Author: Eichin, M.
Paper Title Page
THCPA06 A Real-Time Beam Monitoring System for Highly Dynamic Irradiations in Scanned Proton Therapy 1224
 
  • G. Klimpki, C. Bula, M. Eichin, A.L. Lomax, D. Meer, S. Psoroulas, U. Rechsteiner, D.C. Weber
    PSI, Villigen PSI, Switzerland
  • D.C. Weber
    University of Zurich, University Hospital, Zurich, Switzerland
 
  Funding: This work is supported by the Giuliana and Giorgio Stefanini Foundation.
Patient treatments in scanned proton therapy exhibit dead times, e.g. when adjusting beamline settings for a different energy or lateral position. On the one hand, such dead times prolong the overall treatment time, but on the other hand they grant possibilities to (retrospectively) validate that the correct amount of protons has been delivered to the correct position. Efforts in faster beam delivery aim to minimize such dead times, which calls for different means of monitoring irradiation parameters. To address this issue, we report on a real-time beam monitoring system that supervises the proton beam position and current during beam-on, hence while the patient is under irradiation. For this purpose, we sample 1-axis Hall probes placed in beam-scanning magnets and plane-parallel ionization chambers every 10 μs. FPGAs compare sampled signals against verification tables - time vs. position/current charts containing upper and lower tolerances for each signal - and issue interlocks whenever samples fall outside. Furthermore, we show that by implementing real-time beam monitoring in our facility, we are able to respect patient safety margins given by international norms and guidelines.
 
slides icon Slides THCPA06 [1.841 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICALEPCS2017-THCPA06  
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THPHA098 Development of a PXI Based Test Stand for Automatization of the Quality Assurance of the Patient Safety System in a Proton Therapy Centre 1604
 
  • P. Fernandez Carmona, M. Eichin, M. Grossmann, F. Heimann, H.A. Regele, D.C. Weber, R. van der Meer
    PSI, Villigen PSI, Switzerland
 
  At the Centre for Proton Therapy at the Paul Scherrer Institute a cyclotron, two gantries and a fixed beamline are being used to treat tumours. In order to prevent non-optimal beam delivery, an interlock patient safety system (PaSS) was implemented that interrupts the treatment if any sub-system reports an error. To ensure correct treatment, the PaSS needs to be thoroughly tested as part of the regular quality assurance as well as after each change. This typically required weeks of work, extensive beam-time and may not comprehensively detect all possible failure modes. With the opportunity of the installation of a new gantry, an automated PaSS test stand was developed that can emulate the rest of the facility. It consists of a NI PXI chassis with virtually unlimited IOs synchronously stimulated or sampled at 1MHz, a set of adapters to connect each type of interfaced signal and a runtime environment. We have also developed a VHDL based formal language to describe stimuli, assertions and specific measurements. We present the use of our test stand in the verification and validation of the PaSS, showing how its full quality assurance, including report generation was reduced to minutes.  
poster icon Poster THPHA098 [1.561 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICALEPCS2017-THPHA098  
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