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Volz L, Graeff C, Durante M, Collins-Fekete CA. Focus stacking single-event particle radiography for high spatial resolution images and 3D feature localization. Phys Med Biol 2024; 69:024001. [PMID: 38056016 PMCID: PMC10777170 DOI: 10.1088/1361-6560/ad131a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 11/22/2023] [Accepted: 12/06/2023] [Indexed: 12/08/2023]
Abstract
Objective.We demonstrate a novel focus stacking technique to improve spatial resolution of single-event particle radiography (pRad), and exploit its potential for 3D feature detection.Approach.Focus stacking, used typically in optical photography and microscopy, is a technique to combine multiple images with different focal depths into a single super-resolution image. Each pixel in the final image is chosen from the image with the largest gradient at that pixel's position. pRad data can be reconstructed at different depths in the patient based on an estimate of each particle's trajectory (called distance-driven binning; DDB). For a given feature, there is a depth of reconstruction for which the spatial resolution of DDB is maximal. Focus stacking can hence be applied to a series of DDB images reconstructed from a single pRad acquisition for different depths, yielding both a high-resolution projection and information on the features' radiological depth at the same time. We demonstrate this technique with Geant4 simulated pRads of a water phantom (20 cm thick) with five bone cube inserts at different depths (1 × 1 × 1 cm3) and a lung cancer patient.Main results.For proton radiography of the cube phantom, focus stacking achieved a median resolution improvement of 136% compared to a state-of-the-art maximum likelihood pRad reconstruction algorithm and a median of 28% compared to DDB where the reconstruction depth was the center of each cube. For the lung patient, resolution was visually improved, without loss in accuracy. The focus stacking method also enabled to estimate the depth of the cubes within few millimeters accuracy, except for one shallow cube, where the depth was underestimated by 2.5 cm.Significance.Focus stacking utilizes the inherent 3D information encoded in pRad by the particle's scattering, overcoming current spatial resolution limits. It further opens possibilities for 3D feature localization. Therefore, focus stacking holds great potential for future pRad applications.
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Affiliation(s)
- Lennart Volz
- Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany
| | - Christian Graeff
- Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany
- Department of Electrical Engineering and Information Technology, Technical University of Darmstadt, Darmstadt, Germany
| | - Marco Durante
- Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany
- Department of Condensed Matter Physics, Technical University of Darmstadt, Darmstadt, Germany
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Aehle M, Alme J, Gábor Barnaföldi G, Blühdorn J, Bodova T, Borshchov V, van den Brink A, Eikeland V, Feofilov G, Garth C, Gauger NR, Grøttvik O, Helstrup H, Igolkin S, Keidel R, Kobdaj C, Kortus T, Kusch L, Leonhardt V, Mehendale S, Ningappa Mulawade R, Harald Odland O, O'Neill G, Papp G, Peitzmann T, Pettersen HES, Piersimoni P, Pochampalli R, Protsenko M, Rauch M, Ur Rehman A, Richter M, Röhrich D, Sagebaum M, Santana J, Schilling A, Seco J, Songmoolnak A, Sudár Á, Tambave G, Tymchuk I, Ullaland K, Varga-Kofarago M, Volz L, Wagner B, Wendzel S, Wiebel A, Xiao R, Yang S, Zillien S. Exploration of differentiability in a proton computed tomography simulation framework. Phys Med Biol 2023; 68:244002. [PMID: 37949060 DOI: 10.1088/1361-6560/ad0bdd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 11/10/2023] [Indexed: 11/12/2023]
Abstract
Objective.Gradient-based optimization using algorithmic derivatives can be a useful technique to improve engineering designs with respect to a computer-implemented objective function. Likewise, uncertainty quantification through computer simulations can be carried out by means of derivatives of the computer simulation. However, the effectiveness of these techniques depends on how 'well-linearizable' the software is. In this study, we assess how promising derivative information of a typical proton computed tomography (pCT) scan computer simulation is for the aforementioned applications.Approach.This study is mainly based on numerical experiments, in which we repeatedly evaluate three representative computational steps with perturbed input values. We support our observations with a review of the algorithmic steps and arithmetic operations performed by the software, using debugging techniques.Main results.The model-based iterative reconstruction (MBIR) subprocedure (at the end of the software pipeline) and the Monte Carlo (MC) simulation (at the beginning) were piecewise differentiable. However, the observed high density and magnitude of jumps was likely to preclude most meaningful uses of the derivatives. Jumps in the MBIR function arose from the discrete computation of the set of voxels intersected by a proton path, and could be reduced in magnitude by a 'fuzzy voxels' approach. The investigated jumps in the MC function arose from local changes in the control flow that affected the amount of consumed random numbers. The tracking algorithm solves an inherently non-differentiable problem.Significance.Besides the technical challenges of merely applying AD to existing software projects, the MC and MBIR codes must be adapted to compute smoother functions. For the MBIR code, we presented one possible approach for this while for the MC code, this will be subject to further research. For the tracking subprocedure, further research on surrogate models is necessary.
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Affiliation(s)
- Max Aehle
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Johan Alme
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | | | - Johannes Blühdorn
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Tea Bodova
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | | | | | - Viljar Eikeland
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | | | - Christoph Garth
- Scientific Visualization Lab, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Nicolas R Gauger
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Ola Grøttvik
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Håvard Helstrup
- Department of Computer Science, Electrical Engineering and Mathematical Sciences, Western Norway University of Applied Sciences, NO-5020 Bergen, Norway
| | | | - Ralf Keidel
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Chinorat Kobdaj
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Tobias Kortus
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Lisa Kusch
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Viktor Leonhardt
- Scientific Visualization Lab, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Shruti Mehendale
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Raju Ningappa Mulawade
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Odd Harald Odland
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
- Department of Oncology and Medical Physics, Haukeland University Hospital, NO-5021 Bergen, Norway
| | - George O'Neill
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Gábor Papp
- Institute for Physics, Eötvös Loránd University, 1/A Pázmány P. Sétány, H-1117 Budapest, Hungary
| | - Thomas Peitzmann
- Institute for Subatomic Physics, Utrecht University/Nikhef, Utrecht, Netherlands
| | | | - Pierluigi Piersimoni
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
- FSN Department, ENEA, Frascati Research Center, I-00044, Frascati, Italy
| | - Rohit Pochampalli
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Maksym Protsenko
- Research and Production Enterprise 'LTU' (RPE LTU), Kharkiv, Ukraine
| | - Max Rauch
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Attiq Ur Rehman
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | | | - Dieter Röhrich
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Max Sagebaum
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Joshua Santana
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Alexander Schilling
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Joao Seco
- Department of Biomedical Physics in Radiation Oncology, DKFZGerman Cancer Research Center, Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Arnon Songmoolnak
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Ákos Sudár
- Wigner Research Centre for Physics, Budapest, Hungary
| | - Ganesh Tambave
- Center for Medical and Radiation Physics (CMRP), National Institute of Science Education and Research (NISER), Bhubaneswar, India
| | - Ihor Tymchuk
- Research and Production Enterprise 'LTU' (RPE LTU), Kharkiv, Ukraine
| | - Kjetil Ullaland
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | | | - Lennart Volz
- Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Boris Wagner
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Steffen Wendzel
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Alexander Wiebel
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - RenZheng Xiao
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
- College of Mechanical & Power Engineering, China Three Gorges University, Yichang, People's Republic of China
| | - Shiming Yang
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Sebastian Zillien
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
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Schilling A, Aehle M, Alme J, Barnaföldi GG, Bodova T, Borshchov V, van den Brink A, Eikeland V, Feofilov G, Garth C, Gauger NR, Grøttvik O, Helstrup H, Igolkin S, Keidel R, Kobdaj C, Kortus T, Leonhardt V, Mehendale S, Ningappa Mulawade R, Harald Odland O, O'Neill G, Papp G, Peitzmann T, Pettersen HES, Piersimoni P, Protsenko M, Rauch M, Ur Rehman A, Richter M, Röhrich D, Santana J, Seco J, Songmoolnak A, Sudár Á, Tambave G, Tymchuk I, Ullaland K, Varga-Kofarago M, Volz L, Wagner B, Wendzel S, Wiebel A, Xiao R, Yang S, Zillien S. Uncertainty-aware spot rejection rate as quality metric for proton therapy using a digital tracking calorimeter. Phys Med Biol 2023; 68:194001. [PMID: 37652034 DOI: 10.1088/1361-6560/acf5c2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/31/2023] [Indexed: 09/02/2023]
Abstract
Objective.Proton therapy is highly sensitive to range uncertainties due to the nature of the dose deposition of charged particles. To ensure treatment quality, range verification methods can be used to verify that the individual spots in a pencil beam scanning treatment fraction match the treatment plan. This study introduces a novel metric for proton therapy quality control based on uncertainties in range verification of individual spots.Approach.We employ uncertainty-aware deep neural networks to predict the Bragg peak depth in an anthropomorphic phantom based on secondary charged particle detection in a silicon pixel telescope designed for proton computed tomography. The subsequently predicted Bragg peak positions, along with their uncertainties, are compared to the treatment plan, rejecting spots which are predicted to be outside the 95% confidence interval. The such-produced spot rejection rate presents a metric for the quality of the treatment fraction.Main results.The introduced spot rejection rate metric is shown to be well-defined for range predictors with well-calibrated uncertainties. Using this method, treatment errors in the form of lateral shifts can be detected down to 1 mm after around 1400 treated spots with spot intensities of 1 × 107protons. The range verification model used in this metric predicts the Bragg peak depth to a mean absolute error of 1.107 ± 0.015 mm.Significance.Uncertainty-aware machine learning has potential applications in proton therapy quality control. This work presents the foundation for future developments in this area.
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Affiliation(s)
- Alexander Schilling
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, D-67549 Worms, Germany
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Max Aehle
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Johan Alme
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | | | - Tea Bodova
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | | | | | - Viljar Eikeland
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | | | - Christoph Garth
- Scientific Visualization Lab, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Nicolas R Gauger
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Ola Grøttvik
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Håvard Helstrup
- Department of Computer Science, Electrical Engineering and Mathematical Sciences, Western Norway University of Applied Sciences, NO-5020 Bergen, Norway
| | | | - Ralf Keidel
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, D-67549 Worms, Germany
- Chair for Scientific Computing, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Chinorat Kobdaj
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Tobias Kortus
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, D-67549 Worms, Germany
| | - Viktor Leonhardt
- Scientific Visualization Lab, University of Kaiserslautern-Landau, D-67663 Kaiserslautern, Germany
| | - Shruti Mehendale
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Raju Ningappa Mulawade
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, D-67549 Worms, Germany
| | - Odd Harald Odland
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
- Department of Oncology and Medical Physics, Haukeland University Hospital, NO-5021 Bergen, Norway
| | - George O'Neill
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Gábor Papp
- Institute for Physics, Eötvös Loránd University, 1/A Pázmány P. Sétány, H-1117 Budapest, Hungary
| | - Thomas Peitzmann
- Institute for Subatomic Physics, Utrecht University/Nikhef, Utrecht, Netherlands
| | | | - Pierluigi Piersimoni
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
- UniCamillus-Saint Camillus International University of Health Sciences, Rome, Italy
| | - Maksym Protsenko
- Research and Production Enterprise 'LTU' (RPELTU), Kharkiv, Ukraine
| | - Max Rauch
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Attiq Ur Rehman
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Matthias Richter
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Dieter Röhrich
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Joshua Santana
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, D-67549 Worms, Germany
| | - Joao Seco
- Department of Biomedical Physics in Radiation Oncology, DKFZ-German Cancer Research Center, Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Arnon Songmoolnak
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Ákos Sudár
- Wigner Research Centre for Physics, Budapest, Hungary
- Budapest University of Technology and Economics, Budapest, Hungary
| | - Ganesh Tambave
- Center for Medical and Radiation Physics (CMRP), National Institute of Science Education and Research (NISER), Bhubaneswar, India
| | - Ihor Tymchuk
- Research and Production Enterprise 'LTU' (RPELTU), Kharkiv, Ukraine
| | - Kjetil Ullaland
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | | | - Lennart Volz
- Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Boris Wagner
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Steffen Wendzel
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, D-67549 Worms, Germany
| | - Alexander Wiebel
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, D-67549 Worms, Germany
| | - RenZheng Xiao
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
- College of Mechanical & Power Engineering, China Three Gorges University, Yichang, People's Republic of China
| | - Shiming Yang
- Department of Physics and Technology, University of Bergen, NO-5007 Bergen, Norway
| | - Sebastian Zillien
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, D-67549 Worms, Germany
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Sheng Y, Volz L, Wang W, Durante M, Graeff C. Evaluation of proton and carbon ion beam models in TReatment Planning for Particles 4D (TRiP4D) referring to a commercial treatment planning system. Z Med Phys 2023:S0939-3889(23)00079-X. [PMID: 37455229 DOI: 10.1016/j.zemedi.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/25/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023]
Abstract
PURPOSE To investigate the accuracy of the treatment planning system (TPS) TRiP4D in reproducing doses computed by the clinically used TPS SyngoRT. METHODS Proton and carbon ion beam models in TRiP4D were converted from SyngoRT. Cubic plans with different depths in a water-tank phantom (WP) and previously treated and experimentally verified patient plans from SyngoRT were recalculated in TRiP4D. The target mean dose deviation (ΔDmean,T) and global gamma index (2%-2 mm for the absorbed dose and 3%-3mm for the RBE-weighted dose with 10% threshold) were evaluated. RESULTS The carbon and proton absorbed dose gamma passing rates (γ-PRs) were ≥99.93% and ΔDmean,T smaller than -0.22%. On average, the RBE-weighted dose Dmean,T was -1.26% lower for TRiP4D than SyngoRT for cubic plans. In TRiP4D, the faster analytical 'low dose approximation' (Krämer, 2006) was used, while SyngoRT used a stochastic implementation (Krämer, 2000). The average ΔDmean, T could be reduced to -0.59% when applying the same biological effect calculation algorithm. However, the dose recalculation time increased by a factor of 79-477. ΔDmean,T variation up to -2.27% and -2.79% was observed for carbon absorbed and RBE-weighted doses in patient plans. The γ-PRs were ≥93.92% and ≥91.83% for patient plans, except for one proton beam with a range shifter (γ-PR of 64.19%). CONCLUSION The absorbed dose between TRiP4D and SyngoRT were identical for both proton and carbon ion plans in the WP. Compared to SyngoRT, TRiP4D underestimated the target RBE-weighted dose; however more efficient in RBE-weighted dose calculation. Large variation for proton beam with range shifter was observed. TRiP4D will be used to evaluate doses delivered to moving targets. Uncertainties inherent to the 4D-dose reconstruction calculation are expected to be significantly larger than the dose errors reported here. For this reason, the residual differences between TRiP4D and SyngoRT observed in this study are considered acceptable. The study was approved by the Institutional Research Board of Shanghai Proton and Heavy Ion Center (approval number SPHIC-MP-2020-04, RS).
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Affiliation(s)
- Yinxiangzi Sheng
- Biophysics GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany; Department of Medical Physics, Shanghai Proton and Heavy Ion Center, Shanghai, China; School of Sensing Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Lennart Volz
- Biophysics GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany
| | - Weiwei Wang
- Department of Medical Physics, Shanghai Proton and Heavy Ion Center, Shanghai, China
| | - Marco Durante
- Biophysics GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany; Institute of Condensed Matter Physics, Technical University of Darmstadt, Darmstadt, Germany
| | - Christian Graeff
- Biophysics GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany; Institute of Electrical Engineering and Information Technology, Technical University of Darmstadt, Darmstadt, Germany.
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Abstract
Cancer therapy with accelerated charged particles is one of the most valuable biomedical applications of nuclear physics. The technology has vastly evolved in the past 50 years, the number of clinical centers is exponentially growing, and recent clinical results support the physics and radiobiology rationale that particles should be less toxic and more effective than conventional X-rays for many cancer patients. Charged particles are also the most mature technology for clinical translation of ultra-high dose rate (FLASH) radiotherapy. However, the fraction of patients treated with accelerated particles is still very small and the therapy is only applied to a few solid cancer indications. The growth of particle therapy strongly depends on technological innovations aiming to make the therapy cheaper, more conformal and faster. The most promising solutions to reach these goals are superconductive magnets to build compact accelerators; gantryless beam delivery; online image-guidance and adaptive therapy with the support of machine learning algorithms; and high-intensity accelerators coupled to online imaging. Large international collaborations are needed to hasten the clinical translation of the research results.
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Affiliation(s)
- Christian Graeff
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Department, Planckstraße 1, 64291 Darmstadt, Germany
- Technische Universität Darmstadt, Darmstadt, Germany
| | - Lennart Volz
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Department, Planckstraße 1, 64291 Darmstadt, Germany
| | - Marco Durante
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Department, Planckstraße 1, 64291 Darmstadt, Germany
- Technische Universität Darmstadt, Darmstadt, Germany
- Dipartimento di Fisica “Ettore Pancini”, University Federico II, Naples, Italy
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Steinsberger T, Donetti M, Lis M, Volz L, Wolf M, Durante M, Graeff C. Experimental Validation of a Real-Time Adaptive 4D-Optimized Particle Radiotherapy Approach to Treat Irregularly Moving Tumors. Int J Radiat Oncol Biol Phys 2023; 115:1257-1268. [PMID: 36462690 DOI: 10.1016/j.ijrobp.2022.11.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 11/04/2022] [Accepted: 11/15/2022] [Indexed: 12/05/2022]
Abstract
PURPOSE Treatment of locally advanced lung cancer is limited by toxicity and insufficient local control. Particle therapy could enable more conformal treatment than intensity modulated photon therapy but is challenged by irregular tumor motion, associated range changes, and tumor deformations. We propose a new strategy for robust, online adaptive particle therapy, synergizing 4-dimensional optimization with real-time adaptive beam tracking. The strategy was tested and the required motion monitoring precision was determined. METHODS AND MATERIALS In multiphase 4-dimensional dose delivery (MP4D), a dedicated quasistatic treatment plan is delivered to each motion phase of periodic 4-dimensional computed tomography (4DCT). In the new extension, "MP4D with residual tracking" (MP4DRT), lateral beam tracking compensates for the displacement of the tumor center-of-mass relative to the current phase in the planning 4DCT. We implemented this method in the dose delivery system of a clinical carbon facility and tested it experimentally for a lung cancer plan based on a periodic subset of a virtual lung 4DCT (planned motion amplitude 20 mm). Treatments were delivered in a quality assurance-like setting to a moving ionization chamber array. We considered variable motion amplitudes and baseline drifts. The required motion monitoring precision was evaluated by adding noise to the motion signal. Log-file-based dose reconstructions were performed in silico on the entire 4DCT phantom data set capable of simulating nonperiodic motion. MP4DRT was compared with MP4D, rescanned beam tracking, and internal target volume plans. Treatment quality was assessed in terms of target coverage (D95), dose homogeneity (D5-D95), conformity number, and dose to heart and lung. RESULTS For all considered motion scenarios and metrics, MP4DRT produced the most favorable metrics among the tested motion mitigation strategies and delivered high-quality treatments. The conformity was similar to static treatments. The motion monitoring precision required for D95 >95% was 1.9 mm. CONCLUSIONS With clinically feasible motion monitoring, MP4DRT can deliver highly conformal dose distributions to irregularly moving targets.
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Affiliation(s)
- Timo Steinsberger
- Biophysics, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany; Institute for Condensed Matter Physics, Technical University of Darmstadt, Darmstadt, Germany
| | - Marco Donetti
- Research and Development Department, CNAO National Center for Oncological Hadrontherapy, Pavia, Italy
| | - Michelle Lis
- Biophysics, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany; Physics Research, Leo Cancer Care, Middleton, Wisconsin; Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana
| | - Lennart Volz
- Biophysics, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - Moritz Wolf
- Biophysics, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - Marco Durante
- Biophysics, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany; Institute for Condensed Matter Physics, Technical University of Darmstadt, Darmstadt, Germany
| | - Christian Graeff
- Biophysics, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany; Department of Electrical Engineering and Information Technology, Technical University, Darmstadt, Germany.
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Fullarton R, Volz L, Dikaios N, Schulte R, Royle G, Evans PM, Seco J, Collins‐Fekete C. A likelihood-based particle imaging filter using prior information. Med Phys 2023; 50:2336-2353. [PMID: 36727634 PMCID: PMC10947404 DOI: 10.1002/mp.16258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 01/13/2023] [Accepted: 01/13/2023] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Particle imaging can increase precision in proton and ion therapy. Interactions with nuclei in the imaged object increase image noise and reduce image quality, especially for multinucleon ions that can fragment, such as helium. PURPOSE This work proposes a particle imaging filter, referred to as the Prior Filter, based on using prior information in the form of an estimated relative stopping power (RSP) map and the principles of electromagnetic interaction, to identify particles that have undergone nuclear interaction. The particles identified as having undergone nuclear interactions are then excluded from the image reconstruction, reducing the image noise. METHODS The Prior Filter uses Fermi-Eyges scattering and Tschalär straggling theories to determine the likelihood that a particle only interacts electromagnetically. A threshold is then set to reject those particles with a low likelihood. The filter was evaluated and compared with a filter that estimates this likelihood based on the measured distribution of energy and scattering angle within pixels, commonly implemented as the 3σ filter. Reconstructed radiographs from simulated data of a 20-cm water cylinder and an anthropomorphic chest phantom were generated with both protons and helium ions to assess the effect of the filters on noise reduction. The simulation also allowed assessment of secondary particle removal through the particle histories. Experimental data were acquired of the Catphan CTP 404 Sensitometry phantom using the U.S. proton CT (pCT) collaboration prototype scanner. The proton and helium images were filtered with both the prior filtering method and a state-of-the-art method including an implementation of the 3σ filter. For both cases, a dE-E telescope filter, designed for this type of detector, was also applied. RESULTS The proton radiographs showed a small reduction in noise (1 mm of water-equivalent thickness [WET]) but a larger reduction in helium radiographs (up to 5-6 mm of WET) due to better secondary filtering. The proton and helium CT images reflected this, with similar noise at the center of the phantom (0.02 RSP) for the proton images and an RSP noise of 0.03 for the proposed filter and 0.06 for the 3σ filter in the helium images. Images reconstructed from data with a dose reduction, up to a factor of 9, maintained a lower noise level using the Prior Filter over the state-of-the-art filtering method. CONCLUSIONS The proposed filter results in images with equal or reduced noise compared to those that have undergone a filtering method typical of current particle imaging studies. This work also demonstrates that the proposed filter maintains better performance against the state of the art with up to a nine-fold dose reduction.
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Affiliation(s)
- Ryan Fullarton
- Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonUK
| | - Lennart Volz
- Department of Biomedical Physics in Radiation OncologyDeutsches Krebsforschungszentrum (DKFZ)HeidelbergGermany
- Department of Physics and AstronomyHeidelberg UniversityHeidelbergGermany
- GSI Helmholtz Centre for Heavy Ion Research GmbHDarmstadtGermany
| | - Nikolaos Dikaios
- Centre for Vision Speech and Signal ProcessingUniversity of SurreyGuildfordUK
- Mathematics Research CenterAcademy of AthensAthensGreece
| | - Reinhard Schulte
- Department of Basic SciencesDivision of Biomedical Engineering SciencesLoma Linda UniversityLoma LindaCaliforniaUSA
| | - Gary Royle
- Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonUK
| | - Philip M. Evans
- Centre for Vision Speech and Signal ProcessingUniversity of SurreyGuildfordUK
- Chemical, Medical and Environmental ScienceNational Physical LaboratoryTeddingtonUK
| | - Joao Seco
- Department of Biomedical Physics in Radiation OncologyDeutsches Krebsforschungszentrum (DKFZ)HeidelbergGermany
- Department of Physics and AstronomyHeidelberg UniversityHeidelbergGermany
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Volz L, Sheng Y, Durante M, Graeff C. Considerations for Upright Particle Therapy Patient Positioning and Associated Image Guidance. Front Oncol 2022; 12:930850. [PMID: 35965576 PMCID: PMC9372451 DOI: 10.3389/fonc.2022.930850] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/17/2022] [Indexed: 11/16/2022] Open
Abstract
Particle therapy is a rapidly growing field in cancer therapy. Worldwide, over 100 centers are in operation, and more are currently in construction phase. The interest in particle therapy is founded in the superior target dose conformity and healthy tissue sparing achievable through the particles’ inverse depth dose profile. This physical advantage is, however, opposed by increased complexity and cost of particle therapy facilities. Particle therapy, especially with heavier ions, requires large and costly equipment to accelerate the particles to the desired treatment energy and steer the beam to the patient. A significant portion of the cost for a treatment facility is attributed to the gantry, used to enable different beam angles around the patient for optimal healthy tissue sparing. Instead of a gantry, a rotating chair positioning system paired with a fixed horizontal beam line presents a suitable cost-efficient alternative. Chair systems have been used already at the advent of particle therapy, but were soon dismissed due to increased setup uncertainty associated with the upright position stemming from the lack of dedicated image guidance systems. Recently, treatment chairs gained renewed interest due to the improvement in beam delivery, commercial availability of vertical patient CT imaging and improved image guidance systems to mitigate the problem of anatomical motion in seated treatments. In this review, economical and clinical reasons for an upright patient positioning system are discussed. Existing designs targeted for particle therapy are reviewed, and conclusions are drawn on the design and construction of chair systems and associated image guidance. Finally, the different aspects from literature are channeled into recommendations for potential upright treatment layouts, both for retrofitting and new facilities.
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Affiliation(s)
- Lennart Volz
- Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany.,Department of Medical Physics, Shanghai Proton and Heavy Ion Center, Shanghai, China
| | - Yinxiangzi Sheng
- Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany.,Department of Medical Physics, Shanghai Proton and Heavy Ion Center, Shanghai, China
| | - Marco Durante
- Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany.,Institute of Condensed Matter Physics, Technical University of Darmstadt, Darmstadt, Germany
| | - Christian Graeff
- Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany.,Institute of Electrical Engineering and Information Technology, Technical University of Darmstadt, Darmstadt, Germany
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Volz L, Durante M, Graeff C. PO-1494 A-priori beam energy selection for heavy ion arc therapy. Radiother Oncol 2022. [DOI: 10.1016/s0167-8140(22)03458-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Fullarton R, Volz L, Dikaios N, Schulte R, Royle G, Evans P, Seco J, Collins Fekete C. MO-0218 A likelihood-based particle imaging filter using prior information. Radiother Oncol 2022. [DOI: 10.1016/s0167-8140(22)02320-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Steinsberger T, Donetti M, Lis M, Volz L, Wolf M, Durante M, Graeff C. PD-0238 Experimental demonstration of conformal carbon ion therapy for irregularly moving tumors. Radiother Oncol 2022. [DOI: 10.1016/s0167-8140(22)02793-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Bär E, Volz L, Collins-Fekete CA, Brons S, Runz A, Schulte RW, Seco J. Experimental comparison of photon versus particle computed tomography to predict tissue relative stopping powers. Med Phys 2022; 49:474-487. [PMID: 34709667 DOI: 10.1002/mp.15283] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 09/18/2021] [Accepted: 09/20/2021] [Indexed: 01/21/2023] Open
Abstract
PURPOSE Measurements comparing relative stopping power (RSP) accuracy of state-of-the-art systems representing single-energy and dual-energy computed tomography (SECT/DECT) with proton CT (pCT) and helium CT (HeCT) in biological tissue samples. METHODS We used 16 porcine and bovine samples of various tissue types and water, covering an RSP range from 0.90 ± 0.06 to 1.78 ± 0.05. Samples were packed and sealed into 3D-printed cylinders ( d = 2 cm, h = 5 cm) and inserted into an in-house designed cylindrical polymethyl methacrylate (PMMA) phantom ( d = 10 cm, h = 10 cm). We scanned the phantom in a commercial SECT and DECT (120 kV; 100 and 140 kV/Sn (tin-filtered)); and acquired pCT and HeCT ( E ∼ 200 MeV/u, 2 ∘ steps, ∼ 6.2 × 10 6 (p)/ ∼ 2.3 × 10 6 (He) particles/projection) with a particle imaging prototype. RSP maps were calculated from SECT/DECT using stoichiometric methods and from pCT/HeCT using the DROP-TVS algorithm. We estimated the average RSP of each tissue per modality in cylindrical volumes of interest and compared it to ground truth RSP taken from peak-detection measurements. RESULTS Throughout all samples, we observe the following root-mean-squared RSP prediction errors ± combined uncertainty from reference measurement and imaging: SECT 3.10 ± 2.88%, DECT 0.75 ± 2.80%, pCT 1.19 ± 2.81%, and HeCT 0.78 ± 2.81%. The largest mean errors ± combined uncertainty per modality are SECT 8.22 ± 2.79% in cortical bone, DECT 1.74 ± 2.00% in back fat, pCT 1.80 ± 4.27% in bone marrow, and HeCT 1.37 ± 4.25% in bone marrow. Ring artifacts were observed in both pCT and HeCT reconstructions, imposing a systematic shift to predicted RSPs. CONCLUSION Comparing state-of-the-art SECT/DECT technology and a pCT/HeCT prototype, DECT provided the most accurate RSP prediction, closely followed by particle imaging. The novel modalities pCT and HeCT have the potential to further improve on RSP accuracies with work focusing on the origin and correction of ring artifacts. Future work will study accuracy of proton treatment plans using RSP maps from investigated imaging modalities.
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Affiliation(s)
- Esther Bär
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK.,Department of Radiotherapy Physics, University College London Hospitals NHS Foundation Trust, Radiotherapy Physics, London, UK
| | - Lennart Volz
- Biomedical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld, Heidelberg, Germany
| | | | - Stephan Brons
- Heidelberg Ion Beam Therapy Center, Im Neuenheimer Feld, Heidelberg, Germany
| | - Armin Runz
- Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld, Heidelberg, Germany
| | | | - Joao Seco
- Biomedical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld, Heidelberg, Germany.,Department of Physics and Astronomy, Heidelberg University, Germany
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Soto-Heras S, Volz L, Miller D. 98  In vitro fertilisation with sperm prebound to oviduct glycans immobilised on a coverslip. Reprod Fertil Dev 2021; 34:286. [PMID: 35231228 DOI: 10.1071/rdv34n2ab98] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- S Soto-Heras
- Department of Animal Sciences, University of Illinois, Urbana, IL, USA
| | - L Volz
- Department of Animal Sciences, University of Illinois, Urbana, IL, USA
| | - D Miller
- Department of Animal Sciences, University of Illinois, Urbana, IL, USA
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14
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Volz L, Collins-Fekete CA, Bär E, Brons S, Graeff C, Johnson RP, Runz A, Sarosiek C, Schulte RW, Seco J. The accuracy of helium ion CT based particle therapy range prediction: an experimental study comparing different particle and x-ray CT modalities. Phys Med Biol 2021; 66:10.1088/1361-6560/ac33ec. [PMID: 34706355 PMCID: PMC8792995 DOI: 10.1088/1361-6560/ac33ec] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 10/27/2021] [Indexed: 11/12/2022]
Abstract
This work provides a quantitative assessment of helium ion CT (HeCT) for particle therapy treatment planning. For the first time, HeCT based range prediction accuracy in a heterogeneous tissue phantom is presented and compared to single-energy x-ray CT (SECT), dual-energy x-ray CT (DECT) and proton CT (pCT). HeCT and pCT scans were acquired using the US pCT collaboration prototype particle CT scanner at the Heidelberg Ion-Beam Therapy Center. SECT and DECT scans were done with a Siemens Somatom Definition Flash and converted to RSP. A Catphan CTP404 module was used to study the RSP accuracy of HeCT. A custom phantom of 20 cm diameter containing several tissue equivalent plastic cubes was used to assess the spatial resolution of HeCT and compare it to DECT. A clinically realistic heterogeneous tissue phantom was constructed using cranial slices from a pig head placed inside a cylindrical phantom (ø150 mm). A proton beam (84.67 mm range) depth-dose measurement was acquired using a stack of GafchromicTM EBT-XD films in a central dosimetry insert in the phantom. CT scans of the phantom were acquired with each modality, and proton depth-dose estimates were simulated based on the reconstructions. The RSP accuracy of HeCT for the plastic phantom was found to be 0.3 ± 0.1%. The spatial resolution for HeCT of the cube phantom was 5.9 ± 0.4 lp cm-1for central, and 7.6 ± 0.8 lp cm-1for peripheral cubes, comparable to DECT spatial resolution (7.7 ± 0.3 lp cm-1and 7.4 ± 0.2 lp cm-1, respectively). For the pig head, HeCT, SECT, DECT and pCT predicted range accuracy was 0.25%, -1.40%, -0.45% and 0.39%, respectively. In this study, HeCT acquired with a prototype system showed potential for particle therapy treatment planning, offering RSP accuracy, spatial resolution, and range prediction accuracy comparable to that achieved with a commercial DECT scanner. Still, technical improvements of HeCT are needed to enable clinical implementation.
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Affiliation(s)
- L Volz
- Department of Biomedical Physics in Radiation Oncology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - C-A Collins-Fekete
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - E Bär
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
- Department of Radiotherapy Physics, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - S Brons
- Heidelberg Ion-Beam Therapy Center, Universitäts Klinikum Heidelberg, Heidelberg, Germany
| | - C Graeff
- Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany
| | - R P Johnson
- Department of Physics, University of California at Santa Cruz, Santa Cruz, United States of America
| | - A Runz
- Department of Medical Physics in Radiation Therapy, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - C Sarosiek
- Department of Physics, Northern Illinois University, DeKalb, United States of America
| | - R W Schulte
- Department of Basic Sciences, Division of Biomedical Engineering Sciences, Loma Linda University, Loma Linda, United States of America
| | - J Seco
- Department of Biomedical Physics in Radiation Oncology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
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15
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Pettersen HES, Aehle M, Alme J, Barnaföldi GG, Borshchov V, van den Brink A, Chaar M, Eikeland V, Feofilov G, Garth C, Gauger NR, Genov G, Grøttvik O, Helstrup H, Igolkin S, Keidel R, Kobdaj C, Kortus T, Leonhardt V, Mehendale S, Mulawade RN, Odland OH, Papp G, Peitzmann T, Piersimoni P, Protsenko M, Rehman AU, Richter M, Santana J, Schilling A, Seco J, Songmoolnak A, Sølie JR, Tambave G, Tymchuk I, Ullaland K, Varga-Kofarago M, Volz L, Wagner B, Wendzel S, Wiebel A, Xiao R, Yang S, Yokoyama H, Zillien S, Röhrich D. Investigating particle track topology for range telescopes in particle radiography using convolutional neural networks. Acta Oncol 2021; 60:1413-1418. [PMID: 34259117 DOI: 10.1080/0284186x.2021.1949037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND Proton computed tomography (pCT) and radiography (pRad) are proposed modalities for improved treatment plan accuracy and in situ treatment validation in proton therapy. The pCT system of the Bergen pCT collaboration is able to handle very high particle intensities by means of track reconstruction. However, incorrectly reconstructed and secondary tracks degrade the image quality. We have investigated whether a convolutional neural network (CNN)-based filter is able to improve the image quality. MATERIAL AND METHODS The CNN was trained by simulation and reconstruction of tens of millions of proton and helium tracks. The CNN filter was then compared to simple energy loss threshold methods using the Area Under the Receiver Operating Characteristics curve (AUROC), and by comparing the image quality and Water Equivalent Path Length (WEPL) error of proton and helium radiographs filtered with the same methods. RESULTS The CNN method led to a considerable improvement of the AUROC, from 74.3% to 97.5% with protons and from 94.2% to 99.5% with helium. The CNN filtering reduced the WEPL error in the helium radiograph from 1.03 mm to 0.93 mm while no improvement was seen in the CNN filtered pRads. CONCLUSION The CNN improved the filtering of proton and helium tracks. Only in the helium radiograph did this lead to improved image quality.
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Affiliation(s)
| | - Max Aehle
- Chair for Scientific Computing, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - Johan Alme
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | | | | | | | - Mamdouh Chaar
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Viljar Eikeland
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Grigory Feofilov
- Department of High Energy and Elementary Particles Physics, St. Petersburg University, St. Petersburg, Russia
| | - Christoph Garth
- Scientific Visualization Lab, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - Nicolas R. Gauger
- Chair for Scientific Computing, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - Georgi Genov
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Ola Grøttvik
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Håvard Helstrup
- Department of Computer Science, Electrical Engineering and Mathematical Sciences, Western Norway University of Applied Sciences, Bergen, Norway
| | - Sergey Igolkin
- Department of High Energy and Elementary Particles Physics, St. Petersburg University, St. Petersburg, Russia
| | - Ralf Keidel
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Chinorat Kobdaj
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Tobias Kortus
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Viktor Leonhardt
- Scientific Visualization Lab, Technische Universität Kaiserslautern, Kaiserslautern, Germany
| | - Shruti Mehendale
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Raju Ningappa Mulawade
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Odd Harald Odland
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Gábor Papp
- Institute for Physics, Eötvös Loránd University, Budapest, Hungary
| | - Thomas Peitzmann
- Institute for Subatomic Physics, Utrecht University/Nikhef, Utrecht, Netherlands
| | | | - Maksym Protsenko
- Research and Production Enterprise “LTU” (RPE LTU), Kharkiv, Ukraine
| | - Attiq Ur Rehman
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | | | - Joshua Santana
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Alexander Schilling
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Joao Seco
- Department of Biomedical Physics in Radiation Oncology, DKFZ-German Cancer Research Center, Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Arnon Songmoolnak
- Department of Physics and Technology, University of Bergen, Bergen, Norway
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Jarle Rambo Sølie
- Department of Diagnostic Physics, Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway
| | - Ganesh Tambave
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Ihor Tymchuk
- Research and Production Enterprise “LTU” (RPE LTU), Kharkiv, Ukraine
| | - Kjetil Ullaland
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | | | - Lennart Volz
- Department of Biophysics, GSI Helmholtz Center for Heavy Ion Research GmbH, Darmstadt, Germany
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Boris Wagner
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Steffen Wendzel
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Alexander Wiebel
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - RenZheng Xiao
- Department of Physics and Technology, University of Bergen, Bergen, Norway
- College of Mechanical & Power Engineering, China Three Gorges University, Yichang, People’s Republic of China
| | - Shiming Yang
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Hiroki Yokoyama
- Institute for Subatomic Physics, Utrecht University/Nikhef, Utrecht, Netherlands
| | - Sebastian Zillien
- Center for Technology and Transfer (ZTT), University of Applied Sciences Worms, Worms, Germany
| | - Dieter Röhrich
- Department of Physics and Technology, University of Bergen, Bergen, Norway
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Volz L, Vichtl T, Collins-Fekete C, Seco J. PO-1682 Towards a clinical helium ion imaging system. Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)08133-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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Pettersen HES, Volz L, Sølie JR, Alme J, Barnaföldi GG, Barthel R, van den Brink A, Borshchov V, Chaar M, Eikeland V, Genov G, Grøttvik O, Helstrup H, Keidel R, Kobdaj C, van der Kolk N, Mehendale S, Meric I, Harald Odland O, Papp G, Peitzmann T, Piersimoni P, Protsenko M, Ur Rehman A, Richter M, Tefre Samnøy A, Seco J, Shafiee H, Songmoolnak A, Tambave G, Tymchuk I, Ullaland K, Varga-Kofarago M, Wagner B, Xiao R, Yang S, Yokoyama H, Röhrich D. Helium radiography with a digital tracking calorimeter-a Monte Carlo study for secondary track rejection. Phys Med Biol 2021; 66:035004. [PMID: 33181502 DOI: 10.1088/1361-6560/abca03] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Radiation therapy using protons and heavier ions is a fast-growing therapeutic option for cancer patients. A clinical system for particle imaging in particle therapy would enable online patient position verification, estimation of the dose deposition through range monitoring and a reduction of uncertainties in the calculation of the relative stopping power of the patient. Several prototype imaging modalities offer radiography and computed tomography using protons and heavy ions. A Digital Tracking Calorimeter (DTC), currently under development, has been proposed as one such detector. In the DTC 43 longitudinal layers of laterally stacked ALPIDE CMOS monolithic active pixel sensor chips are able to reconstruct a large number of simultaneously recorded proton tracks. In this study, we explored the capability of the DTC for helium imaging which offers favorable spatial resolution over proton imaging. Helium ions exhibit a larger cross section for inelastic nuclear interactions, increasing the number of produced secondaries in the imaged object and in the detector itself. To that end, a filtering process able to remove a large fraction of the secondaries was identified, and the track reconstruction process was adapted for helium ions. By filtering on the energy loss along the tracks, on the incoming angle and on the particle ranges, 97.5% of the secondaries were removed. After passing through 16 cm water, 50.0% of the primary helium ions survived; after the proposed filtering 42.4% of the primaries remained; finally after subsequent image reconstruction 31% of the primaries remained. Helium track reconstruction leads to more track matching errors compared to protons due to the increased available focus strength of the helium beam. In a head phantom radiograph, the Water Equivalent Path Length error envelope was 1.0 mm for helium and 1.1 mm for protons. This accuracy is expected to be sufficient for helium imaging for pre-treatment verification purposes.
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Kelleter L, Radogna R, Volz L, Attree D, Basharina-Freshville A, Seco J, Saakyan R, Jolly S. A scintillator-based range telescope for particle therapy. Phys Med Biol 2020; 65:165001. [PMID: 32422621 DOI: 10.1088/1361-6560/ab9415] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The commissioning and operation of a particle therapy centre requires an extensive set of detectors for measuring various parameters of the treatment beam. Among the key devices are detectors for beam range quality assurance. In this work, a novel range telescope based on a plastic scintillator and read out by a large-scale CMOS sensor is presented. The detector is made of a stack of 49 plastic scintillator sheets with a thickness of 2-3 mm and an active area of 100 × 100 mm2, resulting in a total physical stack thickness of 124.2 mm. This compact design avoids optical artefacts that are common in other scintillation detectors. The range of a proton beam is reconstructed using a novel Bragg curve model that incorporates scintillator quenching effects. Measurements to characterise the performance of the detector were carried out at the Heidelberger Ionenstrahl-Therapiezentrum (HIT, Heidelberg, GER) and the Clatterbridge Cancer Centre (CCC, Bebington, UK). The maximum difference between the measured range and the reference range was found to be 0.41 mm at a proton beam range of 310 mm and was dominated by detector alignment uncertainties. With the new detector prototype, the water-equivalent thickness of PMMA degrader blocks has been reconstructed within ± 0.1 mm. An evaluation of the radiation hardness proves that the range reconstruction algorithm is robust following the deposition of 6,300 Gy peak dose into the detector. Furthermore, small variations in the beam spot size and transverse beam position are shown to have a negligible effect on the range reconstruction accuracy. The potential for range measurements of ion beams is also investigated.
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Affiliation(s)
- Laurent Kelleter
- Dept. Physics and Astronomy, University College London, Gower Street, WC1E 6BT London, United Kingdom
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Rambo Sølie J, Volz L, Egil Seime Pettersen H, Piersimoni P, Harald Odland O, Röhrich D, Helstrup H, Peitzmann T, Ullaland K, Varga-Kofarago M, Mehendale S, Slettevoll Grøttvik O, Nilsen Eikeland V, Meric I, Seco J. Image quality of list-mode proton imaging without front trackers. ACTA ACUST UNITED AC 2020; 65:135012. [DOI: 10.1088/1361-6560/ab8ddb] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Volz L, Collins-Fekete CA, Sølie JR, Seco J. Theoretical considerations on the spatial resolution limit of single-event particle radiography. Biomed Phys Eng Express 2020; 6:055002. [DOI: 10.1088/2057-1976/ab9c3f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Volz L, Kelleter L, Brons S, Burigo L, Graeff C, Niebuhr NI, Radogna R, Scheloske S, Schömers C, Jolly S, Seco J. Experimental exploration of a mixed helium/carbon beam for online treatment monitoring in carbon ion beam therapy. ACTA ACUST UNITED AC 2020; 65:055002. [DOI: 10.1088/1361-6560/ab6e52] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Dedes G, Dickmann J, Niepel K, Wesp P, Johnson RP, Pankuch M, Bashkirov V, Rit S, Volz L, Schulte RW, Landry G, Parodi K. Experimental comparison of proton CT and dual energy x-ray CT for relative stopping power estimation in proton therapy. ACTA ACUST UNITED AC 2019; 64:165002. [DOI: 10.1088/1361-6560/ab2b72] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Volz L, Piersimoni P, Johnson RP, Bashkirov VA, Schulte RW, Seco J. Improving single-event proton CT by removing nuclear interaction events within the energy/range detector. ACTA ACUST UNITED AC 2019; 64:15NT01. [DOI: 10.1088/1361-6560/ab2671] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Volz L, Piersimoni P, Bashkirov VA, Brons S, Collins-Fekete CA, Johnson RP, Schulte RW, Seco J. The impact of secondary fragments on the image quality of helium ion imaging. Phys Med Biol 2018; 63:195016. [PMID: 30183679 PMCID: PMC6380898 DOI: 10.1088/1361-6560/aadf25] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Single-event ion imaging enables the direct reconstruction of the relative stopping power (RSP) information required for ion-beam therapy. Helium ions were recently hypothesized to be the optimal species for such technique. The purpose of this work is to investigate the effect of secondary fragments on the image quality of helium CT (HeCT) and to assess the performance of a prototype proton CT (pCT) scanner when operated with helium beams in Monte Carlo simulations and experiment. Experiments were conducted installing the U.S. pCT consortium prototype scanner at the Heidelberg Ion-Beam Therapy Center (HIT). Simulations were performed with the scanner using the TOPAS toolkit. HeCT images were reconstructed for a cylindrical water phantom, the CTP404 (sensitometry), and the CTP528 (line-pair) [Formula: see text] ® modules. To identify and remove individual events caused by fragmentation, the multistage energy detector of the scanner was adapted to function as a [Formula: see text] telescope. The use of the developed filter eliminated the otherwise arising ring artifacts in the HeCT reconstructed images. For the HeCT reconstructed images of a water phantom, the maximum RSP error was improved by almost a factor 8 with respect to unfiltered images in the simulation and a factor 10 in the experiment. Similarly, for the CTP404 module, the mean RSP accuracy improved by a factor 6 in both the simulation and the experiment when the filter was applied (mean relative error 0.40% in simulation, 0.45% in experiment). In the evaluation of the spatial resolution through the CTP528 module, the main effect of the filter was noise reduction. For both simulated and experimental images the spatial resolution was ∼4 lp cm-1. In conclusion, the novel filter developed for secondary fragments proved to be effective in improving the visual quality and RSP accuracy of the reconstructed images. With the filter, the pCT scanner is capable of accurate HeCT imaging.
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Affiliation(s)
- Lennart Volz
- German Cancer Research Center (DKFZ) Heidelberg, Baden-Württemberg, Germany. Department of Physics and Astronomy, Heidelberg University, Heidelberg, Baden-Württemberg, Germany. These authors contributed equally to this work
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Piersimoni P, Faddegon BA, Méndez JR, Schulte RW, Volz L, Seco J. Helium CT: Monte Carlo simulation results for an ideal source and detector with comparison to proton CT. Med Phys 2018; 45:3264-3274. [PMID: 29727481 DOI: 10.1002/mp.12942] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 02/19/2018] [Accepted: 04/17/2018] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To evaluate the accuracy of relative stopping power and spatial resolution of images reconstructed with simulated helium CT (HeCT) in comparison to proton CT (pCT). METHODS A Monte Carlo (MC) study with the TOPAS tool was performed to compare the accuracy of relative stopping power (RSP) reconstruction and spatial resolution of low-fluence HeCT to pCT, both using 200 MeV/u particles. An ideal setup consisting of a flat beam source and a totally absorbing energy-range detector was implemented to estimate the theoretically best achievable RSP accuracy for the calibration and reconstruction methods currently used for pCT. The phantoms imaged included a cylindrical water phantom with inserts of different materials, sizes, and positions, a Catphan phantom with a module containing high-contrast line pairs (CTP528) and a module with cylindrical inserts of different RSP (CTP404), as well as a voxelized 10-year-old female phantom. Dose to the cylindrical water phantom was also calculated. The RSP accuracy was studied for all phantoms except the CTP528 module. The latter was used for the estimation of the spatial resolution, evaluated as the modulation transfer function (MTF) at 10%. RESULTS An overall error under 0.5% was achieved for HeCT for the water phantoms with the different inserts, in all cases better than that for pCT, in some cases by a factor 3. The inserts in the CTP404 module were reconstructed with an average RSP accuracy of 0.3% for HeCT and 0.2% for pCT. Anatomic structures (brain, bones, air cavities, etc.) in the digitized head phantom were well recognizable and no artifacts were visible with both HeCT and pCT. The three main tissue materials (soft tissue, brain, and cranium) were well identifiable in the reconstructed RSP-volume distribution with both imaging modalities. Using 360 projection angles, the spatial resolution was 4 lp/cm for HeCT and 3 lp/cm for pCT. Generally, spatial resolution increased with the number of projection angles and was always higher for HeCT than for pCT for the same number of projections. When HeCT and pCT scan were performed to deliver the same dose in the phantom, the resolution for HeCT was higher than pCT. CONCLUSION MC simulations were used to compare HeCT and pCT image reconstruction. HeCT images had similar or better RSP accuracy and higher spatial resolution compared to pCT. Further investigation of the potential of helium ion imaging is warranted.
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Affiliation(s)
- Pierluigi Piersimoni
- Department of Biomedical Physics in Radiation Oncology, German Cancer Research Center - DKFZ, Heidelberg, 69120, Germany
| | - Bruce A Faddegon
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, 94115, USA
| | - José Ramos Méndez
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, 94115, USA
| | - Reinhard W Schulte
- Division of Biomedical Engineering Sciences, Loma Linda University, Loma Linda, CA, 92350, USA
| | - Lennart Volz
- Department of Biomedical Physics in Radiation Oncology, German Cancer Research Center - DKFZ, Heidelberg, 69120, Germany.,Department of Physics and Astronomy, Heidelberg University, 69120, Heidelberg, Germany
| | - Joao Seco
- Department of Biomedical Physics in Radiation Oncology, German Cancer Research Center - DKFZ, Heidelberg, 69120, Germany.,Department of Physics and Astronomy, Heidelberg University, 69120, Heidelberg, Germany
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Collins-Fekete CA, Bär E, Volz L, Bouchard H, Beaulieu L, Seco J. Extension of the Fermi–Eyges most-likely path in heterogeneous medium with prior knowledge information. ACTA ACUST UNITED AC 2017; 62:9207-9219. [DOI: 10.1088/1361-6560/aa955d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Volz L, Collins-Fekete CA, Piersimoni P, Johnson RP, Bashkirov V, Schulte R, Seco J. Stopping power accuracy and achievable spatial resolution of helium ion imaging using a prototype particle CT detector system. Current Directions in Biomedical Engineering 2017; 3:401-404. [PMID: 36258816 PMCID: PMC9576402 DOI: 10.1515/cdbme-2017-0084] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A precise relative stopping power map of the patient is crucial for accurate particle therapy. Charged particle imaging determines the stopping power either tomographically – particle computed tomography (pCT) – or by combining prior knowledge from particle radiography (pRad) and x-ray CT. Generally, multiple Coulomb scattering limits the spatial resolution. Compared to protons, heavier particles scatter less due to their lower charge/mass ratio. A theoretical framework to predict the most likely trajectory of particles in matter was developed for light ions up to carbon and was found to be the most accurate for helium comparing for fixed initial velocity. To further investigate the potential of helium in particle imaging, helium computed tomography (HeCT) and radiography (HeRad) were studied at the Heidelberg Ion-Beam Therapy Centre (HIT) using a prototype pCT detector system registering individual particles, originally developed by the U.S. pCT collaboration. Several phantoms were investigated: modules of the Catphan QA phantom for analysis of spatial resolution and achievable stopping power accuracy, a paediatric head phantom (CIRS) and a custommade phantom comprised of animal meat enclosed in a 2 % agarose mixture representing human tissue. The pCT images were reconstructed applying the CARP iterative reconstruction algorithm. The MTF10% was investigated using a sharp edge gradient technique. HeRad provides a spatial resolution above that of protons (MTF1010%=6.07 lp/cm for HeRad versus MTF10%=3.35 lp/cm for proton radiography). For HeCT, the spatial resolution was limited by the number of projections acquired (90 projections for a full scan). The RSP accuracy for all inserts of the Catphan CTP404 module was found to be 2.5% or better and is subject to further optimisation. In conclusion, helium imaging appears to offer higher spatial resolution compared to proton imaging. In future studies, the advantage of helium imaging compared to other imaging modalities in clinical applications will be further explored.
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Affiliation(s)
- Lennart Volz
- German Cancer Research Center (DKFZ), INF280, 69120 Heidelberg, Germany
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
| | - Charles-Antoine Collins-Fekete
- Départment de physique, de génie physique et d‘optique et centre de recherche sur le cancer, Université Laval, Québec, Canada
- Départment de radio-oncologie et CRCHU de Québec, CHU de Québec, Canada
| | | | | | - Vladimir Bashkirov
- Division of biomedical engineering sciences, department of basic sciences, Loma Linda University, Loma Linda, USA
| | - Reinhard Schulte
- Division of biomedical engineering sciences, department of basic sciences, Loma Linda University, Loma Linda, USA
| | - Joao Seco
- Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
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Collins-Fekete CA, Volz L, Portillo SKN, Beaulieu L, Seco J. A theoretical framework to predict the most likely ion path in particle imaging. Phys Med Biol 2017; 62:1777-1790. [DOI: 10.1088/1361-6560/aa58ce] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Tscherpel C, Hensel L, Lemberg K, Vollmer M, Volz L, Fink G, Grefkes C. EPV 9. The role of ipsilateral motor areas in hand motor function in healthy ageing – Insights from online TMS. Clin Neurophysiol 2016. [DOI: 10.1016/j.clinph.2016.05.050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Lemberg K, Tscherpel C, Hensel L, Vollmer M, Volz L, Fink G, Grefkes C. EP 8. The role of contralesional motor areas in early motor recovery – evidence from event-related (“online”) TMS. Clin Neurophysiol 2016. [DOI: 10.1016/j.clinph.2016.05.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Volz L, Grefkes C. Neurophysiologische und bildgebende Prädiktoren der Funktionserholung nach Schlaganfall. KLIN NEUROPHYSIOL 2013. [DOI: 10.1055/s-0033-1357207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- L. Volz
- AG Neuromodulation & Neurorehabilitation, Max Planck Institut für neurologische Forschung, Köln
| | - C. Grefkes
- AG Neuromodulation & Neurorehabilitation, Max Planck Institut für neurologische Forschung, Köln
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Nettekoven C, Volz L, Kutscha M, Pool EM, Rehme AK, Grefkes C. Dosis-abhängige Effekte der Theta-Burst rTMS auf die Erregbarkeit und fMRT-Konnektivität des primär motorischen Kortex. KLIN NEUROPHYSIOL 2013. [DOI: 10.1055/s-0033-1337134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kretschmer BD, Zadow B, Volz TL, Volz L, Schmidt WJ. The contribution of the different binding sites of the N-methyl-D-aspartate (NMDA) receptor to the expression of behavior. J Neural Transm (Vienna) 1992; 87:23-35. [PMID: 1346965 DOI: 10.1007/bf01253108] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The effects of competitive (CGP 37849 and CGP 39551) and non-competitive (dizocilpine) N-methyl-D-aspartate (NMDA) antagonists were tested in three animal models (catalepsy, sniffing, locomotion) and, in addition, the modulation of these effects by an agonist of the strychnine-insensitive glycine binding site was investigated. Both competitive and non-competitive NMDA antagonists reduced neuroleptic-induced catalepsy. Weak sniffing was induced by the competitive antagonist but strong sniffing by the non-competitive NMDA antagonist. Due to muscle relaxation the competitive antagonist reduced locomotion, in contrast to stimulation of locomotor activity induced by the non-competitive NMDA antagonist. The glycine agonist (D-cycloserine) potentiated the effects of the non-competitive but antagonized those of the competitive NMDA antagonist.
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Affiliation(s)
- B D Kretschmer
- Department of Neuropharmacology, University of Tübingen, Federal Republic of Germany
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Volz L. Der Unterricht im Absehen der Sprache. Eur Arch Otorhinolaryngol 1954. [DOI: 10.1007/bf02134821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Volz L. Die ärztliche Verordnung von Hörapparaten und die Hörmittelberatung 1. Dtsch Med Wochenschr 1954. [DOI: 10.1055/s-0028-1115560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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