IPAC2018 - List of Authors (Mayor, A.)

Paper	Title	Page
MOPML059	Precise Beam Delivery for Proton Therapy with Dynamic Energy Modulation	540
	O. Actis, A. Mayor, D. Meer, D.C. Weber PSI, Villigen PSI, Switzerland D.C. Weber University of Zurich, University Hospital, Zurich, Switzerland
	Gantry 2 at PSI is a Pencil Beam Scanning (PBS) cyclotron based proton therapy system. PBS proved to be an effective treatment method for static tumors but for mobile targets (e.g lung) organ motion interferes with beam delivery lowering the treatment quality. A method to mitigate motion effects is to re-scan the treatment volume multiple times. The downside of re-scanning is the increase of treatment time due to high number of energy switches and magnet initializations (ramping) between scans. Our current re-scanning implementation is performed with a decreasing energy sequence and takes about 6s/scan thanks to fast energy switching of 100ms. Ramping adds 8s more leading to a treatment time of >60s. We developed beam line settings for reverse energy sequence and removed the full ramping between scans. This dynamic beam delivery leads to non-negligible beam position errors of >1.5mm which we compensate by field specific corrections. Using a patient file we proved that our novel re-scanning concept doubles the treatment efficiency. Using in-house developed measurement equipment we obtained a precision of <0.5mm in position and <1mm in range which fulfills all clinical requirements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML059
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Paper

Title

Page

Precise Beam Delivery for Proton Therapy with Dynamic Energy Modulation

540

O. Actis, A. Mayor, D. Meer, D.C. Weber
PSI, Villigen PSI, Switzerland
D.C. Weber
University of Zurich, University Hospital, Zurich, Switzerland

Gantry 2 at PSI is a Pencil Beam Scanning (PBS) cyclotron based proton therapy system. PBS proved to be an effective treatment method for static tumors but for mobile targets (e.g lung) organ motion interferes with beam delivery lowering the treatment quality. A method to mitigate motion effects is to re-scan the treatment volume multiple times. The downside of re-scanning is the increase of treatment time due to high number of energy switches and magnet initializations (ramping) between scans. Our current re-scanning implementation is performed with a decreasing energy sequence and takes about 6s/scan thanks to fast energy switching of 100ms. Ramping adds 8s more leading to a treatment time of >60s. We developed beam line settings for reverse energy sequence and removed the full ramping between scans. This dynamic beam delivery leads to non-negligible beam position errors of >1.5mm which we compensate by field specific corrections. Using a patient file we proved that our novel re-scanning concept doubles the treatment efficiency. Using in-house developed measurement equipment we obtained a precision of <0.5mm in position and <1mm in range which fulfills all clinical requirements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPML059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)