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Jeong S, Kim CE, Kim C, Pak SI, An S, Cheon W, Shin D, Lim YK, Jeong JH, Kim H, Chung Y, Choi SH, Lee SB. Feasibility study for the development of multilayered solar cells for proton linear energy transfer depth profile measurement. Med Phys 2024. [PMID: 38828894 DOI: 10.1002/mp.17234] [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: 11/28/2023] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 06/05/2024] Open
Abstract
BACKGROUND Previous study proposed a method to measure linear energy transfer (LET) at specific points using the quenching magnitude of thin film solar cells. This study was conducted to propose a more advanced method for measuring the LET distribution. PURPOSE This study focuses on evaluating the feasibility of estimating the proton LET distribution in proton therapy. The feasibility of measuring the proton LET and dose distribution simultaneously using a single-channel configuration comprising two solar cells with distinct quenching constants is investigated with the objective of paving the way for enhanced proton therapy dosimetry. METHODS Two solar cells with different quenching constants were used to estimate the proton LET distribution. Detector characteristics (e.g., dose linearity and dose-rate dependency) of the solar cells were evaluated to assess their suitability for dosimetry applications. First, using a reference beam condition, the quenching constants of the two solar cells were determined according to the modified Birks equation. The signal ratios of the two solar cells were then evaluated according to proton LET in relation to the estimated quenching constants. The proton LET distributions of six test beams were obtained by measuring the signal ratios of the two solar cells at each depth, and the ratios were evaluated by comparing them with those calculated by Monte Carlo simulation. RESULTS The detector characterization of the two solar cells including dose linearity and dose-rate dependence affirmed their suitability for use in dosimetry applications. The maximum difference between the LET measured using the two solar cells and that calculated by Monte Carlo simulation was 2.34 keV/µm. In the case of the dose distribution measured using the method proposed in this study, the maximum difference between range measured using the proposed method and that measured using a multilayered ionization chamber was 0.7 mm. The expected accuracy of simultaneous LET and dose distribution measurement using the method proposed in this study were estimated to be 3.82%. The signal ratios of the two solar cells, which are related to quenching constants, demonstrated the feasibility of measuring LET and dose distribution simultaneously. CONCLUSION The feasibility of measuring proton LET and dose distribution simultaneously using two solar cells with different quenching constants was demonstrated. Although the method proposed in this study was evaluated using a single channel by varying the measuring depth, the results suggest that the proton LET and dose distribution can be simultaneously measured if the detector is configured in a multichannel form. We believe that the results presented in this study provide the envisioned transition to a multichannel configuration, with the promise of substantially advancing proton therapy's accuracy and efficacy in cancer treatment.
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Affiliation(s)
- Seonghoon Jeong
- Department of Neurosurgery, College of Medicine, Ilsan Paik Hospital, Inje University, Goyang, Republic of Korea
| | - Chae-Eon Kim
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Chankyu Kim
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Sang-Il Pak
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Seohyeon An
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
- Department of Physics, Hanyang University, Seoul, Republic of Korea
| | - Wonjoong Cheon
- Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Dongho Shin
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Young Kyung Lim
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Jong Hwi Jeong
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Haksoo Kim
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
| | - Yoonsun Chung
- Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea
| | - Sang Hyoun Choi
- Radiation Therapy Technology and Standards, Korea Institute of Radiological & Medical Sciences, Seoul, Republic of Korea
| | - Se Byeong Lee
- Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea
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Amstutz F, Krcek R, Bachtiary B, Weber DC, Lomax AJ, Unkelbach J, Zhang Y. Treatment planning comparison for head and neck cancer between photon, proton, and combined proton-photon therapy - From a fixed beam line to an arc. Radiother Oncol 2024; 190:109973. [PMID: 37913953 DOI: 10.1016/j.radonc.2023.109973] [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: 01/11/2023] [Revised: 09/25/2023] [Accepted: 10/26/2023] [Indexed: 11/03/2023]
Abstract
BACKGROUND AND PURPOSE This study investigates whether combined proton-photon therapy (CPPT) improves treatment plan quality compared to single-modality intensity-modulated radiation therapy (IMRT) or intensity-modulated proton therapy (IMPT) for head and neck cancer (HNC) patients. Different proton beam arrangements for CPPT and IMPT are compared, which could be of specific interest concerning potential future upright-positioned treatments. Furthermore, it is evaluated if CPPT benefits remain under inter-fractional anatomical changes for HNC treatments. MATERIAL AND METHODS Five HNC patients with a planning CT and multiple (4-7) repeated CTs were studied. CPPT with simultaneously optimized photon and proton fluence, single-modality IMPT, and IMRT treatment plans were optimized on the planning CT and then recalculated and reoptimized on each repeated CT. For CPPT and IMPT, plans with different degrees of freedom for the proton beams were optimized. Fixed horizontal proton beam line (FHB), gantry-like, and arc-like plans were compared. RESULTS The target coverage for CPPT without adaptation is insufficient (average V95%=88.4 %), while adapted plans can recover the initial treatment plan quality for target (average V95%=95.5 %) and organs-at-risk. CPPT with increased proton beam flexibility increases plan quality and reduces normal tissue complication probability of Xerostomia and Dysphagia. On average, Xerostomia NTCP reductions compared to IMRT are -2.7 %/-3.4 %/-5.0 % for CPPT FHB/CPPT Gantry/CPPT Arc. The differences for IMPT FHB/IMPT Gantry/IMPT Arc are + 0.8 %/-0.9 %/-4.3 %. CONCLUSION CPPT for HNC needs adaptive treatments. Increasing proton beam flexibility in CPPT, either by using a gantry or an upright-positioned patient, improves treatment plan quality. However, the photon component is substantially reduced, therefore, the balance between improved plan quality and costs must be further determined.
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Affiliation(s)
- Florian Amstutz
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland; Department of Physics, ETH Zurich, Switzerland
| | - Reinhardt Krcek
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland; Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | | | - Damien C Weber
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland; Department of Radiation Oncology, University Hospital Zurich, Switzerland; Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Antony J Lomax
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland; Department of Physics, ETH Zurich, Switzerland
| | - Jan Unkelbach
- Department of Radiation Oncology, University Hospital Zurich, Switzerland
| | - Ye Zhang
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland.
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Sato S, Yokokawa H, Hosobuchi M, Kataoka J. A simulation study of in-beam visualization system for proton therapy by monitoring scattered protons. Front Med (Lausanne) 2023; 10:1038348. [PMID: 37521357 PMCID: PMC10375415 DOI: 10.3389/fmed.2023.1038348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 06/20/2023] [Indexed: 08/01/2023] Open
Abstract
Recently, in-beam positron emission tomography (PET) has been actively researched for reducing biological washout effects and dose monitoring during irradiation. However, the positron distribution does not precisely reflect the dose distribution since positron production and ionization are completely different physical processes. Thus, a novel in-beam system was proposed to determine proton dose range by measuring scattered protons with dozens of scintillation detectors surrounding the body surface. While previous studies conducted a preliminary experiment with a simple phantom, we simulated more complex situations in this paper. Especially, we conducted three stepwise simulation studies to demonstrate the feasibility of the proposed method. First, a simple rectangular phantom was reproduced on simulation and irradiated with protons for obtaining current values and Monte Carlo (MC) dose. Next, we trained a deep learning model to estimate 2-dimensional-dose range (2D-DL dose) from measured current values for simulation (A). We simulated plastic scintillators as detectors to measure the scattered protons. Second, a rectangular phantom with an air layer was used, and 3D-DL dose was estimated in simulation (B). Finally, a cylindrical phantom that mimics the human body was used for confirming the estimation quality of the simulation (C). Consequently, the position of the Bragg peak was estimated with an error of 1.0 mm in simulation (A). In addition, the position of the air layer, as well as the verifying peak position with an error of 2.1 mm, was successfully estimated in simulation (B). Although the estimation error of the peak position was 12.6 mm in simulation (C), the quality was successfully further improved to 9.3 mm by incorporating the mass density distribution obtained from the computed tomography (CT). These simulation results demonstrated the potential of the as-proposed verification system. Additionally, the effectiveness of CT utilization for estimating the DL dose was also indicated.
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Graeff C, Volz L, Durante M. Emerging technologies for cancer therapy using accelerated particles. PROGRESS IN PARTICLE AND NUCLEAR PHYSICS 2023; 131:104046. [PMID: 37207092 PMCID: PMC7614547 DOI: 10.1016/j.ppnp.2023.104046] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Cancer therapy with accelerated charged particles is one of the most valuable biomedical applications of nuclear physics. The technology has vastly evolved in the past 50 years, the number of clinical centers is exponentially growing, and recent clinical results support the physics and radiobiology rationale that particles should be less toxic and more effective than conventional X-rays for many cancer patients. Charged particles are also the most mature technology for clinical translation of ultra-high dose rate (FLASH) radiotherapy. However, the fraction of patients treated with accelerated particles is still very small and the therapy is only applied to a few solid cancer indications. The growth of particle therapy strongly depends on technological innovations aiming to make the therapy cheaper, more conformal and faster. The most promising solutions to reach these goals are superconductive magnets to build compact accelerators; gantryless beam delivery; online image-guidance and adaptive therapy with the support of machine learning algorithms; and high-intensity accelerators coupled to online imaging. Large international collaborations are needed to hasten the clinical translation of the research results.
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Affiliation(s)
- Christian Graeff
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Department, Planckstraße 1, 64291 Darmstadt, Germany
- Technische Universität Darmstadt, Darmstadt, Germany
| | - Lennart Volz
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Department, Planckstraße 1, 64291 Darmstadt, Germany
| | - Marco Durante
- GSI Helmholtzzentrum für Schwerionenforschung, Biophysics Department, Planckstraße 1, 64291 Darmstadt, Germany
- Technische Universität Darmstadt, Darmstadt, Germany
- Dipartimento di Fisica “Ettore Pancini”, University Federico II, Naples, Italy
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5
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Yang M, Wohlfahrt P, Shen C, Bouchard H. Dual- and multi-energy CT for particle stopping-power estimation: current state, challenges and potential. Phys Med Biol 2023; 68. [PMID: 36595276 DOI: 10.1088/1361-6560/acabfa] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Range uncertainty has been a key factor preventing particle radiotherapy from reaching its full physical potential. One of the main contributing sources is the uncertainty in estimating particle stopping power (ρs) within patients. Currently, theρsdistribution in a patient is derived from a single-energy CT (SECT) scan acquired for treatment planning by converting CT number expressed in Hounsfield units (HU) of each voxel toρsusing a Hounsfield look-up table (HLUT), also known as the CT calibration curve. HU andρsshare a linear relationship with electron density but differ in their additional dependence on elemental composition through different physical properties, i.e. effective atomic number and mean excitation energy, respectively. Because of that, the HLUT approach is particularly sensitive to differences in elemental composition between real human tissues and tissue surrogates as well as tissue variations within and among individual patients. The use of dual-energy CT (DECT) forρsprediction has been shown to be effective in reducing the uncertainty inρsestimation compared to SECT. The acquisition of CT data over different x-ray spectra yields additional information on the material elemental composition. Recently, multi-energy CT (MECT) has been explored to deduct material-specific information with higher dimensionality, which has the potential to further improve the accuracy ofρsestimation. Even though various DECT and MECT methods have been proposed and evaluated over the years, these approaches are still only scarcely implemented in routine clinical practice. In this topical review, we aim at accelerating this translation process by providing: (1) a comprehensive review of the existing DECT/MECT methods forρsestimation with their respective strengths and weaknesses; (2) a general review of uncertainties associated with DECT/MECT methods; (3) a general review of different aspects related to clinical implementation of DECT/MECT methods; (4) other potential advanced DECT/MECT applications beyondρsestimation.
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Affiliation(s)
- Ming Yang
- The University of Texas MD Anderson Cancer Center, Department of Radiation Physics, 1515 Holcombe Blvd Houston, TX 77030, United States of America
| | - Patrick Wohlfahrt
- Massachusetts General Hospital and Harvard Medical School, Department of Radiation Oncology, Boston, MA 02115, United States of America
| | - Chenyang Shen
- University of Texas Southwestern Medical Center, Department of Radiation Oncology, 2280 Inwood Rd Dallas, TX 75235, United States of America
| | - Hugo Bouchard
- Département de physique, Université de Montréal, Complexe des sciences, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, Québec H2V0B3, Canada.,Centre de recherche du Centre hospitalier de l'Université de Montréal, 900 Rue Saint-Denis, Montréal, Québec, H2X 0A9, Canada.,Département de radio-oncologie, Centre hospitalier de l'Université de Montréal, 1051 Rue Sanguinet, Montréal, Québec H2X 3E4, Canada
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Eliasson L, Lillhök J, Bäck T, Billnert-Maróti R, Dasu A, Liszka M. Range-shifter effects on the stray field in proton therapy measured with the variance–covariance method. Front Oncol 2022; 12:882230. [PMID: 35982965 PMCID: PMC9380888 DOI: 10.3389/fonc.2022.882230] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 07/05/2022] [Indexed: 01/09/2023] Open
Abstract
Measurements in the stray radiation field from a proton therapy pencil beam at energies 70 and 146 MeV were performed using microdosimetric tissue-equivalent proportional counters (TEPCs). The detector volumes were filled with a propane-based tissue-equivalent gas at low pressure simulating a mean chord length of 2 μm in tissue. Investigations were performed with and without a beam range shifter, and with different air gaps between the range shifter and a solid water phantom. The absorbed dose, the dose-mean lineal energy, and the dose equivalent were determined for different detector positions using the variance–covariance method. The influence from beam energy, detector- and range-shifter positions on absorbed dose, LET, and dose equivalent were investigated. Monte Carlo simulations of the fluence, detector response, and absorbed dose contribution from different particles were performed with MCNP 6.2. The simulated dose response for protons, neutrons, and photons were compared with, and showed good agreement with, previously published experimental data. The simulations also showed that the TEPC absorbed dose agrees well with the ambient absorbed dose for neutron energies above 20 MeV. The results illustrate that changes in both dose and LET variations in the stray radiation field can be identified from TEPC measurements using the variance–covariance method. The results are in line with the changes seen in the simulated relative dose contributions from different particles associated with different proton energies and range-shifter settings. It is shown that the proton contribution scattered directly from the range shifter dominates in some situations, and although the LET of the radiation is decreased, the ambient dose equivalent is increased up to a factor of 3.
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Affiliation(s)
- Linda Eliasson
- Department of Physics, KTH, Stockholm, Sweden
- *Correspondence: Linda Eliasson,
| | - Jan Lillhök
- The Swedish Radiation Safety Authority, Solna, Sweden
| | | | | | - Alexandru Dasu
- Medical Radiation Sciences, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
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7
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Liu R, Zhao X, Medrano M. Experimental validation of proton physics models of Geant4 for calculating stopping power ratio. JOURNAL OF RADIOLOGICAL PROTECTION : OFFICIAL JOURNAL OF THE SOCIETY FOR RADIOLOGICAL PROTECTION 2022; 42:10.1088/1361-6498/ac7918. [PMID: 35705062 PMCID: PMC9462414 DOI: 10.1088/1361-6498/ac7918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
In this work, we conducted experiments to validate the proton physics models of Geant4 (version 10.6). The stopping power ratios (SPRs) of 11 inserts, such as acrylic, delrin, high density polyethylene, and polytetrafluoroethylene, etc, were measured using a superconducting synchrocyclotron that produces a scattering proton beam. The SPRs of the inserts were also calculated based on Geant4 simulation with six physics lists, i.e. QGSP_ FTFP_ BERT, QGSP_BIC_HP, QGSP_BIC, QGSP_FTFP_BERT, QSGP_BERT, and QBBC. The calculated SPRs were compared to the experimental SPRs, and relative per cent error was used to quantify the accuracy of the simulated SPRs of inserts. The comparison showed that the five physics lists generally agree well with the experimental SPRs with a relative difference of less than 1%. The lowest overall percentage error was observed for QGSP_FTFP_BERT and the highest overall percentage error was observed for QGSP_BIC_HP. The 0.1 mm range cut value consistently led to higher percentage error for all physics lists except for QGSP_BIC_HP and QBBC. Based on the validation, we recommend QGSP_BERT_HP physics list for proton dose calculation.
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Affiliation(s)
- Ruirui Liu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, United States of America
| | - Xiandong Zhao
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Maria Medrano
- Department of Electrical and Systems Engineering, Washington University, St. Louis, MO, United States of America
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Medical Resource Use and Medical Costs for Radiotherapy-Related Adverse Effects: A Systematic Review. Cancers (Basel) 2022; 14:cancers14102444. [PMID: 35626049 PMCID: PMC9139402 DOI: 10.3390/cancers14102444] [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: 04/18/2022] [Revised: 05/09/2022] [Accepted: 05/11/2022] [Indexed: 12/03/2022] Open
Abstract
Simple Summary Cancer patients who receive radiotherapy often suffer from adverse effects that require healthcare resources to manage. This study summarized evidence of healthcare resource use and costs related to radiotherapy-induced adverse effects and provided recommendations for including this evidence in economic evaluations. Our findings revealed unignorable differences for the same adverse effects, which implied that the potential for the economic burden of adverse effects was overestimated or underestimated. Abstract Background: Despite the need for a proper economic evaluation of new radiotherapies, the economic burden of radiotherapy-induced adverse effects remains unclear. A systematic review has been conducted to identify the existing evidence of healthcare resource use and costs related to radiotherapy-induced adverse effects and also to provide recommendations for including this evidence in economic evaluations. Methods: This systematic review of healthcare resource use and/or medical costs related to radiotherapy-induced adverse effects was performed up until 2020, focusing on patients with head and neck cancer, brain cancer, prostate cancer, eye cancer and breast cancer. Results: Resource use for treating the same adverse effects varied considerably across studies; for instance, the cost for mucositis ranged from USD 2949 to USD 17,244. This broad range could be related to differences in (1) severity of adverse effects in the study population, (2) study design, (3) cost estimation approach and (4) country and clinical practice. Conclusions: Our findings revealed unignorable differences for the same adverse effects, which implied that the potential for the economic burden of adverse effects was being overestimated or underestimated in economic evaluation for radiotherapy.
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9
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Mohan R. A review of proton therapy – Current status and future directions. PRECISION RADIATION ONCOLOGY 2022; 6:164-176. [DOI: 10.1002/pro6.1149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Radhe Mohan
- Department of Radiation Physics, MD Anderson Cancer Center Houston Texas USA
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10
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Nakamura Y, Takayanagi T, Uesaka T, Unlu MB, Kuriyama Y, Ishi Y, Uesugi T, Kobayashi M, Kudo N, Tanaka S, Umegaki K, Tomioka S, Matsuura T. Technical Note: Range verification of pulsed proton beams from fixed-field alternating gradient accelerator by means of time-of-flight measurement of ionoacoustic waves. Med Phys 2021; 48:5490-5500. [PMID: 34173991 DOI: 10.1002/mp.15060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 05/24/2021] [Accepted: 06/16/2021] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Ionoacoustics is one of the promising approaches to verify the beam range in proton therapy. However, the weakness of the wave signal remains a main hindrance to its application in clinics. Here we studied the potential use of a fixed-field alternating gradient accelerator (FFA), one of the accelerator candidates for future proton therapy. For such end, magnitude of the pressure wave and range accuracy achieved by the short-pulsed beam of FFA were assessed, using both simulation and experimental procedure. METHODS A 100 MeV proton beam from the FFA was applied on a water phantom, through the acrylic wall. The beam range measured by the Bragg peak (BP)-ionization chamber (BPC) was 77.6 mm, while the maximum dose at BP was estimated to be 0.35 Gy/pulse. A hydrophone was placed 20 mm downstream of the BP, and signals were amplified and stored by a digital oscilloscope, averaged, and low-pass filtered. Time-of-flight (TOF) and two relative TOF values were analyzed in order to determine the beam range. Furthermore, an acoustic wave transport simulation was conducted to estimate the amplitude of the pressure waves. RESULTS The range calculated when using two relative TOF was 78.16 ± 0.01 and 78.14 ± 0.01 mm, respectively, both values being coherent with the range measured by the BPC (the difference was 0.5-0.6 mm). In contrast, utilizing the direct TOF resulted in a range error of 1.8 mm. Fivefold and 50-fold averaging were required to suppress the range variation to below 1 mm for TOF and relative TOF measures, respectively. The simulation suggested the magnitude of pressure wave at the detector exceeded 7 Pascal. CONCLUSION A submillimeter range accuracy was attained with a pulsed beam of about 21 ns from an FFA, at a clinical energy using relative TOF. To precisely quantify the range with a single TOF measurement, subsequent improvement in the measuring system is required.
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Affiliation(s)
- Yuta Nakamura
- Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Taisuke Takayanagi
- Graduate School of Biomedical Science and Engineering, Hokkaido University, Sapporo, Hokkaido, Japan.,Hitachi Ltd, Hitachi-shi, Ibaraki, Japan
| | - Tomoki Uesaka
- Graduate School of Biomedical Science and Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | | | - Yasutoshi Kuriyama
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Yoshihiro Ishi
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Tomonori Uesugi
- Institute for Integrated Radiation and Nuclear Science, Kyoto University, Osaka, Japan
| | - Masanori Kobayashi
- Planetary Exploration Research Institute, Chiba Institute of Technology, Chiba, Japan
| | - Nobuki Kudo
- Faculty of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Sodai Tanaka
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Kikuo Umegaki
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan.,Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo, Hokkaido, Japan
| | - Satoshi Tomioka
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Taeko Matsuura
- Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido, Japan.,Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo, Hokkaido, Japan
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11
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Hyer DE, Bennett LC, Geoghegan TJ, Bues M, Smith BR. Innovations and the Use of Collimators in the Delivery of Pencil Beam Scanning Proton Therapy. Int J Part Ther 2021; 8:73-83. [PMID: 34285937 PMCID: PMC8270095 DOI: 10.14338/ijpt-20-00039.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/19/2020] [Indexed: 12/29/2022] Open
Abstract
Purpose The development of collimating technologies has become a recent focus in pencil beam scanning (PBS) proton therapy to improve the target conformity and healthy tissue sparing through field-specific or energy-layer–specific collimation. Given the growing popularity of collimators for low-energy treatments, the purpose of this work was to summarize the recent literature that has focused on the efficacy of collimators for PBS and highlight the development of clinical and preclinical collimators. Materials and Methods The collimators presented in this work were organized into 3 categories: per-field apertures, multileaf collimators (MLCs), and sliding-bar collimators. For each case, the system design and planning methodologies are summarized and intercompared from their existing literature. Energy-specific collimation is still a new paradigm in PBS and the 2 specific collimators tailored toward PBS are presented including the dynamic collimation system (DCS) and the Mevion Adaptive Aperture. Results Collimation during PBS can improve the target conformity and associated healthy tissue and critical structure avoidance. Between energy-specific collimators and static apertures, static apertures have the poorest dose conformity owing to collimating only the largest projection of a target in the beam's eye view but still provide an improvement over uncollimated treatments. While an external collimator increases secondary neutron production, the benefit of collimating the primary beam appears to outweigh the risk. The greatest benefit has been observed for low- energy treatment sites. Conclusion The consensus from current literature supports the use of external collimators in PBS under certain conditions, namely low-energy treatments or where the nominal spot size is large. While many recent studies paint a supportive picture, it is also important to understand the limitations of collimation in PBS that are specific to each collimator type. The emergence and paradigm of energy-specific collimation holds many promises for PBS proton therapy.
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Affiliation(s)
- Daniel E Hyer
- Department of Radiation Oncology, University of Iowa, Iowa City, IA, USA
| | - Laura C Bennett
- Department of Radiation Oncology, University of Iowa, Iowa City, IA, USA
| | | | - Martin Bues
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, USA
| | - Blake R Smith
- Department of Radiation Oncology, University of Iowa, Iowa City, IA, USA
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12
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Arjunan M, Krishnan G, Sharma DS, M P N, Patro KC, Thiyagarajan R, Srinivas C, Jalali R. Dosimetric impact of random spot positioning errors in intensity modulated proton therapy plans of small and large volume tumors. Br J Radiol 2021; 94:20201031. [PMID: 33529057 DOI: 10.1259/bjr.20201031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To study dosimetric impact of random spot positioning errors on the clinical pencil beam scanning proton therapy plans. METHODS AND MATERIALS IMPT plans of 10 patients who underwent proton therapy for tumors in brain or pelvic regions representing small and large volumes, respectively, were included in the study. Spot positioning errors of 1 mm, -1 mm or ±1 mm were introduced in these clinical plans by modifying the geometrical co-ordinates of proton spots using a script in the MATLAB programming environment. Positioning errors were simulated to certain numbers of (20%, 40%, 60%, 80%) randomly chosen spots in each layer of these treatment plans. Treatment plans with simulated errors were then imported back to the Raystation (Version 7) treatment planning system and the resultant dose distribution was calculated using Monte-Carlo dose calculation algorithm.Dosimetric plan evaluation parameters for target and critical organs of nominal treatment plans delivered for clinical treatments were compared with that of positioning error simulated treatment plans. For targets, D95% and D2% were used for the analysis. Dose received by optic nerve, chiasm, brainstem, rectum, sigmoid, and bowel were analyzed using relevant plan evaluation parameters depending on the critical structure. In case of intracranial lesions, the dose received by 0.03 cm3 volume (D0.03 cm3) was analyzed for optic nerve, chiasm and brainstem. In rectum, the volume of it receiving a dose of 65 Gy(RBE) (V65) and 40 Gy(RBE) (V40) were compared between the nominal and error introduced plans. Similarly, V65 and V63 were analyzed for Sigmoid and V50 and V15 were analyzed for bowel. RESULTS The maximum dose variation in PTV D95% (1.88 %) was observed in a brain plan in which the target volume was the smallest (2.7 cm3) among all 10 plans included in the study. This variation in D95% drops down to 0.3% for a sacral chordoma plan in which the PTV volume is significantly higher at 672 cm3. The maximum difference in OARs in terms of absolute dose (D0.03 cm3) was found in left optic nerve (9.81%) and the minimum difference was observed in brainstem (2.48%). Overall, the magnitude of dose errors in chordoma plans were less significant in comparison to brain plans. CONCLUSION The dosimetric impact of different error scenarios in spot positioning becomes more prominent for treatment plans involving smaller target volume compared to plans involving larger target volumes. ADVANCES IN KNOWLEDGE Provides information on the dosimetric impact of various possible spot positioning errors and its dependence on the tumor volume in intensity modulated proton therapy.
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Affiliation(s)
- Manikandan Arjunan
- Department of Medical Physics, Apollo Proton Cancer Centre, Chennai, Tamil Nadu, India
| | | | | | - Noufal M P
- Department of Medical Physics, Apollo Proton Cancer Centre, Chennai, Tamil Nadu, India
| | - Kartikeshwar C Patro
- Department of Medical Physics, Apollo Proton Cancer Centre, Chennai, Tamil Nadu, India
| | - Rajesh Thiyagarajan
- Department of Medical Physics, Apollo Proton Cancer Centre, Chennai, Tamil Nadu, India
| | - Chilukuri Srinivas
- Department of Radiation Oncology, Apollo Proton Cancer Center, Chennai, Tamil Nadu, India
| | - Rakesh Jalali
- Department of Radiation Oncology, Apollo Proton Cancer Center, Chennai, Tamil Nadu, India
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Scholey JE, Chandramohan D, Naren T, Liu W, Larson PEZ, Sudhyadhom A. Technical Note: A methodology for improved accuracy in stopping power estimation using MRI and CT. Med Phys 2020; 48:342-353. [PMID: 33107997 DOI: 10.1002/mp.14555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 09/21/2020] [Accepted: 10/19/2020] [Indexed: 01/13/2023] Open
Abstract
PURPOSE Proton therapy is becoming an increasingly popular cancer treatment modality due to the proton's physical advantage in that it deposits the majority of its energy at the distal end of its track where the tumor is located. The proton range in a material is determined from the stopping power ratio (SPR) of the material. However, SPR is typically estimated based on a computed tomography (CT) scan which can lead to range estimation errors due to the difference in x-ray and proton interactions in matter, which can preclude the ability to utilize protons to their full potential. Applications of magnetic resonance imaging (MRI) in radiotherapy have increased over the past decade and using MRI to calculate SPR directly could provide numerous advantages. The purpose of this study was to develop a practical implementation of a novel multimodal imaging method for estimating SPR and compare the results of this method to physical measurements in which values were computed directly using tissue substitute materials fabricated to mimic skin, muscle, adipose, and spongiosa bone. METHODS For both the multimodal imaging method and physical measurements, SPR was calculated using the Bethe-Bloch equation from values of relative electron density and mean ionization potential determined for each tissue. Parameters used to estimate SPR using the multimodal imaging method were extracted from Dixon water-only and (1 H) proton density-weighted zero echo time MRI sequences and CT, with both kVCT and MVCT used separately to evaluate the performance of each. For comparison, SPR was also computed from kVCT using the stoichiometric method, the current clinical standard. RESULTS Results showed that our multimodal imaging approach using MRI with either kVCT or MVCT was in close agreement to SPR calculated from physical measurements for the four tissue substitutes evaluated. Using MRI and MVCT, SPR values estimated using our method were within 1% of physical measurements and were more accurate than the stoichiometric method for the tissue types studied. CONCLUSIONS We have demonstrated the methodology for improved estimation of SPR using the proposed multimodal imaging framework.
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Affiliation(s)
- Jessica E Scholey
- Department of Radiation Oncology, The University of California, San Francisco, CA, USA
| | - Dharshan Chandramohan
- Department of Radiation Oncology, The University of California, San Francisco, CA, USA
| | - Tarun Naren
- Department of Radiation Oncology, The University of California, San Francisco, CA, USA
| | - William Liu
- Department of Radiation Oncology, The University of California, San Francisco, CA, USA
| | - Peder Eric Zufall Larson
- Department of Radiology and Biomedical Imaging, The University of California, San Francisco, CA, USA
| | - Atchar Sudhyadhom
- Department of Radiation Oncology, The University of California, San Francisco, CA, USA
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Hu Z, Li G, Zhang X, Ye K, Lu J, Peng H. A machine learning framework with anatomical prior for online dose verification using positron emitters and PET in proton therapy. Phys Med Biol 2020; 65:185003. [PMID: 32460246 DOI: 10.1088/1361-6560/ab9707] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We developed a machine learning framework in order to establish the correlation between dose and activity distributions in proton therapy. A recurrent neural network was used to predict dose distribution in three dimensions based on the information of proton-induced positron emitters. Hounsfield Unit (HU) information from CT images and analytically derived stopping power (SP) information were incorporated as auxiliary inputs. Four different scenarios were investigated: Activity only, Activity + HU, Activity + SP and Activity + HU + SP. The performance was quantitatively studied in terms of mean absolute error (MAE) and mean relative error (MRE), under different signal-to-noise ratios (SNRs). In addition to the first dataset of mono-energetic beams, three additional datasets were validated to help evaluate the generalization capability of our proposed model: a dataset of a lower SNR, five reconstructed PET images, and a dataset of spread-out Bragg peaks. Good verification accuracy of dose verification in three dimensions is demonstrated. The inclusion of anatomical information improves both accuracy and generalization. For an activity profile with an SNR of 4 (the mono-energetic case), the framework is able to obtain an MRE of ∼ 0.99% over the whole range and a range uncertainty of ∼ 0.27 mm. The machine learning-based framework may emerge as a useful tool to allow for online dose verification and quality assurance in proton therapy.
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Affiliation(s)
- Zongsheng Hu
- Department of Medical Physics, Wuhan University, Wuhan, 430072 People's Republic of China
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15
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Lazos D, Collins-Fekete CA, Evans P, Dikaios N. Molière maximum likelihood proton path estimation approximated by cubic Bézier curve for scatter corrected proton CT reconstruction. ACTA ACUST UNITED AC 2020; 65:175003. [DOI: 10.1088/1361-6560/ab9413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Sun S, Liu Y, Ouyang X. Design and performance evaluation of a coded aperture imaging system for real-time prompt gamma-ray monitoring during proton therapy. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.108891] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Ma S, Hu Z, Ye K, Zhang X, Wang Y, Peng H. Feasibility study of patient-specific dose verification in proton therapy utilizing positron emission tomography (PET) and generative adversarial network (GAN). Med Phys 2020; 47:5194-5208. [PMID: 32772377 DOI: 10.1002/mp.14443] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 07/05/2020] [Accepted: 07/29/2020] [Indexed: 02/03/2023] Open
Abstract
PURPOSE Online dose verification based on proton-induced positron emitters is a promising strategy for quality assurance in proton therapy. Because of the nonlinear correlation between dose and the activity distributions, a machine learning-based approach was developed to establish their relationship. METHODS Simulations were carried out using a pencil beam scanning system and a computed tomography (CT) image-based phantom. A DiscoGAN model was developed to perform dose verification for both central and off-center lines. Besides the activity as input, HU information from CT images and stopping power (SP) prior were incorporated as auxiliary features for the model. The performance was quantitatively studied in terms of mean absolute error (MAE) and mean relative error (MRE), under different signal-to-noise ratios (SNRs). In addition to a dataset comprising monoenergetic beams, two additional datasets were generated to evaluate the model's generalization capability: five reconstructed PET images based on an in-beam PET system and a dataset comprising spread-out Bragg peaks (SOBPs). RESULTS The feasibility of dose verification was successfully demonstrated for all three datasets. For the monoenergetic case (i.e., raw activity of positron emitters), the MRE is found to be <1% for the central lines and 5% for the off-center lines, respectively. The range uncertainty is found to be less than 1 mm. The prediction based on five PET images, which take into account the detection of 511-keV photons and image reconstruction, yields slightly inferior performance. For the SOBP case, the MRE of the center lines is found to be <3% and the range uncertainty is <1 mm. The inclusion of anatomical information (HU and SP) improves both accuracy and generalization of the DiscoGAN model. CONCLUSION The combination of proton-induced positron emitters, in-beam PET, and machine learning may become a useful tool allowing for patient-specific online dose verification in proton therapy.
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Affiliation(s)
- Saiqun Ma
- Department of Medical Physics, Wuhan University, Wuhan, Hubei, 430072, China
| | - Zongsheng Hu
- Department of Medical Physics, Wuhan University, Wuhan, Hubei, 430072, China
| | - Kuangkuang Ye
- Institute for Advanced Studies, Wuhan University, Wuhan, Hubei, 430072, China
| | - Xiaoke Zhang
- Department of Medical Physics, Wuhan University, Wuhan, Hubei, 430072, China
| | - Yuenan Wang
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, China
| | - Hao Peng
- Department of Medical Physics, Wuhan University, Wuhan, Hubei, 430072, China
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Developing a Monte Carlo model for MEVION S250i with HYPERSCAN and Adaptive Aperture™ pencil beam scanning proton therapy system. JOURNAL OF RADIOTHERAPY IN PRACTICE 2020. [DOI: 10.1017/s1460396920000266] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractAim:As the number of proton therapy facilities has steadily increased, the need for the tool to provide precise dose simulation for complicated clinical and research scenarios also increase. In this study, the treatment head of Mevion HYPERSCAN pencil beam scanning (PBS) proton therapy system including energy modulation system (EMS) and Adaptive Aperture™ (AA) was modelled using TOPAS (TOolkit for PArticle Simulation) Monte Carlo (MC) code and was validated during commissioning process.Materials and methods:The proton beam characteristics including integral depth doses (IDDs) of pristine Bragg peak and in-air beam spot sizes were simulated and compared with measured beam data. The lateral profiles, with and without AA, were also verified against calculation from treatment planning system (TPS).Results:All beam characteristics for IDDs and in-air spot size agreed well within 1 mm and 10% separately. The full width at half maximum and penumbra of lateral dose profile also agree well within 2 mm.Finding:The TOPAS MC simulation of the MEVION HYPERSCAN PBS proton therapy system has been modelled and validated; it could be a viable tool for research and verification of the proton treatment in the future.
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Zhang H, Fan P, Wang S, Xia Y, Xu T, Wei Q, Lu W, Wu Z, Liu Y, Ma T. Design and Performance Evaluation of a BGO + SiPM Detector for High-Energy Prompt Gamma Imaging in Proton Therapy Monitoring. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2020. [DOI: 10.1109/trpms.2020.2972594] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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20
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Brooke MD, Penfold SN. An inhomogeneous most likely path formalism for proton computed tomography. Phys Med 2020; 70:184-195. [PMID: 32036335 PMCID: PMC7026699 DOI: 10.1016/j.ejmp.2020.01.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 12/07/2019] [Accepted: 01/27/2020] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Multiple Coulomb scattering (MCS) poses a challenge in proton CT (pCT) image reconstruction. The assumption of straight paths is replaced with Bayesian models of the most likely path (MLP). Current MLP-based pCT reconstruction approaches assume a water scattering environment. We propose an MLP formalism based on accurate determination of scattering moments in inhomogeneous media. METHODS Scattering power relative to water (RScP) was calculated for a range of human tissues and investigated against relative stopping power (RStP). Monte Carlo simulation was used to compare the new inhomogeneous MLP formalism to the water approach in a slab geometry and a human head phantom. An MLP-Spline-Hybrid method was investigated for improved computational efficiency. RESULTS A piecewise-linear correlation between RStP and RScP was shown, which may assist in iterative pCT reconstruction. The inhomogeneous formalism predicted Monte Carlo proton paths through a water cube with thick bone inserts to within 1.0 mm for beams ranging from 210 to 230 MeV incident energy. Improvement in accuracy over the conventional MLP ranged from 5% for a 230 MeV beam to 17% for 210 MeV. There was no noticeable gain in accuracy when predicting 200 MeV proton paths through a clinically relevant human head phantom. The MLP-Spline-Hybrid method reduced computation time by half while suffering negligible loss of accuracy. CONCLUSIONS We have presented an MLP formalism that accounts for material composition. In most clinical cases a water scattering environment can be assumed, however in certain cases of significant heterogeneity the proposed algorithm may improve proton path estimation.
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Affiliation(s)
- Mark D Brooke
- Department of Oncology, University of Oxford, Oxford OX3 7DQ, United Kingdom; Department of Physics, University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Scott N Penfold
- Department of Physics, University of Adelaide, Adelaide, South Australia 5005, Australia; Department of Medical Physics, Royal Adelaide Hospital, Adelaide, South Australia 5000, Australia
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Jeong S, Chung K, Ahn SH, Lee B, Seo J, Yoon M. Feasibility study of a plastic scintillating plate-based treatment beam fluence monitoring system for use in pencil beam scanning proton therapy. Med Phys 2019; 47:703-712. [PMID: 31732965 DOI: 10.1002/mp.13922] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 10/14/2019] [Accepted: 11/06/2019] [Indexed: 11/11/2022] Open
Abstract
PURPOSE The purpose of this study was to describe a plastic scintillating plate-based gantry-attachable dosimetry system for pencil beam scanning proton therapy to monitor entrance proton beam fluence, and to evaluate the dosimetric characteristics of this system and its feasibility for clinical use. METHODS The dosimetry system, consisting of a plastic scintillating plate and a CMOS camera, was attached to a dedicated scanning nozzle and scintillation during proton beam irradiation was recorded. Dose distribution was calculated from the accumulated recorded frames. The dosimetric characteristics (energy dependency, dose linearity, dose rate dependency, and reproducibility) of the gantry-attachable dosimetry system for use with therapeutic proton beams were measured, and the feasibility of this system during clinical use was evaluated by determining selected quality assurance items at our institution. RESULTS The scintillating plate shortened the range of the proton beam by the water-equivalent thickness of the plate and broadened the spatial profile of the single proton spot by 11% at 70 MeV. The developed system functioned independently of the beam energy (<1.3%) and showed dose linearity, and also functioned independently of the dose rate. The feasibility of the system for clinical use was evaluated by comparing the measured quality assurance dose distribution to that of the treatment planning system. The gamma passing rate with a criterion of 3%/3 mm was 97.58%. CONCLUSIONS This study evaluated the dosimetric characteristics of a plastic scintillating plate-based dosimetry system for use with scanning proton beams. The ability to account for the interference of the dosimetry system on the therapeutic beam enabled offline monitoring of the entrance beam fluence of the pencil beam scanning proton therapy independent of the treatment system with high resolution and in a cost-effective manner.
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Affiliation(s)
- Seonghoon Jeong
- Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea
| | - Kwangzoo Chung
- Department of Radiation Oncology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea
| | - Sung Hwan Ahn
- Department of Radiation Oncology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea
| | - Boram Lee
- Department of Radiation Oncology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea
| | - Jaehyeon Seo
- Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea
| | - Myonggeun Yoon
- Department of Bio-Convergence Engineering, Korea University, Seoul, Republic of Korea
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22
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Shen J, Ding X, Hu Y, Kang Y, Liu W, Deng W, Bues M. Technical Note: Comprehensive evaluation and implementation of two independent methods for beam monitor calibration for proton scanning beam. Med Phys 2019; 46:5867-5875. [DOI: 10.1002/mp.13866] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/29/2019] [Accepted: 10/10/2019] [Indexed: 11/10/2022] Open
Affiliation(s)
- Jiajian Shen
- Department of Radiation Oncology Mayo Clinic Phoenix AZ 85054USA
| | - Xiaoning Ding
- Department of Radiation Oncology Mayo Clinic Phoenix AZ 85054USA
| | - Yanle Hu
- Department of Radiation Oncology Mayo Clinic Phoenix AZ 85054USA
| | - Yixiu Kang
- Department of Radiation Oncology Mayo Clinic Phoenix AZ 85054USA
| | - Wei Liu
- Department of Radiation Oncology Mayo Clinic Phoenix AZ 85054USA
| | - Wei Deng
- Department of Radiation Oncology Mayo Clinic Phoenix AZ 85054USA
| | - Martin Bues
- Department of Radiation Oncology Mayo Clinic Phoenix AZ 85054USA
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Li Z, Wang Y, Yu Y, Fan K, Xing L, Peng H. Technical Note: Machine learning approaches for range and dose verification in proton therapy using proton‐induced positron emitters. Med Phys 2019; 46:5748-5757. [DOI: 10.1002/mp.13827] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 09/06/2019] [Accepted: 09/06/2019] [Indexed: 12/16/2022] Open
Affiliation(s)
- Zhongxing Li
- Department of Medical Physics Wuhan University Wuhan 430072China
| | - Yiang Wang
- Department of Medical Physics Wuhan University Wuhan 430072China
| | - Yajun Yu
- Department of Medical Physics Wuhan University Wuhan 430072China
| | - Kuanjun Fan
- School of Electrical Engineering Huazhong University of Science & Technology Wuhan 430074China
| | - Lei Xing
- Department of Radiation Oncology Stanford University Stanford CA 94305USA
| | - Hao Peng
- Department of Medical Physics Wuhan University Wuhan 430072China
- Department of Radiation Oncology Stanford University Stanford CA 94305USA
- Global Institution for Collaborative Research and Education (GI‐CoRE) Hokkaido University Sapporo Japan
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24
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Liu C, Li Z, Hu W, Xing L, Peng H. Range and dose verification in proton therapy using proton-induced positron emitters and recurrent neural networks (RNNs). ACTA ACUST UNITED AC 2019; 64:175009. [DOI: 10.1088/1361-6560/ab3564] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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25
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Arjomandy B, Taylor P, Ainsley C, Safai S, Sahoo N, Pankuch M, Farr JB, Yong Park S, Klein E, Flanz J, Yorke ED, Followill D, Kase Y. AAPM task group 224: Comprehensive proton therapy machine quality assurance. Med Phys 2019; 46:e678-e705. [DOI: 10.1002/mp.13622] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 12/11/2022] Open
Affiliation(s)
- Bijan Arjomandy
- Karmanos Cancer Institute at McLaren‐Flint McLaren Proton Therapy Center Flint MI USA
| | - Paige Taylor
- Imaging and Radiation Oncology Core (IROC) Houston University of Texas MD Anderson Cancer Center Houston TX USA
| | | | - Sairos Safai
- Center for Proton Therapy Paul Scherrer Institute Villigen Switzerland
| | - Narayan Sahoo
- University of Texas, MD Anderson Cancer Center Houston TX USA
| | - Mark Pankuch
- Northwestern Medicine Chicago Proton Center Warrenville IL USA
| | - Jonathan B. Farr
- Applications of Detectors and Accelerators to Medicine 1217Meyrin Switzerland
| | | | - Eric Klein
- Rhode Island Hospital, The Warren Alpert Medical School of Brown University Providence RI USA
| | - Jacob Flanz
- Massachusetts General Hospital, Burr Proton Therapy Center Boston MA
- Harvard Medical School Cambridge MA USA
| | | | - David Followill
- Imaging and Radiation Oncology Core (IROC) Houston University of Texas MD Anderson Cancer Center Houston TX USA
| | - Yuki Kase
- Proton Therapy Division Shizuoka Cancer Center Shizuoka Japan
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Smith BR, Pankuch M, Hammer CG, DeWerd LA, Culberson WS. LET response variability of Gafchromic TM EBT3 film from a 60 Co calibration in clinical proton beam qualities. Med Phys 2019; 46:2716-2728. [PMID: 30740699 DOI: 10.1002/mp.13442] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/01/2019] [Accepted: 02/02/2019] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To establish a method of accurate dosimetry required to quantify the expected linear energy transfer (LET) quenching effect of EBT3 film used to benchmark the dose distribution for a given treatment field and specified measurement depth. In order to facilitate this technique, a full analysis of film calibration which considers LET variability at the plane of measurement and as a function of proton beam quality is demonstrated. Additionally, the corresponding uncertainty from the process was quantified for several measurement scenarios. MATERIALS AND METHODS The net change in optical density (OD) from a single version of Gafchromic TM EBT3 film was measured using an Epson flatbed scanner and NIST-traceable OD filters. Film OD response was characterized with respect to the known dose to water at the point of measurement for both a NIST-traceable 60 Co beam at the UWADCL and several clinical single-energy and spread-out Bragg peak (SOBP) proton beam qualities at the Northwestern Medicine Chicago Proton Center. Increasing proton LET environments were acquired by placing film at increasing depths of Gammex HE Solid Water® whose water-equivalent thickness was characterized prior to measurement. RESULTS A strong LET dependence was observed near the Bragg peak (BP) consistent with previous studies performed with earlier versions of EBT3 film. The influence of range straggling on the film's LET response appears to have a uniform effect toward the BP regardless of the nominal beam energy. Proximal to this depth, the film's response decreased with decreasing energy at the same dose-average LET. The opposite trend was observed for depths past the BP. Changes in the SOBP energy modulation showed a linear relationship between the film's relative response and dose-averaged LET. Relative effectiveness factors (RE) were observed to range between 2%-7% depending on the width of the SOBP and depth of the film. Using the field-specific calibration technique, a total k = 1 uncertainty in the absorbed dose to water was estimated to range from 4.68%-5.21%. CONCLUSION While EBT3 film's strong LET dependence is a common problem in proton beam dosimetry, this work has shown that the LET dependence can be taken into account by carefully considering the depth and energy modulation across the film using field-specific corrections. RE factors were determined with a combined k = 1 uncertainty of 3.57% for SOBP environments and between 3.17%-4.69% for uniform, monoenergetic fields proximal to the distal 80% of the BP.
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Affiliation(s)
- Blake R Smith
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Mark Pankuch
- Division of Medical Physics, Northwestern Medicine Chicago Proton Center, 4455 Weaver Parkway, Warrenville, IL, 60555, USA
| | - Clifford G Hammer
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Larry A DeWerd
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Wesley S Culberson
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
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Esposito M, Waltham C, Taylor JT, Manger S, Phoenix B, Price T, Poludniowski G, Green S, Evans PM, Allport PP, Manolopulos S, Nieto-Camero J, Symons J, Allinson NM. PRaVDA: The first solid-state system for proton computed tomography. Phys Med 2018; 55:149-154. [PMID: 30420271 PMCID: PMC6250048 DOI: 10.1016/j.ejmp.2018.10.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 09/26/2018] [Accepted: 10/23/2018] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Proton CT is widely recognised as a beneficial alternative to conventional X-ray CT for treatment planning in proton beam radiotherapy. A novel proton CT imaging system, based entirely on solid-state detector technology, is presented. Compared to conventional scintillator-based calorimeters, positional sensitive detectors allow for multiple protons to be tracked per read out cycle, leading to a potential reduction in proton CT scan time. Design and characterisation of its components are discussed. An early proton CT image obtained with a fully solid-state imaging system is shown and accuracy (as defined in Section IV) in Relative Stopping Power to water (RSP) quantified. METHOD A solid-state imaging system for proton CT, based on silicon strip detectors, has been developed by the PRaVDA collaboration. The system comprises a tracking system that infers individual proton trajectories through an imaging phantom, and a Range Telescope (RT) which records the corresponding residual energy (range) for each proton. A back-projection-then-filtering algorithm is used for CT reconstruction of an experimentally acquired proton CT scan. RESULTS An initial experimental result for proton CT imaging with a fully solid-state system is shown for an imaging phantom, namely a 75 mm diameter PMMA sphere containing tissue substitute inserts, imaged with a passively-scattered 125 MeV beam. Accuracy in RSP is measured to be ⩽1.6% for all the inserts shown. CONCLUSIONS A fully solid-state imaging system for proton CT has been shown capable of imaging a phantom with protons and successfully improving RSP accuracy. These promising results, together with system the capability to cope with high proton fluences (2×108 protons/s), suggests that this research platform could improve current standards in treatment planning for proton beam radiotherapy.
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Affiliation(s)
| | - Chris Waltham
- University of Lincoln, School of Computer Science, Lincoln, UK
| | | | - Sam Manger
- University of Warwick, Department of Physics, Warwick, UK
| | - Ben Phoenix
- University of Birmingham, School of Physics and Astronomy, Birmingham, UK
| | - Tony Price
- University of Birmingham, School of Physics and Astronomy, Birmingham, UK
| | | | - Stuart Green
- University of Birmingham, School of Physics and Astronomy, Birmingham, UK
| | - Philip M Evans
- University of Surrey, Centre for Vision, Speech and Signal Processing, Guildford, UK
| | - Philip P Allport
- University of Birmingham, School of Physics and Astronomy, Birmingham, UK
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Optimization of combined proton–photon treatments. Radiother Oncol 2018; 128:133-138. [DOI: 10.1016/j.radonc.2017.12.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 11/20/2022]
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Deng W, Liu W, Robertson DG, Bues M, Sio TT, Keole SR, Shen J. Technical Note: Using dual step wedge and 2D scintillator to achieve highly precise and robust proton range quality assurance. Med Phys 2018; 45:2947-2951. [PMID: 29754455 DOI: 10.1002/mp.12951] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/23/2018] [Accepted: 04/23/2018] [Indexed: 11/11/2022] Open
Abstract
PURPOSE The purpose of this study was to develop a fast method for proton range quality assurance (QA) using a dual step wedge and two-dimensional (2D) scintillator and to evaluate the robustness, sensitivity, and long-term reproducibility of this method. METHODS An in-house customized dual step wedge and a 2D scintillator were developed to measure proton ranges. Proton beams with homogenous fluence were delivered through wedge, and the images captured by the scintillator were used to calculate the proton ranges by a simple trigonometric method. The range measurements of 97 energies, comprising all clinically available synchrotron energies at our facility (ranges varying from 4 to 32 cm) were repeated ten times in all four gantry rooms for range baseline values. They were then used for evaluating room-to-room range consistencies. The robustness to setup uncertainty was evaluated by measuring ranges with ±2 mm setup deviations in the x, y, and z directions. The long-term reproducibility was evaluated by 1 month of daily range measurements by this method. RESULTS Ranges of all 97 energies were measured in less than 10 minutes including setup time. The reproducibility in a single day and daily over 1 month is within 0.1 and 0.15 mm, respectively. The method was very robust to setup uncertainty, with measured range consistencies within 0.15 mm for ±2 mm couch shifts. The method was also sensitive enough for validating range consistencies among gantry rooms and for detecting small range variations. CONCLUSIONS The new method of using a dual step wedge and scintillator for proton range QA was efficient, highly reproducible, and robust. This method of proton range QA was highly feasible and appealing from a workflow point of view.
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Affiliation(s)
- Wei Deng
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, 85054, USA
| | - Wei Liu
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, 85054, USA
| | | | - Martin Bues
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, 85054, USA
| | - Terence T Sio
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, 85054, USA
| | - Sameer R Keole
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, 85054, USA
| | - Jiajian Shen
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ, 85054, USA
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Multiple energy extraction reduces beam delivery time for a synchrotron-based proton spot-scanning system. Adv Radiat Oncol 2018; 3:412-420. [PMID: 30197942 PMCID: PMC6127977 DOI: 10.1016/j.adro.2018.02.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/13/2018] [Indexed: 11/27/2022] Open
Abstract
Purpose Multiple energy extraction (MEE) is a technology that was recently introduced by Hitachi for its spot-scanning proton treatment system, which allows multiple energies to be delivered in a single synchrotron spill. The purpose of this paper is to investigate how much beam delivery time (BDT) can be reduced with MEE compared with single energy extraction (SEE), in which one energy is delivered per spill. Methods and Materials A recently developed model based on BDT measurements of our synchrotron's delivery performance was used to compute BDT. The total BDT for 2694 beam deliveries in a cohort of 79 patients treated at our institution was computed in both SEE and 9 MEE configurations to determine BDT reduction. The cohort BDT reduction was also calculated for hypothetical accelerators with increased deliverable charge and compared with the results of our current delivery system. Results A vendor-provided MEE configuration with 4 energy layers per spill reduced the total BDT on average by 35% (41 seconds) compared with SEE, with up to 65% BDT reduction for individual fields. Adding an MEE layer reduced the total BDT by <1% of SEE BDT. However, improving charge recapture efficiency increased BDT savings by up to 42% of SEE BDT. Conclusions The MEE delivery technique reduced the total BDT by 35%. Increasing the charge per spill and charge recapture efficiency is necessary to further reduce BDT and thereby take full advantage of our MEE system's potential to improve treatment delivery efficiency and operational throughput.
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31
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Younkin JE, Shen J, Bues M, Robertson DG, Mundy DW, Clouser E, Liu W, Ding X, Stoker JB. Technical Note: An efficient daily QA procedure for proton pencil beam scanning. Med Phys 2018; 45:1040-1049. [DOI: 10.1002/mp.12787] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 12/13/2017] [Accepted: 01/14/2018] [Indexed: 11/08/2022] Open
Affiliation(s)
- James E. Younkin
- Department of Radiation Oncology; Mayo Clinic Arizona; Phoenix AZ 85259 USA
| | - Jiajian Shen
- Department of Radiation Oncology; Mayo Clinic Arizona; Phoenix AZ 85259 USA
| | - Martin Bues
- Department of Radiation Oncology; Mayo Clinic Arizona; Phoenix AZ 85259 USA
| | | | - Daniel W. Mundy
- Department of Radiation Oncology; Mayo Clinic Rochester; Rochester MN 55905 USA
| | - Edward Clouser
- Department of Radiation Oncology; Mayo Clinic Arizona; Phoenix AZ 85259 USA
| | - Wei Liu
- Department of Radiation Oncology; Mayo Clinic Arizona; Phoenix AZ 85259 USA
| | - Xiaoning Ding
- Department of Radiation Oncology; Mayo Clinic Arizona; Phoenix AZ 85259 USA
| | - Joshua B. Stoker
- Department of Radiation Oncology; Mayo Clinic Arizona; Phoenix AZ 85259 USA
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Shen C, Li B, Chen L, Yang M, Lou Y, Jia X. Material elemental decomposition in dual and multi-energy CT via a sparsity-dictionary approach for proton stopping power ratio calculation. Med Phys 2018; 45:1491-1503. [PMID: 29405340 DOI: 10.1002/mp.12796] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 12/11/2017] [Accepted: 01/20/2018] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Accurate calculation of proton stopping power ratio (SPR) relative to water is crucial to proton therapy treatment planning, since SPR affects prediction of beam range. Current standard practice derives SPR using a single CT scan. Recent studies showed that dual-energy CT (DECT) offers advantages to accurately determine SPR. One method to further improve accuracy is to incorporate prior knowledge on human tissue composition through a dictionary approach. In addition, it is also suggested that using CT images with multiple (more than two) energy channels, i.e., multi-energy CT (MECT), can further improve accuracy. In this paper, we proposed a sparse dictionary-based method to convert CT numbers of DECT or MECT to elemental composition (EC) and relative electron density (rED) for SPR computation. METHOD A dictionary was constructed to include materials generated based on human tissues of known compositions. For a voxel with CT numbers of different energy channels, its EC and rED are determined subject to a constraint that the resulting EC is a linear non-negative combination of only a few tissues in the dictionary. We formulated this as a non-convex optimization problem. A novel algorithm was designed to solve the problem. The proposed method has a unified structure to handle both DECT and MECT with different number of channels. We tested our method in both simulation and experimental studies. RESULTS Average errors of SPR in experimental studies were 0.70% in DECT, 0.53% in MECT with three energy channels, and 0.45% in MECT with four channels. We also studied the impact of parameter values and established appropriate parameter values for our method. CONCLUSION The proposed method can accurately calculate SPR using DECT and MECT. The results suggest that using more energy channels may improve the SPR estimation accuracy.
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Affiliation(s)
- Chenyang Shen
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75287, USA
| | - Bin Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75287, USA.,Department of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Liyuan Chen
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75287, USA
| | - Ming Yang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75287, USA
| | - Yifei Lou
- Department of Mathematical Science, University of Texas at Dallas, Dallas, TX, 75080, USA
| | - Xun Jia
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, 75287, USA
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Sudhyadhom A. Determination of mean ionization potential using magnetic resonance imaging for the reduction of proton beam range uncertainties: theory and application. ACTA ACUST UNITED AC 2017; 62:8521-8535. [DOI: 10.1088/1361-6560/aa8d9e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Shen J, Tryggestad E, Younkin JE, Keole SR, Furutani KM, Kang Y, Herman MG, Bues M. Technical Note: Using experimentally determined proton spot scanning timing parameters to accurately model beam delivery time. Med Phys 2017; 44:5081-5088. [PMID: 28777447 DOI: 10.1002/mp.12504] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 07/27/2017] [Accepted: 07/28/2017] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To accurately model the beam delivery time (BDT) for a synchrotron-based proton spot scanning system using experimentally determined beam parameters. METHODS A model to simulate the proton spot delivery sequences was constructed, and BDT was calculated by summing times for layer switch, spot switch, and spot delivery. Test plans were designed to isolate and quantify the relevant beam parameters in the operation cycle of the proton beam therapy delivery system. These parameters included the layer switch time, magnet preparation and verification time, average beam scanning speeds in x- and y-directions, proton spill rate, and maximum charge and maximum extraction time for each spill. The experimentally determined parameters, as well as the nominal values initially provided by the vendor, served as inputs to the model to predict BDTs for 602 clinical proton beam deliveries. The calculated BDTs (TBDT ) were compared with the BDTs recorded in the treatment delivery log files (TLog ): ∆t = TLog -TBDT . RESULTS The experimentally determined average layer switch time for all 97 energies was 1.91 s (ranging from 1.9 to 2.0 s for beam energies from 71.3 to 228.8 MeV), average magnet preparation and verification time was 1.93 ms, the average scanning speeds were 5.9 m/s in x-direction and 19.3 m/s in y-direction, the proton spill rate was 8.7 MU/s, and the maximum proton charge available for one acceleration is 2.0 ± 0.4 nC. Some of the measured parameters differed from the nominal values provided by the vendor. The calculated BDTs using experimentally determined parameters matched the recorded BDTs of 602 beam deliveries (∆t = -0.49 ± 1.44 s), which were significantly more accurate than BDTs calculated using nominal timing parameters (∆t = -7.48 ± 6.97 s). CONCLUSIONS An accurate model for BDT prediction was achieved by using the experimentally determined proton beam therapy delivery parameters, which may be useful in modeling the interplay effect and patient throughput. The model may provide guidance on how to effectively reduce BDT and may be used to identifying deteriorating machine performance.
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Affiliation(s)
- Jiajian Shen
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
| | - Erik Tryggestad
- Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, MN, 55905, USA
| | - James E Younkin
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
| | - Sameer R Keole
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
| | - Keith M Furutani
- Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, MN, 55905, USA
| | - Yixiu Kang
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
| | - Michael G Herman
- Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, MN, 55905, USA
| | - Martin Bues
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
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Li B, Lee HC, Duan X, Shen C, Zhou L, Jia X, Yang M. Comprehensive analysis of proton range uncertainties related to stopping-power-ratio estimation using dual-energy CT imaging. Phys Med Biol 2017; 62:7056-7074. [PMID: 28678019 DOI: 10.1088/1361-6560/aa7dc9] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The dual-energy CT-based (DECT) approach holds promise in reducing the overall uncertainty in proton stopping-power-ratio (SPR) estimation as compared to the conventional stoichiometric calibration approach. The objective of this study was to analyze the factors contributing to uncertainty in SPR estimation using the DECT-based approach and to derive a comprehensive estimate of the range uncertainty associated with SPR estimation in treatment planning. Two state-of-the-art DECT-based methods were selected and implemented on a Siemens SOMATOM Force DECT scanner. The uncertainties were first divided into five independent categories. The uncertainty associated with each category was estimated for lung, soft and bone tissues separately. A single composite uncertainty estimate was eventually determined for three tumor sites (lung, prostate and head-and-neck) by weighting the relative proportion of each tissue group for that specific site. The uncertainties associated with the two selected DECT methods were found to be similar, therefore the following results applied to both methods. The overall uncertainty (1σ) in SPR estimation with the DECT-based approach was estimated to be 3.8%, 1.2% and 2.0% for lung, soft and bone tissues, respectively. The dominant factor contributing to uncertainty in the DECT approach was the imaging uncertainties, followed by the DECT modeling uncertainties. Our study showed that the DECT approach can reduce the overall range uncertainty to approximately 2.2% (2σ) in clinical scenarios, in contrast to the previously reported 1%.
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Affiliation(s)
- B Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States of America. Department of Biomedical Engineering, Southern Medical University, Guangzhou, Guangdong 510515, People's Republic of China
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36
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Lin HH, Chang HT, Chao TC, Chuang KS. A comparison of two prompt gamma imaging techniques with collimator-based cameras for range verification in proton therapy. Radiat Phys Chem Oxf Engl 1993 2017. [DOI: 10.1016/j.radphyschem.2016.04.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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37
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Shen J, Allred BC, Robertson DG, Liu W, Sio TT, Remmes NB, Keole SR, Bues M. A novel and fast method for proton range verification using a step wedge and 2D scintillator. Med Phys 2017; 44:4409-4414. [PMID: 28665529 DOI: 10.1002/mp.12439] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/11/2017] [Accepted: 06/22/2017] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To implement and evaluate a novel and fast method for proton range verification by using a planar scintillator and step wedge. METHODS A homogenous proton pencil beam plan with 35 energies was designed and delivered to a 2D flat scintillator with a step wedge. The measurement was repeated 15 times (3 different days, 5 times per day). The scintillator image was smoothed, the Bragg peak and distal fall off regions were fitted by an analytical equation, and the proton range was calculated using simple trigonometry. The accuracy of this method was verified by comparing the measured ranges to those obtained using an ionization chamber and a scanning water tank, the gold standard. The reproducibility was evaluated by comparing the ranges over 15 repeated measurements. The sensitivity was evaluated by delivering to same beam to the system with a film inserted under the wedge. RESULTS The range accuracy of all 35 proton energies measured over 3 days was within 0.2 mm. The reproducibility in 15 repeated measurements for all 35 proton ranges was ±0.045 mm. The sensitivity to range variation is 0.1 mm for the worst case. This efficient procedure permits measurement of 35 proton ranges in less than 3 min. The automated data processing produces results immediately. The setup of this system took less than 5 min. The time saving by this new method is about two orders of magnitude when compared with the time for water tank range measurements. CONCLUSIONS A novel method using a scintillator with a step wedge to measure the proton range was implemented and evaluated. This novel method is fast and sensitive, and the proton range measured by this method was accurate and highly reproducible.
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Affiliation(s)
- Jiajian Shen
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
| | - Bryce C Allred
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
| | - Daniel G Robertson
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
| | - Wei Liu
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
| | - Terence T Sio
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
| | - Nicholas B Remmes
- Department of Radiation Oncology, Mayo Clinic Rochester, Rochester, MN, 55905, USA
| | - Sameer R Keole
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
| | - Martin Bues
- Department of Radiation Oncology, Mayo Clinic Arizona, Phoenix, AZ, 85054, USA
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38
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Oborn BM, Dowdell S, Metcalfe PE, Crozier S, Mohan R, Keall PJ. Future of medical physics: Real-time MRI-guided proton therapy. Med Phys 2017; 44:e77-e90. [PMID: 28547820 DOI: 10.1002/mp.12371] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 03/12/2017] [Accepted: 05/15/2017] [Indexed: 12/20/2022] Open
Abstract
With the recent clinical implementation of real-time MRI-guided x-ray beam therapy (MRXT), attention is turning to the concept of combining real-time MRI guidance with proton beam therapy; MRI-guided proton beam therapy (MRPT). MRI guidance for proton beam therapy is expected to offer a compelling improvement to the current treatment workflow which is warranted arguably more than for x-ray beam therapy. This argument is born out of the fact that proton therapy toxicity outcomes are similar to that of the most advanced IMRT treatments, despite being a fundamentally superior particle for cancer treatment. In this Future of Medical Physics article, we describe the various software and hardware aspects of potential MRPT systems and the corresponding treatment workflow. Significant software developments, particularly focused around adaptive MRI-based planning will be required. The magnetic interaction between the MRI and the proton beamline components will be a key area of focus. For example, the modeling and potential redesign of a magnetically compatible gantry to allow for beam delivery from multiple angles towards a patient located within the bore of an MRI scanner. Further to this, the accuracy of pencil beam scanning and beam monitoring in the presence of an MRI fringe field will require modeling, testing, and potential further development to ensure that the highly targeted radiotherapy is maintained. Looking forward we envisage a clear and accelerated path for hardware development, leveraging from lessons learnt from MRXT development. Within few years, simple prototype systems will likely exist, and in a decade, we could envisage coupled systems with integrated gantries. Such milestones will be key in the development of a more efficient, more accurate, and more successful form of proton beam therapy for many common cancer sites.
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Affiliation(s)
- Bradley M Oborn
- Illawarra Cancer Care Centre (ICCC), Wollongong, NSW, 2500, Australia.,Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW, 2500, Australia
| | | | - Peter E Metcalfe
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW, 2500, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia
| | - Stuart Crozier
- School of Information Technology and Electric Engineering, University of Queensland, QLD, 4072, Australia
| | - Radhe Mohan
- Department of Radiation Oncology, MD Anderson, Houston, TX, 77030, USA
| | - Paul J Keall
- Ingham Institute for Applied Medical Research, Liverpool, NSW, 2170, Australia.,Sydney Medical School, University of Sydney, NSW, 2006, Australia
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Kipergil EA, Erkol H, Kaya S, Gulsen G, Unlu MB. An analysis of beam parameters on proton-acoustic waves through an analytic approach. Phys Med Biol 2017; 62:4694-4710. [PMID: 28252450 DOI: 10.1088/1361-6560/aa642c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It has been reported that acoustic waves are generated when a high-energy pulsed proton beam is deposited in a small volume within tissue. One possible application of proton-induced acoustics is to get real-time feedback for intra-treatment adjustments by monitoring such acoustic waves. A high spatial resolution in ultrasound imaging may reduce proton range uncertainty. Thus, it is crucial to understand the dependence of the acoustic waves on the proton beam characteristics. In this manuscript, firstly, an analytic solution for the proton-induced acoustic wave is presented to reveal the dependence of the signal on the beam parameters; then it is combined with an analytic approximation of the Bragg curve. The influence of the beam energy, pulse duration and beam diameter variation on the acoustic waveform are investigated. Further analysis is performed regarding the Fourier decomposition of the proton-acoustic signals. Our results show that the smaller spill time of the proton beam upsurges the amplitude of the acoustic wave for a constant number of protons, which is hence beneficial for dose monitoring. The increase in the energy of each individual proton in the beam leads to the spatial broadening of the Bragg curve, which also yields acoustic waves of greater amplitude. The pulse duration and the beam width of the proton beam do not affect the central frequency of the acoustic wave, but they change the amplitude of the spectral components.
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40
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Mohan R, Grosshans D. Proton therapy - Present and future. Adv Drug Deliv Rev 2017; 109:26-44. [PMID: 27919760 PMCID: PMC5303653 DOI: 10.1016/j.addr.2016.11.006] [Citation(s) in RCA: 239] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 12/13/2022]
Abstract
In principle, proton therapy offers a substantial clinical advantage over conventional photon therapy. This is because of the unique depth-dose characteristics of protons, which can be exploited to achieve significant reductions in normal tissue doses proximal and distal to the target volume. These may, in turn, allow escalation of tumor doses and greater sparing of normal tissues, thus potentially improving local control and survival while at the same time reducing toxicity and improving quality of life. Protons, accelerated to therapeutic energies ranging from 70 to 250MeV, typically with a cyclotron or a synchrotron, are transported to the treatment room where they enter the treatment head mounted on a rotating gantry. The initial thin beams of protons are spread laterally and longitudinally and shaped appropriately to deliver treatments. Spreading and shaping can be achieved by electro-mechanical means to treat the patients with "passively-scattered proton therapy" (PSPT) or using magnetic scanning of thin "beamlets" of protons of a sequence of initial energies. The latter technique can be used to treat patients with optimized intensity modulated proton therapy (IMPT), the most powerful proton modality. Despite the high potential of proton therapy, the clinical evidence supporting the broad use of protons is mixed. It is generally acknowledged that proton therapy is safe, effective and recommended for many types of pediatric cancers, ocular melanomas, chordomas and chondrosarcomas. Although promising results have been and continue to be reported for many other types of cancers, they are based on small studies. Considering the high cost of establishing and operating proton therapy centers, questions have been raised about their cost effectiveness. General consensus is that there is a need to conduct randomized trials and/or collect outcomes data in multi-institutional registries to unequivocally demonstrate the advantage of protons. Treatment planning and plan evaluation of PSPT and IMPT require special considerations compared to the processes used for photon treatment planning. The differences in techniques arise from the unique physical properties of protons but are also necessary because of the greater vulnerability of protons to uncertainties, especially from inter- and intra-fractional variations in anatomy. These factors must be considered in designing as well as evaluating treatment plans. In addition to anatomy variations, other sources of uncertainty in dose delivered to the patient include the approximations and assumptions of models used for computing dose distributions for planning of treatments. Furthermore, the relative biological effectiveness (RBE) of protons is simplistically assumed to have a constant value of 1.1. In reality, the RBE is variable and a complex function of the energy of protons, dose per fraction, tissue and cell type, end point, etc. These uncertainties, approximations and current technological limitations of proton therapy may limit the achievement of its true potential. Ongoing research is aimed at better understanding the consequences of the various uncertainties on proton therapy and reducing the uncertainties through image-guidance, adaptive radiotherapy, further study of biological properties of protons and the development of novel dose computation and optimization methods. However, residual uncertainties will remain in spite of the best efforts. To increase the resilience of dose distributions in the face of uncertainties and improve our confidence in dose distributions seen on treatment plans, robust optimization techniques are being developed and implemented. We assert that, with such research, proton therapy will be a commonly applied radiotherapy modality for most types of solid cancers in the near future.
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Affiliation(s)
- Radhe Mohan
- Department of Radiation Physics, MD Anderson Cancer Center, Houston, TX 77030, United States.
| | - David Grosshans
- Department of Radiation Oncology, MD Anderson Cancer Center, Houston, TX 77030, United States
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Durante M, Paganetti H. Nuclear physics in particle therapy: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:096702. [PMID: 27540827 DOI: 10.1088/0034-4885/79/9/096702] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Charged particle therapy has been largely driven and influenced by nuclear physics. The increase in energy deposition density along the ion path in the body allows reducing the dose to normal tissues during radiotherapy compared to photons. Clinical results of particle therapy support the physical rationale for this treatment, but the method remains controversial because of the high cost and of the lack of comparative clinical trials proving the benefit compared to x-rays. Research in applied nuclear physics, including nuclear interactions, dosimetry, image guidance, range verification, novel accelerators and beam delivery technologies, can significantly improve the clinical outcome in particle therapy. Measurements of fragmentation cross-sections, including those for the production of positron-emitting fragments, and attenuation curves are needed for tuning Monte Carlo codes, whose use in clinical environments is rapidly increasing thanks to fast calculation methods. Existing cross sections and codes are indeed not very accurate in the energy and target regions of interest for particle therapy. These measurements are especially urgent for new ions to be used in therapy, such as helium. Furthermore, nuclear physics hardware developments are frequently finding applications in ion therapy due to similar requirements concerning sensors and real-time data processing. In this review we will briefly describe the physics bases, and concentrate on the open issues.
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Affiliation(s)
- Marco Durante
- Trento Institute for Fundamental Physics and Applications (TIFPA), National Institute of Nuclear Physics (INFN), University of Trento, Via Sommarive 14, 38123 Povo (TN), Italy. Department of Physics, University Federico II, Naples, Italy
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Suzuki K, Palmer MB, Sahoo N, Zhang X, Poenisch F, Mackin DS, Liu AY, Wu R, Zhu XR, Frank SJ, Gillin MT, Lee AK. Quantitative analysis of treatment process time and throughput capacity for spot scanning proton therapy. Med Phys 2016; 43:3975. [DOI: 10.1118/1.4952731] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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Matney JE, Park PC, Li H, Court LE, Zhu XR, Dong L, Liu W, Mohan R. Perturbation of water-equivalent thickness as a surrogate for respiratory motion in proton therapy. J Appl Clin Med Phys 2016; 17:368-378. [PMID: 27074459 PMCID: PMC5546214 DOI: 10.1120/jacmp.v17i2.5795] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 12/02/2015] [Accepted: 11/18/2015] [Indexed: 12/25/2022] Open
Abstract
Respiratory motion is traditionally assessed using tumor motion magnitude. In proton therapy, respiratory motion causes density variations along the beam path that result in uncertainties of proton range. This work has investigated the use of water‐equivalent thickness (WET) to quantitatively assess the effects of respiratory motion on calculated dose in passively scattered proton therapy (PSPT). A cohort of 29 locally advanced non‐small cell lung cancer patients treated with 87 PSPT treatment fields were selected for analysis. The variation in WET (ΔWET) along each field was calculated between exhale and inhale phases of the simulation four‐dimensional computed tomography. The change in calculated dose (ΔDose) between full‐inhale and full‐exhale phase was quantified for each field using dose differences, 3D gamma analysis, and differential area under the curve (ΔAUC) analysis. Pearson correlation coefficients were calculated between ΔDose and ΔWET. Three PSPT plans were redesigned using field angles to minimize variations in ΔWET and compared to the original plans. The median ΔWET over 87 treatment fields ranged from 1‐9 mm, while the ΔWET 95th percentile value ranged up to 42 mm. The ΔWET was significantly correlated (p<0.001) to the ΔDose for all metrics analyzed. The patient plans that were redesigned using ΔWET analysis to select field angles were more robust to the effects of respiratory motion, as ΔAUC values were reduced by more than 60% in all three cases. The tumor motion magnitude alone does not capture the potential dosimetric error due to respiratory motion because the proton range is sensitive to the motion of all patient anatomy. The use of ΔWET has been demonstrated to identify situations where respiratory motion can impact the calculated dose. Angular analysis of ΔWET may be capable of designing radiotherapy plans that are more robust to the effects of respiratory motion. PACS number(s): 87.55.‐x
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Dolney D, Ainsley C, Hollebeek R, Maughan R. Monte Carlo simulations of a novel Micromegas 2D array for proton dosimetry. Phys Med Biol 2016; 61:1563-72. [PMID: 26816338 DOI: 10.1088/0031-9155/61/4/1563] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Modern proton therapy affords control of the delivery of radiotherapeutic dose on fine length and temporal scales. The authors have developed a novel detector technology based on Micromesh Gaseous Structure (Micromegas) that is uniquely tailored for applications using therapeutic proton beams. An implementation of a prototype Micromegas detector for Monte Carlo using Geant4 is presented here. Comparison of simulation results with measurements demonstrates agreement in relative dose along the proton longitudinal dose profile to be 1%. The effect of a radioactive calibration source embedded in the chamber gas is demonstrated by measurements and reproduced by simulations, also at the 1% level. Our Monte Carlo simulations are shown to reproduce the time structure of ionization pulses produced by a double-scattering delivery system.
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Affiliation(s)
- D Dolney
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA 19104, USA
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Parodi K. Vision 20/20: Positron emission tomography in radiation therapy planning, delivery, and monitoring. Med Phys 2015; 42:7153-68. [DOI: 10.1118/1.4935869] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Assmann W, Kellnberger S, Reinhardt S, Lehrack S, Edlich A, Thirolf PG, Moser M, Dollinger G, Omar M, Ntziachristos V, Parodi K. Ionoacoustic characterization of the proton Bragg peak with submillimeter accuracy. Med Phys 2015; 42:567-74. [PMID: 25652477 DOI: 10.1118/1.4905047] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
PURPOSE Range verification in ion beam therapy relies to date on nuclear imaging techniques which require complex and costly detector systems. A different approach is the detection of thermoacoustic signals that are generated due to localized energy loss of ion beams in tissue (ionoacoustics). Aim of this work was to study experimentally the achievable position resolution of ionoacoustics under idealized conditions using high frequency ultrasonic transducers and a specifically selected probing beam. METHODS A water phantom was irradiated by a pulsed 20 MeV proton beam with varying pulse intensity and length. The acoustic signal of single proton pulses was measured by different PZT-based ultrasound detectors (3.5 and 10 MHz central frequencies). The proton dose distribution in water was calculated by Geant4 and used as input for simulation of the generated acoustic wave by the matlab toolbox k-WAVE. RESULTS In measurements from this study, a clear signal of the Bragg peak was observed for an energy deposition as low as 10(12) eV. The signal amplitude showed a linear increase with particle number per pulse and thus, dose. Bragg peak position measurements were reproducible within ±30 μm and agreed with Geant4 simulations to better than 100 μm. The ionoacoustic signal pattern allowed for a detailed analysis of the Bragg peak and could be well reproduced by k-WAVE simulations. CONCLUSIONS The authors have studied the ionoacoustic signal of the Bragg peak in experiments using a 20 MeV proton beam with its correspondingly localized energy deposition, demonstrating submillimeter position resolution and providing a deep insight in the correlation between the acoustic signal and Bragg peak shape. These results, together with earlier experiments and new simulations (including the results in this study) at higher energies, suggest ionoacoustics as a technique for range verification in particle therapy at locations, where the tumor can be localized by ultrasound imaging. This acoustic range verification approach could offer the possibility of combining anatomical ultrasound and Bragg peak imaging, but further studies are required for translation of these findings to clinical application.
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Affiliation(s)
- W Assmann
- Department for Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching 85748, Germany
| | - S Kellnberger
- Institute for Biological and Medical Imaging, Technische Universität München and Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany
| | - S Reinhardt
- Department for Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching 85748, Germany
| | - S Lehrack
- Department for Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching 85748, Germany
| | - A Edlich
- Department for Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching 85748, Germany
| | - P G Thirolf
- Department for Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching 85748, Germany
| | - M Moser
- Institute for Applied Physics and Measurement Technology, Universität der Bundeswehr, Werner-Heisenberg-Weg 39, Neubiberg 85577, Germany
| | - G Dollinger
- Institute for Applied Physics and Measurement Technology, Universität der Bundeswehr, Werner-Heisenberg-Weg 39, Neubiberg 85577, Germany
| | - M Omar
- Institute for Biological and Medical Imaging, Technische Universität München and Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany
| | - V Ntziachristos
- Institute for Biological and Medical Imaging, Technische Universität München and Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg 85764, Germany
| | - K Parodi
- Department for Medical Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching 85748, Germany
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Hofmann KM, Masood U, Pawelke J, Wilkens JJ. A treatment planning study to assess the feasibility of laser-driven proton therapy using a compact gantry design. Med Phys 2015; 42:5120-9. [DOI: 10.1118/1.4927717] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Mills MD, Schulz RJ. Proton-beam therapy: are physicists ignoring clinical realities? J Appl Clin Med Phys 2015; 16:5710. [PMID: 26103506 PMCID: PMC5690119 DOI: 10.1120/jacmp.v16i3.5710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 03/17/2015] [Indexed: 12/25/2022] Open
Affiliation(s)
- Michael D Mills
- University of Louisville 529 South Jackson Street Louisville, KY 40202 USA.
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Mori S, Amano S, Furukawa T, Shirai T, Noda K. Effect of secondary particles on image quality of dynamic flat panels in carbon ion scanning beam treatment. Br J Radiol 2014; 88:20140567. [PMID: 25536444 DOI: 10.1259/bjr.20140567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE Real-time markerless tumour tracking using radiographic fluoroscopic imaging is one of the better solutions to improving respiratory-gated radiotherapy. However, particle beams cause secondary particles from patients, which could affect radiographs. Here, we evaluated the quality of radiographs during carbon ion pencil beam scanning (CPBS) irradiation for respiratory gating. METHODS A water phantom and chest phantom were used. The phantoms were irradiated with CPBS at 290 MeV n(-1) from orthogonal directions. Dose rates were 3.4 × 10(8), 1.14 × 10(8) and 3.79 × 10(7) particles per second. A dynamic flat panel detector (DFPD) was installed on the upstream (DFPD1) or downstream (DFPD2) side of the vertical irradiation port. DFPD images were acquired during CPBS at 15.00, 7.50 and 3.75 frames per second (fps). Charge on the DFPD was cleaned using fast readout technique every 30 fps. DFPD images were acquired during CPBS with radiographic exposure, and results with and without fast readout technique were compared. RESULTS Secondary particles were visualized as spots or streak-like shapes. Capture of secondary particles from the horizontal beam direction was lower with fast readout technique than without it. With regard to beam irradiation direction dependency, CPBS from the horizontal direction resulted in a greater magnitude of secondary particles reaching DFPD2 than reaching DFPD1. When CPBS was delivered from the vertical direction, however, the magnitude of secondary particles on both DFPDs was very similar. CONCLUSION Fast readout technique minimized the effect of secondary particles on DFPD images during CPBS. ADVANCES IN KNOWLEDGE This technique may be useful for markerless tumour tracking for respiratory gating.
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Affiliation(s)
- S Mori
- 1 Research Center for Charged Particle Therapy, Medical Physics Research Program, National Institute of Radiological Sciences, Chiba, Japan
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Zhu XR, Poenisch F, Li H, Zhang X, Sahoo N, Wu RY, Li X, Lee AK, Chang EL, Choi S, Pugh T, Frank SJ, Gillin MT, Mahajan A, Grosshans DR. A single-field integrated boost treatment planning technique for spot scanning proton therapy. Radiat Oncol 2014; 9:202. [PMID: 25212571 PMCID: PMC4262206 DOI: 10.1186/1748-717x-9-202] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 09/05/2014] [Indexed: 01/25/2023] Open
Abstract
Purpose Intensity modulated proton therapy (IMPT) plans are normally generated utilizing multiple field optimization (MFO) techniques. Similar to photon based IMRT, MFO allows for the utilization of a simultaneous integrated boost in which multiple target volumes are treated to discrete doses simultaneously, potentially improving plan quality and streamlining quality assurance and treatment delivery. However, MFO may render plans more sensitive to the physical uncertainties inherent to particle therapy. Here we present clinical examples of a single-field integrated boost (SFIB) technique for spot scanning proton therapy based on single field optimization (SFO) treatment-planning techniques. Methods and materials We designed plans of each type for illustrative patients with central nervous system (brain and spine), prostate and head and neck malignancies. SFIB and IMPT plans were constructed to deliver multiple prescription dose levels to multiple targets using SFO or MFO, respectively. Dose and fractionation schemes were based on the current clinical practice using X-ray IMRT in our clinic. For inverse planning, dose constraints were employed to achieve the desired target coverage and normal tissue sparing. Conformality and inhomogeneity indices were calculated to quantify plan quality. We also compared the worst-case robustness of the SFIB, sequential boost SFUD, and IMPT plans. Results The SFIB technique produced more conformal dose distributions than plans generated by sequential boost using a SFUD technique (conformality index for prescription isodose levels; 0.585 ± 0.30 vs. 0.435 ± 0.24, SFIB vs. SFUD respectively, Wilcoxon matched-pair signed rank test, p < 0.01). There was no difference in the conformality index between SFIB and IMPT plans (0.638 ± 0.27 vs. 0.633 ± 0.26, SFIB vs. IMPT, respectively). Heterogeneity between techniques was not significantly different. With respect to clinical metrics, SFIB plans proved more robust than the corresponding IMPT plans. Conclusions SFIB technique for scanning beam proton therapy (SSPT) is now routinely employed in our clinic. The SFIB technique is a natural application of SFO and offers several advantages over SFUD, including more conformal plans, seamless treatment delivery and more efficient planning and QA. SFIB may be more robust than IMPT and has been the treatment planning technique of choice for some patients.
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Affiliation(s)
- Xiaorong Ronald Zhu
- Departments of Radiation Physics, The University of Texas MD Anderson Cancer Center, Unit 1150, 1515 Holcombe Boulevard, Houston, TX, USA.
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