotrons however offer very stable beam currents, and allow regulating the beam intensity online to match the requested beam intensity profile as a function of time (’time-driven’ delivery). To realise time-driven delivery at the COMET cyclotron at PSI*, we have designed a beam intensity controller** which is able to partially compensate for the non-linearity and the delay introduced by the physical limitations of the beam line elements and its drivers; this is particularly important when trying to achieve a very fast modulation of the beam, as required by the clinical plans. Experimental results have shown good performance for most current clinical scenarios, though we are investigating more advanced solutions for higher dose rates scenarios.
(*) Klimpki, G., et al. (2018). PMB, 63(14), 145006
(**) Fernandez Carmona, P., et al., (2018) Proceedings of PCaPAC2018, FRCC2
|Slides TUB04 [10.992 MB]|
|DOI •||reference for this paper ※ https://doi.org/10.18429/JACoW-Cyclotrons2019-TUB04|
|About •||paper received ※ 14 September 2019 paper accepted ※ 26 September 2019 issue date ※ 20 June 2020|
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