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Huang Z, Tian L, Janssens G, Smeets J, Xie Y, Kevin Teo BK, Nilsson R, Traneus E, Parodi K, Pinto M. An experimental validation of a filtering approach for prompt gamma prediction in a research proton treatment planning system. Phys Med Biol 2024; 69:155025. [PMID: 38981589 DOI: 10.1088/1361-6560/ad6116] [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: 01/24/2024] [Accepted: 07/09/2024] [Indexed: 07/11/2024]
Abstract
Objective.Prompt gamma (PG) radiation generated from nuclear reactions between protons and tissue nuclei can be employed for range verification in proton therapy. A typical clinical workflow for PG range verification compares the detected PG profile with a predicted one. Recently, a novel analytical PG prediction algorithm based on the so-called filtering formalism has been proposed and implemented in a research version of RayStation (RaySearch Laboratories AB), which is a widely adopted treatment planning system. This work validates the performance of the filtering PG prediction approach.Approach.The said algorithm is validated against experimental data and benchmarked with another well-established PG prediction algorithm implemented in a MATLAB-based software REGGUI. Furthermore, a new workflow based on several PG profile quality criteria and analytical methods is proposed for data selection. The workflow also calculates sensitivity and specificity information, which can help practitioners to decide on irradiation course interruption during treatment and monitor spot selection at the treatment planning stage. With the proposed workflow, the comparison can be performed on a limited number of selected high-quality irradiation spots without neighbouring-spot aggregation.Main results.The mean shifts between the experimental data and the predicted PG detection (PGD) profiles (ΔPGD) by the two algorithms are estimated to be1.5±2.1mm and-0.6±2.2mm for the filtering and REGGUI prediction methods, respectively. The ΔPGD difference between two algorithms is observed to be consistent with the beam model difference within uncertainty. However, the filtering approach requires a much shorter computation time compared to the REGGUI approach.Significance.The novel filtering approach is successfully validated against experimental data and another widely used PG prediction algorithm. The workflow designed in this work selects spots with high-quality PGD shift calculation results, and performs sensitivity and specificity analyses to assist clinical decisions.
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Affiliation(s)
- Ze Huang
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Liheng Tian
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Munich, Germany
| | | | | | - Yunhe Xie
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, United States of America
| | - Boon-Keng Kevin Teo
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, United States of America
| | | | | | - Katia Parodi
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Marco Pinto
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Munich, Germany
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Zhang R, Mu D, Ma Q, Wan L, Xiao P, Qi P, Liu G, Zhang S, Yang K, Yang Z, Xie Q. Proton spot dose estimation based on positron activity distributions with neural network. Med Phys 2024. [PMID: 38984805 DOI: 10.1002/mp.17297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 04/23/2024] [Accepted: 06/20/2024] [Indexed: 07/11/2024] Open
Abstract
BACKGROUND Positron emission tomography (PET) has been investigated for its ability to reconstruct proton-induced positron activity distributions in proton therapy. This technique holds potential for range verification in clinical practice. Recently, deep learning-based dose estimation from positron activity distributions shows promise for in vivo proton dose monitoring and guided proton therapy. PURPOSE This study evaluates the effectiveness of three classical neural network models, recurrent neural network (RNN), U-Net, and Transformer, for proton dose estimating. It also investigates the characteristics of these models, providing valuable insights for selecting the appropriate model in clinical practice. METHODS Proton dose calculations for spot beams were simulated using Geant4. Computed tomography (CT) images from four head cases were utilized, with three for training neural networks and the remaining one for testing. The neural networks were trained with one-dimensional (1D) positron activity distributions as inputs and generated 1D dose distributions as outputs. The impact of the number of training samples on the networks was examined, and their dose prediction performance in both homogeneous brain and heterogeneous nasopharynx sites was evaluated. Additionally, the effect of positron activity distribution uncertainty on dose prediction performance was investigated. To quantitatively evaluate the models, mean relative error (MRE) and absolute range error (ARE) were used as evaluation metrics. RESULTS The U-Net exhibited a notable advantage in range verification with a smaller number of training samples, achieving approximately 75% of AREs below 0.5 mm using only 500 training samples. The networks performed better in the homogeneous brain site compared to the heterogeneous nasopharyngeal site. In the homogeneous brain site, all networks exhibited small AREs, with approximately 90% of the AREs below 0.5 mm. The Transformer exhibited the best overall dose distribution prediction, with approximately 92% of MREs below 3%. In the heterogeneous nasopharyngeal site, all networks demonstrated acceptable AREs, with approximately 88% of AREs below 3 mm. The Transformer maintained the best overall dose distribution prediction, with approximately 85% of MREs below 5%. The performance of all three networks in dose prediction declined as the uncertainty of positron activity distribution increased, and the Transformer consistently outperformed the other networks in all cases. CONCLUSIONS Both the U-Net and the Transformer have certain advantages in the proton dose estimation task. The U-Net proves well suited for range verification with a small training sample size, while the Transformer outperforms others at dose-guided proton therapy.
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Affiliation(s)
- Ruilin Zhang
- Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Dengyun Mu
- Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Qiuhui Ma
- School of Artificial Intelligence and Automation, Huazhong University of Science and Technology, Wuhan, China
| | - Lin Wan
- School of Software Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Peng Xiao
- Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
- Wuhan National Laboratory of Optoelectronics, Wuhan, China
- Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei, China
| | - Pengyuan Qi
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Precision Radiation Oncology, Wuhan, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gang Liu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Precision Radiation Oncology, Wuhan, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sheng Zhang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Precision Radiation Oncology, Wuhan, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kunyu Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Precision Radiation Oncology, Wuhan, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhiyong Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Precision Radiation Oncology, Wuhan, China
- Institute of Radiation Oncology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qingguo Xie
- Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan, China
- Wuhan National Laboratory of Optoelectronics, Wuhan, China
- Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei, China
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Létang JM, Allegrini O, Testa É. Prompt-gamma track-length estimator with time tagging from proton tracking. Phys Med Biol 2024; 69:115052. [PMID: 38729180 DOI: 10.1088/1361-6560/ad4a01] [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: 12/30/2023] [Accepted: 05/10/2024] [Indexed: 05/12/2024]
Abstract
The design of prompt-gamma detectors necessitates numerous Monte Carlo simulations to precisely develop and optimize the detection stages in proton therapy. Alongside the advancement of MC simulations, various variance reduction methods have been explored to speed-up calculations. Among these techniques, track-length estimators are interesting scoring methods for achieving both speed and accuracy in Monte Carlo simulations of rare events. This paper introduces an extension of the GATE vpgTLE module that incorporates the prompt-gamma emission time, which is tagged from the proton tracking, enhancing its utility for studies focused on detector design and optimization that rely on time measurements. The results obtained from a clinical radiotherapy plan are presented. We demonstrate that the new vpgTLE tally with time tagging is accurate, except for certain prompt-gamma lines corresponding to long mean-life nuclei.
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Affiliation(s)
- Jean M Létang
- INSA-Lyon, Universite Claude Bernard Lyon 1, CNRS UMR5220, Inserm U1294, Centre Léon Bérard, CREATIS, F-69373 Lyon, France
| | - Oreste Allegrini
- Universite Claude Bernard Lyon 1, CNRS/IN2P3 UMR5822, IP2I, F-69622 Villeurbanne, France
| | - Étienne Testa
- Universite Claude Bernard Lyon 1, CNRS/IN2P3 UMR5822, IP2I, F-69622 Villeurbanne, France
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Ellin J, Rebolo L, Backfish M, Prebys E, Ariño-Estrada G. Prompt gamma timing for proton range verification with TlBr and TlCl as pure Cherenkov emitters. Phys Med Biol 2024; 69:115002. [PMID: 38657638 PMCID: PMC11106777 DOI: 10.1088/1361-6560/ad4304] [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: 01/04/2024] [Revised: 04/18/2024] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
Objective. Prompt gamma timing (PGT) uses the detection time of prompt gammas emitted along the range of protons in proton radiotherapy to verify the position of the Bragg peak (BP). Cherenkov detectors offer the possibility of enhanced signal-to-noise ratio (SNR) due to the inherent physics of Cherenkov emission which enhances detection of high energy prompt gamma rays relative to other induced uncorrelated signals. In this work, the PGT technique was applied to 3 semiconductor material slabs that emit only Cherenkov light for use in a full scale system: a 3 × 3 × 20 mm3TlBr, a 12 × 12 × 12 mm3TlBr, and a 5 × 5 × 5 mm3TlCl.Approach. A polymethyl methacrylate (PMMA) target was exposed to a 67.5 MeV, 0.5 nA proton beam and shifted in 3 mm increments at the Crocker nuclear laboratory (CNL) in Davis, CA, USA. A fast plastic scintillator coupled to a photomultiplier tube (PMT) provided the start reference for the proton time of flight. Time of flight (TOF) distributions were generated using this reference and the gamma-ray timestamp in the Cherenkov detector.Main results. The SNR of the proton correlated peaks relative to the background was 20, 29, and 30 for each of the three samples, respectively. The upper limit of the position resolutions with the TlCl sample were 2 mm, 3 mm, and 5 mm for 30k, 10k, and 5k detected events, respectively. The time distribution of events with respect to the reference reproduced with clarity the periodicity of the beam, implying a very high SNR of the Cherenkov crystals to detect prompt gammas. Background presence from the neutron-induced continuum, prompt gammas from deuterium, or positron activation were not observed. Material choice and crystal dimensions did not seem to affect significantly the outcome of the results.Significance. These results show the high SNR of the pure Cherenkov emitters TlBr and TlCl for the detection of prompt gammas in a proton beam with current of clinical significance and their potential for verifying the proton range. The accuracy in determining shifts of the BP was highly dependent on the number of events acquired, therefore, the performance of these detectors are expected to vary with different beam conditions such as current, pulse repetition, and proton bunch width.
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Affiliation(s)
- Justin Ellin
- Department of Biomedical Engineering, University of California Davis, CA, United States of America
| | - Leonor Rebolo
- Department of Biomedical Engineering, University of California Davis, CA, United States of America
| | - Michael Backfish
- Crocker Nuclear Laboratory, University of California Davis, CA, United States of America
| | - Eric Prebys
- Crocker Nuclear Laboratory, University of California Davis, CA, United States of America
- Department of Physics, University of California Davis, CA, United States of America
| | - Gerard Ariño-Estrada
- Department of Biomedical Engineering, University of California Davis, CA, United States of America
- Institut de Física d’Altes Energies—Barcelona Institute of Science and Technology, Bellaterra, Barcelona, Spain
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Kazemi Kozani M. Machine learning approach for proton range verification using real-time prompt gamma imaging with Compton cameras: addressing the total deposited energy information gap. Phys Med Biol 2024; 69:075019. [PMID: 38417182 DOI: 10.1088/1361-6560/ad2e6a] [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: 06/26/2023] [Accepted: 02/28/2024] [Indexed: 03/01/2024]
Abstract
Objective.Compton camera imaging shows promise as a range verification technique in proton therapy. This work aims to assess the performance of a machine learning model in Compton camera imaging for proton beam range verification improvement.Approach.The presented approach was used to recognize Compton events and estimate more accurately the prompt gamma (PG) energy in the Compton camera to reconstruct the PGs emission profile during proton therapy. This work reports the results obtained from the Geant4 simulation for a proton beam impinging on a polymethyl methacrylate (PMMA) target. To validate the versatility of such an approach, the produced PG emissions interact with a scintillating fiber-based Compton camera.Main results.A trained multilayer perceptron (MLP) neural network shows that it was possible to achieve a notable three-fold increase in the signal-to-total ratio. Furthermore, after event selection by the trained MLP, the loss of full-energy PGs was compensated by means of fitting an MLP energy regression model to the available data from true Compton (signal) events, predicting more precisely the total deposited energy for Compton events with incomplete energy deposition.Significance.A considerable improvement in the Compton camera's performance was demonstrated in determining the distal falloff and identifying a few millimeters of target displacements. This approach has shown great potential for enhancing online proton range monitoring with Compton cameras in future clinical applications.
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Affiliation(s)
- Majid Kazemi Kozani
- Department of Radiology, University of Pennsylvania, Philadelphia, United States of America
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Wulff J, Paul A, Bäcker CM, Baumann KS, Esser JN, Koska B, Timmermann B, Verbeek NG, Bäumer C. Consistency of Faraday cup and ionization chamber dosimetry of proton fields and the role of nuclear interactions. Med Phys 2024; 51:2277-2292. [PMID: 37991110 DOI: 10.1002/mp.16819] [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: 01/13/2023] [Revised: 09/21/2023] [Accepted: 09/28/2023] [Indexed: 11/23/2023] Open
Abstract
BACKGROUND A Faraday cup (FC) facilitates a quite clean measurement of the proton fluence emerging from clinical spot-scanning nozzles with narrow pencil-beams. The utilization of FCs appears to be an attractive option for high dose rate delivery modes and the source models of Monte-Carlo (MC) dose engines. However, previous studies revealed discrepancies of 3%-6% between reference dosimetry with ionization chambers (ICs) and FC-based dosimetry. This has prevented the widespread use of FCs for dosimetry in proton therapy. PURPOSE The current study aims at bridging the gap between FC dosimetry and IC dosimetry of proton fields delivered with spot-scanning treatment heads. Particularly, a novel method to evaluate FC measurements is introduced. METHODS A consistency check is formulated, which makes use of the energy balance and the reciprocity theorem. The measurement data comprise central-axis depth distributions of the absorbed dose of quasi-monochromatic fields with a width of about 28.5 cm and FC measurements of the reciprocal fields with a single spot. These data are complemented by a look-up of energy-range tables, the average Q-value of transmutations, and the escape energy carried away by neutrons and photons. The latter data are computed by MC simulations, which in turn are validated with measurements of the distal dose tail and neutron out-of-field doses. For comparison, the conventional approach of FC evaluation is performed, which computes absorbed dose from the product of fluence and stopping power. The results from the FC measurements are compared with the standard dosimetry protocols and improved reference dosimetry methods. RESULTS The deviation between the conventional FC-based dosimetry and the IC-based one according to standard dosimetry protocols was -4.7 ( ± $\pm$ 3.3)% for a 100 MeV field and -3.6 ( ± $\pm$ 3.5)% for 200 MeV, thereby agreeing within the reported uncertainties. The deviations could be reduced to -4.0 ( ± $\pm$ 2.9)% and -3.0 ( ± $\pm$ 3.1)% by adopting state-of-the-art reference dosimetry methods. The alternative approach using the energy balance gave deviations of only -1.9% (100 MeV) and -2.6% (200 MeV) using state-of-the-art dosimetry. The standard uncertainty of this novel approach was estimated to be about 2%. CONCLUSIONS An alternative concept has been established to determine the absorbed dose of monoenergetic proton fields with an FC. It eliminates the strong dependence of the conventional FC-based approach on the MC simulation of the stopping-power and of the secondary ions, which according to the study at hand is the major contributor to the underestimation of the absorbed dose. Some contributions to the uncertainty of the novel approach could potentially be reduced in future studies. This would allow for accurate consistency tests of conventional dosimetry procedures.
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Affiliation(s)
- Jörg Wulff
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Anne Paul
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
- Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Claus Maximilian Bäcker
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Kilian-Simon Baumann
- Department of Radiotherapy and Radiation Oncology, Marburg University Hospital, Marburg, Germany
- Marburg Ion-Beam Therapy Center (MIT), Marburg, Germany
- University of Applied Sciences, Institute of Medical Physics and Radiation Protection, Giessen, Germany
| | - Johannes Niklas Esser
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Benjamin Koska
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Beate Timmermann
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
- Heinrich Heine University Düsseldorf, Düsseldorf, Germany
- German Cancer Consortium (DKTK), Essen, Germany
- Department of Particle Therapy, University Hospital Essen, Essen, Germany
| | - Nico Gerd Verbeek
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
| | - Christian Bäumer
- West German Proton Therapy Centre Essen, Essen, Germany
- University Hospital Essen, Essen, Germany
- West German Cancer Center (WTZ), Essen, Germany
- German Cancer Consortium (DKTK), Essen, Germany
- Department of Physics, Technische Universität Dortmund, Dortmund, Germany
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Kim SH, Jeong JH, Ku Y, Lee SB, Shin D, Lim YK, Kim H, Kim CH. Range shift verification in spot scanning proton therapy using gamma electron vertex imaging. Med Phys 2024; 51:1985-1996. [PMID: 37722712 DOI: 10.1002/mp.16739] [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: 01/06/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/20/2023] Open
Abstract
BACKGROUND In proton therapy, a highly steep distal dose penumbra can be utilized for dose conformity, given the Bragg peak characteristic of protons. However, the location of the Bragg peak in patients (i.e., the beam range) is very sensitive to range uncertainty. Even a small shift of beam range can produce a significant variation of delivered dose to tumor and normal tissues, thus degrading treatment quality and threatening patient safety. This range uncertainty issue, therefore, is one of the important aspects to be managed in proton therapy. PURPOSE For better management of range uncertainty, range verification has been widely studied, and prompt gamma imaging (PGI) is considered one of the promising methods in that effort. In this context, a PGI system named the gamma electron vertex imaging (GEVI) system was developed and recently upgraded for application to pencil-beam scanning (PBS) proton therapy. Here, we report the first experimental results using the therapeutic spot scanning proton beams. METHODS A homogeneous slab phantom and an anthropomorphic phantom were employed. Spherical and cubic planning target volumes (PTVs) were defined. Various range shift scenarios were introduced. Prompt gamma (PG) measurement was synchronized with beam irradiation. The measured PG distributions were aggregated to improve the PG statistics. The range shift was estimated based on the relative change of the centroid in the measured PG distribution. The estimated range shifts were analyzed by range shift mapping, confidence interval (CI) estimation, and statistical hypothesis testing. RESULTS The range shift mapping results showed an obvious measured range shift tendency following the true shift values. However, some fluctuations were found for spots that had still-low PG statistics after spot aggregation. The 99% CI distributions showed clearly distributed range shift measurement data. The overall accuracy and precision for all investigated scenarios were 0.36 and 0.20 mm, respectively. The results of one-sample t-tests confirmed that every shift scenario could be observed up to 1 mm of shift. The ANOVA results proved that the measured range shift data could be discriminated from one another, except for 16 (of 138) comparison cases having 1-2 mm shift differences. CONCLUSIONS This study demonstrated the feasibility of the GEVI system for measurement of range shift in spot scanning proton therapy. Our experimental results showed that the proton beam can be measured up to 1 mm of range shift with high accuracy and precision. We believe that the GEVI system is one of the most promising PGI systems for in vivo range verification. Further research for application to more various cases and patient treatments is planned.
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Affiliation(s)
- Sung Hun Kim
- Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of Korea
| | - Jong Hwi Jeong
- Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of Korea
| | - Youngmo Ku
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Se Byeong Lee
- Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of Korea
| | - Dongho Shin
- Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of Korea
| | - Young Kyung Lim
- Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of Korea
| | - Haksoo Kim
- Center for Proton Therapy, National Cancer Center, Gyeonggi-do, Republic of Korea
| | - Chan Hyeong Kim
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
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Tattenberg S, Liu P, Mulhem A, Cong X, Thome C, Ding X. Impact of and interplay between proton arc therapy and range uncertainties in proton therapy for head-and-neck cancer. Phys Med Biol 2024; 69:055015. [PMID: 38324904 DOI: 10.1088/1361-6560/ad2718] [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: 09/01/2023] [Accepted: 02/07/2024] [Indexed: 02/09/2024]
Abstract
Objective. Proton therapy reduces the integral dose to the patient compared to conventional photon treatments. However,in vivoproton range uncertainties remain a considerable hurdle. Range uncertainty reduction benefits depend on clinical practices. During intensity-modulated proton therapy (IMPT), the target is irradiated from only a few directions, but proton arc therapy (PAT), for which the target is irradiated from dozens of angles, may see clinical implementation by the time considerable range uncertainty reductions are achieved. It is therefore crucial to determine the impact of PAT on range uncertainty reduction benefits.Approach. For twenty head-and-neck cancer patients, four different treatment plans were created: an IMPT and a PAT treatment plan assuming current clinical range uncertainties of 3.5% (IMPT3.5%and PAT3.5%), and an IMPT and a PAT treatment plan assuming that range uncertainties can be reduced to 1% (IMPT1%and PAT1%). Plans were evaluated with respect to target coverage and organ-at-risk doses as well as normal tissue complication probabilities (NTCPs) for parotid glands (endpoint: parotid gland flow <25%) and larynx (endpoint: larynx edema).Main results. Implementation of PAT (IMPT3.5%-PAT3.5%) reduced mean NTCPs in the nominal and worst-case scenario by 3.2 percentage points (pp) and 4.2 pp, respectively. Reducing range uncertainties from 3.5% to 1% during use of IMPT (IMPT3.5%-IMPT1%) reduced evaluated NTCPs by 0.9 pp and 2.0 pp. Benefits of range uncertainty reductions subsequently to PAT implementation (PAT3.5%-PAT1%) were 0.2 pp and 1.0 pp, with considerably higher benefits in bilateral compared to unilateral cases.Significance. The mean clinical benefit of implementing PAT was more than twice as high as the benefit of a 3.5%-1% range uncertainty reduction. Range uncertainty reductions are expected to remain beneficial even after PAT implementation, especially in cases with target positions allowing for full leveraging of the higher number of gantry angles during PAT.
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Affiliation(s)
- Sebastian Tattenberg
- Laurentian University, Sudbury P3E 2C6, Ontario, Canada
- Northern Ontario School of Medicine University, Sudbury P3E 2C6, Ontario, Canada
- TRIUMF, 4004 Wesbrook Mall, Vancouver V6T 2A3, British Columbia, Canada
| | - Peilin Liu
- Department of Radiation Oncology, William Beaumont University Hospital, Corewell Health, 3601 W 13 Mile Road, MI, United States of America
| | - Anthony Mulhem
- Department of Radiation Oncology, William Beaumont University Hospital, Corewell Health, 3601 W 13 Mile Road, MI, United States of America
- Department of Human Biology, Michigan State University, Natural Science Building, 288 Farm Ln, East Lansing, MI 48824, United States of America
| | - Xiaoda Cong
- Department of Radiation Oncology, William Beaumont University Hospital, Corewell Health, 3601 W 13 Mile Road, MI, United States of America
| | - Christopher Thome
- Laurentian University, Sudbury P3E 2C6, Ontario, Canada
- Northern Ontario School of Medicine University, Sudbury P3E 2C6, Ontario, Canada
| | - Xuanfeng Ding
- Department of Radiation Oncology, William Beaumont University Hospital, Corewell Health, 3601 W 13 Mile Road, MI, United States of America
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Hetzel R, Urbanevych V, Bolke A, Kasper J, Kercz M, Kołodziej M, Magiera A, Mueller F, Müller S, Rafecas M, Rusiecka K, Schug D, Schulz V, Stahl A, Weissler B, Wong ML, Wrońska A. Near-field coded-mask technique and its potential for proton therapy monitoring. Phys Med Biol 2023; 68:245028. [PMID: 37863101 DOI: 10.1088/1361-6560/ad05b2] [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: 02/10/2023] [Accepted: 10/20/2023] [Indexed: 10/22/2023]
Abstract
Objective.Prompt-gamma imaging encompasses several approaches to the online monitoring of the beam range or deposited dose distribution in proton therapy. We test one of the imaging techniques - a coded mask approach - both experimentally and via simulations.Approach.Two imaging setups have been investigated experimentally. Each of them comprised a structured tungsten collimator in the form of a modified uniformly redundant array mask and a LYSO:Ce scintillation detector of fine granularity. The setups differed in detector dimensions and operation mode (1D or 2D imaging). A series of measurements with radioactive sources have been conducted, testing the performance of the setups for near-field gamma imaging. Additionally, Monte Carlo simulations of a larger setup of the same type were conducted, investigating its performance with a realistic gamma source distribution occurring during proton therapy.Main results.The images of point-like sources reconstructed from two small-scale prototypes' data using the maximum-likelihood expectation maximisation algorithm constitute the experimental proof of principle for the near-field coded-mask imaging modality, both in the 1D and the 2D mode. Their precision allowed us to calibrate out certain systematic offsets appearing due to the limited alignment accuracy of setup elements. The simulation of the full-scale setup yielded a mean distal falloff retrieval precision of 0.72 mm in the studies for beam energy range 89.5-107.9 MeV and with 1 × 108protons (a typical number for distal spots). The implemented algorithm of image reconstruction is relatively fast-a typical procedure needs several seconds.Significance.Coded-mask imaging appears a valid option for proton therapy monitoring. The results of simulations let us conclude that the proposed full-scale setup is competitive with the knife-edge-shaped and the multi-parallel slit cameras investigated by other groups.
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Affiliation(s)
- Ronja Hetzel
- III. Physikalisches Institut B, RWTH Aachen University, Aachen, Germany
| | - Vitalii Urbanevych
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland
| | - Andreas Bolke
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - Jonas Kasper
- III. Physikalisches Institut B, RWTH Aachen University, Aachen, Germany
| | - Monika Kercz
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland
- Doctoral School of Exact and Natural Sciences, Jagiellonian University, Kraków, Poland
| | - Magdalena Kołodziej
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland
- Doctoral School of Exact and Natural Sciences, Jagiellonian University, Kraków, Poland
| | - Andrzej Magiera
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland
| | - Florian Mueller
- Physics of Molecular Imaging Systems, RWTH Aachen University, Aachen, Germany
| | - Sara Müller
- III. Physikalisches Institut B, RWTH Aachen University, Aachen, Germany
| | - Magdalena Rafecas
- Institute of Medical Engineering, University of Lübeck, Lübeck, Germany
| | - Katarzyna Rusiecka
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland
| | - David Schug
- Physics of Molecular Imaging Systems, RWTH Aachen University, Aachen, Germany
- Hyperion Hybrid Imaging Systems GmbH, Aachen, Germany
| | - Volkmar Schulz
- III. Physikalisches Institut B, RWTH Aachen University, Aachen, Germany
- Physics of Molecular Imaging Systems, RWTH Aachen University, Aachen, Germany
- Hyperion Hybrid Imaging Systems GmbH, Aachen, Germany
| | - Achim Stahl
- III. Physikalisches Institut B, RWTH Aachen University, Aachen, Germany
| | - Bjoern Weissler
- Physics of Molecular Imaging Systems, RWTH Aachen University, Aachen, Germany
- Hyperion Hybrid Imaging Systems GmbH, Aachen, Germany
| | - Ming-Liang Wong
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland
| | - Aleksandra Wrońska
- Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland
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10
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Abouzahr F, Cesar JP, Crespo P, Gajda M, Hu Z, Klein K, Kuo AS, Majewski S, Mawlawi O, Morozov A, Ojha A, Poenisch F, Proga M, Sahoo N, Seco J, Takaoka T, Tavernier S, Titt U, Wang X, Zhu XR, Lang K. The first probe of a FLASH proton beam by PET. Phys Med Biol 2023; 68:235004. [PMID: 37918021 DOI: 10.1088/1361-6560/ad0901] [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: 08/17/2023] [Accepted: 11/02/2023] [Indexed: 11/04/2023]
Abstract
The recently observed FLASH effect related to high doses delivered with high rates has the potential to revolutionize radiation cancer therapy if promising results are confirmed and an underlying mechanism understood. Comprehensive measurements are essential to elucidate the phenomenon. We report the first-ever demonstration of measurements of successive in-spill and post-spill emissions of gammas arising from irradiations by a FLASH proton beam. A small positron emission tomography (PET) system was exposed in an ocular beam of the Proton Therapy Center at MD Anderson Cancer Center to view phantoms irradiated by 3.5 × 1010protons with a kinetic energy of 75.8 MeV delivered in 101.5 ms-long spills yielding a dose rate of 164 Gy s-1. Most in-spill events were due to prompt gammas. Reconstructed post-spill tomographic events, recorded for up to 20 min, yielded quantitative imaging and dosimetric information. These findings open a new and novel modality for imaging and monitoring of FLASH proton therapy exploiting in-spill prompt gamma imaging followed by post-spill PET imaging.
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Affiliation(s)
- F Abouzahr
- Department of Physics, University of Texas at Austin, Austin, TX 78712, United States of America
| | - J P Cesar
- Department of Physics, University of Texas at Austin, Austin, TX 78712, United States of America
| | - P Crespo
- Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra, Portugal
- Departamento de Física, Universidade de Coimbra, 3004-516 Coimbra, Portugal
| | - M Gajda
- Department of Physics, University of Texas at Austin, Austin, TX 78712, United States of America
| | - Z Hu
- Department of Radiation Physics, MD Anderson Cancer Center, University of Texas, Houston, TX 77030, United States of America
| | - K Klein
- Department of Physics, University of Texas at Austin, Austin, TX 78712, United States of America
| | - A S Kuo
- Department of Physics, University of Texas at Austin, Austin, TX 78712, United States of America
| | - S Majewski
- Department of Physics, University of Texas at Austin, Austin, TX 78712, United States of America
- Biomedical Engineering, University of California Davis, CA 96616, United States of America
| | - O Mawlawi
- Department of Imaging Physics, MD Anderson Cancer Center, University of Texas, Houston, TX, 77054, United States of America
| | - A Morozov
- Laboratório de Instrumentação e Física Experimental de Partículas, 3004-516 Coimbra, Portugal
| | - A Ojha
- Department of Physics, University of Texas at Austin, Austin, TX 78712, United States of America
| | - F Poenisch
- Proton Therapy Center, MD Anderson Cancer Center, University of Texas, Houston, TX 77054, United States of America
| | - M Proga
- Department of Physics, University of Texas at Austin, Austin, TX 78712, United States of America
| | - N Sahoo
- Proton Therapy Center, MD Anderson Cancer Center, University of Texas, Houston, TX 77054, United States of America
| | - J Seco
- Div. of Biomed. Physics in Rad. Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - T Takaoka
- Particle Therapy Division, Hitachi America Ltd, Houston, TX 77054, United States of America
| | - S Tavernier
- PETsys Electronics, SA, 2740-257 Taguspark, Portugal
| | - U Titt
- Department of Radiation Physics, MD Anderson Cancer Center, University of Texas, Houston, TX 77030, United States of America
| | - X Wang
- Proton Therapy Center, MD Anderson Cancer Center, University of Texas, Houston, TX 77054, United States of America
| | - X R Zhu
- Proton Therapy Center, MD Anderson Cancer Center, University of Texas, Houston, TX 77054, United States of America
| | - K Lang
- Department of Physics, University of Texas at Austin, Austin, TX 78712, United States of America
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11
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Kasanda E, Bildstein V, Hymers D, Easter J, Richard AL, Baumann T, Spyrou A, Höhr C, Mücher D. Range verification in heavy-ion therapy using a hadron tumour marker. Phys Med Biol 2023; 68:195018. [PMID: 37747082 DOI: 10.1088/1361-6560/acf557] [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: 03/02/2023] [Accepted: 08/30/2023] [Indexed: 09/26/2023]
Abstract
Objective.A new method to estimate the range of an ion beam in a patient during heavy-ion therapy was investigated, which was previously verified for application in proton therapy.Approach.The method consists of placing a hadron tumour marker (HTM) close to the tumour. As the treatment beam impinges on the HTM, the marker undergoes nuclear reactions. When the HTM material is carefully chosen, the activation results in the emission of several delayed, characteristicγrays, whose intensities are correlated with the remaining range inside the patient. When not just one but two reaction channels are investigated, the ratio between these twoγray emissions can be measured, and the ratio is independent of any beam delivery uncertainties.Main results.A proof-of-principle experiment with an16O ion beam and Ag foils as HTM was successfully executed. The107Ag(16O,x)112Sb and the107Ag(16O,x)114Sb reaction channels were identified as suitable for the HTM technique. When only oneγ-ray emission is measured, the resulting range-uncertainty estimation is at the 0.5 mm scale. When both channels are considered, a theoretical limit on the range uncertainty of a clinical fiducal marker was found to be ±290μm.Significance.Range uncertainty of a heavy-ion beam limits the prescribed treatment plan for cancer patients, especially the direction of the ion beam in relation to any organ at risk. An easy to implement range-verification technique which can be utilized during clinical treatment would allow treatment plans to take full advantage of the sharp fall-off of the Bragg peak without the risk of depositing excessive dose into healthy tissue.
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Affiliation(s)
- E Kasanda
- Department of Physics, University of Guelph, 50 Stone Rd E, Guelph, Ontario, N1G 2W1, Canada
- Laboratory for High Energy Physics, Universität Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
| | - V Bildstein
- Department of Physics, University of Guelph, 50 Stone Rd E, Guelph, Ontario, N1G 2W1, Canada
| | - D Hymers
- Department of Physics, University of Guelph, 50 Stone Rd E, Guelph, Ontario, N1G 2W1, Canada
- Institut für Kernphysik der Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany
| | - J Easter
- Department of Physics, University of Guelph, 50 Stone Rd E, Guelph, Ontario, N1G 2W1, Canada
| | - A L Richard
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI 48824, United States of America
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, United States of America
| | - T Baumann
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI 48824, United States of America
| | - A Spyrou
- Facility for Rare Isotope Beams, Michigan State University, East Lansing, MI 48824, United States of America
- Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, United States of America
| | - C Höhr
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia, V8P 5C2, Canada
| | - D Mücher
- Department of Physics, University of Guelph, 50 Stone Rd E, Guelph, Ontario, N1G 2W1, Canada
- Institut für Kernphysik der Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3, Canada
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12
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Yamamoto S, Yabe T, Akagi T, Yamaguchi M, Kawachi N, Kamada K, Yoshikawa A, Kataoka J. Prompt X-ray imaging during irradiation with spread-out Bragg peak (SOBP) beams of carbon ions. Phys Med 2023; 109:102592. [PMID: 37084677 DOI: 10.1016/j.ejmp.2023.102592] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 04/07/2023] [Accepted: 04/13/2023] [Indexed: 04/23/2023] Open
Abstract
Prompt secondary electron bremsstrahlung X-ray (prompt X-ray) imaging using a low-energy X-ray camera is a promising method for observing a beam shape from outside the subject. However, such imaging has so far been conducted only for pencil beams without a multi-leaf collimator (MLC). The use of spread-out Bragg peak (SOBP) with an MLC may increase the scattered prompt gamma photons and decrease the contrast of the images of prompt X-rays. Consequently, we performed prompt X-ray imaging of SOBP beams formed with an MLC. This imaging was carried out in list mode during irradiation of SOBP beams to a water phantom. An X-ray camera with a 1.5-mm diameter as well as 4-mm-diameter pinhole collimators was used for the imaging. List mode data were sorted to obtain the SOBP beam images as well as energy spectra and time count rate curves. Due to the high background counts from the scattered prompt gamma photons penetrating the tungsten shield of the X-ray camera, the SOBP beam shapes were difficult to observe with a 1.5-mm-diameter pinhole collimator. With the 4-mm-diameter pinhole collimators, images of SOBP beam shapes at clinical dose levels could be obtained with the X-ray camera. The use of a 4-mm-diameter pinhole collimator attached to the X-ray camera is effective for prompt X-ray imaging with high sensitivity and low background counts. This approach makes it possible to image SOBP beams with an MLC when the counts are low and the background levels are high.
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Affiliation(s)
| | - Takuya Yabe
- Takasaki Institute of Advanced Quantum Science, Foundational Quantum Technology Research Directorate, National Institutes for Quantum Science and Technology (QST), Japan
| | | | - Mitsutaka Yamaguchi
- Takasaki Institute of Advanced Quantum Science, Foundational Quantum Technology Research Directorate, National Institutes for Quantum Science and Technology (QST), Japan
| | - Naoki Kawachi
- Takasaki Institute of Advanced Quantum Science, Foundational Quantum Technology Research Directorate, National Institutes for Quantum Science and Technology (QST), Japan
| | - Kei Kamada
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Japan
| | - Akira Yoshikawa
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Japan
| | - Jun Kataoka
- Faculty of Science and Engineering, Waseda University, Japan
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13
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Missaglia A, Bourkadi-Idrissi A, Casamichiela F, Mazzucconi D, Carminati M, Agosteo S, Fiorini C. Prompt-gamma fall-off estimation with C-ion irradiation at clinical energies, using a knife-edge slit camera: A Monte Carlo study. Phys Med 2023; 107:102554. [PMID: 36907030 DOI: 10.1016/j.ejmp.2023.102554] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 02/09/2023] [Accepted: 02/18/2023] [Indexed: 03/12/2023] Open
Abstract
PURPOSE In-vivo range verification has been a hot topic in particle therapy since two decades. Many efforts have been done for proton therapy, while fewer studies were conducted considering a beam of carbon ions. In the present work, a simulation study was performed to show whether it is possible to measure the prompt-gamma fall-off inside the high neutron background typical of carbon-ion irradiation, using a knife-edge slit camera. In addition to this, we wanted to estimate the uncertainty in retrieving the particle range in the case of a pencil beam of C-ions at clinically relevant energy of 150 MeVu. METHODS For these purposes, the Monte Carlo code FLUKA was adopted for simulations and three different analytical methods were implemented to get the accuracy in the range retrieval of the simulated set-up. RESULTS The analysis of simulation data has brought to the promising and desired precision of about 4 mm in the determination of the dose profile fall-off in case of a spill irradiation, for which all the three cited methods were coherent in their predictions. CONCLUSIONS The Prompt Gamma Imaging technique should be further studied as a tool to reduce range uncertainties affecting carbon ion radiation therapy.
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Affiliation(s)
- Andrea Missaglia
- Dipartimento di Elettronica, Informazione e Bioingegneria - Politecnico di Milano, Via Ponzio, 34/5, 20133, Milan, Italy.
| | - Aicha Bourkadi-Idrissi
- Dipartimento di Elettronica, Informazione e Bioingegneria - Politecnico di Milano, Via Ponzio, 34/5, 20133, Milan, Italy; INFN - sezione di Milano, Via Giovanni Celoria, 16, 20133, Milan, Italy.
| | - Francesco Casamichiela
- Dipartimento di Energia - Politecnico di Milano, Via Lambruschini, 4, 20156, Milan, Italy.
| | - Davide Mazzucconi
- INFN - sezione di Milano, Via Giovanni Celoria, 16, 20133, Milan, Italy; Dipartimento di Energia - Politecnico di Milano, Via Lambruschini, 4, 20156, Milan, Italy.
| | - Marco Carminati
- Dipartimento di Elettronica, Informazione e Bioingegneria - Politecnico di Milano, Via Ponzio, 34/5, 20133, Milan, Italy; INFN - sezione di Milano, Via Giovanni Celoria, 16, 20133, Milan, Italy.
| | - Stefano Agosteo
- INFN - sezione di Milano, Via Giovanni Celoria, 16, 20133, Milan, Italy; Dipartimento di Energia - Politecnico di Milano, Via Lambruschini, 4, 20156, Milan, Italy.
| | - Carlo Fiorini
- Dipartimento di Elettronica, Informazione e Bioingegneria - Politecnico di Milano, Via Ponzio, 34/5, 20133, Milan, Italy; INFN - sezione di Milano, Via Giovanni Celoria, 16, 20133, Milan, Italy.
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14
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Yao Z, Xiao Y, Dong M, Deng H. Development of a two-layer dense-pixel LYSO Compton camera prototype for prompt gamma imaging. Phys Med Biol 2023; 68. [PMID: 36657173 DOI: 10.1088/1361-6560/acb4d8] [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: 06/15/2022] [Accepted: 01/19/2023] [Indexed: 01/21/2023]
Abstract
Objective.Lutetium-yttrium orthosilicate (LYSO)-based Compton camera (CC) has been proposed for prompt gamma imaging due to its high detection efficiency and position resolution. However, very few LYSO CC prototypes have been built and used for practical evaluation. In this study, we built a lightweight dense-pixel silicon photomultiplier-based two-layer LYSO CC prototype for future prompt gamma imaging.Approach.We attempt the first-ever effort to use the double-encoding with the thick light guide and coding circuit structure for 46 × 46 dense-pixel LYSO detectors construction and use pixel segmentation based on centroid mapping to obtain 4232 spectral calibrations. We also present a framework for list-mode projection data acquisition based on the decoding of the time series data obtained by data acquisition card in this study. Finally, the standard source calibration, ring-like22Na source with non-uniform intensity, and mixed point-like source with a wide energy spectrum experiments were implemented to evaluate the resolution metrics and imaging performance of the prototype.Main results.The lateral position resolution of the prototype was 1 mm, and the maximum measurement deviation is 2.5 mm and 5 mm in the depth direction for the scatterer and absorber, respectively. In the experiments, the measured energy resolution was 9.63% @ 1.33 MeV for the scatterer and 10.8% @ 1.33 MeV for the absorber. And the detection efficiency of the prototype for a spherical60Co source with a diameter of 2.8 mm at 10 cm far was 5.7 × 10-3@ 1.33 MeV and the full width at half maximum of the reconstruction was 5.5 mm. Besides, the spatial position offset within 2 mm of the radioactive source at 10 cm can be distinguished.Signification.The developed two-layer dense-pixel LYSO CC contributes to incorporating Compton imaging techniques for prompt gamma detection and multiple energy sources into nuclear medical imaging.
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Affiliation(s)
- Zhiyang Yao
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, People's Republic of China
| | - Yongshun Xiao
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, People's Republic of China
| | - Minghao Dong
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing, People's Republic of China
| | - Heng Deng
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, People's Republic of China
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15
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Viegas R, Roser J, Barrientos L, Borja-Lloret M, Casaña J, López JG, Jiménez-Ramos M, Hueso-González F, Ros A, Llosá G. Characterization of a Compton camera based on the TOFPET2 ASIC. Radiat Phys Chem Oxf Engl 1993 2023. [DOI: 10.1016/j.radphyschem.2022.110507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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16
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Towards high sensitivity and high-resolution PET scanners: imaging-guided proton therapy and total body imaging. BIO-ALGORITHMS AND MED-SYSTEMS 2022. [DOI: 10.2478/bioal-2022-0079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Abstract
Quantitative imaging (i.e., providing not just an image but also the related data) guidance in proton radiation therapy to achieve and monitor the precision of planned radiation energy deposition field in-vivo (a.k.a. proton range verification) is one of the most under-invested aspects of radiation cancer treatment despite that it may dramatically enhance the treatment accuracy and lower the exposure related toxicity improving the entire outcome of cancer therapy. In this article, we briefly describe the effort of the TPPT Consortium (a collaborative effort of groups from the University of Texas and Portugal) on building a time-of-flight positron-emission-tomography (PET) scanner to be used in pre-clinical studies for proton therapy at MD Anderson Proton Center in Houston. We also discuss some related ideas towards improving and expanding the use of PET detectors, including the total body imaging.
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17
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Longitudinally Heterogeneous Tumor Dose Optimizes Proton Broadbeam, Interlaced Minibeam, and FLASH Therapy. Cancers (Basel) 2022; 14:cancers14205162. [PMID: 36291946 PMCID: PMC9601234 DOI: 10.3390/cancers14205162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/09/2022] [Accepted: 10/17/2022] [Indexed: 11/21/2022] Open
Abstract
Simple Summary The aim of any kind of external radiation therapy is to control a tumor with the highest possible probability of the lowest possible side effects. Here, we study further opportunities of reducing the side effects of proton therapy by applying longitudinally heterogeneous dose distributions in the tumor respecting the delivery of a minimum prescribed dose. In our simulations, the longitudinally heterogeneous dose distributions show a reduced dose in the healthy tissue already in the case of proton broadbeam irradiations, but a much higher (calculated) mean cell survival in the case of proton minibeam irradiation. This demonstrates its potential to substantially reduce side effects at a simultaneously higher tumor control probability, opening new opportunities of easier application when striving for high dose-rate applications of proton beams (>~10 Gy/s), in order to additionally profit from the so-called FLASH effects. Abstract The prerequisite of any radiation therapy modality (X-ray, electron, proton, and heavy ion) is meant to meet at least a minimum prescribed dose at any location in the tumor for the best tumor control. In addition, there is also an upper dose limit within the tumor according to the International Commission on Radiation Units (ICRU) recommendations in order to spare healthy tissue as well as possible. However, healthy tissue may profit from the lower side effects when waving this upper dose limit and allowing a larger heterogeneous dose deposition in the tumor, but maintaining the prescribed minimum dose level, particularly in proton minibeam therapy. Methods: Three different longitudinally heterogeneous proton irradiation modes and a standard spread-out Bragg peak (SOBP) irradiation mode are simulated for their depth-dose curves under the constraint of maintaining a minimum prescribed dose anywhere in the tumor region. Symmetric dose distributions of two opposing directions are overlaid in a 25 cm-thick water phantom containing a 5 cm-thick tumor region. Interlaced planar minibeam dose distributions are compared to those of a broadbeam using the same longitudinal dose profiles. Results and Conclusion: All longitudinally heterogeneous proton irradiation modes show a dose reduction in the healthy tissue compared to the common SOBP mode in the case of broad proton beams. The proton minibeam cases show eventually a much larger mean cell survival and thus a further reduced equivalent uniform dose (EUD) in the healthy tissue than any broadbeam case. In fact, the irradiation mode using only one proton energy from each side shows better sparing capabilities in the healthy tissue than the common spread-out Bragg peak irradiation mode with the option of a better dose fall-off at the tumor edges and an easier technical realization, particularly in view of proton minibeam irradiation at ultra-high dose rates larger than ~10 Gy/s (so-called FLASH irradiation modes).
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18
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Tattenberg S, Marants R, Niepel K, Bortfeld T, Sudhyadhom A, Landry G, Parodi K, Verburg J. Validation of prompt gamma-ray spectroscopy for proton range verification in tissue-mimicking and porcine samples. Phys Med Biol 2022; 67:10.1088/1361-6560/ac950f. [PMID: 36162404 PMCID: PMC9615459 DOI: 10.1088/1361-6560/ac950f] [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: 06/29/2022] [Accepted: 09/26/2022] [Indexed: 11/12/2022]
Abstract
Objective. Proton therapy of cancer improves dose conformality to the target and sparing of surrounding healthy tissues compared to conventional photon treatments. However, proton therapy's advantage could be even larger if proton range uncertainties were reduced. Sources of range uncertainties include computed tomography treatment planning images and variations in patient anatomy and setup. To reduce range uncertainties, we have developed a system for real-timein vivorange monitoring. The system is based on spectroscopy of prompt gamma-rays emitted through proton-nuclear interactions during irradiation. We validated the performance of our prompt gamma-ray spectroscopy detector prototype using tissue-mimicking and porcine samples.Approach. Measurements were performed in water, four tissue-mimicking samples (spongiosa, muscle, adipose tissue, and cortical bone), and two porcine samples (liver and brain). A dose of 0.9 Gy was delivered to a target at a depth of 12.5-17.5 cm. Multi-layer ionization chamber measurements were performed to determine stopping power ratios relative to water and ground truth proton ranges. Ground truth elemental compositions were determined using combustion analysis. Proton ranges and elemental compositions measured using prompt gamma-ray spectroscopy were compared to the ground truth.Main results. For all samples, the mean measured range over all pencil-beam spots differed from the ground truth by less than 1.2 mm. The mean standard deviation was 0.9 mm (range: 0.4-1.6 mm). The mean difference between ground truth and measured elemental compositions was 0.06gcm3(range: 0.00gcm3to 0.12gcm3).Significance. We verified the performance of our prompt gamma-ray spectroscopy detector prototype for proton range verification using tissue-mimicking and porcine samples. Measured proton ranges and elemental sample compositions were in good agreement with the ground truth. These measurements confirm the system's reliability for a variety of tissues and bridge the gap between previously-reported experiments and ongoingin vivopatient measurements.
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Affiliation(s)
- Sebastian Tattenberg
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching, Germany
- Division of Radiation Biophysics, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Raanan Marants
- Department of Radiation Oncology, Brigham and Women’s Hospital/Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Katharina Niepel
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching, Germany
| | - Thomas Bortfeld
- Division of Radiation Biophysics, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Atchar Sudhyadhom
- Department of Radiation Oncology, Brigham and Women’s Hospital/Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
| | - Guillaume Landry
- Department of Radiation Oncology, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
- German Cancer Consortium (DKTK), Partner Site Munich, Munich, Germany
| | - Katia Parodi
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Garching, Germany
| | - Joost Verburg
- Division of Radiation Biophysics, Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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19
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Parajuli RK, Sakai M, Parajuli R, Tashiro M. Development and Applications of Compton Camera-A Review. SENSORS (BASEL, SWITZERLAND) 2022; 22:7374. [PMID: 36236474 PMCID: PMC9573429 DOI: 10.3390/s22197374] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/08/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
The history of Compton cameras began with the detection of radiation sources originally for applications in astronomy. A Compton camera is a promising γ-ray detector that operates in the wide energy range of a few tens of keV to MeV. The γ-ray detection method of a Compton camera is based on Compton scattering kinematics, which is used to determine the direction and energy of the γ-rays without using a mechanical collimator. Although the Compton camera was originally designed for astrophysical applications, it was later applied in medical imaging as well. Moreover, its application in environmental radiation measurements is also under study. Although a few review papers regarding Compton cameras have been published, they either focus very specifically on the detectors used in such cameras or the particular applications of Compton cameras. Thus, the aim of this paper is to review the features and types of Compton cameras and introduce their applications, associated imaging algorithms, improvement scopes, and their future aspects.
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Affiliation(s)
- Raj Kumar Parajuli
- Department of Molecular Imaging and Theranostics, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan
- Gunma University Heavy Ion Medical Center, Gunma University, 3-39-22 Showa-machi, Maebashi 371-8511, Japan
| | - Makoto Sakai
- Gunma University Heavy Ion Medical Center, Gunma University, 3-39-22 Showa-machi, Maebashi 371-8511, Japan
| | | | - Mutsumi Tashiro
- Gunma University Heavy Ion Medical Center, Gunma University, 3-39-22 Showa-machi, Maebashi 371-8511, Japan
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Giacomo SD, Utica G, Carminati M, Borghi G, Picciotto A, Fiorini C. Timing Performances of SDD as Photodetector Candidate for Proton Therapy Application. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2022. [DOI: 10.1109/trpms.2021.3137668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- S. Di Giacomo
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - G. Utica
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - M. Carminati
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - G. Borghi
- Integrated Radiation and Image Sensors, Fondazione Bruno Kessler, Trento, Italy
| | - A. Picciotto
- Integrated Radiation and Image Sensors, Fondazione Bruno Kessler, Trento, Italy
| | - C. Fiorini
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
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21
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Kazemi Kozani M, Magiera A. Machine learning-based event recognition in SiFi Compton camera imaging for proton therapy monitoring. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac71f2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 05/20/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Objective. Online monitoring of dose distribution in proton therapy is currently being investigated with the detection of prompt gamma (PG) radiation emitted from a patient during irradiation. The SiPM and scintillation Fiber based Compton Camera (SiFi-CC) setup is being developed for this aim. Approach. A machine learning approach to recognize Compton events is proposed, reconstructing the PG emission profile during proton therapy. The proposed method was verified on pseudo-data generated by a Geant4 simulation for a single proton beam impinging on a polymethyl methacrylate (PMMA) phantom. Three different models including the boosted decision tree (BDT), multilayer perception (MLP) neural network, and k-nearest neighbour (k-NN) were trained using 10-fold cross-validation and then their performances were assessed using the receiver operating characteristic (ROI) curves. Subsequently, after event selection by the most robust model, a software based on the List-Mode Maximum Likelihood Estimation Maximization (LM-MLEM) algorithm was applied for the reconstruction of the PG emission distribution profile. Main results. It was demonstrated that the BDT model excels in signal/background separation compared to the other two. Furthermore, the reconstructed PG vertex distribution after event selection showed a significant improvement in distal falloff position determination. Significance. A highly satisfactory agreement between the reconstructed distal edge position and that of the simulated Compton events was achieved. It was also shown that a position resolution of 3.5 mm full width at half maximum (FWHM) in distal edge position determination is feasible with the proposed setup.
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22
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Cramér–Rao Bound Evaluations of Compton Imager Designs for Proton Beam Range Verification. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2022. [DOI: 10.1109/trpms.2021.3116118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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23
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Valencia Lozano I, Dedes G, Peterson S, Mackin D, Zoglauer A, Beddar S, Avery S, Polf J, Parodi K. Comparison of reconstructed prompt gamma emissions using maximum likelihood estimation and origin ensemble algorithms for a Compton camera system tailored to proton range monitoring. Z Med Phys 2022:S0939-3889(22)00060-5. [PMID: 35750591 DOI: 10.1016/j.zemedi.2022.04.005] [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: 09/19/2021] [Revised: 04/26/2022] [Accepted: 04/26/2022] [Indexed: 10/18/2022]
Abstract
Compton-based prompt gamma (PG) imaging is being investigated by several groups as a potential solution for in vivo range monitoring in proton therapy. The performance of this technique depends on the detector system as well as the ability of the reconstruction method to obtain good spatial resolution to establish a quantitative correlation between the PG emission and the proton beam range in the patient. To evaluate the feasibility of PG imaging for range monitoring, we quantitatively evaluated the emission distributions reconstructed by a Maximum Likelihood Expectation Maximization (MLEM) and a Stochastic Origin Ensemble (SOE) algorithm. To this end, we exploit experimental and Monte Carlo (MC) simulation data acquired with the Polaris-J Compton Camera (CC) prototype. The differences between the proton beam range (RD) defined as the 80% distal dose fall-off and the PG range (RPG), obtained by fitting the distal end of the reconstructed profile with a sigmoid function, were quantified. A comparable performance of both reconstruction algorithms was found. For both experimental and simulated irradiation scenarios, the correlation between RD and RPG was within 5 mm. These values were consistent with the ground truth distance (RD-RPGg≈ 3 mm) calculated by using the expected PG emission available from MC simulation. Furthermore, shifts of 3 mm in the proton beam range were resolved with the MLEM algorithm by calculating the relative difference between the RPG for each reconstructed profile. In non-homogeneous targets, the spatial changes in the PG emission due to the different materials could not be fully resolved from the reconstructed profiles; however, the fall-off region still resembled the ground truth emission. For this scenario, the PG correlation (RD-RPG) varied from 0.1 mm to 4 mm, which is close to the ground truth correlation (3 mm). This work provides a framework for the evaluation of the range monitoring capabilities of a CC device for PG imaging. The two investigated image reconstruction algorithms showed a comparable and consistent performance for homogeneous and heterogeneous targets.
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Affiliation(s)
- Ingrid Valencia Lozano
- Department of Medical Physics, Ludwig-Maximilians-Universität, Garching b. München, Germany.
| | - George Dedes
- Department of Medical Physics, Ludwig-Maximilians-Universität, Garching b. München, Germany
| | - Steve Peterson
- Department of Physics, University of Cape Town, Rondebosch, Cape Town, South Africa
| | - Dennis Mackin
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Andreas Zoglauer
- Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA
| | - Sam Beddar
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Stephen Avery
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jerimy Polf
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Katia Parodi
- Department of Medical Physics, Ludwig-Maximilians-Universität, Garching b. München, Germany
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24
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Galanakou P, Leventouri T, Muhammad W. Non-radioactive elements for prompt gamma enhancement in proton therapy. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Polf JC, Barajas CA, Peterson SW, Mackin DS, Beddar S, Ren L, Gobbert MK. Applications of Machine Learning to Improve the Clinical Viability of Compton Camera Based in vivo Range Verification in Proton Radiotherapy. FRONTIERS IN PHYSICS 2022; 10:838273. [PMID: 36119562 PMCID: PMC9481064 DOI: 10.3389/fphy.2022.838273] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We studied the application of a deep, fully connected Neural Network (NN) to process prompt gamma (PG) data measured by a Compton camera (CC) during the delivery of clinical proton radiotherapy beams. The network identifies 1) recorded "bad" PG events arising from background noise during the measurement, and 2) the correct ordering of PG interactions in the CC to help improve the fidelity of "good" data used for image reconstruction. PG emission from a tissue-equivalent target during irradiation with a 150 MeV proton beam delivered at clinical dose rates was measured with a prototype CC. Images were reconstructed from both the raw measured data and the measured data that was further processed with a neural network (NN) trained to identify "good" and "bad" PG events and predict the ordering of individual interactions within the good PG events. We determine if NN processing of the CC data could improve the reconstructed PG images to a level in which they could provide clinically useful information about the in vivo range and range shifts of the proton beams delivered at full clinical dose rates. Results showed that a deep, fully connected NN improved the achievable contrast to noise ratio (CNR) in our images by more than a factor of 8x. This allowed the path, range, and lateral width of the clinical proton beam within a tissue equivalent target to easily be identified from the PG images, even at the highest dose rates of a 150 MeV proton beam used for clinical treatments. On average, shifts in the beam range as small as 3 mm could be identified. However, when limited by the amount of PG data measured with our prototype CC during the delivery of a single proton pencil beam (~1 × 109 protons), the uncertainty in the reconstructed PG images limited the identification of range shift to ~5 mm. Substantial improvements in CC images were obtained during clinical beam delivery through NN pre-processing of the measured PG data. We believe this shows the potential of NNs to help improve and push CC-based PG imaging toward eventual clinical application for proton RT treatment delivery verification.
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Affiliation(s)
- Jerimy C. Polf
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Carlos A. Barajas
- Department of Mathematics and Statistics, University of Maryland Baltimore County, Baltimore, MD, United States
| | | | - Dennis S. Mackin
- Department of Medical Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX, United States
| | - Sam Beddar
- Department of Medical Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX, United States
| | - Lei Ren
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Matthias K. Gobbert
- Department of Mathematics and Statistics, University of Maryland Baltimore County, Baltimore, MD, United States
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26
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Pennazio F, Ferrero V, D'Onghia G, Garbolino S, Fiorina E, Marti Villarreal OA, Mas Milian F, Monaco V, Monti V, Patera A, Werner J, Wheadon R, Rafecas M. Proton therapy monitoring: spatiotemporal emission reconstruction with prompt gamma timing and implementation with PET detectors. Phys Med Biol 2022; 67. [PMID: 35193131 DOI: 10.1088/1361-6560/ac5765] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 02/22/2022] [Indexed: 12/17/2022]
Abstract
Objective. In this study we introduce spatiotemporal emission reconstruction prompt gamma timing (SER-PGT), a new method to directly reconstruct the prompt photon emission in the space and time domains inside the patient in proton therapy.Approach. SER-PGT is based on the numerical optimisation of a multidimensional likelihood function, followed by a post-processing of the results. The current approach relies on a specific implementation of the maximum-likelihood expectation maximisation algorithm. The robustness of the method is guaranteed by the complete absence of any information about the target composition in the algorithm.Main results. Accurate Monte Carlo simulations indicate a range resolution of about 0.5 cm (standard deviation) when considering 107primary protons impinging on an homogeneous phantom. Preliminary results on an anthropomorphic phantom are also reported.Significance. By showing the feasibility for the reconstruction of the primary particle range using PET detectors, this study provides significant basis for the development of an hybrid in-beam PET and prompt photon device.
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Affiliation(s)
| | | | | | | | | | | | - Felix Mas Milian
- INFN, Torino, Italy.,Universitá degli Studi di Torino, Torino, Italy.,Universidade Estadual de Santa Cruz, Ilheus, Brazil
| | - Vincenzo Monaco
- INFN, Torino, Italy.,Universitá degli Studi di Torino, Torino, Italy
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27
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Polf JC, Maggi P, Panthi R, Peterson S, Mackin D, Beddar S. The effects of Compton camera data acquisition and readout timing on PG imaging for proton range verification. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2022; 6:366-373. [PMID: 36092269 PMCID: PMC9457195 DOI: 10.1109/trpms.2021.3057341] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The purpose of this study 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 60× 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 <5× 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.
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Affiliation(s)
- Jerimy C. Polf
- University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Paul Maggi
- University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
| | - Rajesh Panthi
- University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA
| | | | - Dennis Mackin
- University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030
| | - Sam Beddar
- University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
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28
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Towards machine learning aided real-time range imaging in proton therapy. Sci Rep 2022; 12:2735. [PMID: 35177663 PMCID: PMC8854574 DOI: 10.1038/s41598-022-06126-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 01/20/2022] [Indexed: 11/08/2022] Open
Abstract
Compton imaging represents a promising technique for range verification in proton therapy treatments. In this work, we report on the advantageous aspects of the i-TED detector for proton-range monitoring, based on the results of the first Monte Carlo study of its applicability to this field. i-TED is an array of Compton cameras, that have been specifically designed for neutron-capture nuclear physics experiments, which are characterized by [Formula: see text]-ray energies spanning up to 5-6 MeV, rather low [Formula: see text]-ray emission yields and very intense neutron induced [Formula: see text]-ray backgrounds. Our developments to cope with these three aspects are concomitant with those required in the field of hadron therapy, especially in terms of high efficiency for real-time monitoring, low sensitivity to neutron backgrounds and reliable performance at the high [Formula: see text]-ray energies. We find that signal-to-background ratios can be appreciably improved with i-TED thanks to its light-weight design and the low neutron-capture cross sections of its LaCl[Formula: see text] crystals, when compared to other similar systems based on LYSO, CdZnTe or LaBr[Formula: see text]. Its high time-resolution (CRT [Formula: see text] 500 ps) represents an additional advantage for background suppression when operated in pulsed HT mode. Each i-TED Compton module features two detection planes of very large LaCl[Formula: see text] monolithic crystals, thereby achieving a high efficiency in coincidence of 0.2% for a point-like 1 MeV [Formula: see text]-ray source at 5 cm distance. This leads to sufficient statistics for reliable image reconstruction with an array of four i-TED detectors assuming clinical intensities of 10[Formula: see text] protons per treatment point. The use of a two-plane design instead of three-planes has been preferred owing to the higher attainable efficiency for double time-coincidences than for threefold events. The loss of full-energy events for high energy [Formula: see text]-rays is compensated by means of machine-learning based algorithms, which allow one to enhance the signal-to-total ratio up to a factor of 2.
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29
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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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30
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Metallic Nanoparticles: A Useful Prompt Gamma Emitter for Range Monitoring in Proton Therapy? RADIATION 2021. [DOI: 10.3390/radiation1040025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In clinical practice, dose delivery in proton therapy treatment is affected by uncertainties related to the range of the beam in the patient, which requires medical physicists to introduce safety margins on the penetration depth of the beam. Although this ensures an irradiation of the entire clinical target volume with the prescribed dose, these safety margins also lead to the exposure of nearby healthy tissues and a subsequent risk of side effects. Therefore, non-invasive techniques that allow for margin reduction through online monitoring of prompt gammas emitted along the proton tracks in the patient are currently under development. This study provides the proof-of-concept of metal-based nanoparticles, injected into the tumor, as a prompt gamma enhancer, helping in the beam range verification. It identifies the limitations of this application, suggesting a low feasibility in a realistic clinical scenario but opens some avenues for improvement.
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31
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Freitas H, Magalhaes Martins P, Tessonnier T, Ackermann B, Brons S, Seco J. Dataset for predicting single-spot proton ranges in proton therapy of prostate cancer. Sci Data 2021; 8:252. [PMID: 34588458 PMCID: PMC8481263 DOI: 10.1038/s41597-021-01028-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 08/05/2021] [Indexed: 11/09/2022] Open
Abstract
The number of radiotherapy patients treated with protons has increased from less than 60,000 in 2007 to more than 220,000 in 2019. However, the considerable uncertainty in the positioning of the Bragg peak deeper in the patient raised new challenges in the proton therapy of prostate cancer (PCPT). Here, we describe and share a dataset where 43 single-spot anterior beams with defined proton energies were delivered to a prostate phantom with an inserted endorectal balloon (ERB) filled either with water only or with a silicon-water mixture. The nuclear reactions between the protons and the silicon yield a distinct prompt gamma energy line of 1.78 MeV. Such energy peak could be identified by means of prompt gamma spectroscopy (PGS) for the protons hitting the ERB with a three-sigma threshold. The application of a background-suppression technique showed an increased rejection capability for protons hitting the prostate and the ERB with water only. We describe each dataset, document the full processing chain, and provide the scripts for the statistical analysis.
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Affiliation(s)
- Hugo Freitas
- German Cancer Research Center - DKFZ, Heidelberg, Germany
- Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Paulo Magalhaes Martins
- German Cancer Research Center - DKFZ, Heidelberg, Germany.
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal.
| | - Thomas Tessonnier
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Benjamin Ackermann
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Stephan Brons
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Joao Seco
- German Cancer Research Center - DKFZ, Heidelberg, Germany.
- Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
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32
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Magalhaes Martins P, Freitas H, Tessonnier T, Ackermann B, Brons S, Seco J. Towards real-time PGS range monitoring in proton therapy of prostate cancer. Sci Rep 2021; 11:15331. [PMID: 34321492 PMCID: PMC8319377 DOI: 10.1038/s41598-021-93612-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 06/24/2021] [Indexed: 11/09/2022] Open
Abstract
Proton therapy of prostate cancer (PCPT) was linked with increased levels of gastrointestinal toxicity in its early use compared to intensity-modulated radiation therapy (IMRT). The higher radiation dose to the rectum by proton beams is mainly due to anatomical variations. Here, we demonstrate an approach to monitor rectal radiation exposure in PCPT based on prompt gamma spectroscopy (PGS). Endorectal balloons (ERBs) are used to stabilize prostate movement during radiotherapy. These ERBs are usually filled with water. However, other water solutions containing elements with higher atomic numbers, such as silicon, may enable the use of PGS to monitor the radiation exposure of the rectum. Protons hitting silicon atoms emit prompt gamma rays with a specific energy of 1.78 MeV, which can be used to monitor whether the ERB is being hit. In a binary approach, we search the silicon energy peaks for every irradiated prostate region. We demonstrate this technique for both single-spot irradiation and real treatment plans. Real-time feedback based on the ERB being hit column-wise is feasible and would allow clinicians to decide whether to adapt or continue treatment. This technique may be extended to other cancer types and organs at risk, such as the oesophagus.
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Affiliation(s)
- Paulo Magalhaes Martins
- German Cancer Research Center - DKFZ, Heidelberg, Germany.
- Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.
| | - Hugo Freitas
- German Cancer Research Center - DKFZ, Heidelberg, Germany
- Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal
| | - Thomas Tessonnier
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Benjamin Ackermann
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Stephan Brons
- Heidelberg Ion-Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Joao Seco
- German Cancer Research Center - DKFZ, Heidelberg, Germany.
- Department of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
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Kawula M, Binder TM, Liprandi S, Viegas R, Parodi K, Thirolf PG. Sub-millimeter precise photon interaction position determination in large monolithic scintillators via convolutional neural network algorithms. Phys Med Biol 2021; 66. [PMID: 34062523 DOI: 10.1088/1361-6560/ac06e2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 06/01/2021] [Indexed: 11/11/2022]
Abstract
In this work, we present the development and application of a convolutional neural network (CNN)-based algorithm to precisely determine the interaction position ofγ-quanta in large monolithic scintillators. Those are used as an absorber component of a Compton camera (CC) system under development for ion beam range verification via prompt-gamma imaging. We examined two scintillation crystals: LaBr3:Ce and CeBr3. Each crystal had dimensions of 50.8 mm × 50.8 mm × 30 mm and was coupled to a 64-fold segmented multi-anode photomultiplier tube (PMT) with an 8 × 8 pixel arrangement. We determined the spatial resolution for three photon energies of 662, 1.17 and 1.33 MeV obtained from 2D detector scans with tightly collimated137Cs and60Co photon sources. With the new algorithm we achieved a spatial resolution for the CeBr3 crystal below 1.11(8) mm and below 0.98(7) mm for the LaBr3:Ce detector for all investigated energies between 662 keV and 1.33 MeV. We thereby improved the performance by more than a factor of 2.5 compared to the previously used categorical average pattern algorithm, which is a variation of the well-established k-nearest neighbor algorithm. The trained CNN has a low memory footprint and enables the reconstruction of up to 104events per second with only one GPU. Those improvements are crucial on the way to future clinicalin vivoapplicability of the CC for ion beam range verification.
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Affiliation(s)
- M Kawula
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
| | - T M Binder
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany.,KETEK GmbH, Munich, Germany
| | - S Liprandi
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
| | - R Viegas
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany.,University of Coimbra, Portugal
| | - K Parodi
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
| | - P G Thirolf
- Department of Medical Physics, Ludwig-Maximilians-Universität München, Garching b. München, Germany
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Jacquet M, Marcatili S, Gallin-Martel ML, Bouly JL, Boursier Y, Dauvergne D, Dupont M, Gallin-Martel L, Hérault J, Létang JM, Manéval D, Morel C, Muraz JF, Testa É. A time-of-flight-based reconstruction for real-time prompt-gamma imaging in proton therapy. Phys Med Biol 2021; 66. [PMID: 34020438 DOI: 10.1088/1361-6560/ac03ca] [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: 12/16/2020] [Accepted: 05/21/2021] [Indexed: 11/12/2022]
Abstract
We propose a novel prompt-gamma (PG) imaging modality for real-time monitoring in proton therapy: PG time imaging (PGTI). By measuring the time-of-flight (TOF) between a beam monitor and a PG detector, our goal is to reconstruct the PG vertex distribution in 3D. In this paper, a dedicated, non-iterative reconstruction strategy is proposed (PGTI reconstruction). Here, it was resolved under a 1D approximation to measure a proton range shift along the beam direction. In order to show the potential of PGTI in the transverse plane, a second method, based on the calculation of the centre of gravity (COG) of the TIARA pixel detectors' counts was also explored. The feasibility of PGTI was evaluated in two different scenarios. Under the assumption of a 100 ps (rms) time resolution (achievable in single proton regime), MC simulations showed that a millimetric proton range shift is detectable at 2σwith 108incident protons in simplified simulation settings. With the same proton statistics, a potential 2 mm sensitivity (at 2σwith 108incident protons) to beam displacements in the transverse plane was found using the COG method. This level of precision would allow to act in real-time if the treatment does not conform to the treatment plan. A worst case scenario of a 1 ns (rms) TOF resolution was also considered to demonstrate that a degraded timing information can be compensated by increasing the acquisition statistics: in this case, a 2 mm range shift would be detectable at 2σwith 109incident protons. By showing the feasibility of a time-based algorithm for the reconstruction of the PG vertex distribution for a simplified anatomy, this work poses a theoretical basis for the future development of a PG imaging detector based on the measurement of particle TOF.
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Affiliation(s)
- Maxime Jacquet
- Université Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3 UMR 5821, F-38000 Grenoble, France
| | - Sara Marcatili
- Université Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3 UMR 5821, F-38000 Grenoble, France
| | | | - Jean-Luc Bouly
- Université Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3 UMR 5821, F-38000 Grenoble, France
| | | | - Denis Dauvergne
- Université Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3 UMR 5821, F-38000 Grenoble, France
| | | | - Laurent Gallin-Martel
- Université Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3 UMR 5821, F-38000 Grenoble, France
| | | | - Jean-Michel Létang
- University of Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, F-69373 Lyon, France
| | | | | | - Jean-François Muraz
- Université Grenoble Alpes, CNRS, Grenoble INP, LPSC-IN2P3 UMR 5821, F-38000 Grenoble, France
| | - Étienne Testa
- Univ. Lyon, Univ. Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, F-69622, Villeurbanne, France
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35
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Distal edge determination precision for a multi-slat prompt-gamma camera: A comprehensive simulation and optimization of the detection system. Phys Med 2021; 84:85-100. [PMID: 33882445 DOI: 10.1016/j.ejmp.2021.03.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 11/22/2022] Open
Abstract
Multi-slat prompt-gamma camera is a promising tool for range monitoring during proton therapy. We report the results of a comprehensive simulation study analyzing the precision which is possible to reach with this camera in determination of the position of the distal edge of the Bragg peak. For the first time we include simulation of optical photons. The proton beam (single pencil beam, 130 MeV, 10 ns bunch period, total of 1·108 protons) is interacting with a polymethyl methacrylate (PMMA) phantom, which is a cylinder of 200 mm in diameter and length. The prompt gamma rays generated in the phantom are collimated with a multi-slat collimator and detected using a combination of yttrium aluminum perovskite (YAP) scintillators, installed in the collimator apertures, and light sensors. Two scintillator packing schemes, with one and with two scintillator plates per aperture, are considered. The collimator configuration (the septal thickness, aperture and height), resulting in the best precision, is determined using two methods of detector optimization. Precision of 2.1 mm (full width at half maximum) in the edge position determination is demonstrated.
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36
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Burbadge C, Kasanda E, Bildstein V, Dublin G, Olaizola B, Höhr C, Mücher D. Proton therapy range verification method via delayed γ-ray spectroscopy of a molybdenum tumour marker. Phys Med Biol 2021; 66:025005. [PMID: 32998122 DOI: 10.1088/1361-6560/abbd16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this work, a new method of range verification for proton therapy (PT) is experimentally demonstrated for the first time. If a metal marker is implanted near the tumour site, its response to proton activation will result in the emission of characteristic γ rays. The relative intensity of γ rays originating from competing fusion-evaporation reaction channels provides a unique signature of the average proton energy at the marker, and by extension the beam's range, in vivo and in real time. The clinical feasibility of this method was investigated at the PT facility at TRIUMF with a proof-of-principle experiment which irradiated a naturally-abundant molybdenum foil at various proton beam energies. Delayed characteristic γ rays were measured with two Compton-shielded LaBr3 scintillators. The technique was successfully demonstrated by relating the relative intensity of two γ-ray peaks to the energy of the beam at the Mo target, opening the door to future clinical applications where the range of the beam can be verified in real time.
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Affiliation(s)
- C Burbadge
- Department of Physics, University of Guelph, 50 Stone Rd E, Guelph, Ontario, N1G 2W1, Canada
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37
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Marcatili S, Collot J, Curtoni S, Dauvergne D, Hostachy JY, Koumeir C, Létang JM, Livingstone J, Métivier V, Gallin-Martel L, Gallin-Martel ML, Muraz JF, Servagent N, Testa É, Yamouni M. Ultra-fast prompt gamma detection in single proton counting regime for range monitoring in particle therapy. ACTA ACUST UNITED AC 2020; 65:245033. [DOI: 10.1088/1361-6560/ab7a6c] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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38
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Kasanda E, Burbadge C, Bildstein V, Turko J, Spyrou A, Höhr C, Mücher D. GEANT4 simulation of a range verification method using delayed γ spectroscopy of a 92Mo marker. Phys Med Biol 2020; 65:245047. [PMID: 33331299 DOI: 10.1088/1361-6560/abbd15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In this work, we propose a novel technique for in-vivo proton therapy range verification. This technique makes use of a molybdenum hadron tumour marker, implanted at a short distance from the clinical treatment volume. Signals emitted from the marker during treatment can provide a direct measurement of the proton beam energy at the marker's position. Fusion-evaporation reactions between the proton beam and marker nucleus result in the emission of delayed characteristic γ rays, which are detected off-beam for an improved signal-to-noise ratio. In order to determine the viability of this technique and to establish an experimental setup for future work, the Monte Carlo package GEANT4 was used in combination with ROOT to simulate a treatment scenario with the new method outlined in this work. These simulations show that the intensity of delayed γ rays produced from competing reactions yields a precise measurement of the range of the proton beam relative to the marker, with sub-millimetre uncertainty.
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Affiliation(s)
- E Kasanda
- Department of Physics, University of Guelph, 50 Stone Rd E, Guelph, ON, N1G 2W1, Canada
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Farr JB, Moyers MF, Allgower CE, Bues M, Hsi WC, Jin H, Mihailidis DN, Lu HM, Newhauser WD, Sahoo N, Slopsema R, Yeung D, Zhu XR. Clinical commissioning of intensity-modulated proton therapy systems: Report of AAPM Task Group 185. Med Phys 2020; 48:e1-e30. [PMID: 33078858 DOI: 10.1002/mp.14546] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 02/06/2023] Open
Abstract
Proton therapy is an expanding radiotherapy modality in the United States and worldwide. With the number of proton therapy centers treating patients increasing, so does the need for consistent, high-quality clinical commissioning practices. Clinical commissioning encompasses the entire proton therapy system's multiple components, including the treatment delivery system, the patient positioning system, and the image-guided radiotherapy components. Also included in the commissioning process are the x-ray computed tomography scanner calibration for proton stopping power, the radiotherapy treatment planning system, and corresponding portions of the treatment management system. This commissioning report focuses exclusively on intensity-modulated scanning systems, presenting details of how to perform the commissioning of the proton therapy and ancillary systems, including the required proton beam measurements, treatment planning system dose modeling, and the equipment needed.
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Affiliation(s)
- Jonathan B Farr
- Department of Medical Physics, Applications of Detectors and Accelerators to Medicine, Meyrin, 1217, Switzerland
| | | | - Chris E Allgower
- Richard L. Roudebush VA Medical Center, Indianapolis, IN, 46202, USA
| | - Martin Bues
- Department of Radiation Oncology, Mayo Clinic, Scottsdale, AZ, 85259, USA
| | - Wen-Chien Hsi
- University of Florida Proton Therapy Institute, University of Florida, Jacksonville, FL, 32206, USA
| | - Hosang Jin
- Department of Radiation Oncology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Dimitris N Mihailidis
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Hsiao-Ming Lu
- Department of Radiation Oncology, Hefei Ion Medical Center, 1700 Changning Avenue, Gaoxin District, Hefei, Anhui, 230088, China
| | - Wayne D Newhauser
- Department of Physics & Astronomy, Louisiana State University, Baton Rouge, LA, 70803, USA.,Mary Bird Perkins Cancer Center, Baton Rouge, LA, 70809, USA
| | - Narayan Sahoo
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Roelf Slopsema
- Department of Radiation Oncology, Emory Proton Therapy Center, Emory University, Atlanta, GA, 30322, USA
| | - Daniel Yeung
- Saudi Proton Therapy Center, King Fahad Medical City, Riyadh, Riyadh Province, 11525, Saudi Arabia
| | - X Ronald Zhu
- Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
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40
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Xie Y, Petzoldt J, Janssens G, O'Grady F, Yin L, Bentefour EH, Smeets J, Prieels D, Lustig RA, Lin A, Teo BK. Prompt gamma imaging for the identification of regional proton range deviations due to anatomic change in a heterogeneous region. Br J Radiol 2020; 93:20190619. [PMID: 32960655 DOI: 10.1259/bjr.20190619] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVES Prompt gamma (PG) imaging has previously been demonstrated for use in proton range verification of a brain treatment with a homogeneous target region. In this study, the feasibility of PG imaging to detect anatomic change within a heterogeneous region is presented. METHODS A prompt gamma camera recorded several fractions of a patient treatment to the base of skull. An evaluation CT revealed a decrease in sinus cavity filling during the treatment course. Comparison of PG profiles between measurement and simulation was performed to investigate range variations between planned and measured pencil beam spot positions. RESULTS For one field, an average over range of 3 mm due to the anatomic change could be detected for a subset of spots traversing the sinus cavity region. The two other fields appeared less impacted by the change but predicted range variations could not be detected. These results were partially consistent with the simulations of the evaluation CT. CONCLUSION We report the first clinical application of PG imaging that detected some of the expected small regional proton range deviations due to anatomic change in a heterogeneous region. However, several limitations exist with the technology that may limit its sensitivity to detect range deviations in heterogeneous regions. ADVANCES IN KNOWLEDGE We report on the first detection of range variations due to anatomic change in a heterogeneous region using PGI. The results confirm the feasibility of using PG-based range verification in highly heterogeneous target regions to identify deviations from the treatment plan.
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Affiliation(s)
- Yunhe Xie
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA.,Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA
| | | | | | - Fionnbarr O'Grady
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Lingshu Yin
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Julien Smeets
- Ion Beam Applications S.A., Louvain-la-Neuve, Belgium
| | | | - Robert A Lustig
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Alexander Lin
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Boon-Keng Teo
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
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The SiFi-CC project – Feasibility study of a scintillation-fiber-based Compton camera for proton therapy monitoring. Phys Med 2020; 76:317-325. [DOI: 10.1016/j.ejmp.2020.07.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 06/19/2020] [Accepted: 07/09/2020] [Indexed: 11/15/2022] Open
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42
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Khamfongkhruea C, Berthold J, Janssens G, Petzoldt J, Smeets J, Pausch G, Richter C. Classification of the source of treatment deviation in proton therapy using prompt-gamma imaging information. Med Phys 2020; 47:5102-5111. [PMID: 32678913 DOI: 10.1002/mp.14393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/30/2020] [Accepted: 07/03/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Prompt-gamma imaging (PGI)-based range verification has been successfully implemented in clinical proton therapy recently and its sensitivity to detect treatment deviations is currently investigated. The cause of treatment deviations can be multiple - for example, computed tomography (CT)-based range prediction, patient setup, and anatomical changes. Hence, it would be beneficial, if PGI-based verification would not only detect a treatment deviation but would also be able to directly identify its most probable source. Here, we propose a heuristically derived decision tree approach to automatically classify the sources of range deviation in proton pencil-beam scanning (PBS) treatments of head and neck tumors based on range information obtained with a PGI slit camera. MATERIALS AND METHODS The decision tree model was iteratively generated on a training dataset of different anatomical complexities, for an anthropomorphic head phantom and patient CT data (planning and control CTs) from five patients. Different range prediction errors, setup changes and relevant and nonrelevant anatomical changes were introduced or derived from control CTs, summing up to a total of 98 training scenarios. Independent validation was performed for another 98 scenarios, derived solely from patient CT data of another seven patients. PBS head and neck treatment plans were generated for the nominal scenario. For all PBS spots in the investigated field, PGI profiles were simulated using a dedicated analytical model of the slit camera for the nominal as well as the different error scenarios. From comparison of PGI profiles for nominal and error scenarios, a spot-wise range shift after spot aggregation with a kernel of 7 mm sigma was determined for each error scenario. The heuristic approach includes a prefiltering of the most suitable PBS spots for PGI treatment verification. From the validation, the accuracy, sensitivity, and specificity of the model were determined. RESULTS A five-step consecutive filter was developed to preselect PBS spots. On average, 25% of spots (1044 spots) remained as input for the classification model. The derived heuristic decision tree model is based on five parameters: The coefficient of determination (R2 ), the slope and intercept of the linear regression between PGI-derived range shifts and the respectively predicted proton ranges for the investigated PBS spots, as well as the average and standard deviation of the PGI-derived shifts. With this approach, 94 of 98 error scenarios could be classified correctly in validation (accuracy of 96%). A sensitivity and specificity of 100% and 86% were reached. CONCLUSIONS In this simulation study it was demonstrated that the source of a treatment deviation can be identified from simulated noiseless PGI information in head and neck tumor treatments with high sensitivity and specificity. The application, refinement, and evaluation of the approach on measured PGI data will be the next step to show the clinical feasibility of PGI-based error source classification.
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Affiliation(s)
- Chirasak Khamfongkhruea
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany.,Faculty of Medicine and Public Health, HRH Princess Chulabhorn College of Medical Science, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Jonathan Berthold
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany
| | | | | | | | - Guntram Pausch
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany.,Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany
| | - Christian Richter
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany.,Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany.,Department of Radiotherapy and Radiation Oncology, Faculty of Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.,German Cancer Consortium (DKTK), partner site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany
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43
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Panaino CM, Mackay RI, Sotiropoulos M, Kirkby KJ, Taylor MJ. Full 3D position reconstruction of a radioactive source based on a novel hyperbolic geometrical algorithm. COMPUTER PHYSICS COMMUNICATIONS 2020; 252:107131. [PMID: 32624585 PMCID: PMC7233137 DOI: 10.1016/j.cpc.2019.107131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 12/02/2019] [Accepted: 12/16/2019] [Indexed: 06/11/2023]
Abstract
A new method to locate, with millimetre uncertainty, in 3D, a γ -ray source emitting multiple γ -rays in a cascade, employing conventional LaBr3(Ce) scintillation detectors, has been developed. Using 16 detectors in a symmetrical configuration the detector energy and time signals, resulting from the γ -ray interactions, are fed into a new source position reconstruction algorithm. The Monte-Carlo based Geant4 framework has been used to simulate the detector array and a 60Co source located at two positions within the spectrometer central volume. For a source located at (0,0,0) the algorithm reports X, Y, Z values of -0.3 ± 2.5, -0.4 ± 2.4, and -0.6 ± 2.5 mm, respectively. For a source located at (20,20,20) mm, with respect to the array centre, the algorithm reports X, Y, Z values of 20.2 ± 1.0, 20.2 ± 0.9, and 20.1 ± 1.2 mm. The resulting precision of the reconstruction means that this technique could find application in a number of areas including nuclear medicine, national security, radioactive waste assay and proton beam therapy.
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Affiliation(s)
| | - Ranald I. Mackay
- Division of Cancer Sciences, University of Manchester, M13 9PL, Manchester, UK
- The Christie NHS Foundation Trust, M20 4BX, Manchester, UK
| | - Marios Sotiropoulos
- Division of Cancer Sciences, University of Manchester, M13 9PL, Manchester, UK
| | - Karen J. Kirkby
- Division of Cancer Sciences, University of Manchester, M13 9PL, Manchester, UK
- The Christie NHS Foundation Trust, M20 4BX, Manchester, UK
| | - Michael J. Taylor
- Division of Cancer Sciences, University of Manchester, M13 9PL, Manchester, UK
- The Christie NHS Foundation Trust, M20 4BX, Manchester, UK
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44
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Mohammadi A, Tashima H, Iwao Y, Takyu S, Akamatsu G, Kang HG, Nishikido F, Yoshida E, Chacon A, Safavi-Naeini M, Parodi K, Yamaya T. Influence of momentum acceptance on range monitoring of 11C and 15O ion beams using in-beam PET. Phys Med Biol 2020; 65:125006. [PMID: 32176873 DOI: 10.1088/1361-6560/ab8059] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In heavy-ion therapy, the stopping position of primary ions in tumours needs to be monitored for effective treatment and to prevent overdose exposure to normal tissues. Positron-emitting ion beams, such as 11C and 15O, have been suggested for range verification in heavy-ion therapy using in-beam positron emission tomography (PET) imaging, which offers the capability of visualizing the ion stopping position with a high signal-to-noise ratio. We have previously demonstrated the feasibility of in-beam PET imaging for the range verification of 11C and 15O ion beams and observed a slight shift between the beam stopping position and the dose peak position in simulations, depending on the initial beam energy spread. In this study, we focused on the experimental confirmation of the shift between the Bragg peak position and the position of the maximum detected positron-emitting fragments via a PET system for positron-emitting ion beams of 11C (210 MeV u-1) and 15O (312 MeV u-1) with momentum acceptances of 5% and 0.5%. For this purpose, we measured the depth doses and performed in-beam PET imaging using a polymethyl methacrylate (PMMA) phantom for both beams with different momentum acceptances. The shifts between the Bragg peak position and the PET peak position in an irradiated PMMA phantom for the 15O ion beams were 1.8 mm and 0.3 mm for momentum acceptances of 5% and 0.5%, respectively. The shifts between the positions of two peaks for the 11C ion beam were 2.1 mm and 0.1 mm for momentum acceptances of 5% and 0.5%, respectively. We observed larger shifts between the Bragg peak and the PET peak positions for a momentum acceptance of 5% for both beams, which is consistent with the simulation results reported in our previous study. The biological doses were also estimated from the calculated relative biological effectiveness (RBE) values using a modified microdosimetric kinetic model (mMKM) and Monte Carlo simulation. Beams with a momentum acceptance of 5% should be used with caution for therapeutic applications to avoid extra dose to normal tissues beyond the tumour when the dose distal fall-off is located beyond the treatment volume.
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Affiliation(s)
- Akram Mohammadi
- National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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Dal Bello R, Magalhaes Martins P, Brons S, Hermann G, Kihm T, Seimetz M, Seco J. Prompt gamma spectroscopy for absolute range verification of 12C ions at synchrotron-based facilities. Phys Med Biol 2020; 65:095010. [PMID: 32092707 DOI: 10.1088/1361-6560/ab7973] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The physical range uncertainty limits the exploitation of the full potential of charged particle therapy. In this work, we face this issue aiming to measure the absolute Bragg peak position in the target. We investigate p, 4He, 12C and 16O beams accelerated at the Heidelberg Ion-Beam Therapy Center. The residual range of the primary 12C ions is correlated to the energy spectrum of the prompt gamma radiation. The prompt gamma spectroscopy method was demonstrated for proton beams accelerated by cyclotrons and is developed here for the first time for heavier ions accelerated by a synchrotron. We develop a detector system that includes (i) a spectroscopic unit based on cerium(III) bromide and bismuth germanium oxide scintillating crystals, (ii) a beam trigger based on an array of scintillating fibers and (iii) a data acquisition system based on a FlashADC. We test the system in two different scenarios. In the first series of experiments, we detect and identify 19 independent spectral lines over a wide gamma energy spectrum in the presence of the four ion species for different targets, including a water target with a titanium insert. In the second series of experiments, we introduce a collimator aiming to relate the spectral information to the range of the primary particles. We perform extensive measurements for a 12C beam and demonstrate submillimetric precision for the measurement of its Bragg peak position in the experimental setup. The features of the energy and time spectra for gamma radiation induced by p, 4He and 16O are investigated upstream and downstream from the Bragg peak position. We conclude the analysis by extrapolating the required future developments, which would be needed to achieve range verification with a 2 mm accuracy during a single fraction delivery of [Formula: see text] physical dose.
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Affiliation(s)
- Riccardo Dal Bello
- Division of Biomedical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany. Department of Physics and Astronomy, Heidelberg University, Heidelberg, Germany
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PIBS: Proton and ion beam spectroscopy for in vivo measurements of oxygen, carbon, and calcium concentrations in the human body. Sci Rep 2020; 10:7007. [PMID: 32332815 PMCID: PMC7181859 DOI: 10.1038/s41598-020-63215-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 03/25/2020] [Indexed: 12/03/2022] Open
Abstract
Proton and ion beam therapy has proven to benefit tumour control with lower side-effects, mostly in paediatrics. Here we demonstrate a feasible technique for proton and ion beam spectroscopy (PIBS) capable of determining the elemental compositions of the irradiated tissues during particle therapy. This follows the developments in prompt gamma imaging for online range verification and the inheritance from prompt gamma neutron activation analysis. Samples of water solutions were prepared to emulate varying oxygen and carbon concentrations. The irradiation of those samples and other tissue surrogate inserts by protons and ion beams under clinical conditions clearly showed a logarithmic relationship between the target elemental composition and the prompt gamma production. This finding is in line with the known logarithmic dependence of the pH with the proton molar concentration. Elemental concentration changes of 1% for calcium and 2% for oxygen in adipose, brain, breast, liver, muscle and bone-related tissue surrogates were clearly identified. Real-time in vivo measurements of oxygen, carbon and calcium concentrations will be evaluated in a pre-clinical and clinical environment. This technique should have an important impact in the assessment of tumour hypoxia over the course of several treatment fractions and the tracking of calcifications in brain metastases.
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Hueso-González F, Bortfeld T. Compact Method for Proton Range Verification Based on Coaxial Prompt Gamma-Ray Monitoring: a Theoretical Study. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2020; 4:170-183. [PMID: 32258856 PMCID: PMC7111431 DOI: 10.1109/trpms.2019.2930362] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Range uncertainties in proton therapy hamper treatment precision. Prompt gamma-rays were suggested 16 years ago for real-time range verification, and have already shown promising results in clinical studies with collimated cameras. Simultaneously, alternative imaging concepts without collimation are investigated to reduce the footprint and price of current prototypes. In this manuscript, a compact range verification method is presented. It monitors prompt gamma-rays with a single scintillation detector positioned coaxially to the beam and behind the patient. Thanks to the solid angle effect, proton range deviations can be derived from changes in the number of gamma-rays detected per proton, provided that the number of incident protons is well known. A theoretical background is formulated and the requirements for a future proof-of-principle experiment are identified. The potential benefits and disadvantages of the method are discussed, and the prospects and potential obstacles for its use during patient treatments are assessed. The final milestone is to monitor proton range differences in clinical cases with a statistical precision of 1 mm, a material cost of 25000 USD and a weight below 10 kg. This technique could facilitate the widespread application of in vivo range verification in proton therapy and eventually the improvement of treatment quality.
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Affiliation(s)
- F Hueso-González
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
| | - T Bortfeld
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, United States of America
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Lens E, Tolboom E, Schaart DR. An Approach for Optimizing Prompt Gamma Photon-Based Range Estimation in Proton Therapy Using Cramér–Rao Theory. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2020. [DOI: 10.1109/trpms.2019.2921634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Van Delinder KW, Crawford D, Zhang T, Khan R, Gräfe JL. Investigating neutron activated contrast agent imaging for tumor localization in proton therapy: a feasibility study for proton neutron gamma-x detection (PNGXD). Phys Med Biol 2020; 65:035005. [PMID: 31851952 DOI: 10.1088/1361-6560/ab63b5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Proton neutron gamma-x detection (PNGXD) is a novel imaging concept being investigated for tumor localization during proton therapy that uses secondary neutron interactions with a gadolinium contrast agent (GDCA) to produce characteristic photons within the 40-200 keV energy region. The purpose of this study is to experimentally investigate the feasibility of implementing this procedure by performing experimental measurements on a passive double scattering proton treatment unit. Five experimental measurements were performed with varying concentrations and irradiation conditions. Photon spectra were measured with a 25 mm2, 1 mm thick uncollimated X-123 CdTe spectrometer. For a 10.4 Gy administration on a 100 ml volume phantom with 10 mg g-1 Gd solution placed in a water phantom, 1129 ± 184 K-shell Gd counts were detected. For an administered dose of 21 Gy and the same Gd solution measured in air, resulted in 3296 ± 256 counts. A total of 1094 ± 171, 421 ± 150 and 23 ± 141 K-shell Gd counts were measured for Gd concentrations of 10 mg g-1, 1 mg g-1 and 0 mg g-1 for 7 Gy dose in air. The signal to noise ratio for these five measurements were: 7, 15, 6, 3, and 0.2, respectively. The spectrum contained 43 keV K α and 49 keV K β peaks, however a small amount of 79.5 and 181.9 keV prompt gamma rays were detected from gadolinium neutron capture. This discrepancy is due to a drop in the intrinsic detection efficiency of the CdTe spectrometer over this energy range. The measurements were compared with Monte-Carlo simulation to determine the contributions of Gd neutron capture from internal and external neutrons on a passive scattering proton therapy unit and to investigate the discrepancy in detected characteristic x-rays versus prompt gamma rays.
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Affiliation(s)
- Kurt W Van Delinder
- Department of Physics, Faculty of Science, Ryerson University, 350 Victoria St., Toronto, Ontario M5B 2K3, Canada. Author to whom any correspondence should be addressed
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A deep learning approach for converting prompt gamma images to proton dose distributions: A Monte Carlo simulation study. Phys Med 2020; 69:110-119. [DOI: 10.1016/j.ejmp.2019.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 11/11/2019] [Accepted: 12/05/2019] [Indexed: 11/20/2022] Open
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