On the accuracy of Monte Carlo based beam dynamics models for the degrader in proton therapy facilities

Rizzoglio, V.; Adelmann, Andreas; Baumgarten, C.; Meer, D.; Snuverink, J.; Talanov, V.

doi:10.1016/j.nima.2018.04.057

Cited by 14 publications

(8 citation statements)

References 20 publications

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“…Based on the relative position of the wedges, the beam energies in the range 230-70 MeV are obtained. The growth of phase space and emittance is limited within the acceptance of the following transport line by a set of collimators [16]. The first achromatic bending section that the beam encounters works as Energy Selection System (ESS).…”

Section: Uq Analysis For Beam Transport Linesmentioning

confidence: 99%

Uncertainty quantification analysis and optimization for proton therapy beam lines

et al. 2020

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Since many years proton therapy is an effective treatment solution against deep-seated tumors. A precise quantification of sources of uncertainty in each proton therapy aspect (e.g. accelerator, beam lines, patient positioning, treatment planning) is of profound importance to increase the accuracy of the dose delivered to the patient. Together with Monte Carlo techniques, a new research field called Uncertainty Quantification (UQ) has been recently introduced to verify the robustness of the treatment planning. In this work we present the first application of UQ as a method to identify typical errors in the transport lines of a cyclotron-based proton therapy facility and analyze their impact on the properties of the therapeutic beams. We also demonstrate the potential of UQ methods in developing optimized beam optics solutions for high-dimensional problems. Sensitivity analysis and surrogate models offer a fast way to exclude unimportant parameters frcomplex optimization problems such as the design of a superconducting gantry performed at Paul Scherrer Institute in Switzerland. Uncertainty Quantification theoryThe outcomes of a numerical model are influenced by uncertainties

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Section: Uq Analysis For Beam Transport Linesmentioning

confidence: 99%

Uncertainty quantification analysis and optimization for proton therapy beam lines

et al. 2020

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“…The multiple-wedge case represents the present geometry of the degrader used in the PROSCAN system. We also examined a degrader of equal overall length (and therefore equal air gap for a given exit energy) comprised of multiple rectangular slabs rather than wedges; we studied this because it is used in some published Monte-Carlo simulations [10] as a geometry that is considered simpler to implement yet physically equivalent to a multiple-wedge arrangement; we will confirm later in this paper that this assumption is correct. Finally, a single block degrader (with no intervening air gaps) was also examined, as it was also previously proposed as a model in simulation to predict the possible benefits of novel degrader materials such as boron carbide [11,12].…”

Section: Degrader Geometriesmentioning

confidence: 99%

“…Figure 10: (Top) particle transmission from the cyclotron to monitor MMAP11/12 for different energy settings and various degrader geometries (top); (bottom) ratio of the particle transmission for the single block geometry to the transmission through the conventional multi-wedge degrader at MMAP11/12. The relative transmission peaks at 150 MeV are probably due to the relative inelastic scattering rate reaching a maximum at this energy[10].…”

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confidence: 96%

Geometry optimisation of graphite energy degrader for proton therapy

et al. 2020

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Introduction: Cyclotron-based proton therapy facilities use an energy degrader of variable thickness to deliver beams of the different energies required by a patient treatment plan; scattering and straggling in the degrader give rise to an inherent emittance increase and subsequent particle loss in the downstream energy-selection system (ESS). Here we study alternative graphite degrader geometries and examine with Monte-Carlo simulations the induced emittance growth and consequent particle transmission. Methods: We examined the conventional multiple-wedge degrader used in the Paul Scherrer Institute PROSCAN proton therapy system, the equivalent parallel-sided degrader, and a single block degrader of equivalent thickness. G4Beamline Monte-Carlo tracking of protons was benchmarked against measurements of the existing degrader for proton energies from 75 to 230 MeV, and used to validate simulations of the alternative geometries. Results: Using a careful calculation of the beam emittance growth, we determined that a single-block degrader placed close to the collimators of the ESS is expected to deliver significantly larger transmission, up to 17% larger at 150 MeV. At the lowest deliverable of 75 MeV there is still a clear improvement in beam transmission. Conclusions: Whilst dose rates are not presently limited on the PROSCAN system at higher energies, a single-block degrader offers the ability to access either lower energies for treatment or a larger dose rate at 75 MeV in case transmission optimisation is desired. Single-block degraders should be considered for the delivery of low-energy protons from a cyclotron-based particle therapy system.

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“…Further comparisons between different Monte-Carlo codes and OPAL for the degrader in proton therapy facilities are discussed in [90].…”

Section: Single Slabmentioning

confidence: 99%

OPAL a Versatile Tool for Charged Particle Accelerator Simulations

Adelmann,

Calvo,

Frey

et al. 2019

Preprint

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Many sophisticated computer models have been developed to understand the behaviour of particle accelerators. Even these complex models often do not describe the measured data. Interactions of the beam with external fields, other particles in the same beam and the beam walls all present modelling challenges. These can be challenging to model correctly even with modern supercomputers. This paper describes OPAL (Object Oriented Parallel Accelerator Library), a parallel open source tool for chargedparticle optics in linear accelerators and rings, including 3D space charge. OPAL is built from the ground up as a parallel application exemplifying the fact that high performance computing is the third leg of science, complementing theory and experiment. Using the MAD language with extensions, OPAL can run on a laptop as well as on the largest high performance computing systems. The OPAL framework makes it easy to add new features in the form of new C++ classes, enabling the modelling of many physics processes and field types. OPAL comes in two flavours: OPAL-cycl: tracks particles with 3D space charge including neighbouring turns in cyclotrons and FFAs with time as the independent variable. OPAL-t: models beam lines, linacs, rf-photo injectors and complete XFELs excluding the undulator. The code is managed through the git distributed version control system. A suite of unit tests have been developed for various parts of OPAL, validating each part of the code independently. System tests validate the overall integration of different elements.

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On the accuracy of Monte Carlo based beam dynamics models for the degrader in proton therapy facilities

Cited by 14 publications

References 20 publications

Uncertainty quantification analysis and optimization for proton therapy beam lines

Uncertainty quantification analysis and optimization for proton therapy beam lines

Geometry optimisation of graphite energy degrader for proton therapy

OPAL a Versatile Tool for Charged Particle Accelerator Simulations

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