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Bjegovic K, Sun L, Pandey P, Grilj V, Ballesteros-Zebadua P, Paisley R, Gonzalez G, Wang S, Vozenin MC, Limoli CL, Xiang SL. 4D in vivodosimetry for a FLASH electron beam using radiation-induced acoustic imaging. Phys Med Biol 2024; 69:115053. [PMID: 38722574 DOI: 10.1088/1361-6560/ad4950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 05/09/2024] [Indexed: 06/01/2024]
Abstract
Objective. The primary goal of this research is to demonstrate the feasibility of radiation-induced acoustic imaging (RAI) as a volumetric dosimetry tool for ultra-high dose rate FLASH electron radiotherapy (FLASH-RT) in real time. This technology aims to improve patient outcomes by accurate measurements ofin vivodose delivery to target tumor volumes.Approach. The study utilized the FLASH-capable eRT6 LINAC to deliver electron beams under various doses (1.2 Gy pulse-1to 4.95 Gy pulse-1) and instantaneous dose rates (1.55 × 105Gy s-1to 2.75 × 106Gy s-1), for imaging the beam in water and in a rabbit cadaver with RAI. A custom 256-element matrix ultrasound array was employed for real-time, volumetric (4D) imaging of individual pulses. This allowed for the exploration of dose linearity by varying the dose per pulse and analyzing the results through signal processing and image reconstruction in RAI.Main Results. By varying the dose per pulse through changes in source-to-surface distance, a direct correlation was established between the peak-to-peak amplitudes of pressure waves captured by the RAI system and the radiochromic film dose measurements. This correlation demonstrated dose rate linearity, including in the FLASH regime, without any saturation even at an instantaneous dose rate up to 2.75 × 106Gy s-1. Further, the use of the 2D matrix array enabled 4D tracking of FLASH electron beam dose distributions on animal tissue for the first time.Significance. This research successfully shows that 4Din vivodosimetry is feasible during FLASH-RT using a RAI system. It allows for precise spatial (∼mm) and temporal (25 frames s-1) monitoring of individual FLASH beamlets during delivery. This advancement is crucial for the clinical translation of FLASH-RT as enhancing the accuracy of dose delivery to the target volume the safety and efficacy of radiotherapeutic procedures will be improved.
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Affiliation(s)
- Kristina Bjegovic
- The Department of Biomedical Engineering, University of California, Irvine, CA 92617, United States of America
| | - Leshan Sun
- The Department of Biomedical Engineering, University of California, Irvine, CA 92617, United States of America
| | - Prabodh Pandey
- Department of Radiological Sciences, University of California, Irvine, Irvine, CA 92697, United States of Americaica
| | - Veljko Grilj
- Laboratory of Radiation Oncology, Radiation Oncology Service and Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Paola Ballesteros-Zebadua
- Laboratory of Radiation Oncology, Radiation Oncology Service and Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- Laboratory of Medical Physics, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Ryan Paisley
- Laboratory of Radiation Oncology, Radiation Oncology Service and Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Gilberto Gonzalez
- Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, United States of America
| | - Siqi Wang
- The Department of Biomedical Engineering, University of California, Irvine, CA 92617, United States of America
| | - Marie Catherine Vozenin
- Laboratory of Radiation Oncology, Radiation Oncology Service and Oncology Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
- Sector of Radiobiology applied to Radiation Oncology, Radiation Oncology Service, Geneva University Hospital and University of Geneva, Geneva, Switzerland
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, Irvine, CA 92697-2695, United States of America
| | - Shawn Liangzhong Xiang
- The Department of Biomedical Engineering, University of California, Irvine, CA 92617, United States of America
- Department of Radiological Sciences, University of California, Irvine, Irvine, CA 92697, United States of Americaica
- Beckman Laser Institute & Medical Clinic, University of California, Irvine, Irvine, CA 92612, United States of America
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Mast TD, Johnstone DA, Dumoulin CL, Lamba MA, Patch SK. Reconstruction of thermoacoustic emission sources induced by proton irradiation using numerical time reversal. Phys Med Biol 2023; 68:10.1088/1361-6560/acabfc. [PMID: 36595327 PMCID: PMC9976196 DOI: 10.1088/1361-6560/acabfc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Objective.Mapping of dose delivery in proton beam therapy can potentially be performed by analyzing thermoacoustic emissions measured by ultrasound arrays. Here, a method is derived and demonstrated for spatial mapping of thermoacoustic sources using numerical time reversal, simulating re-transmission of measured emissions into the medium.Approach.Spatial distributions of thermoacoustic emission sources are shown to be approximated by the analytic-signal form of the time-reversed acoustic field, evaluated at the time of the initial proton pulse. Given calibration of the array sensitivity and knowledge of tissue properties, this approach approximately reconstructs the acoustic source amplitude, equal to the product of the time derivative of the radiation dose rate, mass density, and Grüneisen parameter. This approach was implemented using two models for acoustic fields of the array elements, one modeling elements as line sources and the other as rectangular radiators. Thermoacoustic source reconstructions employed previously reported measurements of emissions from proton energy deposition in tissue-mimicking phantoms. For a phantom incorporating a bone layer, reconstructions accounted for the higher sound speed in bone. Dependence of reconstruction quality on array aperture size and signal-to-noise ratio was consistent with previous acoustic simulation studies.Main results.Thermoacoustic source distributions were successfully reconstructed from acoustic emissions measured by a linear ultrasound array. Spatial resolution of reconstructions was significantly improved in the azimuthal (array) direction by incorporation of array element diffraction. Source localization agreed well with Monte Carlo simulations of energy deposition, and was improved by incorporating effects of inhomogeneous sound speed.Significance.The presented numerical time reversal approach reconstructs thermoacoustic sources from proton beam radiation, based on straightforward processing of acoustic emissions measured by ultrasound arrays. This approach may be useful for ranging and dosimetry of clinical proton beams, if acoustic emissions of sufficient amplitude and bandwidth can be generated by therapeutic proton sources.
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Affiliation(s)
- T Douglas Mast
- Biomedical Engineering, University of Cincinnati, United States of America
| | - David A Johnstone
- Radiation Oncology, University of Cincinnati, United States of America
| | - Charles L Dumoulin
- Radiology, Cincinnati Children's Hospital Medical Center, United States of America
| | - Michael A Lamba
- Radiation Oncology, University of Cincinnati, United States of America
| | - Sarah K Patch
- Acoustic Range Estimates, Chicago, Illinois, United States of America
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Sueyasu S, Takayanagi T, Miyazaki K, Kuriyama Y, Ishi Y, Uesugi T, Unlu MB, Kudo N, Chen Y, Kasamatsu K, Fujii M, Kobayashi M, Rohringer W, Matsuura T. Ionoacoustic application of an optical hydrophone to detect proton beam range in water. Med Phys 2022; 50:2438-2449. [PMID: 36565440 DOI: 10.1002/mp.16189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/22/2022] [Accepted: 12/14/2022] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Proton range uncertainty has been the main factor limiting the ability of proton therapy to concentrate doses to tumors to their full potential. Ionoacoustic (IA) range verification is an approach to reducing this uncertainty by detecting thermoacoustic waves emitted from an irradiated volume immediately following a pulsed proton beam delivery; however, the signal weakness has been an obstacle to its clinical application. To increase the signal-to-noise ratio (SNR) with the conventional piezoelectric hydrophone (PH), the detector-sensitive volume needs to be large, but it could narrow the range of available beam angles and disturb real-time images obtained during beam delivery. PURPOSE To prevent this issue, we investigated a millimeter-sized optical hydrophone (OH) that exploits the laser interferometric principle. For two types of IA waves [γ-wave emitted from the Bragg peak (BP) and a spherical IA wave with resonant frequency (SPIRE) emitted from the gold fiducial marker (GM)], comparisons were made with PH in terms of waveforms, SNR, range detection accuracy, and signal intensity robustness against the small detector misalignment, particularly for SPIRE. METHODS A 100-MeV proton beam with a 27 ns pulse width and 4 mm beam size was produced using a fixed-field alternating gradient accelerator and was irradiated to the water phantom. The GM was set on the beam's central axis. Acrylic plates of various thicknesses, up to 12 mm, were set in front of the phantoms to shift the proton range. OH was set distal and lateral to the beam, and the range was estimated using the time-of-flight method for γ-wave and by comparing with the calibration data (SPIRE intensity versus the distance between the GM and BP) derived from an IA wave transport simulation for SPIRE. The BP dose per pulse was 0.5-0.6 Gy. To measure the variation in SPIRE amplitude against the hydrophone misalignment, the hydrophone was shifted by ± 2 mm at a maximum in lateral directions. RESULTS Despite its small size, OH could detect γ-wave with a higher SNR than the conventional PH (diameter, 29 mm), and a single measurement was sufficient to detect the beam range with a submillimeter accuracy in water. In the SPIRE measurement, OH was far more robust against the detector misalignment than the focused PH (FPH) used in our previous study [5%/mm (OH) versus 80%/mm (FPH)], and the correlation between the measured SPIRE intensity and the distance between the GM and BP agreed well with the simulation results. However, the OH sensitivity was lower than the FPH sensitivity, and about 5.6-Gy dose was required to decrease the intensity variation among measurements to less than 10%. CONCLUSION The miniature OH was found to detect weak IA signals produced by proton beams with a BP dose used in hypofractionated regimens. The OH sensitivity improvement at the MHz regime is worth exploring as the next step.
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Affiliation(s)
- Shota Sueyasu
- Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Taisuke Takayanagi
- Hitachi Ltd, Research and Development Group, Center for Technology Innovation-Energy, Hitachi-shi, Ibaraki, Japan
| | - Koichi Miyazaki
- Hitachi Ltd, Research and Development Group, Center for Technology Innovation-Energy, Hitachi-shi, Ibaraki, Japan
| | - Yasutoshi Kuriyama
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Yoshihiro Ishi
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Tomonori Uesugi
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Mehmet Burcin Unlu
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan.,Department of Physics, Bogazici University, Bebek, Istanbul, Turkey
| | - Nobuki Kudo
- Faculty of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Ye Chen
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Koki Kasamatsu
- Graduate School of Biomedical Science and Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | | | - Masanori Kobayashi
- Planetary Exploration Research Institute, Chiba Institute of Technology, Narashino, Chiba, Japan
| | | | - Taeko Matsuura
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan.,Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo, Hokkaido, Japan
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4
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Schauer J, Wieser HP, Huang Y, Ruser H, Lascaud J, Würl M, Chmyrov A, Vidal M, Herault J, Ntziachristos V, Assmann W, Parodi K, Dollinger G. Proton beam range verification by means of ionoacoustic measurements at clinically relevant doses using a correlation-based evaluation. Front Oncol 2022; 12:925542. [PMID: 36408153 PMCID: PMC9670173 DOI: 10.3389/fonc.2022.925542] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/31/2022] [Indexed: 11/06/2022] Open
Abstract
Purpose The Bragg peak located at the end of the ion beam range is one of the main advantages of ion beam therapy compared to X-Ray radiotherapy. However, verifying the exact position of the Bragg peak within the patient online is a major challenge. The goal of this work was to achieve submillimeter proton beam range verification for pulsed proton beams of an energy of up to 220 MeV using ionoacoustics for a clinically relevant dose deposition of typically 2 Gy per fraction by i) using optimal proton beam characteristics for ionoacoustic signal generation and ii) improved signal detection by correlating the signal with simulated filter templates. Methods A water tank was irradiated with a preclinical 20 MeV proton beam using different pulse durations ranging from 50 ns up to 1 μs in order to maximise the signal-to-noise ratio (SNR) of ionoacoustic signals. The ionoacoustic signals were measured using a piezo-electric ultrasound transducer in the MHz frequency range. The signals were filtered using a cross correlation-based signal processing algorithm utilizing simulated templates, which enhances the SNR of the recorded signals. The range of the protons is evaluated by extracting the time of flight (ToF) of the ionoacoustic signals and compared to simulations from a Monte Carlo dose engine (FLUKA). Results Optimised SNR of 28.0 ± 10.6 is obtained at a beam current of 4.5 μA and a pulse duration of 130 ns at a total peak dose deposition of 0.5 Gy. Evaluated ranges coincide with Monte Carlo simulations better than 0.1 mm at an absolute range of 4.21 mm. Higher beam energies require longer proton pulse durations for optimised signal generation. Using the correlation-based post-processing filter a SNR of 17.8 ± 5.5 is obtained for 220 MeV protons at a total peak dose deposition of 1.3 Gy. For this clinically relevant dose deposition and proton beam energy, submillimeter range verification was achieved at an absolute range of 303 mm in water. Conclusion Optimal proton pulse durations ensure an ideal trade-off between maximising the ionoacoustic amplitude and minimising dose deposition. In combination with a correlation-based post-processing evaluation algorithm, a reasonable SNR can be achieved at low dose levels putting clinical applications for online proton or ion beam range verification into reach.
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Affiliation(s)
- Jannis Schauer
- Institute for Applied Physics and Metrology, Bundeswehr University Munich, Neubiberg, Germany
- *Correspondence: Jannis Schauer,
| | - Hans-Peter Wieser
- Faculty of Physics, Chair of Medical and Experimental Physics, Ludwig-Maximilians-University, München, Germany
| | - Yuanhui Huang
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
- Chair of Biological Imaging for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, Germany
| | - Heinrich Ruser
- Institute for Applied Physics and Metrology, Bundeswehr University Munich, Neubiberg, Germany
| | - Julie Lascaud
- Faculty of Physics, Chair of Medical and Experimental Physics, Ludwig-Maximilians-University, München, Germany
| | - Matthias Würl
- Faculty of Physics, Chair of Medical and Experimental Physics, Ludwig-Maximilians-University, München, Germany
| | - Andriy Chmyrov
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
- Chair of Biological Imaging for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, Germany
| | - Marie Vidal
- Centre Antoine Lacassagne (CAL), Department of Radiation Oncology, Nice, France
| | - Joel Herault
- Centre Antoine Lacassagne (CAL), Department of Radiation Oncology, Nice, France
| | - Vasilis Ntziachristos
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg, Germany
- Chair of Biological Imaging for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, Germany
| | - Walter Assmann
- Faculty of Physics, Chair of Medical and Experimental Physics, Ludwig-Maximilians-University, München, Germany
| | - Katia Parodi
- Faculty of Physics, Chair of Medical and Experimental Physics, Ludwig-Maximilians-University, München, Germany
| | - Günther Dollinger
- Institute for Applied Physics and Metrology, Bundeswehr University Munich, Neubiberg, Germany
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5
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Wieser HP, Huang Y, Schauer J, Lascaud J, Würl M, Lehrack S, Radonic D, Vidal M, Hérault J, Chmyrov A, Ntziachristos V, Assmann W, Parodi K, Dollinger G. Experimental demonstration of accurate Bragg peak localization with ionoacoustic tandem phase detection (iTPD). Phys Med Biol 2021; 66. [PMID: 34847532 DOI: 10.1088/1361-6560/ac3ead] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 11/30/2021] [Indexed: 11/12/2022]
Abstract
Accurate knowledge of the exact stopping location of ions inside the patient would allow full exploitation of their ballistic properties for patient treatment. The localized energy deposition of a pulsed particle beam induces a rapid temperature increase of the irradiated volume and leads to the emission of ionoacoustic (IA) waves. Detecting the time-of-flight (ToF) of the IA wave allows inferring information on the Bragg peak location and can henceforth be used forin-vivorange verification. A challenge for IA is the poor signal-to-noise ratio at clinically relevant doses and viable machines. We present a frequency-based measurement technique, labeled as ionoacoustic tandem phase detection (iTPD) utilizing lock-in amplifiers. The phase shift of the IA signal to a reference signal is measured to derive theToF. Experimental IA measurements with a 3.5 MHz lead zirconate titanate (PZT) transducer and lock-in amplifiers were performed in water using 22 MeV proton bursts. A digital iTPD was performedin-silicoat clinical dose levels on experimental data obtained from a clinical facility and secondly, on simulations emulating a heterogeneous geometry. For the experimental setup using 22 MeV protons, a localization accuracy and precision obtained through iTPD deviates from a time-based reference analysis by less than 15μm. Several methodological aspects were investigated experimentally in systematic manner. Lastly, iTPD was evaluatedin-silicofor clinical beam energies indicating that iTPD is in reach of sub-mm accuracy for fractionated doses < 5 Gy. iTPD can be used to accurately measure theToFof IA signals online via its phase shift in frequency domain. An application of iTPD to the clinical scenario using a single pulsed beam is feasible but requires further development to reach <1 Gy detection capabilities.
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Affiliation(s)
- H P Wieser
- Department for Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, D-85748 Garching b. München, Germany
| | - Y Huang
- Chair of Biological Imaging (CBI) and Center for Translational Cancer Research (TranslaTUM) Technical University Munich, D-81675 Munich, Germany.,Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, D-85764 Neuherberg, Germany
| | - J Schauer
- Institute for Applied Physics and Metrology, Department of Aerospace Engineering, Universität der Bundeswehr München, D-85577 Neubiberg, Germany
| | - J Lascaud
- Department for Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, D-85748 Garching b. München, Germany
| | - M Würl
- Department for Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, D-85748 Garching b. München, Germany
| | - S Lehrack
- Department for Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, D-85748 Garching b. München, Germany
| | - D Radonic
- Department for Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, D-85748 Garching b. München, Germany
| | - M Vidal
- Centre Antoine Lacassagne-Fédération Claude Lalanne, 227 avenue de Lanterne, F-06200 Nice, France
| | - J Hérault
- Centre Antoine Lacassagne-Fédération Claude Lalanne, 227 avenue de Lanterne, F-06200 Nice, France
| | - A Chmyrov
- Chair of Biological Imaging (CBI) and Center for Translational Cancer Research (TranslaTUM) Technical University Munich, D-81675 Munich, Germany.,Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, D-85764 Neuherberg, Germany
| | - V Ntziachristos
- Chair of Biological Imaging (CBI) and Center for Translational Cancer Research (TranslaTUM) Technical University Munich, D-81675 Munich, Germany.,Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, D-85764 Neuherberg, Germany
| | - W Assmann
- Department for Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, D-85748 Garching b. München, Germany
| | - K Parodi
- Department for Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, D-85748 Garching b. München, Germany
| | - G Dollinger
- Institute for Applied Physics and Metrology, Department of Aerospace Engineering, Universität der Bundeswehr München, D-85577 Neubiberg, Germany
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6
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Lascaud J, Dash P, Wieser HP, Kalunga R, Würl M, Assmann W, Parodi K. Investigating the accuracy of co-registered ionoacoustic and ultrasound images in pulsed proton beams. Phys Med Biol 2021; 66. [PMID: 34438378 DOI: 10.1088/1361-6560/ac215e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 08/26/2021] [Indexed: 11/11/2022]
Abstract
The sharp spatial and temporal dose gradients of pulsed ion beams result in an acoustic emission (ionoacoustics), which can be used to reconstruct the dose distribution from measurements at different positions. The accuracy of range verification from ionoacoustic images measured with an ultrasound linear array configuration is investigated both theoretically and experimentally for monoenergetic proton beams at energies relevant for pre-clinical studies (20 and 22 MeV). The influence of the linear sensor array arrangement (length up to 4 cm and number of elements from 5 to 200) and medium properties on the range estimation accuracy are assessed using time-reversal reconstruction. We show that for an ideal homogeneous case, the ionoacoustic images enable a range verification with a relative error lower than 0.1%, however, with limited lateral dose accuracy. Similar results were obtained experimentally by irradiating a water phantom and taking into account the spatial impulse response (geometry) of the acoustic detector during the reconstruction of pressures obtained by moving laterally a single-element transducer to mimic a linear array configuration. Finally, co-registered ionoacoustic and ultrasound images were investigated using silicone inserts immersed in the water phantom across the proton beam axis. By accounting for the sensor response and speed of sound variations (deduced from co-registration with ultrasound images) the accuracy is improved to a few tens of micrometers (relative error less than to 0.5%), confirming the promise of ongoing developments for ionoacoustic range verification in pre-clinical and clinical proton therapy applications.
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Affiliation(s)
- Julie Lascaud
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
| | - Pratik Dash
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
| | - Hans-Peter Wieser
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
| | - Ronaldo Kalunga
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
| | - Matthias Würl
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
| | - Walter Assmann
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
| | - Katia Parodi
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
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7
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Yu Y, Qi P, Peng H. Feasibility study of 3D time-reversal reconstruction of proton-induced acoustic signals for dose verification in the head and the liver: A simulation study. Med Phys 2021; 48:4485-4497. [PMID: 34120348 DOI: 10.1002/mp.15046] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 05/08/2021] [Accepted: 05/31/2021] [Indexed: 01/15/2023] Open
Abstract
PURPOSE In vivo range and dose verification based on proton-induced acoustics (protoacoustics) is potentially a useful tool for proton therapy. Built upon our previous study with two-dimensional reconstruction, the time reversal (TR) method was extended to three-dimensional (3D) and evaluated at two treatment sites (head and liver) through simulation, with the emphasis on a number of aspects such as increased spatial coverage, computational workload, and signal interference among slices. METHODS Two mono-energetic pencil beams were modeled in each site. The k-Wave toolbox was used to investigate the propagation and TR reconstruction of acoustic waves. The performance was quantitatively assessed based on mean square error (MSE) for dose verification and Bragg peak localization error (ΔBP ) for range verification, with regard to five parameters: number of sensors, sampling duration, sampling timestep, spill time, and noise level. RESULTS The respective impacts of five parameters are examined. Under the optimum setting, the achievable ΔBP can be limited within 1 voxel (voxel size: 3 × 3 × 3 mm3 ) and the achievable MSE can be limited below 0.02, for the head case (56 sensors) and the liver case (204 sensors), respectively. CONCLUSIONS The feasibility of range and dose verification utilizing the 3D TR method is demonstrated, as the very first step. In spite of several challenges unique to the 3D case (spatial coverage, computational workload, and signal interference among slices, etc.), promising performance is found and can be further improved through optimizing the deployment of sensors. The proposed approach may find potential use in several applications: beam diagnostics, in vivo dosimetry, and treatment monitoring.
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Affiliation(s)
- Yajun Yu
- Department of Medical Physics, Wuhan University, Wuhan, China.,Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, China
| | - Pengyuan Qi
- The Institute for Advanced Studies, Wuhan University, Wuhan, China
| | - Hao Peng
- Department of Medical Physics, Wuhan University, Wuhan, China.,ProtonSmart Ltd, Wuhan, China
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8
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Nakamura Y, Takayanagi T, Uesaka T, Unlu MB, Kuriyama Y, Ishi Y, Uesugi T, Kobayashi M, Kudo N, Tanaka S, Umegaki K, Tomioka S, Matsuura T. Technical Note: Range verification of pulsed proton beams from fixed-field alternating gradient accelerator by means of time-of-flight measurement of ionoacoustic waves. Med Phys 2021; 48:5490-5500. [PMID: 34173991 DOI: 10.1002/mp.15060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 05/24/2021] [Accepted: 06/16/2021] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Ionoacoustics is one of the promising approaches to verify the beam range in proton therapy. However, the weakness of the wave signal remains a main hindrance to its application in clinics. Here we studied the potential use of a fixed-field alternating gradient accelerator (FFA), one of the accelerator candidates for future proton therapy. For such end, magnitude of the pressure wave and range accuracy achieved by the short-pulsed beam of FFA were assessed, using both simulation and experimental procedure. METHODS A 100 MeV proton beam from the FFA was applied on a water phantom, through the acrylic wall. The beam range measured by the Bragg peak (BP)-ionization chamber (BPC) was 77.6 mm, while the maximum dose at BP was estimated to be 0.35 Gy/pulse. A hydrophone was placed 20 mm downstream of the BP, and signals were amplified and stored by a digital oscilloscope, averaged, and low-pass filtered. Time-of-flight (TOF) and two relative TOF values were analyzed in order to determine the beam range. Furthermore, an acoustic wave transport simulation was conducted to estimate the amplitude of the pressure waves. RESULTS The range calculated when using two relative TOF was 78.16 ± 0.01 and 78.14 ± 0.01 mm, respectively, both values being coherent with the range measured by the BPC (the difference was 0.5-0.6 mm). In contrast, utilizing the direct TOF resulted in a range error of 1.8 mm. Fivefold and 50-fold averaging were required to suppress the range variation to below 1 mm for TOF and relative TOF measures, respectively. The simulation suggested the magnitude of pressure wave at the detector exceeded 7 Pascal. CONCLUSION A submillimeter range accuracy was attained with a pulsed beam of about 21 ns from an FFA, at a clinical energy using relative TOF. To precisely quantify the range with a single TOF measurement, subsequent improvement in the measuring system is required.
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Affiliation(s)
- Yuta Nakamura
- Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Taisuke Takayanagi
- Graduate School of Biomedical Science and Engineering, Hokkaido University, Sapporo, Hokkaido, Japan.,Hitachi Ltd, Hitachi-shi, Ibaraki, Japan
| | - Tomoki Uesaka
- Graduate School of Biomedical Science and Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | | | - Yasutoshi Kuriyama
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Yoshihiro Ishi
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Tomonori Uesugi
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Masanori Kobayashi
- Planetary Exploration Research Institute, Chiba Institute of Technology, Chiba, Japan
| | - Nobuki Kudo
- Faculty of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Sodai Tanaka
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kikuo Umegaki
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan.,Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo, Hokkaido, Japan
| | - Satoshi Tomioka
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Taeko Matsuura
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan.,Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo, Hokkaido, Japan
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9
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Analog Filters Design for Improving Precision in Proton Sound Detectors. JOURNAL OF LOW POWER ELECTRONICS AND APPLICATIONS 2021. [DOI: 10.3390/jlpea11010012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This paper analyzes how to improve the precision of ionoacoustic proton range verification by optimizing the analog signal processing stages with particular emphasis on analog filters. The ionoacoustic technique allows one to spatially detect the proton beam penetration depth/range in a water absorber, with interesting possible applications in real-time beam monitoring during hadron therapy treatments. The state of the art uses nonoptimized detectors that have low signal quality and thus require a higher total dose, which is not compatible with clinical applications. For these reasons, a comprehensive analysis of acoustic signal bandwidth, signal-to-noise-ratio and noise power/bandwidth will be presented. The correlation between these signal-quality parameters with maximum achievable proton range measurement precision will be discussed. In particular, the use of an optimized analog filter allows one to decrease the dose required to achieve a given precision by as much as 98.4% compared to a nonoptimized filter approach.
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10
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Heymans SV, Carlier B, Toumia Y, Nooijens S, Ingram M, Giammanco A, d'Agostino E, Crijns W, Bertrand A, Paradossi G, Himmelreich U, D'hooge J, Sterpin E, Van Den Abeele K. Modulating ultrasound contrast generation from injectable nanodroplets for proton range verification by varying the degree of superheat. Med Phys 2021; 48:1983-1995. [PMID: 33587754 DOI: 10.1002/mp.14778] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 01/21/2021] [Accepted: 02/08/2021] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Despite the physical benefits of protons over conventional photon radiation in cancer treatment, range uncertainties impede the ability to harness the full potential of proton therapy. While monitoring the proton range in vivo could reduce the currently adopted safety margins, a routinely applicable range verification technique is still lacking. Recently, phase-change nanodroplets were proposed for proton range verification, demonstrating a reproducible relationship between the proton range and generated ultrasound contrast after radiation-induced vaporization at 25°C. In this study, previous findings are extended with proton irradiations at different temperatures, including the physiological temperature of 37°C, for a novel nanodroplet formulation. Moreover, the potential to modulate the linear energy transfer (LET) threshold for vaporization by varying the degree of superheat is investigated, where the aim is to demonstrate vaporization of nanodroplets directly by primary protons. METHODS Perfluorobutane nanodroplets with a shell made of polyvinyl alcohol (PVA-PFB) or 10,12-pentacosadyinoic acid (PCDA-PFB) were dispersed in polyacrylamide hydrogels and irradiated with 62 MeV passively scattered protons at temperatures of 37°C and 50°C. Nanodroplet transition into echogenic microbubbles was assessed using ultrasound imaging (gray value and attenuation analysis) and optical images. The proton range was measured independently and compared to the generated contrast. RESULTS Nanodroplet design proved crucial to ensure thermal stability, as PVA-shelled nanodroplets dramatically outperformed their PCDA-shelled counterpart. At body temperature, a uniform radiation response proximal to the Bragg peak is attributed to nuclear reaction products interacting with PVA-PFB nanodroplets, with the 50% drop in ultrasound contrast being 0.17 mm ± 0.20 mm (mean ± standard deviation) in front of the proton range. Also at 50°C, highly reproducible ultrasound contrast profiles were obtained with shifts of -0.74 mm ± 0.09 mm (gray value analysis), -0.86 mm ± 0.04 mm (attenuation analysis) and -0.64 mm ± 0.29 mm (optical analysis). Moreover, a strong contrast enhancement was observed near the Bragg peak, suggesting that nanodroplets were sensitive to primary protons. CONCLUSIONS By varying the degree of superheat of the nanodroplets' core, one can modulate the intensity of the generated ultrasound contrast. Moreover, a submillimeter reproducible relationship between the ultrasound contrast and the proton range was obtained, either indirectly via the visualization of secondary reaction products or directly through the detection of primary protons, depending on the degree of superheat. The potential of PVA-PFB nanodroplets for in vivo proton range verification was confirmed by observing a reproducible radiation response at physiological temperature, and further studies aim to assess the nanodroplets' performance in a physiological environment. Ultimately, cost-effective online or offline ultrasound imaging of radiation-induced nanodroplet vaporization could facilitate the reduction of safety margins in treatment planning and enable adaptive proton therapy.
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Affiliation(s)
- Sophie V Heymans
- Department of Physics, KU Leuven Campus Kulak, Kortrijk, Belgium
| | - Bram Carlier
- Department of Oncology, KU Leuven, Leuven, Belgium.,Molecular Small Animal Imaging Center, KU Leuven, Leuven, Belgium
| | - Yosra Toumia
- Department of Chemical Sciences and Technology, University of Rome Tor Vergata, Rome, Italy
| | - Sjoerd Nooijens
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Marcus Ingram
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | | | | | | | | | - Gaio Paradossi
- Department of Chemical Sciences and Technology, University of Rome Tor Vergata, Rome, Italy
| | - Uwe Himmelreich
- Molecular Small Animal Imaging Center, KU Leuven, Leuven, Belgium.,Department of Imaging & Pathology, KU Leuven, Leuven, Belgium
| | - Jan D'hooge
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
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11
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Freijo C, Herraiz JL, Sanchez-Parcerisa D, Udias JM. Dictionary-based protoacoustic dose map imaging for proton range verification. PHOTOACOUSTICS 2021; 21:100240. [PMID: 33520652 PMCID: PMC7820918 DOI: 10.1016/j.pacs.2021.100240] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 02/07/2023]
Abstract
Proton radiotherapy has the potential to provide state-of-the-art dose conformality in the tumor area, reducing possible adverse effects on surrounding organs at risk. However, uncertainties in the exact location of the proton Bragg peak inside the patient prevent this technique from achieving full clinical potential. In this context, in vivo verification of the range of protons in patients is key to reduce uncertainty margins. Protoacoustic range verification employs acoustic pressure waves generated by protons due to the radio-induced thermoacoustic effect to reconstruct the dose deposited in a patient during proton therapy. In this paper, we propose to use the a priori knowledge of the shape of the proton dose distribution to create a dictionary with the expected ultrasonic signals at predetermined detector locations. Using this dictionary, the reconstruction of deposited dose is performed by matching pre-calculated dictionary acoustic signals with data acquired online during treatment. The dictionary method was evaluated on a single-field proton plan for a prostate cancer patient. Dose calculation was performed with the open-source treatment planning system matRad, while acoustic wave propagation was carried out with k-Wave. We studied the ability of the proposed dictionary method to detect range variations caused by anatomical changes in tissue density, and alterations of lateral and longitudinal beam position. Our results show that the dictionary-based protoacoustic method was able to identify the changes in range originated by all the alterations introduced, with an average accuracy of 1.4 mm. This procedure could be used for in vivo verification, comparing the measured signals with the precalculated dictionary.
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Affiliation(s)
- Clara Freijo
- Nuclear Physics Group, EMFTEL and IPARCOS, Faculty of Physical Sciences, University Complutense of Madrid, CEI Moncloa, 28040 Madrid, Spain
- Corresponding author.
| | - Joaquin L. Herraiz
- Nuclear Physics Group, EMFTEL and IPARCOS, Faculty of Physical Sciences, University Complutense of Madrid, CEI Moncloa, 28040 Madrid, Spain
- Health Research Institute of the Hospital Clinico San Carlos (IdISSC), 28040 Madrid, Spain
| | - Daniel Sanchez-Parcerisa
- Nuclear Physics Group, EMFTEL and IPARCOS, Faculty of Physical Sciences, University Complutense of Madrid, CEI Moncloa, 28040 Madrid, Spain
- Health Research Institute of the Hospital Clinico San Carlos (IdISSC), 28040 Madrid, Spain
- Sedecal, Molecular Imaging, 28119, Algete, Madrid, Spain
| | - José Manuel Udias
- Nuclear Physics Group, EMFTEL and IPARCOS, Faculty of Physical Sciences, University Complutense of Madrid, CEI Moncloa, 28040 Madrid, Spain
- Health Research Institute of the Hospital Clinico San Carlos (IdISSC), 28040 Madrid, Spain
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12
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Ozoemelam I, van der Graaf E, van Goethem MJ, Kapusta M, Zhang N, Brandenburg S, Dendooven P. Feasibility of quasi-prompt PET-based range verification in proton therapy. Phys Med Biol 2020; 65:245013. [PMID: 32650323 DOI: 10.1088/1361-6560/aba504] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Compared to photon therapy, proton therapy allows a better conformation of the dose to the tumor volume with reduced radiation dose to co-irradiated tissues. In vivo verification techniques including positron emission tomography (PET) have been proposed as quality assurance tools to mitigate proton range uncertainties. Detection of differences between planned and actual dose delivery on a short timescale provides a fast trigger for corrective actions. Conventional PET-based imaging of 15O (T1/2 = 2 min) and 11C (T1/2 = 20 min) distributions precludes such immediate feedback. We here present a demonstration of near real-time range verification by means of PET imaging of 12N (T1/2 = 11 ms). PMMA and graphite targets were irradiated with a 150 MeV proton pencil beam consisting of a series of pulses of 10 ms beam-on and 90 ms beam-off. Two modules of a modified Siemens Biograph mCT PET scanner (21 × 21 cm2 each), installed 25 cm apart, were used to image the beam-induced PET activity during the beam-off periods. The modifications enable the detectors to be switched off during the beam-on periods. 12N images were reconstructed using planar tomography. Using a 1D projection of the 2D reconstructed 12N image, the activity range was obtained from a fit of the activity profile with a sigmoid function. Range shifts due to modified target configurations were assessed for multiples of the clinically relevant 108 protons per pulse (approximately equal to the highest intensity spots in the pencil beam scanning delivery of a dose of 1 Gy over a cubic 1 l volume). The standard deviation of the activity range, determined from 30 datasets obtained from three irradiations on PMMA and graphite targets, was found to be 2.5 and 2.6 mm (1σ) with 108 protons per pulse and 0.9 and 0.8 mm (1σ) with 109 protons per pulse. Analytical extrapolation of the results from this study shows that using a scanner with a solid angle coverage of 57%, with optimized detector switching and spot delivery times much smaller than the 12N half-life, an activity range measurement precision of 2.0 mm (1σ) and 1.3 mm (1σ) within 50 ms into an irradiation with 4 × 107 and 108 protons per pencil beam spot can be potentially realized. Aggregated imaging of neighboring spots or, if possible, increasing the number of protons for a few probe beam spots will enable the realization of higher precision range measurement.
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Affiliation(s)
- Ikechi Ozoemelam
- KVI-Center for Advanced Radiation Technology, University of Groningen, The Netherlands
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13
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Ozoemelam I, van der Graaf E, Brandenburg S, Dendooven P. The production of positron emitters with millisecond half-life during helium beam radiotherapy. Phys Med Biol 2019; 64:235012. [PMID: 31658450 DOI: 10.1088/1361-6560/ab51c3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Therapy with helium ions is currently receiving significantly increasing interest because helium ions have a sharper penumbra than protons and undergo less fragmentation than carbon ions and thus require less complicated dose calculations. For any ion of interest in hadron therapy, the accuracy of dose delivery is limited by range uncertainties. This has led to efforts by several groups to develop in vivo verification techniques, including positron emission tomography (PET), for monitoring of the dose delivery. Beam-on PET monitoring during proton therapy through the detection of short-lived positron emitters such as 12N (T 1/2 = 11 ms), an emerging PET technique, provides an attractive option given the achievable range accuracy, minimal susceptibility to biological washout and provision of near prompt feedback. Extension of this approach to helium ions requires information on the production yield of relevant short-lived positron emitters. This study presents the first measurements of the production of short-lived positron emitters in water, graphite, calcium and phosphorus targets irradiated with 59 MeV/u 3He and 50 MeV/u 4He beams. For these targets, the most produced short-lived nuclides are 13O/12N (T 1/2 = 8.6/11 ms) on water, 13O/12N on graphite, 43Ti/41Sc/42Sc (T 1/2 = 509-680 ms) on calcium, 28P (T 1/2 = 268 ms) on phosphorus. A translation of the results from elemental targets to PMMA and representative tissues such as adipose tissue, muscle, compact and cortical bone, shows the dominance of 13O/12N in at least the first 20 s of an irradiation with 4He and somewhat longer with 3He. As the production of 13O/12N in a 3He irradiation is 3-4 times higher than in a 4He irradiation, from a statistical point of view, range verification using 13O/12N PET imaging will be about 2 times more precise for a 3He irradiation compared to a 4He irradiation.
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14
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van Dongen KWA, de Blécourt AJ, Lens E, Schaart DR, Vos FM. Reconstructing 3D proton dose distribution using ionoacoustics. Phys Med Biol 2019; 64:225005. [PMID: 31600743 DOI: 10.1088/1361-6560/ab4cd5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In proton therapy high energy protons are used to irradiate a tumor. Ideally, the delivered proton dose distribution is measured during treatment to ensure patient safety and treatment effectiveness. Here we investigate if we can use the ionoacoustic wave field to monitor the actual proton dose distribution for the two most commonly used proton accelerators; the isochronous cyclotron and the synchrocyclotron. To this end we model the acoustic field generated by the protons when irradiating a heterogeneous cancerous breast with a 89 MeV proton beam. To differentiate between the systems, idealized temporal micro-structures of the beams have been implemented. Results show that by employing model-based inversion we are able to reconstruct the 3D dose distributions from the simulated noisy pressure fields. Good results are obtained for both systems; the absolute error in the position of the maximum amplitude of the dose distribution is 5.0 mm for the isochronous cyclotron and 5.2 mm for the synchrocyclotron. In conclusion, this numerical study suggests that the ionoacoustic wave field may be used to monitor the proton dose distribution during breast cancer treatment.
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Affiliation(s)
- K W A van Dongen
- Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands. Author to whom correspondence should be addressed
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15
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Yu Y, Li Z, Zhang D, Xing L, Peng H. Simulation studies of time reversal-based protoacoustic reconstruction for range and dose verification in proton therapy. Med Phys 2019; 46:3649-3662. [PMID: 31199511 DOI: 10.1002/mp.13661] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 05/06/2019] [Accepted: 06/07/2019] [Indexed: 12/21/2022] Open
Abstract
PURPOSE In vivo range verification in proton therapy is a critical step to help minimize range and dose uncertainty. We propose to employ a time reversal (TR)-based approach using proton-induced acoustics (protoacoustics) to reconstruct pressure/dose distribution in heterogeneous tissues. METHODS The dose distribution of mono-energetic proton pencil beam in a CT-based patient phantom was calculated by Monte Carlo simulation. K-wave toolbox was used to investigate protoacoustic pressurization, propagation and reconstruction in 2D. To address the tissue heterogeneity effect, a number of physical parameters, including mass density (ρ), speed of sound (c), volumetric thermal expansion coefficient (αV ), isobaric specific heat capacity (Cp ) and attenuation power law prefactor (α0 ), were empirically converted from CT number. The performance was evaluated using two figures of merit: mean square error (MSE) of pressure profiles and Bragg peak localization error (ΔBP ). The impact of six parameters of the TR inversion was examined, including number of sensors, sampling duration, sampling timestep, spill time, noise level and number of iterations. RESULTS The quantitative accuracy of TR reconstruction and its dependency on the selected parameters is presented. Under optimum conditions, the positioning accuracy of the Bragg peak can be controlled below 1 mm. For instance, MSE is 0.0123 and ΔBP is 0.59 mm under the following conditions (32 sensors, sampling duration: 600 µs, sampling timestep: 40 ns, spill time: 1 µs, no noise). CONCLUSIONS The feasibility of TR-based protoacoustic reconstruction in 2D for proton range verification was first demonstrated. The approach is not only applicable to pencil beam, but also has potential to be extended to passive scattering systems.
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Affiliation(s)
- Yajun Yu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Zhongxing Li
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Dong Zhang
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Lei Xing
- Department of Radiation Oncology, Stanford University, Stanford, CA, 94305, USA
| | - Hao Peng
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China.,Department of Radiation Oncology, Stanford University, Stanford, CA, 94305, USA.,Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Japan
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16
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I-BEAT: Ultrasonic method for online measurement of the energy distribution of a single ion bunch. Sci Rep 2019; 9:6714. [PMID: 31040311 PMCID: PMC6491586 DOI: 10.1038/s41598-019-42920-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 04/10/2019] [Indexed: 11/08/2022] Open
Abstract
The shape of a wave carries all information about the spatial and temporal structure of its source, given that the medium and its properties are known. Most modern imaging methods seek to utilize this nature of waves originating from Huygens' principle. We discuss the retrieval of the complete kinetic energy distribution from the acoustic trace that is recorded when a short ion bunch deposits its energy in water. This novel method, which we refer to as Ion-Bunch Energy Acoustic Tracing (I-BEAT), is a refinement of the ionoacoustic approach. With its capability of completely monitoring a single, focused proton bunch with prompt readout and high repetition rate, I-BEAT is a promising approach to meet future requirements of experiments and applications in the field of laser-based ion acceleration. We demonstrate its functionality at two laser-driven ion sources for quantitative online determination of the kinetic energy distribution in the focus of single proton bunches.
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17
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A novel range-verification method using ionoacoustic wave generated from spherical gold markers for particle-beam therapy: a simulation study. Sci Rep 2019; 9:4011. [PMID: 30850625 PMCID: PMC6408528 DOI: 10.1038/s41598-019-38889-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 01/11/2019] [Indexed: 11/09/2022] Open
Abstract
This study proposes a novel alternative range-verification method for proton beam with acoustic waves generated from spherical metal markers. When proton beam is incident on metal markers, most of the resulting pressure waves are confined in the markers because of the large difference in acoustic impedance between the metal and tissue. However, acoustic waves with frequency equal to marker’s resonant frequency escape this confinement; the marker briefly acts as an acoustic transmitter. Herein, this phenomenon is exploited to measure the range of the proton beam. We test the proposed strategy in 3-D simulations, combining the dose calculations with modelling of acoustic-wave propagation. A spherical gold marker of 2.0 mm diameter was placed in water with a 60 MeV proton beam incident on it. We investigated the dependence of pressure waves on the width of beam pulse and marker position. At short beam pulse, specific high-frequency acoustic waves of 1.62 MHz originating from the marker were observed in wave simulations, whose amplitude correlated with the distance between the marker and Bragg peak. Results indicate that the Bragg peak position can be estimated by measuring the acoustic wave amplitudes from the marker, using a single detector properly designed for the resonance frequency.
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18
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Parodi K, Polf JC. In vivo range verification in particle therapy. Med Phys 2018; 45:e1036-e1050. [PMID: 30421803 DOI: 10.1002/mp.12960] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/11/2018] [Accepted: 05/01/2018] [Indexed: 12/19/2022] Open
Abstract
Exploitation of the full potential offered by ion beams in clinical practice is still hampered by several sources of treatment uncertainties, particularly related to the limitations of our ability to locate the position of the Bragg peak in the tumor. To this end, several efforts are ongoing to improve the characterization of patient position, anatomy, and tissue stopping power properties prior to treatment as well as to enable in vivo verification of the actual dose delivery, or at least beam range, during or shortly after treatment. This contribution critically reviews methods under development or clinical testing for verification of ion therapy, based on pretreatment range and tissue probing as well as the detection of secondary emissions or physiological changes during and after treatment, trying to disentangle approaches of general applicability from those more specific to certain anatomical locations. Moreover, it discusses future directions, which could benefit from an integration of multiple modalities or address novel exploitation of the measurable signals for biologically adapted therapy.
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Affiliation(s)
- Katia Parodi
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching b. Munich, 85748, Germany
| | - Jerimy C Polf
- Deparment of Radiation Oncology, Maryland Proton Treatment Center, University of Maryland School of Medicine, 22 South Greene St., Baltimore, MD, 21201, USA
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19
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Patch SK, Santiago-Gonzalez D, Mustapha B. Thermoacoustic range verification in the presence of acoustic heterogeneity and soundspeed errors - Robustness relative to ultrasound image of underlying anatomy. Med Phys 2018; 46:318-327. [PMID: 30362132 DOI: 10.1002/mp.13256] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Revised: 09/11/2018] [Accepted: 10/12/2018] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To demonstrate robustness of thermooacoustic range verification to acoustic heterogeneity and discrepancies between assumed and true propagation speed, i.e., soundspeed errors. METHODS A beam sweeper was used to deliver 250 ns pulses that deposited 0.26 Gy of 16 MeV protons and 2.3 Gy of 60 MeV helium ions into water and oil targets, respectively. Thermoacoustic signals were detected by a 96-channel ultrasound array with a 1-4 MHz sensitivity band (-6 dB), bandpass filtered and backprojected to create thermoacoustic images in the plane of the ultrasound array. The same soundspeed and transducer array were used to estimate range and generate the ultrasound images onto which Bragg peak locations were overlaid. An air-gap phantom that displaced the Bragg peak by 6.5 mm demonstrated accuracy. Robustness to soundspeed errors was demonstrated in a waterbath as the assumed propagation speed scanner setting was altered by ± 5 % . Tissue-mimicking gelatin and a bone sample were introduced to demonstrate robustness to acoustic heterogeneity relative to ultrasound images of the underlying morphology. RESULTS Single ion pulse measurements sufficed during the helium run, but signal averaging was required for protons. Range and entry point into the target were estimated from data collected by transducers placed at least 6 cm distal to the Bragg peak. When ultrasound images depicted the air-target interface where the beam enters, estimates of the entry point agreed with ultrasound images and range estimates agreed with Monte Carlo simulations to within 300 μm, even when thermoacoustic emissions traveled through a strongly scattering bone sample. Estimated Bragg peak locations were translated 6.5 mm by the air-gap phantom and correctly identified scenarios when the beam stopped inside the bone. CONCLUSIONS Soundspeed errors dilate and acoustic heterogeneities deform ultrasound images. When thermoacoustic receivers are co-located with the ultrasound imaging array, the same transformations shift thermoacoustic range estimates. Therefore, thermoacoustic range verification is robust relative to ultrasound images of underlying anatomy. When the treatment target is visible in ultrasound, e.g., prostate, online thermoacoustic range estimates could verify that the treatment spot is inside the target.
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Affiliation(s)
- Sarah K Patch
- Department of Physics, UW-Milwaukee, PO Box 413, Milwaukee, WI, 53201, USA
| | | | - Brahim Mustapha
- Physics Division, Argonne National Laboratory, Argonne, IL, 60439, USA
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20
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Hickling S, Xiang L, Jones KC, Parodi K, Assmann W, Avery S, Hobson M, El Naqa I. Ionizing radiation‐induced acoustics for radiotherapy and diagnostic radiology applications. Med Phys 2018; 45:e707-e721. [DOI: 10.1002/mp.12929] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 02/20/2018] [Accepted: 04/09/2017] [Indexed: 01/29/2023] Open
Affiliation(s)
- Susannah Hickling
- Department of Physics & Medical Physics Unit McGill University 1001 boul Decarie Montreal QC H4A 3J1Canada
| | - Liangzhong Xiang
- School of Electrical and Computer Engineering University of Oklahoma Norman OK 73019USA
| | - Kevin C. Jones
- Department of Radiation Oncology Rush University Medical Center Chicago IL 60612USA
| | - Katia Parodi
- Department of Medical Physics Ludwig‐Maximilians‐Universität Garching b. München 85748Germany
| | - Walter Assmann
- Department of Medical Physics Ludwig‐Maximilians‐Universität Garching b. München 85748Germany
| | - Stephen Avery
- Department of Radiation Oncology University of Pennsylvania Philadelphia PA19104USA
| | - Maritza Hobson
- Medical Physics Unit McGill University Health Centre Montreal QC H4A 3J1Canada
- Department of Oncology Department of Physics & Medical Physics Unit McGill University Montreal QC H4A 3J1Canada
| | - Issam El Naqa
- Department of Radiation Oncology University of Michigan Ann Arbor MI 48103‐4943USA
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21
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Nie W, Jones KC, Petro S, Kassaee A, Sehgal CM, Avery S. Proton range verification in homogeneous materials through acoustic measurements. Phys Med Biol 2018; 63:025036. [PMID: 29160776 DOI: 10.1088/1361-6560/aa9c1f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Clinical proton beam quality assurance (QA) requires a simple and accurate method to measure the proton beam Bragg peak (BP) depth. Protoacoustics, the measurement of the pressure waves emitted by thermal expansion resulting from proton dose deposition, may be used to obtain the depth of the BP in a phantom by measuring the time-of-flight of the pressure wave. Rectangular and cylindrical phantoms of different materials (aluminum, lead, and polyethylene) were used for protoacoustic studies. Four different methods for analyzing the protoacoustic signals are compared. Data analysis shows that, for Methods 1 and 2, plastic phantoms have better accuracy than metallic ones because of the lower speed of sound. Method 3 does not require characterizing the speed of sound in the material, but it results in the largest error. Method 4 exhibits minimal error, less than 3 mm (with an uncertainty ⩽1.5 mm) for all the materials and geometries. Psuedospectral wave-equation simulations (k-Wave MATLAB toolbox) are used to understand the origin of acoustic reflections within the phantom. The presented simulations and experiments show that protoacoustic measurements may provide a low cost and simple QA procedure for proton beam range verification as long as the proper phantoms and calculation methods are used.
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Affiliation(s)
- Wei Nie
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States of America
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22
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Jones KC, Nie W, Chu JCH, Turian JV, Kassaee A, Sehgal CM, Avery S. Acoustic-based proton range verification in heterogeneous tissue: simulation studies. Phys Med Biol 2018; 63:025018. [PMID: 29176057 DOI: 10.1088/1361-6560/aa9d16] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Acoustic-based proton range verification (protoacoustics) is a potential in vivo technique for determining the Bragg peak position. Previous measurements and simulations have been restricted to homogeneous water tanks. Here, a CT-based simulation method is proposed and applied to a liver and prostate case to model the effects of tissue heterogeneity on the protoacoustic amplitude and time-of-flight range verification accuracy. For the liver case, posterior irradiation with a single proton pencil beam was simulated for detectors placed on the skin. In the prostate case, a transrectal probe measured the protoacoustic pressure generated by irradiation with five separate anterior proton beams. After calculating the proton beam dose deposition, each CT voxel's material properties were mapped based on Hounsfield Unit values, and thermoacoustically-generated acoustic wave propagation was simulated with the k-Wave MATLAB toolbox. By comparing the simulation results for the original liver CT to homogenized variants, the effects of heterogeneity were assessed. For the liver case, 1.4 cGy of dose at the Bragg peak generated 50 mPa of pressure (13 cm distal), a 2× lower amplitude than simulated in a homogeneous water tank. Protoacoustic triangulation of the Bragg peak based on multiple detector measurements resulted in 0.4 mm accuracy for a δ-function proton pulse irradiation of the liver. For the prostate case, higher amplitudes are simulated (92-1004 mPa) for closer detectors (<8 cm). For four of the prostate beams, the protoacoustic range triangulation was accurate to ⩽1.6 mm (δ-function proton pulse). Based on the results, application of protoacoustic range verification to heterogeneous tissue will result in decreased signal amplitudes relative to homogeneous water tank measurements, but accurate range verification is still expected to be possible.
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Affiliation(s)
- Kevin C Jones
- Department of Radiation Oncology, Rush University Medical Center, Chicago, IL, United States of America. Author to whom correspondence should be addressed
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Patch SK, Hoff DE, Webb TB, Sobotka LG, Zhao T. Two-stage ionoacoustic range verification leveraging Monte Carlo and acoustic simulations to stably account for tissue inhomogeneity and accelerator-specific time structure - A simulation study. Med Phys 2017; 45:783-793. [DOI: 10.1002/mp.12681] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 10/06/2017] [Accepted: 10/31/2017] [Indexed: 11/06/2022] Open
Affiliation(s)
- Sarah K. Patch
- Department of Physics; University of Wisconsin-Milwaukee; Milwaukee WI USA
| | - Daniel E.M. Hoff
- Departments of Chemistry and Physics; Washington University; St. Louis MO USA
| | - Tyler B. Webb
- Departments of Chemistry and Physics; Washington University; St. Louis MO USA
| | - Lee G. Sobotka
- Departments of Chemistry and Physics; Washington University; St. Louis MO USA
| | - Tianyu Zhao
- Department of Radiation Oncology; Washington University; St. Louis MO USA
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Lehrack S, Assmann W, Bertrand D, Henrotin S, Herault J, Heymans V, Stappen FV, Thirolf PG, Vidal M, Van de Walle J, Parodi K. Submillimeter ionoacoustic range determination for protons in water at a clinical synchrocyclotron. Phys Med Biol 2017; 62:L20-L30. [PMID: 28742053 DOI: 10.1088/1361-6560/aa81f8] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Proton ranges in water between 145 MeV to 227 MeV initial energy have been measured at a clinical superconducting synchrocyclotron using the acoustic signal induced by the ion dose deposition (ionoacoustic effect). Detection of ultrasound waves was performed by a very sensitive hydrophone and signals were stored in a digital oscilloscope triggered by secondary prompt gammas. The ionoacoustic range measurements were compared to existing range data from a calibrated range detector setup on-site and agreement of better than 1 mm was found at a Bragg peak dose of about 10 Gy for 220 MeV initial proton energy, compatible with the experimental errors. Ionoacoustics has thus the potential to measure the Bragg peak position with submillimeter accuracy during proton therapy, possibly correlated with ultrasound tissue imaging.
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Affiliation(s)
- Sebastian Lehrack
- Department of Medical Physics, Ludwig-Maximilians-Universität München, 85748 Garching b. München, Germany
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Kipergil EA, Erkol H, Kaya S, Gulsen G, Unlu MB. An analysis of beam parameters on proton-acoustic waves through an analytic approach. Phys Med Biol 2017; 62:4694-4710. [PMID: 28252450 DOI: 10.1088/1361-6560/aa642c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It has been reported that acoustic waves are generated when a high-energy pulsed proton beam is deposited in a small volume within tissue. One possible application of proton-induced acoustics is to get real-time feedback for intra-treatment adjustments by monitoring such acoustic waves. A high spatial resolution in ultrasound imaging may reduce proton range uncertainty. Thus, it is crucial to understand the dependence of the acoustic waves on the proton beam characteristics. In this manuscript, firstly, an analytic solution for the proton-induced acoustic wave is presented to reveal the dependence of the signal on the beam parameters; then it is combined with an analytic approximation of the Bragg curve. The influence of the beam energy, pulse duration and beam diameter variation on the acoustic waveform are investigated. Further analysis is performed regarding the Fourier decomposition of the proton-acoustic signals. Our results show that the smaller spill time of the proton beam upsurges the amplitude of the acoustic wave for a constant number of protons, which is hence beneficial for dose monitoring. The increase in the energy of each individual proton in the beam leads to the spatial broadening of the Bragg curve, which also yields acoustic waves of greater amplitude. The pulse duration and the beam width of the proton beam do not affect the central frequency of the acoustic wave, but they change the amplitude of the spectral components.
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