Author: Lomax, A.L.
Paper Title Page
TUPAB407 A Novel Beam Optics Concept to Maximize the Transmission Through Cyclotron-based Proton Therapy Gantries 2477
 
  • V. Maradia, A.C. Giovannelli, A.L. Lomax, D. Meer, S. Psoroulas, J.M. Schippers, D.C. Weber
    PSI, Villigen PSI, Switzerland
  • V. Maradia
    ETH, Zurich, Switzerland
  • D.C. Weber
    University of Zurich, University Hospital, Zurich, Switzerland
  • D.C. Weber
    KRO, Bern, Switzerland
 
  Funding: This work is funded by a PSI inter-departmental funding initiative (CROSS).
Most of the conventional beam optics of cyclotron-based proton gantries were designed to provide point-to-point focus in both planes with an imaging factor between 1 and 2 from the entrance of the gantry to the patient. This means that a small beam size at the gantry entrance is required to achieve the required small beam size at the patient. Due to the typically used beam emittance, this in turn results in large beam divergence at the gantry entrance, increasing the possibility of beam losses along the gantry as the beam envelope gets close to the apertures. To maximize transmission through the gantry, we propose a novel beam optics concept using 3:1 imaging. It reduces the beam divergence at the gantry entrance by factor 3 while still achieving a small beam size at the patient. The beam envelope is better controlled and keeps clear of the apertures compared to the 1:1 or 1:2 imaging beam envelope. For PSI Gantry 2, the novel 3:1 imaging beam optics increase the proton beam transmission for lower energies by 40% compare to 1:1 imaging beam optics. The usage of small imaging factors can help to maximize transmission for different gantry lattices, thus reducing treatment times.
 
poster icon Poster TUPAB407 [1.347 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB407  
About • paper received ※ 10 May 2021       paper accepted ※ 02 June 2021       issue date ※ 29 August 2021  
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