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1. Absolute prompt-gamma yield measurements for ion beam therapy monitoring

Author

C. La Tessa, M. De Rydt, Marco Pinto, M. Testa, J. Krimmer, Dieter Schardt, George Dedes, F. Roellinghoff, I Rinaldi, Stephan Brons, Nicolas Freud, Etienne Testa, Cédric Ray, Katia Parodi, R. Pleskac, M. Chevallier, Damien Prieels, M. Bajard, Denis Dauvergne, Jean Michel Létang, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), PRISME (PRISME), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Heidelberg Ion Beam Therapy Center - HIT, Heidelberg University Clinic, Instituut voor Kern- enStralingsfysica, Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Imagerie Tomographique et Radiothérapie, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), Biophysics Department [Darmstadt], Helmholtz Centre for Heavy Ion Research (GSI), Heidelberg University Hospital [Heidelberg], Department of Medical Physics, Ludwig-Maximilians-Universität München (LMU), Ion Beam Applications SA, and IBA

Subjects
Nuclear reaction, Materials science, Ion beam, Proton, carbon ion therapy, Radiation Dosage, 7. Clean energy, Ion, hadrontherapy, monitoring, prompt gammas, proton therapy, Proton Therapy, Gamma Rays, Protons, Radiological and Ultrasound Technology, Radiology, Nuclear Medicine and Imaging, Nuclear Medicine and Imaging, Radiology, Nuclear Medicine and imaging, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Irradiation, Steradian, Charged particle, Yield (chemistry), [PHYS.PHYS.PHYS-MED-PH]Physics [physics]/Physics [physics]/Medical Physics [physics.med-ph], Atomic physics, Radiology
Abstract

International audience; Prompt-gamma emission detection is a promising technique for hadrontherapy monitoring purposes. In this regard, obtaining prompt-gamma yields that can be used to develop monitoring systems based on this principle is of utmost importance since any camera design must cope with the available signal. Herein, a comprehensive study of the data from ten single-slit experiments is presented, five consisting in the irradiation of either PMMA or water targets with lower and higher energy carbon ions, and another five experiments using PMMA targets and proton beams. Analysis techniques such as background subtraction methods, geometrical normalization, and systematic uncertainty estimation were applied to the data in order to obtain absolute prompt-gamma yields in units of prompt-gamma counts per incident ion, unit of field of view, and unit of solid angle. At the entrance of a PMMA target, where the contribution of secondary nuclear reactions is negligible, prompt-gamma counts per incident ion, per millimetre and per steradian equal to (124 ± 0.7stat ± 30sys) × 10−6 for 95 MeV u−1 carbon ions, (79 ± 2stat ± 23sys) × 10−6 for 310 MeV u−1 carbon ions, and (16 ± 0.07stat ± 1sys) × 10−6 for 160 MeV protons were found for prompt gammas with energies higher than 1 MeV. This shows a factor 5 between the yields of two different ions species with the same range in water (160 MeV protons and 310 MeV u−1 carbon ions). The target composition was also found to influence the prompt-gamma yield since, for 300/310 MeV u−1 carbon ions, a 42% greater yield ((112 ± 1stat ± 22sys) × 10−6 counts ion−1 mm−1 sr−1) was obtained with a water target compared to a PMMA one.

Published
2014

2. Design optimisation of a TOF-based collimated camera prototype for online hadrontherapy monitoring

Author

J. Krimmer, Marco Pinto, F. Roellinghoff, Cédric Ray, Nicolas Freud, Etienne Testa, Denis Dauvergne, Jean Michel Létang, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Imagerie Tomographique et Radiothérapie, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
Computer science, medicine.medical_treatment, Physics::Medical Physics, Real-time computing, Monte Carlo method, Online Systems, Collimated light, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Proton Therapy, medicine, Humans, Polymethyl Methacrylate, Radiology, Nuclear Medicine and imaging, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Radiometry, Proton therapy, Image resolution, Simulation, Modality (human–computer interaction), Radiological and Ultrasound Technology, Phantoms, Imaging, Equipment Design, Radiotherapy, Computer-Assisted, Radiation therapy, Gamma Rays, Homogeneous, 030220 oncology & carcinogenesis, [PHYS.PHYS.PHYS-MED-PH]Physics [physics]/Physics [physics]/Medical Physics [physics.med-ph], Key (cryptography), Monte Carlo Method
Abstract

International audience; Hadrontherapy is an innovative radiation therapy modality for which one of the main key advantages is the target conformality allowed by the physical properties of ion species. However, in order to maximise the exploitation of its potentialities, online monitoring is required in order to assert the treatment quality, namely monitoring devices relying on the detection of secondary radiations. Herein is presented a method based on Monte Carlo simulations to optimise a multi-slit collimated camera employing time-of-flight selection of prompt-gamma rays to be used in a clinical scenario. In addition, an analytical tool is developed based on the Monte Carlo data to predict the expected precision for a given geometrical configuration. Such a method follows the clinical workflow requirements to simultaneously have a solution that is relatively accurate and fast. Two different camera designs are proposed, considering different endpoints based on the trade-off between camera detection efficiency and spatial resolution to be used in a proton therapy treatment with active dose delivery and assuming a homogeneous target.

Published
2014

3. Real-time proton beam range monitoring by means of prompt-gamma detection with a collimated camera

Author

Marco Pinto, Denis Dauvergne, Julien Smeets, Jean Michel Létang, A. Benilov, J. Krimmer, George Dedes, Nicolas Freud, Damien Prieels, Cédric Ray, F. Roellinghoff, Etienne Testa, Frédéric Stichelbaut, Guillaume Janssens, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Ion Beam Applications SA, IBA, PRISME (PRISME), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Imagerie Tomographique et Radiothérapie, Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), and Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon)

Subjects
Proton, Physics::Instrumentation and Detectors, Physics::Medical Physics, Bragg peak, Collimated light, Particle detector, 030218 nuclear medicine & medical imaging, Radiotherapy, High-Energy, 03 medical and health sciences, 0302 clinical medicine, Optics, Computer Systems, Proton Therapy, Radiology, Nuclear Medicine and imaging, Gamma Cameras, Radiometry, Nuclear Experiment, Proton therapy, Physics, Radiological and Ultrasound Technology, business.industry, Detector, Gamma ray, Equipment Design, Radiotherapy, Computer-Assisted, Equipment Failure Analysis, Gamma Rays, 030220 oncology & carcinogenesis, Physics::Accelerator Physics, business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, Beam (structure)
Abstract

International audience; Prompt-gamma profile was measured at WPE-Essen using 160 MeV protons impinging a movable PMMA target. A single collimated detector was used with time-of-flight (TOF) to reduce the background due to neutrons. The target entrance rise and the Bragg peak falloff retrieval precision was determined as a function of incident proton number by a fitting procedure using independent data sets. Assuming improved sensitivity of this camera design by using a greater number of detectors, retrieval precisions of 1 to 2 mm (rms) are expected for a clinical pencil beam. TOF improves the contrast-to-noise ratio and the performance of the method significantly.

Published
2014
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4. Probabilistic models and numerical calculation of system matrix and sensitivity in list-mode MLEM 3D reconstruction of Compton camera images

Author

Voichita Maxim, E. Hilaire, X. Lojacono, Rémy Prost, Etienne Testa, Denis Dauvergne, J. Krimmer, Isabelle E. Magnin, Imagerie Tomographique et Radiothérapie, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Imagerie et modélisation Vasculaires, Thoraciques et Cérébrales (MOTIVATE), Images et Modèles, 4 - Imagerie Tomographique et Radiothérapie, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé ( CREATIS ), Hospices Civils de Lyon ( HCL ) -Université Jean Monnet [Saint-Étienne] ( UJM ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon ( INSA Lyon ), Université de Lyon-Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Hospices Civils de Lyon ( HCL ) -Université Jean Monnet [Saint-Étienne] ( UJM ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ), Institut de Physique Nucléaire de Lyon ( IPNL ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), and 1 - Imagerie et modélisation Vasculaires, Thoraciques et Cérébrales ( MOTIVATE )

Subjects
Computer science, Monte Carlo method, Iterative reconstruction, Compton camera, [ SPI.SIGNAL ] Engineering Sciences [physics]/Signal and Image processing, 01 natural sciences, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Quality (physics), Imaging, Three-Dimensional, 0103 physical sciences, Humans, Radiology, Nuclear Medicine and imaging, Computer vision, Sensitivity (control systems), [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], System matrix, [ PHYS.PHYS.PHYS-INS-DET ] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Models, Statistical, Radiological and Ultrasound Technology, 010308 nuclear & particles physics, business.industry, 3D reconstruction, Probabilistic logic, Radiographic Image Interpretation, Computer-Assisted, Artificial intelligence, business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

International audience; This paper addresses the problem of evaluating the system matrix and the sensitivity for iterative reconstruction in Compton camera imaging. Proposed models and numerical calculation strategies are compared through the influence they have on the three-dimensional reconstructed images. The study attempts to address four questions. First, it proposes an analytic model for the system matrix. Second, it suggests a method for its numerical validation with Monte Carlo simulated data. Third, it compares analytical models of the sensitivity factors with Monte Carlo simulated values. Finally, it shows how the system matrix and the sensitivity calculation strategies influence the quality of the reconstructed images.

Published
2015

5. Assessment and improvements of Geant4 hadronic models in the context of prompt-gamma hadrontherapy monitoring

Author

J. Krimmer, Marco Pinto, Denis Dauvergne, Jean Michel Létang, Etienne Testa, Nicolas Freud, Cédric Ray, George Dedes, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Department of Medical Physics, Ludwig-Maximilians-Universität München (LMU), Imagerie Tomographique et Radiothérapie, Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (CREATIS), Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Jean Monnet [Saint-Étienne] (UJM)-Hospices Civils de Lyon (HCL)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Hospices Civils de Lyon (HCL)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear reaction, Range (particle radiation), Radiological and Ultrasound Technology, Proton, Radiotherapy, 010308 nuclear & particles physics, Monte Carlo method, Hadron, Nuclear Theory, Context (language use), 01 natural sciences, Charged particle, 030218 nuclear medicine & medical imaging, Nuclear physics, 03 medical and health sciences, 0302 clinical medicine, Gamma Rays, 0103 physical sciences, Humans, Radiology, Nuclear Medicine and imaging, Neutron, Nuclear Experiment, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, Monte Carlo Method
Abstract

International audience; Monte Carlo simulations are nowadays essential tools for a wide range of research topics in the field of radiotherapy. They also play an important role in the effort to develop a real-time monitoring system for quality assurance in proton and carbon ion therapy, by means of prompt-gamma detection. The internal theoretical nuclear models of Monte Carlo simulation toolkits are of decisive importance for the accurate description of neutral or charged particle emission, produced by nuclear interactions between beam particles and target nuclei. We assess the performance of Geant4 nuclear models in the context of prompt-gamma emission, comparing them with experimental data from proton and carbon ion beams. As has been shown in the past and further indicated in our study, the prompt-gamma yields are consistently overestimated by Geant4 by a factor of about 100% to 200% over an energy range from 80 to 310 MeV/u for the case of 12C, and to a lesser extent for 160 MeV protons. Furthermore, we focus on the quantum molecular dynamics (QMD) modeling of ion-ion collisions, in order to optimize its description of light nuclei, which are abundant in the human body and mainly anticipated in hadrontherapy applications. The optimization has been performed by benchmarking QMD free parameters with well established nuclear properties. In addition, we study the effect of this optimization on charged particle emission. With the usage of the proposed parameter values, discrepancies reduce to less than 70%, with the highest values being attributed to the nucleon-ion induced prompt-gammas. This conclusion, also confirmed by the disagreement we observe in the case of proton beams, indicates the need for further investigation on nuclear models which describe proton and neutron induced nuclear reactions.

Published
2014

6. Study for online range monitoring with the interaction vertex imaging method.

Author

Finck C, Karakaya Y, Reithinger V, Rescigno R, Baudot J, Constanzo J, Juliani D, Krimmer J, Rinaldi I, Rousseau M, Testa E, Vanstalle M, and Ray C

Subjects
Humans, Phantoms, Imaging, Protons, Radiotherapy Dosage, Heavy Ion Radiotherapy methods, Radiotherapy, Computer-Assisted methods
Abstract

Ion beam therapy enables a highly accurate dose conformation delivery to the tumor due to the finite range of charged ions in matter (i.e. Bragg peak (BP)). Consequently, the dose profile is very sensitive to patients anatomical changes as well as minor mispositioning, and so it requires improved dose control techniques. Proton interaction vertex imaging (IVI) could offer an online range control in carbon ion therapy. In this paper, a statistical method was used to study the sensitivity of the IVI technique on experimental data obtained from the Heidelberg Ion-Beam Therapy Center. The vertices of secondary protons were reconstructed with pixelized silicon detectors. The statistical study used the [Formula: see text] test of the reconstructed vertex distributions for a given displacement of the BP position as a function of the impinging carbon ions. Different phantom configurations were used with or without bone equivalent tissue and air inserts. The inflection points in the fall-off region of the longitudinal vertex distribution were computed using different methods, while the relation with the BP position was established. In the present setup, the resolution of the BP position was about 4-5 mm in the homogeneous phantom under clinical conditions (10 6 incident carbon ions). Our results show that the IVI method could therefore monitor the BP position with a promising resolution in clinical conditions.

Published
2017
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7. Probabilistic models and numerical calculation of system matrix and sensitivity in list-mode MLEM 3D reconstruction of Compton camera images.

Author

Maxim V, Lojacono X, Hilaire E, Krimmer J, Testa E, Dauvergne D, Magnin I, and Prost R

Subjects
Humans, Imaging, Three-Dimensional methods, Models, Statistical, Radiographic Image Interpretation, Computer-Assisted methods
Abstract

This paper addresses the problem of evaluating the system matrix and the sensitivity for iterative reconstruction in Compton camera imaging. Proposed models and numerical calculation strategies are compared through the influence they have on the three-dimensional reconstructed images. The study attempts to address four questions. First, it proposes an analytic model for the system matrix. Second, it suggests a method for its numerical validation with Monte Carlo simulated data. Third, it compares analytical models of the sensitivity factors with Monte Carlo simulated values. Finally, it shows how the system matrix and the sensitivity calculation strategies influence the quality of the reconstructed images.

Published
2016
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8. Absolute prompt-gamma yield measurements for ion beam therapy monitoring.

Author

Pinto M, Bajard M, Brons S, Chevallier M, Dauvergne D, Dedes G, De Rydt M, Freud N, Krimmer J, La Tessa C, Létang JM, Parodi K, Pleskač R, Prieels D, Ray C, Rinaldi I, Roellinghoff F, Schardt D, Testa E, and Testa M

Subjects
Proton Therapy instrumentation, Gamma Rays, Proton Therapy methods, Protons, Radiation Dosage
Abstract

Prompt-gamma emission detection is a promising technique for hadrontherapy monitoring purposes. In this regard, obtaining prompt-gamma yields that can be used to develop monitoring systems based on this principle is of utmost importance since any camera design must cope with the available signal. Herein, a comprehensive study of the data from ten single-slit experiments is presented, five consisting in the irradiation of either PMMA or water targets with lower and higher energy carbon ions, and another five experiments using PMMA targets and proton beams. Analysis techniques such as background subtraction methods, geometrical normalization, and systematic uncertainty estimation were applied to the data in order to obtain absolute prompt-gamma yields in units of prompt-gamma counts per incident ion, unit of field of view, and unit of solid angle. At the entrance of a PMMA target, where the contribution of secondary nuclear reactions is negligible, prompt-gamma counts per incident ion, per millimetre and per steradian equal to (124 ± 0.7stat ± 30sys) × 10(-6) for 95 MeV u(-1) carbon ions, (79 ± 2stat ± 23sys) × 10(-6) for 310 MeV u(-1) carbon ions, and (16 ± 0.07stat ± 1sys) × 10(-6) for 160 MeV protons were found for prompt gammas with energies higher than 1 MeV. This shows a factor 5 between the yields of two different ions species with the same range in water (160 MeV protons and 310 MeV u(-1) carbon ions). The target composition was also found to influence the prompt-gamma yield since, for 300/310 MeV u(-1) carbon ions, a 42% greater yield ((112 ± 1stat ± 22sys) × 10(-6) counts ion(-1) mm(-1) sr(-1)) was obtained with a water target compared to a PMMA one.

Published
2015
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9. Design optimisation of a TOF-based collimated camera prototype for online hadrontherapy monitoring.

Author

Pinto M, Dauvergne D, Freud N, Krimmer J, Letang JM, Ray C, Roellinghoff F, and Testa E

Subjects
Equipment Design, Humans, Online Systems, Phantoms, Imaging, Polymethyl Methacrylate chemistry, Gamma Rays, Monte Carlo Method, Proton Therapy, Radiometry instrumentation, Radiometry standards, Radiotherapy, Computer-Assisted instrumentation, Radiotherapy, Computer-Assisted standards
Abstract

Hadrontherapy is an innovative radiation therapy modality for which one of the main key advantages is the target conformality allowed by the physical properties of ion species. However, in order to maximise the exploitation of its potentialities, online monitoring is required in order to assert the treatment quality, namely monitoring devices relying on the detection of secondary radiations. Herein is presented a method based on Monte Carlo simulations to optimise a multi-slit collimated camera employing time-of-flight selection of prompt-gamma rays to be used in a clinical scenario. In addition, an analytical tool is developed based on the Monte Carlo data to predict the expected precision for a given geometrical configuration. Such a method follows the clinical workflow requirements to simultaneously have a solution that is relatively accurate and fast. Two different camera designs are proposed, considering different endpoints based on the trade-off between camera detection efficiency and spatial resolution to be used in a proton therapy treatment with active dose delivery and assuming a homogeneous target.

Published
2014
Full Text
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10. Assessment and improvements of Geant4 hadronic models in the context of prompt-gamma hadrontherapy monitoring.

Author

Dedes G, Pinto M, Dauvergne D, Freud N, Krimmer J, Létang JM, Ray C, and Testa E

Subjects
Humans, Gamma Rays therapeutic use, Monte Carlo Method, Radiotherapy methods
Abstract

Monte Carlo simulations are nowadays essential tools for a wide range of research topics in the field of radiotherapy. They also play an important role in the effort to develop a real-time monitoring system for quality assurance in proton and carbon ion therapy, by means of prompt-gamma detection. The internal theoretical nuclear models of Monte Carlo simulation toolkits are of decisive importance for the accurate description of neutral or charged particle emission, produced by nuclear interactions between beam particles and target nuclei. We assess the performance of Geant4 nuclear models in the context of prompt-gamma emission, comparing them with experimental data from proton and carbon ion beams. As has been shown in the past and further indicated in our study, the prompt-gamma yields are consistently overestimated by Geant4 by a factor of about 100% to 200% over an energy range from 80 to 310 MeV/u for the case of (12)C, and to a lesser extent for 160 MeV protons. Furthermore, we focus on the quantum molecular dynamics (QMD) modeling of ion-ion collisions, in order to optimize its description of light nuclei, which are abundant in the human body and mainly anticipated in hadrontherapy applications. The optimization has been performed by benchmarking QMD free parameters with well established nuclear properties. In addition, we study the effect of this optimization on charged particle emission. With the usage of the proposed parameter values, discrepancies reduce to less than 70%, with the highest values being attributed to the nucleon-ion induced prompt-gammas. This conclusion, also confirmed by the disagreement we observe in the case of proton beams, indicates the need for further investigation on nuclear models which describe proton and neutron induced nuclear reactions.

Published
2014
Full Text
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11. Real-time proton beam range monitoring by means of prompt-gamma detection with a collimated camera.

Author

Roellinghoff F, Benilov A, Dauvergne D, Dedes G, Freud N, Janssens G, Krimmer J, Létang JM, Pinto M, Prieels D, Ray C, Smeets J, Stichelbaut F, and Testa E

Subjects
Computer Systems, Equipment Design, Equipment Failure Analysis, Gamma Rays, Proton Therapy, Gamma Cameras, Radiometry instrumentation, Radiotherapy, Computer-Assisted instrumentation, Radiotherapy, High-Energy instrumentation
Abstract

Prompt-gamma profile was measured at WPE-Essen using 160 MeV protons impinging a movable PMMA target. A single collimated detector was used with time-of-flight (TOF) to reduce the background due to neutrons. The target entrance rise and the Bragg peak falloff retrieval precision was determined as a function of incident proton number by a fitting procedure using independent data sets. Assuming improved sensitivity of this camera design by using a greater number of detectors, retrieval precisions of 1 to 2 mm (rms) are expected for a clinical pencil beam. TOF improves the contrast-to-noise ratio and the performance of the method significantly.

Published
2014
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12. Interaction vertex imaging (IVI) for carbon ion therapy monitoring: a feasibility study.

Author

Henriquet P, Testa E, Chevallier M, Dauvergne D, Dedes G, Freud N, Krimmer J, Létang JM, Ray C, Richard MH, and Sauli F

Subjects
Feasibility Studies, Uncertainty, Carbon therapeutic use, Diagnostic Imaging methods, Protons, Radiotherapy methods
Abstract

Proton imaging can be seen as a powerful technique for online monitoring of ion range during carbon ion therapy irradiations. Indeed, a large number of secondary protons are created during nuclear reactions, and many of these protons are likely to escape from the patient even for deep-seated tumors, carrying accurate information on the reaction vertex position. Two detection techniques have been considered: (i) double-proton detection by means of two forward-located trackers and (ii) single-proton detection in coincidence with the incoming carbon ion detected by means of a beam hodoscope. Geant4 simulations, validated by proton yield measurements performed at GANIL and GSI, show that ion-range monitoring is accessible on a pencil-beam basis with the single-proton imaging technique. Millimetric precision on the Bragg peak position is expected in the ideal case of homogeneous targets. The uncertainties in more realistic conditions should be investigated, in particular the influence of tissue heterogeneity in the very last part of the ion path (about 20 mm).

Published
2012
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