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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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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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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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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: 3] [Impact Index Per Article: 1.0] [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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