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Demonstration of LGADs and Cherenkov Gamma Detectors for Prompt Gamma Timing proton Therapy range verification

IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2025年第4期9卷 508-514页

作者： Heller, Ryan Ellin, Justin Backfish, Michael Cates, Joshua W. Choong, Woon-Seng Kratochwil, Nicolaus Prebys, Eric Rebolo, Leonor St James, Sara Arino-Estrada, Gerard Lawrence Berkeley Natl Lab Nucl Sci Div Berkeley CA 94720 USA Univ Calif Davis Dept Biomed Engn Davis CA 95616 USA Univ Calif Davis Crocker Nucl Lab Davis CA 95616 USA Univ Calif Davis Dept Phys Davis CA 95616 USA Univ Utah Huntsman Canc Inst Salt Lake City UT 84112 USA Barcelona Inst Sci & Technol Inst Fis Altes Energies Barcelona 08028 Spain

The great potential for precision dose delivery with proton therapy remains to be fully exploited, largely due to uncertainties in range that require additional conservative treatment margins. Analysis of time distributions from prompt gamma-ray emissions offers a means to precisely verify the range in real time and shrink treatment margins, thus increasing effectiveness and reducing toxicity. We demonstrate a prototype prompt gamma timing system to detect proton range shifts, based on low gain avalanche detectors, used to time incoming protons, and Cherenkov detectors, to time the outgoing prompt gammas. With this system, we are able to detect range shifts induced in a PMMA phantom with about 1 mm precision consistently.

关键词： Detectors protons Timing Plasmas Particle beams Thallium Production Gamma-rays Tumors Sensors Cherenkov detector low gain avalanche detectors (LGADs) prompt gamma timing (PGT) proton range verification thallium bromide (TlBr) thallium chloride (TlCl)

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Feasibility study of using fall-off gradients of early and late PET scans for proton range verification

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MEDICAL PHYSICS 2017年第5期44卷 1734-1746页

作者： Cho, Jongmin Grogg, Kira Min, Chul Hee Zhu, Xuping Paganetti, Harald Lee, Hyun Cheol El Fakhri, Georges Oklahoma State Univ Dept Phys Stillwater OK 74078 USA Massachusetts Gen Hosp Dept Radiol Boston MA 02114 USA Harvard Med Sch Boston MA 02114 USA Yonsei Univ Coll Hlth Sci Dept Radiol Sci Wonju Kangwon Do South Korea

Purpose: While positron emission tomography (PET) allows for the imaging of tissues activated by proton beams in terms of monitoring the therapy administered, most endogenous tissue elements are activated by relatively high-energy protons. Therefore, a relatively large distance off-set exists between the dose fall-off and activity fall-off. However, O-16(p, 2p, 2n)N-13 has a relatively low energy threshold which peaks around 12 MeV and also a residual proton range that is approximately 1 to 2 mm. In this phantom study, we tested the feasibility of utilizing the N-13 production peak as well as the differences in activity fall-off between early and late PET scans for proton range verification. One of the main purposes for this research was developing a proton range verification methodology that would not require Monte Carlo simulations. Methods and materials: Both monoenergetic and spread-out Bragg peak beams were delivered to two phantoms - a water-like gel and a tissue-like gel where the proton ranges came to be approximately 9.9 and 9.1 cm, respectively. After 1 min of postirradiation delay, the phantoms were scanned for a period of 30 min using an in-room PET. Two separate (Early and Late) PET images were reconstructed using two different postirradiation delays and acquisition times;Early PET: 1 min delay and 3 min acquisition, Late PET: 21 min delay and 10 min acquisition. The depth gradients of the PET signals were then normalized and plotted as functions of depth. The normalized gradient of the early PET images was subtracted from that of the late PET images, to observe the N-13 activity distribution in relation to depth. Monte Carlo simulations were also conducted with the same set-up as the measurements stated previously. Results: The subtracted gradients show peaks at 9.4 and 8.6 cm in water-gel and tissue-gel respectively for both pristine and SOBP beams. These peaks are created in connection with the sudden change of N-13 signals with depth and consistentl

关键词： N-13 Monte Carlo simulation positron emission tomography (PET) proton range verification proton therapy radioactive decay tissue composition

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Phase-change ultrasound contrast agents for proton range verification: towards an in vivo application

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PHYSICS IN MEDICINE AND BIOLOGY 2024年第20期69卷 205014-205014页

作者： Carlier, Bram Heymans, Sophie, V Collado-Lara, Gonzalo Musetta, Luigi Ingram, Marcus Toumia, Yosra Paradossi, Gaio Vos, Hendrik J. Roskams, Tania D'hooge, Jan van den Abeele, Koen Sterpin, Edmond Himmelreich, Uwe Katholieke Univ Leuven Dept Imaging & Pathol Leuven Belgium Katholieke Univ Leuven Dept Oncol Leuven Belgium KU Leuven KULAK Dept Phys & Astron Kortrijk Belgium Katholieke Univ Leuven Dept Cardiovasc Sci Leuven Belgium Erasmus MC Deparment Cardiol Rotterdam Netherlands Univ Roma Tor Vergata Dept Chem Sci & Technol Rome Italy Ist Nazl Fis Nucleare INFN Rome Italy Particle Therapy Interuniv Ctr Leuven PARTICLE Leuven Belgium

Objective. In proton therapy, range uncertainties prevent optimal benefit from the superior depth-dose characteristics of proton beams over conventional photon-based radiotherapy. To reduce these uncertainties we recently proposed the use of phase-change ultrasound contrast agents as an affordable and effective range verification tool. In particular, superheated nanodroplets can convert into echogenic microbubbles upon proton irradiation, whereby the resulting ultrasound contrast relates to the proton range with high reproducibility. Here, we provide a first in vivo proof-of-concept of this technology. Approach. First, the in vitro biocompatibility of radiation-sensitive poly(vinyl alcohol) perfluorobutane nanodroplets was investigated using several colorimetric assays. Then, in vivo ultrasound contrast was characterized using acoustic droplet vaporization (ADV) and later using proton beam irradiations at varying energies (49.7 MeV and 62 MeV) in healthy Sprague Dawley rats. A preliminary evaluation of the in vivo biocompatibility was performed using ADV and a combination of physiology monitoring and histology. Main results. Nanodroplets were non-toxic over a wide concentration range (<1 mM). In healthy rats, intravenously injected nanodroplets primarily accumulated in the organs of the reticuloendothelial system, where the lifetime of the generated ultrasound contrast (<30 min) was compatible with a typical radiotherapy fraction (<5 min). Spontaneous droplet vaporization did not result in significant background signals. Online ultrasound imaging of the liver of droplet-injected rats demonstrated an energy-dependent proton response, which can be tuned by varying the nanodroplet concentration. However, caution is warranted when deciding on the exact nanodroplet dose regimen as a mild physiological response (drop in cardiac rate, granuloma formation) was observed after ADV. Significance. These findings underline the potential of phase-change ultrasound contrast agents

关键词： proton therapy proton range verification in vivo proof-of-concept ultrasound imaging nanodroplets phase-change ultrasound contrast agent radiation-induced droplet vaporization

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The Effects of Compton Camera Data Acquisition and Readout Timing on PG Imaging for proton range verification

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IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2022年第3期6卷 366-373页

作者： Polf, Jerimy C. Maggi, Paul Panthi, Rajesh Peterson, Stephen Mackin, Dennis Beddar, Sam Univ Maryland Sch Med Dept Radiat Oncol Baltimore MD 21201 USA Univ Texas MD Anderson Canc Ctr Dept Med Phys Houston TX 77030 USA Univ Cape Town Dept Phys ZA-7700 Rondebosch South Africa

The purpose of this article was to determine how the characteristics of the data acquisition (DAQ) electronics of a Compton camera (CC) affect the quality of the recorded prompt gamma (PG) interaction data and the reconstructed images, during clinical proton beam delivery. We used the Monte-Carlo-plus-detector-effect (MCDE) model to simulate the delivery of a 150-MeV clinical proton pencil beam to a tissue-equivalent plastic phantom. With the MCDE model, we analyzed how the recorded PG interaction data changed as two characteristics of the DAQ electronics of a CC were changed: 1) the number of data readout channels and 2) the active charge collection, readout, and reset time. As the proton beam dose rate increased, the number of recorded PG single-, double-, and triple-scatter events decreased by a factor of 60x for the current DAQ configuration of the CC. However, as the DAQ readout channels were increased and the readout/reset timing decreased, the number of recorded events decreased by < 5x at the highest clinical dose rate. The increased number of readout channels and reduced readout/reset timing also resulted in higher quality recorded data. That is, a higher percentage of the recorded double- and triple-scatters were "true" events (caused by a single incident gamma) and not "false" events (caused by multiple incident gammas). The increase in the number and the quality of recorded data allowed higher quality PG images to be reconstructed even at the highest clinical dose rates.

关键词： Compton camera (CC) prompt gamma (PG) imaging proton range verification proton therapy

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Super-Resolution Model for High-Precision In Vivo proton range verification Using a Stereo Gamma Camera: A Feasibility Study

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JOURNAL OF THE KOREAN PHYSICAL SOCIETY 2019年第8期75卷 617-627页

作者： Cheon, Wonjoong Lee, Jinyeop Min, Byung Jun Han, Youngyih Sungkyunkwan Univ SAIHST Dept Hlth Sci & Technol Seoul 06351 South Korea Chungbuk Natl Univ Hosp Dept Radiat Oncol Cheongju 28644 South Korea Sungkyunkwan Univ Sch Med Dept Radiat Oncol Samsung Med Ctr Seoul 06351 South Korea

The feasibility of a deep-learning-based super-resolution (SR) model to improve the fiducial marker-tracking accuracy of a stereo portable gamma camera (SPGC) system over the range of an in vivo proton beam was verified in a Monte-Carlo (MC) simulation using the Geometry and Tracking 4 (Geant4) package. The SPGC system is capable of measuring the three-dimensional (3D) position of excited gold markers by detecting proton-induced X-ray emissions (PIXEs) generated by the interactions between the gold marker and a proton beam. The SPGC system was modeled using Geant4 according to manufacturer's specifications. The original image (I-o) acquired by using the SPGC system, which was comprised of 32 x 32 arrays over an area of 104 x 104 mm(2), was subjected to resolution enhancement to produce an SR-enhanced image (I-SR) (128 x 128 arrays) through a fully trained SR model based on a convolutional neural network (CNN). In virtual experiments, two portable gamma cameras were positioned perpendicular to each other. Next, a pair of I-o's were acquired by detecting the radiations from the exited gold marker positioned in a water phantom. Then, the fully trained SR model improved the quality of the I-o's by converting those to I-SR's. The 3D position of the radiation source was calculated by using Anger logic and 3D vector calculations. Virtual experiments for in vivo proton range verification using the SPGC system were performed by irradiating to a gold marker in a water phantom with a proton beam. A gold marker was placed at five different positions along the Bragg curve of a 100.0-MeV proton beam, which had a range of 74.5 mm in water. The proton beam was irradiated to deliver 20.0 Gy to the gold marker when it was positioned at the center of the Bragg peak;then, the PIXEs were measured by using the SPGC system. When a gold marker was at a different position, it was irradiated with the same dose for a quantitative comparison. Then 3D position of the gold marker was calculated

关键词： Monte-Carlo simulation proton range verification Super-resolution Deep-learning Gamma cameras 87 55 N- 87 57 uq 87 19 xj

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proton range verification in homogeneous materials through acoustic measurements

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PHYSICS IN MEDICINE AND BIOLOGY 2018年第2期63卷 025036页

作者： Nie, Wei Jones, Kevin C. Petro, Scott Kassaee, Alireza Sehgal, Chandra M. Avery, Stephen Univ Penn Dept Radiat Oncol Philadelphia PA 19104 USA Rush Univ Med Ctr Dept Radiat Oncol Chicago IL 60612 USA Univ Penn Dept Radiol Philadelphia PA 19104 USA

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 waveequation 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.

关键词： proton radiation therapy proton range verification protoacoustics Bragg peak ultrasound thermal acoustics quality assurance

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Wavelet-based Protoacoustic Signal Denoising for proton range verification

Wavelet-based Protoacoustic Signal Denoising for Proton Rang...

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SPIE Medical Imaging Meeting - Ultrasonic Imaging and Tomography

作者： Sohn, James Nie, Wei Avery, Stephen M. He, Xiuxiu Zhou, Jun Yang, Xiaofeng Liu, Tian Emory Univ Dept Radiat Oncol Atlanta GA 30322 USA Emory Univ Winship Canc Inst Atlanta GA 30322 USA Univ Nebraska Dept Radiat Oncol Omaha NE 68198 USA Univ Penn Dept Radiat Oncol Philadelphia PA 19104 USA

ISBN: (纸本)9781510634060

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 Bragg-peak (BP) by measuring the time-of-flight of the pressure wave. However, using the method in the clinic has a drawback since numerous measured signals were averaged to identify the accurate signal peak from the indistinguishable noises. We proposed a wavelet-based denoising method to significantly reduce noise in collected protoacoustic signals and improve the BP identification accuracy with fewer signal averages. The average 1024 signal, which has been used in the published study, was used as the reference to identify the accurate acoustic location. We used Daubechies (db) 4 wavelet transform to decompose the collected signals to recover the useful protoacoustic signals. Our approach was able to identify the BP signal up to the average 8 signals that correspond to the dose (<1.5 Gy). This denoising technique would be useful for future 2D/3D protoacoustic imaging and make protoacoustic clinically useful for proton range verification.

关键词： Protoacoustic signal denoising wavelet proton range verification

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Dictionary-based protoacoustic dose map imaging for proton range verification

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PHOTOACOUSTICS 2021年 21卷 100240页

作者： Freijo, Clara Herraiz, Joaquin L. Sanchez-Parcerisa, Daniel Manuel Udias, Jose Univ Complutense Madrid Fac Phys Sci CEI Moncloa Nucl Phys GrpEMFTEL Madrid 28040 Spain Univ Complutense Madrid Fac Phys Sci CEI Moncloa IPARCOS Madrid 28040 Spain Hosp Clin San Carlos IdISSC Hlth Res Inst Madrid 28040 Spain Sedecal Mol Imaging Madrid 28119 Spain

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.

关键词： Protoacoustics Thermoacoustics Ultrasounds proton therapy proton range verification

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Acoustic-based proton range verification in heterogeneous tissue: simulation studies

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PHYSICS IN MEDICINE AND BIOLOGY 2018年第2期63卷 025018页

作者： Jones, Kevin C. Nie, Wei Chu, James C. H. Turian, Julius V. Kassaee, Alireza Sehgal, Chandra M. Avery, Stephen Rush Univ Med Ctr Dept Radiat Oncol Chicago IL 60612 USA Univ Penn Dept Radiat Oncol Philadelphia PA 19104 USA Univ Penn Dept Radiol Philadelphia PA 19104 USA

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 2x 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 delta-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 (delta-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.

关键词： proton range verification proton-acoustics protoacoustics ionoacoustics thermoacoustic proton therapy acoustics

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Feasibility study of a novel multi-strip silicon detector for use in proton therapy range verification quality assurance

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RADIATION MEASUREMENTS 2017年 106卷 378-384页

作者： Merchant, A. H. Newall, M. Guatelli, S. Petasecca, M. Lerch, M. Perevertaylo, V. Milluzzo, G. Petringa, G. Romano, F. Cirrone, G. A. P. Cuttone, G. Jackson, M. Rosenfeld, A. B. Univ Wollongong Ctr Med Radiat Phys Wollongong NSW 2522 Australia Univ Wollongong Illawarra Hlth Med Res Inst Wollongong NSW 2522 Australia SPA BIT Kiev Ukraine INFN Catania Italy Prince Wales Hosp Dept Radiat Oncol Sydney NSW 2031 Australia

The characterisation of a novel multi-strip silicon detector, the serial Dose Magnifying Glass, to incident 60 MeV mono-energetic proton beams, typical for ocular melanoma treatment, was performed by means of Geant4 simulations and experimental methods. Geant4 simulations were performed to determine the applicability and potential of the detector for proton beam range verification with high spatial resolution. Experimental characterisation was performed using the CATANA beam line to confirm the Monte Carlo feasibility study and determine the detector response to incident proton beams of 5 mm, 13 mm, 25 mm and 36 mm diameter, in addition to the detector response when PMMA slabs are positioned between the detector and the beam nozzle. Results indicate the suitability of the detector for proton beam range verification in proton therapy Quality Assurance. Crown Copyright (C) 2017 Published by Elsevier Ltd. All rights reserved.

关键词： Particle therapy proton range verification Multi-strip silicon detector Geant4 Monte Carlo

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