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Shiraishi Y, Matsuya Y, Fukunaga H. Reply to comment on 'Modeling for predicting survival fraction of cells after ultra-high dose rate irradiation'. Phys Med Biol 2024; 69:108002. [PMID: 38700988 DOI: 10.1088/1361-6560/ad3edc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 04/15/2024] [Indexed: 05/05/2024]
Abstract
Liew and Mairani commented on our paper 'Modeling for predicting survival fraction of cells after ultra-high dose rate irradiation' (Shiraishiet al2024aPhys. Med. Biol.69015017), which proposed a biophysical model to predict the dose-response curve of surviving cell fractions after ultra-high dose rate irradiation following conventional dose rate irradiation by considering DNA damage yields. They suggested the need to consider oxygen concentration in our prediction model and possible issues related to the data selection process used for the benchmarking test in our paper. In this reply, we discuss the limitations of both the present model and the available experimental data for determining the model's parameters. We also demonstrate that our proposed model can reproduce the experimental survival data even when using only the experimental DNA damage data measured reliably under normoxic conditions.
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Affiliation(s)
- Yuta Shiraishi
- Graduate school of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido, 060-0812, Japan
- Faculty of Health Sciences, Japan Healthcare University, 3-11-1-50 Tsukisamu-higashi, Toyohira-ku, Sapporo, Hokkaido, 062-0053, Japan
| | - Yusuke Matsuya
- Department of Biomedical Science and Engineering, Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido, 060-0812, Japan
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki, 319-1195, Japan
| | - Hisanori Fukunaga
- Department of Biomedical Science and Engineering, Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido, 060-0812, Japan
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McGarrigle JM, Long KR, Prezado Y. The FLASH effect-an evaluation of preclinical studies of ultra-high dose rate radiotherapy. Front Oncol 2024; 14:1340190. [PMID: 38711846 PMCID: PMC11071325 DOI: 10.3389/fonc.2024.1340190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 03/20/2024] [Indexed: 05/08/2024] Open
Abstract
FLASH radiotherapy (FLASH-RT) is a novel radiotherapy approach based on the use of ultra-high dose radiation to treat malignant cells. Although tumours can be reduced or eradicated using radiotherapy, toxicities induced by radiation can compromise healthy tissues. The FLASH effect is the observation that treatment delivered at an ultra-high dose rate is able to reduce adverse toxicities present at conventional dose rates. While this novel technique may provide a turning point for clinical practice, the exact mechanisms underlying the causes or influences of the FLASH effect are not fully understood. The study presented here uses data collected from 41 experimental investigations (published before March 2024) of the FLASH effect. Searchable databases were constructed to contain the outcomes of the various experiments in addition to values of beam parameters that may have a bearing on the FLASH effect. An in-depth review of the impact of the key beam parameters on the results of the experiments was carried out. Correlations between parameter values and experimental outcomes were studied. Pulse Dose Rate had positive correlations with almost all end points, suggesting viability of FLASH-RT as a new modality of radiotherapy. The collective results of this systematic review study suggest that beam parameter qualities from both FLASH and conventional radiotherapy can be valuable for tissue sparing and effective tumour treatment.
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Affiliation(s)
| | - Kenneth Richard Long
- Department of Physics, Imperial College London, London, United Kingdom
- Science and Technology Facilities Council (STFC), Rutherford Appleton Laboratory, Oxford, United Kingdom
| | - Yolanda Prezado
- Institut Curie, Universite Paris-Saclay, Centre national de la recherche scientifique (CNRS) UMR3347, Inserm U1021, Signalisation radiobiologie et cancer, Orsay, France
- Universite Paris-Saclay, Centre national de la recherche scientifique (CNRS) UMR3347, Inserm U1021, Signalisation radiobiologie et cancer, Orsay, France
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Dai T, Sloop AM, Rahman MR, Sunnerberg JP, Clark MA, Young R, Adamczyk S, Von Voigts-Rhetz P, Patane C, Turk M, Jarvis L, Pogue BW, Gladstone DJ, Bruza P, Zhang R. First Monte Carlo beam model for ultra-high dose rate radiotherapy with a compact electron LINAC. Med Phys 2024. [PMID: 38493501 DOI: 10.1002/mp.17031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 03/04/2024] [Accepted: 03/04/2024] [Indexed: 03/19/2024] Open
Abstract
BACKGROUND FLASH radiotherapy based on ultra-high dose rate (UHDR) is actively being studied by the radiotherapy community. Dedicated UHDR electron devices are currently a mainstay for FLASH studies. PURPOSE To present the first Monte Carlo (MC) electron beam model for the UHDR capable Mobetron (FLASH-IQ) as a dose calculation and treatment planning platform for preclinical research and FLASH-radiotherapy (RT) clinical trials. METHODS The initial beamline geometry of the Mobetron was provided by the manufacturer, with the first-principal implementation realized in the Geant4-based GAMOS MC toolkit. The geometry and electron source characteristics, such as energy spectrum and beamline parameters, were tuned to match the central-axis percentage depth dose (PDD) and lateral profiles for the pristine beam measured during machine commissioning. The thickness of the small foil in secondary scatter affected the beam model dominantly and was fine tuned to achieve the best agreement with commissioning data. Validation of the MC beam modeling was performed by comparing the calculated PDDs and profiles with EBT-XD radiochromic film measurements for various combinations of applicators and inserts. RESULTS The nominal 9 MeV electron FLASH beams were best represented by a Gaussian energy spectrum with mean energy of 9.9 MeV and variance (σ) of 0.2 MeV. Good agreement between the MC beam model and commissioning data were demonstrated with maximal discrepancy < 3% for PDDs and profiles. Hundred percent gamma pass rate was achieved for all PDDs and profiles with the criteria of 2 mm/3%. With the criteria of 2 mm/2%, maximum, minimum and mean gamma pass rates were (100.0%, 93.8%, 98.7%) for PDDs and (100.0%, 96.7%, 99.4%) for profiles, respectively. CONCLUSIONS A validated MC beam model for the UHDR capable Mobetron is presented for the first time. The MC model can be utilized for direct dose calculation or to generate beam modeling input required for treatment planning systems for FLASH-RT planning. The beam model presented in this work should facilitate translational and clinical FLASH-RT for trials conducted on the Mobetron FLASH-IQ platform.
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Affiliation(s)
- Tianyuan Dai
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Department of Radiation Oncology Physics and Technology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China
| | - Austin M Sloop
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | | | - Jacob P Sunnerberg
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Megan A Clark
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Ralph Young
- IntraOp Medical Corporation, Sunnyvale, California, USA
| | | | | | - Chris Patane
- IntraOp Medical Corporation, Sunnyvale, California, USA
| | - Michael Turk
- IntraOp Medical Corporation, Sunnyvale, California, USA
| | - Lesley Jarvis
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
- Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Department of Radiation Medicine, New York Medical College, Valhalla, New York, USA
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Bancheri J, Seuntjens J. A semi-analytical procedure to determine the ion recombination correction factor in high dose-per-pulse beams. Med Phys 2024. [PMID: 38446555 DOI: 10.1002/mp.17005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/08/2024] [Accepted: 02/13/2024] [Indexed: 03/08/2024] Open
Abstract
BACKGROUND The conventional theories and methods of determining the ion recombination correction factor, such as Boag theory and the related two voltage method and Jaffé plot extrapolation, do not seem to yield accurate results in FLASH /high dose per pulse (DPP) beams ( > $>$ 10 mGy DPP). This is due to the presence of a large free electron fraction that distorts the electric field inside the chamber sensitive volume. To understand the influence of these effects on the ion recombination correction factor and to develop new expressions for it, it is necessary to re-visit the underlying physics. PURPOSE To present a mathematical procedure to develop an analytical expression for the ion recombination correction factor. The expression is the basis for an extrapolation method so the correction factor can be determined in a clinical setting. METHODS A semi-analytical solution method, the homotopy perturbation method (HPM), is used to solve the partial differential equations (PDEs) describing the charge carrier physics, including space charge and free electrons. The electron velocity and attachment rate are modeled as functions of the electric field strength. An expression for the charge collection efficiency and ion recombination correction factor are developed. A fit procedure based on this expression is used to compare it to measured data from previously published articles. Another fit procedure using a general equation is also proposed and compared to the data. RESULTS The series obtained for the charge collection efficiency and the ion recombination correction factor are determined to be asymptotic series and the optimal truncation established. The ion recombination correction factor exhibits a1 / V 2 $1/V^2$ dependency due to the free electron presence. The fit using this expression agrees well with measured data as long as (1) the DPP is below 1 Gy for chambers with a 1 mm plate separation and (2) when the DPP is below 3 Gy for chambers with a 0.5 mm plate separation. In these DPP ranges, the deviation between measured and fit value did not exceed 6%. In both chamber cases the voltage range where the fit applies decreases as DPP increases. The general equation yielded comparable results. CONCLUSIONS The HPM was shown to be applicable to a complex system of PDEs and generate meaningful and novel solutions, as they include both space charge and free electrons. The HPM also lends itself to other chamber geometries. The fit procedure was also shown to yield accurate results for the ion recombination correction up to the 1 Gy DPP level.
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Affiliation(s)
- Julien Bancheri
- Department of Physics & Medical Physics Unit, McGill University, Montreal, Quebec, Canada
| | - Jan Seuntjens
- Princess Margaret Cancer Centre, Radiation Medicine Program, University Health Network, Department of Medical Biophysics, University of Toronto, Toronto, Canada
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Borghini A, Labate L, Piccinini S, Panaino CMV, Andreassi MG, Gizzi LA. FLASH Radiotherapy: Expectations, Challenges, and Current Knowledge. Int J Mol Sci 2024; 25:2546. [PMID: 38473799 DOI: 10.3390/ijms25052546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 02/12/2024] [Accepted: 02/19/2024] [Indexed: 03/14/2024] Open
Abstract
Major strides have been made in the development of FLASH radiotherapy (FLASH RT) in the last ten years, but there are still many obstacles to overcome for transfer to the clinic to become a reality. Although preclinical and first-in-human clinical evidence suggests that ultra-high dose rates (UHDRs) induce a sparing effect in normal tissue without modifying the therapeutic effect on the tumor, successful clinical translation of FLASH-RT depends on a better understanding of the biological mechanisms underpinning the sparing effect. Suitable in vitro studies are required to fully understand the radiobiological mechanisms associated with UHDRs. From a technical point of view, it is also crucial to develop optimal technologies in terms of beam irradiation parameters for producing FLASH conditions. This review provides an overview of the research progress of FLASH RT and discusses the potential challenges to be faced before its clinical application. We critically summarize the preclinical evidence and in vitro studies on DNA damage following UHDR irradiation. We also highlight the ongoing developments of technologies for delivering FLASH-compliant beams, with a focus on laser-driven plasma accelerators suitable for performing basic radiobiological research on the UHDR effects.
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Affiliation(s)
| | - Luca Labate
- Intense Laser Irradiation Laboratory (ILIL), CNR Istituto Nazionale di Ottica, 56124 Pisa, Italy
| | - Simona Piccinini
- Intense Laser Irradiation Laboratory (ILIL), CNR Istituto Nazionale di Ottica, 56124 Pisa, Italy
| | | | | | - Leonida Antonio Gizzi
- Intense Laser Irradiation Laboratory (ILIL), CNR Istituto Nazionale di Ottica, 56124 Pisa, Italy
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Kaulfers T, Lattery G, Cheng C, Zhao X, Selvaraj B, Wu H, Chhabra AM, Choi JI, Lin H, Simone CB, Hasan S, Kang M, Chang J. Pencil Beam Scanning Proton Bragg Peak Conformal FLASH in Prostate Cancer Stereotactic Body Radiotherapy. Cancers (Basel) 2024; 16:798. [PMID: 38398188 PMCID: PMC10886659 DOI: 10.3390/cancers16040798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/29/2024] [Accepted: 02/12/2024] [Indexed: 02/25/2024] Open
Abstract
Bragg peak FLASH radiotherapy (RT) uses a distal tracking method to eliminate exit doses and can achieve superior OAR sparing. This study explores the application of this novel method in stereotactic body radiotherapy prostate FLASH-RT. An in-house platform was developed to enable intensity-modulated proton therapy (IMPT) planning using a single-energy Bragg peak distal tracking method. The patients involved in the study were previously treated with proton stereotactic body radiotherapy (SBRT) using the pencil beam scanning (PBS) technique to 40 Gy in five fractions. FLASH plans were optimized using a four-beam arrangement to generate a dose distribution similar to the conventional opposing beams. All of the beams had a small angle of two degrees from the lateral direction to increase the dosimetry quality. Dose metrics were compared between the conventional PBS and the Bragg peak FLASH plans. The dose rate histogram (DRVH) and FLASH metrics of 40 Gy/s coverage (V40Gy/s) were investigated for the Bragg peak plans. There was no significant difference between the clinical and Bragg peak plans in rectum, bladder, femur heads, large bowel, and penile bulb dose metrics, except for Dmax. For the CTV, the FLASH plans resulted in a higher Dmax than the clinical plans (116.9% vs. 103.3%). For the rectum, the V40Gy/s reached 94% and 93% for 1 Gy dose thresholds in composite and single-field evaluations, respectively. Additionally, the FLASH ratio reached close to 100% after the application of the 5 Gy threshold in composite dose rate assessment. In conclusion, the Bragg peak distal tracking method can yield comparable plan quality in most OARs while preserving sufficient FLASH dose rate coverage, demonstrating that the ultra-high dose technique can be applied in prostate FLASH SBRT.
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Affiliation(s)
- Tyler Kaulfers
- Department of Physics and Astronomy, Hofstra University, Hempstead, NY 11549, USA; (T.K.); (G.L.)
| | - Grant Lattery
- Department of Physics and Astronomy, Hofstra University, Hempstead, NY 11549, USA; (T.K.); (G.L.)
| | - Chingyun Cheng
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA;
| | - Xingyi Zhao
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (X.Z.); (B.S.); (A.M.C.); (J.I.C.); (H.L.); (S.H.)
| | - Balaji Selvaraj
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (X.Z.); (B.S.); (A.M.C.); (J.I.C.); (H.L.); (S.H.)
| | - Hui Wu
- Department of Radiation Oncology, The Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital, Zhengzhou 450008, China;
| | - Arpit M. Chhabra
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (X.Z.); (B.S.); (A.M.C.); (J.I.C.); (H.L.); (S.H.)
| | - Jehee Isabelle Choi
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (X.Z.); (B.S.); (A.M.C.); (J.I.C.); (H.L.); (S.H.)
| | - Haibo Lin
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (X.Z.); (B.S.); (A.M.C.); (J.I.C.); (H.L.); (S.H.)
| | - Charles B. Simone
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (X.Z.); (B.S.); (A.M.C.); (J.I.C.); (H.L.); (S.H.)
| | - Shaakir Hasan
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (X.Z.); (B.S.); (A.M.C.); (J.I.C.); (H.L.); (S.H.)
| | - Minglei Kang
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (X.Z.); (B.S.); (A.M.C.); (J.I.C.); (H.L.); (S.H.)
| | - Jenghwa Chang
- Department of Physics and Astronomy, Hofstra University, Hempstead, NY 11549, USA; (T.K.); (G.L.)
- Northwell, 2000 Marcus Ave, Suite 300, New Hyde Park, NY 11042, USA
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Oh K, Gallagher KJ, Yan Y, Zhou S. Commissioning and initial validation of Eclipse eMC algorithm for the electron FLASH research extension (FLEX) system for pre-clinical studies. J Appl Clin Med Phys 2024:e14289. [PMID: 38319666 DOI: 10.1002/acm2.14289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 12/13/2023] [Accepted: 01/22/2024] [Indexed: 02/07/2024] Open
Abstract
PURPOSE To investigate the feasibility of commissioning the 16 MeV electron FLASH Extension (FLEX) in the commercial treatment planning system (TPS) for biomedical research with cell and mouse models, and in silico treatment planning studies. METHODS To commission the FLEX system with the electron Monte Carlo (eMC) algorithm in the commercial TPS, radiochromic film was used to measure the vendor-recommended beam data. Once the beam model was generated for the eMC algorithm, supplemental measurements were collected for validation purposes and compared against the TPS-calculated results. Additionally, the newly commissioned 16 MeV FLASH beam was compared to the corresponding 16 MeV conventional electron beam. RESULTS The eMC algorithm effectively modeled the FLEX system. The eMC-calculated PDDs and profiles for the 16 MeV electron FLASH beam agreed with measured values within 1%, on average, for 6 × 6 cm2 and 10 × 10 cm2 applicators. Flatness and symmetry deviated by less than 1%, while FWHM and penumbra agreed within 1 mm for both eMC-calculated and measured profiles. Additionally, the small field (i.e., 2-cm diameter cutout) that was measured for validation purposes agreed with TPS-calculated results within 1%, on average, for both the PDD and profiles. The FLASH and conventional dose rate 16 MeV electron beam were in agreement in regard to energy, but the profiles for larger field sizes began to deviate (>10 × 10 cm2 ) due to the forward-peaked nature of the FLASH beam. For cell irradiation experiments, the measured and eMC-calculated in-plane and cross-plane absolute dose profiles agreed within 1%, on average. CONCLUSIONS The FLEX system was successfully commissioned in the commercial TPS using the eMC algorithm, which accurately modeled the forward-peaked nature of the FLASH beam. A commissioned TPS for FLASH will be useful for pre-clinical cell and animal studies, as well as in silico FLASH treatment planning studies for future clinical implementation.
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Affiliation(s)
- Kyuhak Oh
- Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Kyle J Gallagher
- Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Ying Yan
- Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Sumin Zhou
- Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Spruijt K, Mossahebi S, Lin H, Lee E, Kraus J, Dhabaan A, Poulsen P, Lowe M, Ayan A, Spiessens S, Godart J, Hoogeman M. Multi-institutional consensus on machine QA for isochronous cyclotron-based systems delivering ultra-high dose rate (FLASH) pencil beam scanning proton therapy in transmission mode. Med Phys 2024; 51:786-798. [PMID: 38103260 DOI: 10.1002/mp.16854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 10/07/2023] [Accepted: 10/31/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND The first clinical trials to assess the feasibility of FLASH radiotherapy in humans have started (FAST-01, FAST-02) and more trials are foreseen. To increase comparability between trials it is important to assure treatment quality and therefore establish a standard for machine quality assurance (QA). Currently, the AAPM TG-224 report is considered as the standard on machine QA for proton therapy, however, it was not intended to be used for ultra-high dose rate (UHDR) proton beams, which have gained interest due to the observation of the FLASH effect. PURPOSE The aim of this study is to find consensus on practical guidelines on machine QA for UHDR proton beams in transmission mode in terms of which QA is required, how they should be done, which detectors are suitable for UHDR machine QA, and what tolerance limits should be applied. METHODS A risk assessment to determine the gaps in the current standard for machine QA was performed by an international group of medical physicists. Based on that, practical guidelines on how to perform machine QA for UHDR proton beams were proposed. RESULTS The risk assessment clearly identified the need for additional guidance on temporal dosimetry, addressing dose rate (constancy), dose spillage, and scanning speed. In addition, several minor changes from AAPM TG-224 were identified; define required dose rate levels, the use of clinically relevant dose levels, and the use of adapted beam settings to minimize activation of detector and phantom materials or to avoid saturation effects of specific detectors. The final report was created based on discussions and consensus. CONCLUSIONS Consensus was reached on what QA is required for UHDR scanning proton beams in transmission mode for isochronous cyclotron-based systems and how they should be performed. However, the group discussions also showed that there is a lack of high temporal resolution detectors and sufficient QA data to set appropriate limits for some of the proposed QA procedures.
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Affiliation(s)
- Kees Spruijt
- HollandPTC, Delft, The Netherlands
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Sina Mossahebi
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Haibo Lin
- New York Proton Center, New York, New York, USA
| | - Eunsin Lee
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, Ohio, USA
| | - James Kraus
- Department of Radiation Oncology, University of Alabama-Birmingham, Birmingham, Alabama, USA
| | - Anees Dhabaan
- Department of Radiation Oncology, Emory University of Medicine, Atlanta, Georgia, USA
| | - Per Poulsen
- Danish Center for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Matthew Lowe
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Ahmet Ayan
- Department of Radiation Oncology, Ohio State University Medical Center, Columbus, Ohio, USA
| | - Sylvie Spiessens
- Varian, a Siemens Healthineers Company, Groot-Bijgaarden, Belgium
| | - Jeremy Godart
- HollandPTC, Delft, The Netherlands
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Mischa Hoogeman
- HollandPTC, Delft, The Netherlands
- Department of Radiotherapy, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands
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Konradsson E, Wahlqvist P, Thoft A, Blad B, Bäck S, Ceberg C, Petersson K. Beam control system and output fine-tuning for safe and precise delivery of FLASH radiotherapy at a clinical linear accelerator. Front Oncol 2024; 14:1342488. [PMID: 38304871 PMCID: PMC10830783 DOI: 10.3389/fonc.2024.1342488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 01/03/2024] [Indexed: 02/03/2024] Open
Abstract
Introduction We have previously adapted a clinical linear accelerator (Elekta Precise, Elekta AB) for ultra-high dose rate (UHDR) electron delivery. To enhance reliability in future clinical FLASH radiotherapy trials, the aim of this study was to introduce and evaluate an upgraded beam control system and beam tuning process for safe and precise UHDR delivery. Materials and Methods The beam control system is designed to interrupt the beam based on 1) a preset number of monitor units (MUs) measured by a monitor detector, 2) a preset number of pulses measured by a pulse-counting diode, or 3) a preset delivery time. For UHDR delivery, an optocoupler facilitates external control of the accelerator's thyratron trigger pulses. A beam tuning process was established to maximize the output. We assessed the stability of the delivery, and the independent interruption capabilities of the three systems (monitor detector, pulse counter, and timer). Additionally, we explored a novel approach to enhance dosimetric precision in the delivery by synchronizing the trigger pulse with the charging cycle of the pulse forming network (PFN). Results Improved beam tuning of gun current and magnetron frequency resulted in average dose rates at the dose maximum at isocenter distance of >160 Gy/s or >200 Gy/s, with or without an external monitor chamber in the beam path, respectively. The delivery showed a good repeatability (standard deviation (SD) in total film dose of 2.2%) and reproducibility (SD in film dose of 2.6%). The estimated variation in DPP resulted in an SD of 1.7%. The output in the initial pulse depended on the PFN delay time. Over the course of 50 measurements employing PFN synchronization, the absolute percentage error between the delivered number of MUs calculated by the monitor detector and the preset MUs was 0.8 ± 0.6% (mean ± SD). Conclusion We present an upgraded beam control system and beam tuning process for safe and stable UHDR electron delivery of hundreds of Gy/s at isocenter distance at a clinical linac. The system can interrupt the beam based on monitor units and utilize PFN synchronization for improved dosimetric precision in the dose delivery, representing an important advancement toward reliable clinical FLASH trials.
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Affiliation(s)
- Elise Konradsson
- Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Pontus Wahlqvist
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Andreas Thoft
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Börje Blad
- Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Sven Bäck
- Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Crister Ceberg
- Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Kristoffer Petersson
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
- Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
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10
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Yin L, Masumi U, Ota K, Sforza DM, Miles D, Rezaee M, Wong JW, Jia X, Li H. Feasibility of Synchrotron-Based Ultra-High Dose Rate (UHDR) Proton Irradiation with Pencil Beam Scanning for FLASH Research. Cancers (Basel) 2024; 16:221. [PMID: 38201648 PMCID: PMC10778151 DOI: 10.3390/cancers16010221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/12/2023] [Accepted: 12/15/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND This study aims to present the feasibility of developing a synchrotron-based proton ultra-high dose rate (UHDR) pencil beam scanning (PBS) system. METHODS The RF extraction power in the synchrotron system was increased to generate 142.4 MeV pulsed proton beams for UHDR irradiation at ~100 nA beam current. The charge per spill was measured using a Faraday cup. The spill length and microscopic time structure of each spill was measured with a 2D strip transmission ion chamber. The measured UHDR beam fluence was used to derive the spot dwell time for pencil beam scanning. Absolute dose distributions at various depths and spot spacings were measured using Gafchromic films in a solid-water phantom. RESULTS For proton UHDR beams at 142.4 MeV, the maximum charge per spill is 4.96 ± 0.10 nC with a maximum spill length of 50 ms. This translates to an average beam current of approximately 100 nA during each spill. Using a 2 × 2 spot delivery pattern, the delivered dose per spill at 5 cm and 13.5 cm depth is 36.3 Gy (726.3 Gy/s) and 56.2 Gy (1124.0 Gy/s), respectively. CONCLUSIONS The synchrotron-based proton therapy system has the capability to deliver pulsed proton UHDR PBS beams. The maximum deliverable dose and field size per pulse are limited by the spill length and extraction charge.
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Affiliation(s)
- Lingshu Yin
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (D.M.S.); (D.M.); (M.R.); (J.W.W.); (X.J.); (H.L.)
| | - Umezawa Masumi
- Hitachi, Ltd., Research and Development Group, Center for Technology Innovation–Energy, 7-2-1, Omika-chou, Hitachi-shi 319-1292, Ibaraki-ken, Japan;
| | - Kan Ota
- Pyramid Technical Consultants, Inc., Boston, MA 02452, USA;
| | - Daniel M. Sforza
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (D.M.S.); (D.M.); (M.R.); (J.W.W.); (X.J.); (H.L.)
| | - Devin Miles
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (D.M.S.); (D.M.); (M.R.); (J.W.W.); (X.J.); (H.L.)
| | - Mohammad Rezaee
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (D.M.S.); (D.M.); (M.R.); (J.W.W.); (X.J.); (H.L.)
| | - John W. Wong
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (D.M.S.); (D.M.); (M.R.); (J.W.W.); (X.J.); (H.L.)
| | - Xun Jia
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (D.M.S.); (D.M.); (M.R.); (J.W.W.); (X.J.); (H.L.)
| | - Heng Li
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; (D.M.S.); (D.M.); (M.R.); (J.W.W.); (X.J.); (H.L.)
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11
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Shiraishi Y, Matsuya Y, Kusumoto T, Fukunaga H. Modeling for predicting survival fraction of cells after ultra-high dose rate irradiation. Phys Med Biol 2023; 69:015017. [PMID: 38056015 DOI: 10.1088/1361-6560/ad131b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 12/06/2023] [Indexed: 12/08/2023]
Abstract
Objective. FLASH radiotherapy (FLASH-RT) with ultra-high dose rate (UHDR) irradiation (i.e. > 40 Gy s-1) spares the function of normal tissues while preserving antitumor efficacy, known as the FLASH effect. The biological effects after conventional dose rate-radiotherapy (CONV-RT) with ≤0.1 Gy s-1have been well modeled by considering microdosimetry and DNA repair processes, meanwhile modeling of radiosensitivities under UHDR irradiation is insufficient. Here, we developed anintegrated microdosimetric-kinetic(IMK)model for UHDR-irradiationenabling the prediction of surviving fraction after UHDR irradiation.Approach.TheIMK model for UHDR-irradiationconsiders the initial DNA damage yields by the modification of indirect effects under UHDR compared to CONV dose rate. The developed model is based on the linear-quadratic (LQ) nature with the dose and dose square coefficients, considering the reduction of DNA damage yields as a function of dose rate.Main results.The estimate by the developed model could successfully reproduce thein vitroexperimental dose-response curve for various cell line types and dose rates.Significance.The developed model would be useful for predicting the biological effects under the UHDR irradiation.
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Affiliation(s)
- Yuta Shiraishi
- Graduate school of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido, 060-0812, Japan
- Faculty of Health Sciences, Japan Healthcare University, 3-11-1-50 Tsukisamu-higashi, Toyohira-ku, Sapporo, Hokkaido, 062-0053, Japan
| | - Yusuke Matsuya
- Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido, 060-0812, Japan
- Nuclear Science and Engineering Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki, 319-1195, Japan
| | - Tamon Kusumoto
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Hisanori Fukunaga
- Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido, 060-0812, Japan
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12
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Lattery G, Kaulfers T, Cheng C, Zhao X, Selvaraj B, Lin H, Simone CB, Choi JI, Chang J, Kang M. Pencil Beam Scanning Bragg Peak FLASH Technique for Ultra-High Dose Rate Intensity-Modulated Proton Therapy in Early-Stage Breast Cancer Treatment. Cancers (Basel) 2023; 15:4560. [PMID: 37760528 PMCID: PMC10527307 DOI: 10.3390/cancers15184560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/06/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023] Open
Abstract
Bragg peak FLASH-RT can deliver highly conformal treatment and potentially offer improved normal tissue protection for radiotherapy patients. This study focused on developing ultra-high dose rate (≥40 Gy × RBE/s) intensity-modulated proton therapy (IMPT) for hypofractionated treatment of early-stage breast cancer. A novel tracking technique was developed to enable pencil beaming scanning (PBS) of single-energy protons to adapt the Bragg peak (BP) to the target distally. Standard-of-care PBS treatment plans of consecutively treated early-stage breast cancer patients using multiple energy layers were reoptimized using this technique, and dose metrics were compared between single-energy layer BP FLASH and conventional IMPT plans. FLASH dose rate coverage by volume (V40Gy/s) was also evaluated for the FLASH sparing effect. Distal tracking can precisely stop BP at the target distal edge. All plans (n = 10) achieved conformal IMPT-like dose distributions under clinical machine parameters. No statistically significant differences were observed in any dose metrics for heart, ipsilateral lung, most ipsilateral breast, and CTV metrics (p > 0.05 for all). Conventional plans yielded slightly superior target and skin dose uniformities with 4.5% and 12.9% lower dose maxes, respectively. FLASH-RT plans reached 46.7% and 61.9% average-dose rate FLASH coverage for tissues receiving more than 1 and 5 Gy plan dose total under the 250 minimum MU condition. Bragg peak FLASH-RT techniques achieved comparable plan quality to conventional IMPT while reaching adequate dose rate ratios, demonstrating the feasibility of early-stage breast cancer clinical applications.
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Affiliation(s)
- Grant Lattery
- Department of Physics and Astronomy, Hofstra University, 1000 Hempstead Turnpike, Hempstead, NY 11549, USA; (G.L.); (T.K.)
| | - Tyler Kaulfers
- Department of Physics and Astronomy, Hofstra University, 1000 Hempstead Turnpike, Hempstead, NY 11549, USA; (G.L.); (T.K.)
| | - Chingyun Cheng
- Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA;
| | - Xingyi Zhao
- Beijing Key Laboratory of Medical Physics and Engineering, Peking University, Beijing 100871, China;
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (B.S.); (H.L.); (C.B.S.II); (J.I.C.)
| | - Balaji Selvaraj
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (B.S.); (H.L.); (C.B.S.II); (J.I.C.)
| | - Haibo Lin
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (B.S.); (H.L.); (C.B.S.II); (J.I.C.)
| | - Charles B. Simone
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (B.S.); (H.L.); (C.B.S.II); (J.I.C.)
| | - J. Isabelle Choi
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (B.S.); (H.L.); (C.B.S.II); (J.I.C.)
| | - Jenghwa Chang
- Department of Physics and Astronomy, Hofstra University, 1000 Hempstead Turnpike, Hempstead, NY 11549, USA; (G.L.); (T.K.)
- Radiation Medicine, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, 450 Lakeville Road, Lake Success, NY 11042, USA
| | - Minglei Kang
- New York Proton Center, 225 E 126th Street, New York, NY 10035, USA; (B.S.); (H.L.); (C.B.S.II); (J.I.C.)
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13
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Børresen B, Arendt ML, Konradsson E, Bastholm Jensen K, Bäck SÅJ, Munck af Rosenschöld P, Ceberg C, Petersson K. Evaluation of single-fraction high dose FLASH radiotherapy in a cohort of canine oral cancer patients. Front Oncol 2023; 13:1256760. [PMID: 37766866 PMCID: PMC10520273 DOI: 10.3389/fonc.2023.1256760] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023] Open
Abstract
Background FLASH radiotherapy (RT) is a novel method for delivering ionizing radiation, which has been shown in preclinical studies to have a normal tissue sparing effect and to maintain anticancer efficacy as compared to conventional RT. Treatment of head and neck tumors with conventional RT is commonly associated with severe toxicity, hence the normal tissue sparing effect of FLASH RT potentially makes it especially advantageous for treating oral tumors. In this work, the objective was to study the adverse effects of dogs with spontaneous oral tumors treated with FLASH RT. Methods Privately-owned dogs with macroscopic malignant tumors of the oral cavity were treated with a single fraction of ≥30Gy electron FLASH RT and subsequently followed for 12 months. A modified conventional linear accelerator was used to deliver the FLASH RT. Results Eleven dogs were enrolled in this prospective study. High grade adverse effects were common, especially if bone was included in the treatment field. Four out of six dogs, who had bone in their treatment field and lived at least 5 months after RT, developed osteoradionecrosis at 3-12 months post treatment. The treatment was overall effective with 8/11 complete clinical responses and 3/11 partial responses. Conclusion This study shows that single-fraction high dose FLASH RT was generally effective in this mixed group of malignant oral tumors, but the risk of osteoradionecrosis is a serious clinical concern. It is possible that the risk of osteonecrosis can be mitigated through fractionation and improved dose conformity, which needs to be addressed before moving forward with clinical trials in human cancer patients.
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Affiliation(s)
- Betina Børresen
- Department of Veterinary Clinical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Maja L. Arendt
- Department of Veterinary Clinical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Elise Konradsson
- Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden
| | | | - Sven ÅJ. Bäck
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Per Munck af Rosenschöld
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Crister Ceberg
- Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Kristoffer Petersson
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
- Department of Oncology, Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
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14
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Rahman M, Kozelka J, Hildreth J, Schönfeld A, Sloop AM, Ashraf MR, Bruza P, Gladstone DJ, Pogue BW, Simon WE, Zhang R. Characterization of a diode dosimeter for UHDR FLASH radiotherapy. Med Phys 2023; 50:5875-5883. [PMID: 37249058 DOI: 10.1002/mp.16474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 05/31/2023] Open
Abstract
BACKGROUND Ultra-high dose rate (UHDR) FLASH beams typically deliver dose at rates of >40 Gy/sec. Characterization of these beams with respect to dose, mean dose rate, and dose per pulse requires dosimeters which exhibit high temporal resolution and fast readout capabilities. PURPOSE A diode EDGE Detector with a newly designed electrometer has been characterized for use in an UHDR electron beam and demonstrated appropriateness for UHDR FLASH radiotherapy dosimetry. METHODS Dose linearity, mean dose rate, and dose per pulse dependencies of the EDGE Detector were quantified and compared with dosimeters including a W1 scintillator detector, radiochromic film, and ionization chamber that were irradiated with a 10 MeV UHDR beam. The dose, dose rate, and dose per pulse were controlled via an in-house developed scintillation-based feedback mechanism, repetition rate of the linear accelerator, and source-to-surface distance, respectively. Depth-dose profiles and temporal profiles at individual pulse resolution were compared to the film and scintillation measurements, respectively. The radiation-induced change in response sensitivity was quantified via irradiation of ∼5kGy. RESULTS The EDGE Detector agreed with film measurements in the measured range with varying dose (up to 70 Gy), dose rate (nearly 200 Gy/s), and dose per pulse (up to 0.63 Gy/pulse) on average to within 2%, 5%, and 1%, respectively. The detector also agreed with W1 scintillation detector on average to within 2% for dose per pulse (up to 0.78 Gy/pulse). The EDGE Detector signal was proportional to ion chamber (IC) measured dose, and mean dose rate in the bremsstrahlung tail to within 0.4% and 0.2% respectively. The EDGE Detector measured percent depth dose (PDD) agreed with film to within 3% and per pulse output agreed with W1 scintillator to within -6% to +5%. The radiation-induced response decrease was 0.4% per kGy. CONCLUSIONS The EDGE Detector demonstrated dose linearity, mean dose rate independence, and dose per pulse independence for UHDR electron beams. It can quantify the beam spatially, and temporally at sub millisecond resolution. It's robustness and individual pulse detectability of treatment deliveries can potentially lead to its implementation for in vivo FLASH dosimetry, and dose monitoring.
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Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- UT Southwestern Medical Center, Dallas, Texas, USA
| | | | | | | | - Austin M Sloop
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - M Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Stanford University, Stanford, California, USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Dartmouth Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Department of Medical Physics, Wisconsin Institutes for Medical Research, University of Wisconsin, Madison, Wisconsin, USA
| | | | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, USA
- Department of Radiation Medicine, Westchester Medical Center, New York Medical College,Valhalla, New York, USA
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15
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Ehwald J, Togno M, Lomax AJ, Weber DC, Safai S, Winterhalter C. Detailed Monte-Carlo characterization of a Faraday cup for proton therapy. Med Phys 2023; 50:5828-5841. [PMID: 37227735 DOI: 10.1002/mp.16464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 04/03/2023] [Accepted: 04/09/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Experiments with ultra-high dose rates in proton therapy are of increasing interest for potential treatment benefits. The Faraday Cup (FC) is an important detector for the dosimetry of such ultra-high dose rate beams. So far, there is no consensus on the optimal design of a FC, or on the influence of beam properties and magnetic fields on shielding of the FC from secondary charged particles. PURPOSE To perform detailed Monte Carlo simulations of a Faraday cup to identify and quantify all the charge contributions from primary protons and secondary particles that modify the efficiency of the FC response as a function of a magnetic field employed to improve the detector's reading. METHODS In this paper, a Monte Carlo (MC) approach was used to investigate the Paul Scherrer Institute (PSI) FC and quantify contributions of charged particles to its signal for beam energies of 70, 150, and 228 MeV and magnetic fields between 0 and 25 mT. Finally, we compared our MC simulations to measurements of the response of the PSI FC. RESULTS For maximum magnetic fields, the efficiency (signal of the FC normalized to charged delivered by protons) of the PSI FC varied between 99.97% and 100.22% for the lowest and highest beam energy. We have shown that this beam energy-dependence is mainly caused by contributions of secondary charged particles, which cannot be fully suppressed by the magnetic field. Additionally, it has been demonstrated that these contributions persist, making the FC efficiency beam energy dependent for fields up to 250 mT, posing inevitable limits on the accuracy of FC measurements if not corrected. In particular, we have identified a so far unreported loss of electrons via the outer surfaces of the absorber block and show the energy distributions of secondary electrons ejected from the vacuum window (VW) (up to several hundred keV), together with electrons ejected from the absorber block (up to several MeV). Even though, in general, simulations and measurements were well in agreement, the limitation of the current MC calculations to produce secondary electrons below 990 eV posed a limit in the efficiency simulations in the absence of a magnetic field as compared to the experimental data. CONCLUSION TOPAS-based MC simulations allowed to identify various and previously unreported contributions to the FC signal, which are likely to be present in other FC designs. Estimating the beam energy dependence of the PSI FC for additional beam energies could allow for the implementation of an energy-dependent correction factor to the signal. Dose estimates, based on accurate measurements of the number of delivered protons, provided a valid instrument to challenge the dose determined by reference ionization chambers, not only at ultra-high dose rates but also at conventional dose rates.
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Affiliation(s)
- Julian Ehwald
- Centre for Proton Therapy, Paul Scherrer Institute, Villigen PSI, Switzerland
- Department of Physics, ETH Zurich, Zurich, Switzerland
| | - Michele Togno
- Centre for Proton Therapy, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Antony John Lomax
- Centre for Proton Therapy, Paul Scherrer Institute, Villigen PSI, Switzerland
- Department of Physics, ETH Zurich, Zurich, Switzerland
| | - Damien Charles Weber
- Centre for Proton Therapy, Paul Scherrer Institute, Villigen PSI, Switzerland
- Radiation Oncology Department of University Hospital of Bern, Bern, Switzerland
- Radiation Oncology Department of University Hospital of Zurich, Zurich, Switzerland
| | - Sairos Safai
- Centre for Proton Therapy, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Carla Winterhalter
- Centre for Proton Therapy, Paul Scherrer Institute, Villigen PSI, Switzerland
- Department of Physics, ETH Zurich, Zurich, Switzerland
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16
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Sunnerberg JP, Zhang R, Gladstone DJ, Swartz HM, Gui J, Pogue BW. Mean dose rate in ultra-high dose rate electron irradiation is a significant predictor for O 2consumption and H 2O 2yield. Phys Med Biol 2023; 68:165014. [PMID: 37463588 PMCID: PMC10405361 DOI: 10.1088/1361-6560/ace877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 06/27/2023] [Accepted: 07/18/2023] [Indexed: 07/20/2023]
Abstract
Objective. The objective of this study was to investigate the impact of mean and instantaneous dose rates on the production of reactive oxygen species (ROS) during ultra-high dose rate (UHDR) radiotherapy. The study aimed to determine whether either dose rate type plays a role in driving the FLASH effect, a phenomenon where UHDR radiotherapy reduces damage to normal tissues while maintaining tumor control.Approach. Assays of hydrogen peroxide (H2O2) production and oxygen consumption (ΔpO2) were conducted using UHDR electron irradiation. Aqueous solutions of 4% albumin were utilized as the experimental medium. The study compared the effects of varying mean dose rates and instantaneous dose rates on ROS yields. Instantaneous dose rate was varied by changing the source-to-surface distance (SSD), resulting in instantaneous dose rates ranging from 102to 106Gy s-1. Mean dose rate was manipulated by altering the pulse frequency of the linear accelerator (linac) and by changing the SSD, ranging from 0.14 to 1500 Gy s-1.Main results. The study found that both ΔH2O2and ΔpO2decreased as the mean dose rate increased. Multivariate analysis indicated that instantaneous dose rates also contributed to this effect. The variation in ΔpO2was dependent on the initial oxygen concentration in the solution. Based on the analysis of dose rate variation, the study estimated that 7.51 moles of H2O2were produced for every mole of O2consumed.Significance. The results highlight the significance of mean dose rate as a predictor of ROS production during UHDR radiotherapy. As the mean dose rate increased, there was a decrease in oxygen consumption and in H2O2production. These findings have implications for understanding the FLASH effect and its potential optimization. The study sheds light on the role of dose rate parameters and their impact on radiochemical outcomes, contributing to the advancement of UHDR radiotherapy techniques.
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Affiliation(s)
- Jacob P Sunnerberg
- Thayer School of Engineering at Dartmouth College, Hanover, NH, United States of America
| | - Rongxiao Zhang
- Thayer School of Engineering at Dartmouth College, Hanover, NH, United States of America
- Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States of America
| | - David J Gladstone
- Thayer School of Engineering at Dartmouth College, Hanover, NH, United States of America
- Dartmouth-Hitchcock Medical Center, Lebanon, NH, United States of America
| | - Harold M Swartz
- Geisel School of Medicine at Dartmouth College, Hanover, NH, United States of America
| | - Jiang Gui
- Geisel School of Medicine at Dartmouth College, Hanover, NH, United States of America
| | - Brian W Pogue
- Thayer School of Engineering at Dartmouth College, Hanover, NH, United States of America
- University of Wisconsin—Madison, Madison, WI, United States of America
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17
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Zou W, Zhang R, Schüler E, Taylor PA, Mascia AE, Diffenderfer ES, Zhao T, Ayan AS, Sharma M, Yu SJ, Lu W, Bosch WR, Tsien C, Surucu M, Pollard-Larkin JM, Schuemann J, Moros EG, Bazalova-Carter M, Gladstone DJ, Li H, Simone CB, Petersson K, Kry SF, Maity A, Loo BW, Dong L, Maxim PG, Xiao Y, Buchsbaum JC. Framework for Quality Assurance of Ultrahigh Dose Rate Clinical Trials Investigating FLASH Effects and Current Technology Gaps. Int J Radiat Oncol Biol Phys 2023; 116:1202-1217. [PMID: 37121362 PMCID: PMC10526970 DOI: 10.1016/j.ijrobp.2023.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/28/2023] [Accepted: 04/17/2023] [Indexed: 05/02/2023]
Abstract
FLASH radiation therapy (FLASH-RT), delivered with ultrahigh dose rate (UHDR), may allow patients to be treated with less normal tissue toxicity for a given tumor dose compared with currently used conventional dose rate. Clinical trials are being carried out and are needed to test whether this improved therapeutic ratio can be achieved clinically. During the clinical trials, quality assurance and credentialing of equipment and participating sites, particularly pertaining to UHDR-specific aspects, will be crucial for the validity of the outcomes of such trials. This report represents an initial framework proposed by the NRG Oncology Center for Innovation in Radiation Oncology FLASH working group on quality assurance of potential UHDR clinical trials and reviews current technology gaps to overcome. An important but separate consideration is the appropriate design of trials to most effectively answer clinical and scientific questions about FLASH. This paper begins with an overview of UHDR RT delivery methods. UHDR beam delivery parameters are then covered, with a focus on electron and proton modalities. The definition and control of safe UHDR beam delivery and current and needed dosimetry technologies are reviewed and discussed. System and site credentialing for large, multi-institution trials are reviewed. Quality assurance is then discussed, and new requirements are presented for treatment system standard analysis, patient positioning, and treatment planning. The tables and figures in this paper are meant to serve as reference points as we move toward FLASH-RT clinical trial performance. Some major questions regarding FLASH-RT are discussed, and next steps in this field are proposed. FLASH-RT has potential but is associated with significant risks and complexities. We need to redefine optimization to focus not only on the dose but also on the dose rate in a manner that is robust and understandable and that can be prescribed, validated, and confirmed in real time. Robust patient safety systems and access to treatment data will be critical as FLASH-RT moves into the clinical trials.
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Affiliation(s)
- Wei Zou
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA.
| | - Rongxiao Zhang
- Department of Radiation Oncology, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - Emil Schüler
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Paige A Taylor
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Eric S Diffenderfer
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Tianyu Zhao
- Department of Radiation Oncology, Washington University, St. Louis, MO, USA
| | - Ahmet S Ayan
- Department of Radiation Oncology, Ohio State University, Columbus, OH, USA
| | - Manju Sharma
- Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, USA
| | - Shu-Jung Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Weiguo Lu
- Department of Radiation Oncology, University of Texas Southwestern, Dallas, TX, USA
| | - Walter R Bosch
- Department of Radiation Oncology, Washington University, St. Louis, MO, USA
| | - Christina Tsien
- Department of Radiation Oncology, McGill University Health Center, Montreal, QC, Canada
| | - Murat Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Julianne M Pollard-Larkin
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jan Schuemann
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Eduardo G Moros
- Department of Radiation Oncology, Moffitt Cancer Center, Tampa, FL, USA
| | | | - David J Gladstone
- Department of Radiation Oncology, Geisel School of Medicine, Dartmouth College, Hanover, NH, USA
| | - Heng Li
- Department of Radiation Oncology, Johns Hopkins University, Baltimore, MD, USA
| | - Charles B Simone
- Department of Radiation Oncology, New York Proton Center, New York, NY, USA
| | - Kristoffer Petersson
- Department of Radiation Oncology, MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - Stephen F Kry
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Amit Maity
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Lei Dong
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Peter G Maxim
- Department of Radiation Oncology, University of California Irvine, Irvine, CA, USA
| | - Ying Xiao
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jeffrey C Buchsbaum
- Radiation Research Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, National Institute of Health, Bethesda, MD, USA
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18
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Kim MM, Zou W. Ultra-high dose rate FLASH radiation therapy for cancer. Med Phys 2023; 50 Suppl 1:58-61. [PMID: 36758965 PMCID: PMC11056953 DOI: 10.1002/mp.16271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 01/30/2023] [Indexed: 02/11/2023] Open
Abstract
Conformality has been a key requirement in radiation therapy for cancer to minimize normal tissue toxicity while maintaining tumor control. Since 2014, there has been great interest in ultra-high dose rate (UHDR), "FLASH," radiation therapy to enhance this therapeutic window. In multiple pre-clinical studies, it was seen that normal tissue demonstrated less damage due to radiation of various modalities when the same dose was delivered at ultra-high mean dose rates exceeding ∼40 Gy/s while tumor control remained indifferent to changes in dose rate. The scientific community has large-scale interdisciplinary studies to investigate this potentially breakthrough technique to enhance treatment options for cancer. FLASH studies have been performed using a number of modalities and delivery techniques for many pre-clinical models. There have been several studies reporting evidence of the FLASH effect as well as technological developments relating to UHDR studies. There is sustained interest and motivation for this topic as well as many questions that are yet to be answered. We provide a short overview to highlight some of the major work and challenges to advance research in FLASH radiotherapy.
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Affiliation(s)
- Michele M Kim
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Wei Zou
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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19
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Chaudhary P, Milluzzo G, McIlvenny A, Ahmed H, McMurray A, Maiorino C, Polin K, Romagnani L, Doria D, McMahon SJ, Botchway SW, Rajeev PP, Prise KM, Borghesi M. Cellular irradiations with laser-driven carbon ions at ultra-high dose rates. Phys Med Biol 2023; 68. [PMID: 36625355 DOI: 10.1088/1361-6560/aca387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 11/16/2022] [Indexed: 01/11/2023]
Abstract
Objective.Carbon is an ion species of significant radiobiological interest, particularly in view of its use in cancer radiotherapy, where its large Relative Biological Efficiency is often exploited to overcome radio resistance. A growing interest in highly pulsed carbon delivery has arisen in the context of the development of the FLASH radiotherapy approach, with recent studies carried out at dose rates of 40 Gy s-1. Laser acceleration methods, producing ultrashort ion bursts, can now enable the delivery of Gy-level doses of carbon ions at ultra-high dose rates (UHDRs), exceeding 109Gy s-1. While studies at such extreme dose rate have been carried out so far using low LET particles such as electrons and protons, the radiobiology of high-LET, UHDR ions has not yet been explored. Here, we report the first application of laser-accelerated carbon ions generated by focussing 1020W cm-2intense lasers on 10-25 nm carbon targets, to irradiate radioresistant patient-derived Glioblastoma stem like cells (GSCs).Approach.We exposed GSCs to 1 Gy of 9.5 ± 0.5 MeV/n carbon ions delivered in a single ultra-short (∼400-picosecond) pulse, at a dose rate of 2 × 109Gy s-1, generated using the ASTRA GEMINI laser of the Central Laser Facility at the Rutherford Appleton Laboratory, Didcot, Oxfordshire, UK. We quantified carbon ion-induced DNA double strand break (DSB) damage using the 53BP1 foci formation assay and used 225 kVp x-rays as a reference radiation.Main Results.Laser-accelerated carbon ions induced complex DNA DSB damage, as seen through persistent 53BP1 foci (11.5 ± 0.4 foci/cell/Gy) at 24 h and significantly larger foci (1.69 ± 0.07μm2) than x-rays induced ones (0.63 ± 0.02μm2). The relative foci induction value for laser-driven carbon ions relative to conventional x-rays was 3.2 ± 0.3 at 24 h post-irradiation also confirming the complex nature of the induced damage.Significance.Our study demonstrates the feasibility of radiobiology investigations at unprecedented dose rates using laser-accelerated high-LET carbon ions in clinically relevant models.
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Affiliation(s)
- Pankaj Chaudhary
- The Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Lisburn Road, Belfast, BT9 7AE, Northern Ireland, United Kingdom.,Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom
| | - Giuliana Milluzzo
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom.,Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare,, via S Sofia 62, I-95123 Catania, Sicily, Italy
| | - Aodhan McIlvenny
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom
| | - Hamad Ahmed
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom.,Experimental Science Group, Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxford, OX11 0QX, England, United Kingdom
| | - Aaron McMurray
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom
| | - Carla Maiorino
- The Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Lisburn Road, Belfast, BT9 7AE, Northern Ireland, United Kingdom.,Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare,, via S Sofia 62, I-95123 Catania, Sicily, Italy.,Extreme Light Infrastructure (ELI-NP) and Horia Hulubei National Institute for R & D in Physics and Nuclear Engineering (IFIN-HH), Str. Reactorului No. 30, 077125 Bucharest, Magurele, Romania.,University College Cork, College of Medicine and Health, Discipline of Diagnostic Radiography and Radiation Therapy, Brookfield Health Sciences Complex, Brookfield College Road, T12AK54, Cork, United Kingdom
| | - Kathryn Polin
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom
| | - Lorenzo Romagnani
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom.,Laboratoire LULI, École Polytechnique, Route de Saclay, F-91128 Palaiseau, Paris, France
| | - Domenico Doria
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom.,Extreme Light Infrastructure (ELI-NP) and Horia Hulubei National Institute for R & D in Physics and Nuclear Engineering (IFIN-HH), Str. Reactorului No. 30, 077125 Bucharest, Magurele, Romania
| | - Stephen J McMahon
- The Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Lisburn Road, Belfast, BT9 7AE, Northern Ireland, United Kingdom
| | - Stanley W Botchway
- Research Complex at Harwell & Central Laser facility, Rutherford Appleton Laboratory, Didcot, Oxford, OX11 0QX, England, United Kingdom
| | - Pattathil P Rajeev
- Experimental Science Group, Central Laser Facility, Rutherford Appleton Laboratory, Didcot, Oxford, OX11 0QX, England, United Kingdom
| | - Kevin M Prise
- The Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Lisburn Road, Belfast, BT9 7AE, Northern Ireland, United Kingdom
| | - Marco Borghesi
- Centre for Light-Matter Interactions, School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, Northern Ireland, United Kingdom
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20
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Daugherty EC, Mascia A, Zhang Y, Lee E, Xiao Z, Sertorio M, Woo J, McCann C, Russell K, Levine L, Sharma R, Khuntia D, Bradley J, Simone CB, Perentesis J, Breneman J. FLASH Radiotherapy for the Treatment of Symptomatic Bone Metastases (FAST-01): Protocol for the First Prospective Feasibility Study. JMIR Res Protoc 2023; 12:e41812. [PMID: 36206189 PMCID: PMC9893728 DOI: 10.2196/41812] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/29/2022] [Accepted: 10/04/2022] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND In preclinical studies, FLASH therapy, in which radiation delivered at ultrahigh dose rates of ≥40 Gy per second, has been shown to cause less injury to normal tissues than radiotherapy delivered at conventional dose rates. This paper describes the protocol for the first-in-human clinical investigation of proton FLASH therapy. OBJECTIVE FAST-01 is a prospective, single-center trial designed to assess the workflow feasibility, toxicity, and efficacy of FLASH therapy for the treatment of painful bone metastases in the extremities. METHODS Following informed consent, 10 subjects aged ≥18 years with up to 3 painful bone metastases in the extremities (excluding the feet, hands, and wrists) will be enrolled. A treatment field selected from a predefined library of plans with fixed field sizes (from 7.5 cm × 7.5 cm up to 7.5 cm × 20 cm) will be used for treatment. Subjects will receive 8 Gy of radiation in a single fraction-a well-established palliative regimen evaluated in prior investigations using conventional dose rate photon radiotherapy. A FLASH-enabled Varian ProBeam proton therapy unit will be used to deliver treatment to the target volume at a dose rate of ≥40 Gy per second, using the plateau (transmission) portion of the proton beam. After treatment, subjects will be assessed for pain response as well as any adverse effects of FLASH radiation. The primary end points include assessing the workflow feasibility and toxicity of FLASH treatment. The secondary end point is pain response at the treated site(s), as measured by patient-reported pain scores, the use of pain medication, and any flare in bone pain after treatment. The results will be compared to those reported historically for conventional dose rate photon radiotherapy, using the same radiation dose and fractionation. RESULTS FAST-01 opened to enrollment on November 3, 2020. Initial results are expected to be published in 2022. CONCLUSIONS The results of this investigation will contribute to further developing and optimizing the FLASH-enabled ProBeam proton therapy system workflow. The pain response and toxicity data acquired in our study will provide a greater understanding of FLASH treatment effects on tumor responses and normal tissue toxicities, and they will inform future FLASH trial designs. TRIAL REGISTRATION : ClinicalTrials.gov NCT04592887; http://clinicaltrials.gov/ct2/show/NCT04592887. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) DERR1-10.2196/41812.
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Affiliation(s)
- Emily C Daugherty
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, OH, United States
| | - Anthony Mascia
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, OH, United States
- Cancer and Blood Disease Institute, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Yong Zhang
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, OH, United States
- Cancer and Blood Disease Institute, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Eunsin Lee
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, OH, United States
- Cancer and Blood Disease Institute, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Zhiyan Xiao
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, OH, United States
- Cancer and Blood Disease Institute, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - Mathieu Sertorio
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, OH, United States
| | - Jennifer Woo
- Varian, A Siemens Healthineers Company, Palo Alto, CA, United States
| | - Claire McCann
- Varian, A Siemens Healthineers Company, Palo Alto, CA, United States
| | - Kenneth Russell
- Varian, A Siemens Healthineers Company, Palo Alto, CA, United States
| | - Lisa Levine
- Varian, A Siemens Healthineers Company, Palo Alto, CA, United States
| | - Ricky Sharma
- Varian, A Siemens Healthineers Company, Palo Alto, CA, United States
| | - Deepak Khuntia
- Varian, A Siemens Healthineers Company, Palo Alto, CA, United States
| | - Jeffrey Bradley
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, United States
| | - Charles B Simone
- Department of Radiation Oncology, New York Proton Center, New York, NY, United States
| | - John Perentesis
- Cancer and Blood Disease Institute, Cincinnati Children's Hospital, Cincinnati, OH, United States
| | - John Breneman
- Department of Radiation Oncology, University of Cincinnati, Cincinnati, OH, United States
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21
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Bogaerts E, Macaeva E, Isebaert S, Haustermans K. Potential Molecular Mechanisms behind the Ultra-High Dose Rate "FLASH" Effect. Int J Mol Sci 2022; 23. [PMID: 36292961 DOI: 10.3390/ijms232012109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/26/2022] [Accepted: 10/08/2022] [Indexed: 11/17/2022] Open
Abstract
FLASH radiotherapy, or the delivery of a dose at an ultra-high dose rate (>40 Gy/s), has recently emerged as a promising tool to enhance the therapeutic index in cancer treatment. The remarkable sparing of normal tissues and equivalent tumor control by FLASH irradiation compared to conventional dose rate irradiation—the FLASH effect—has already been demonstrated in several preclinical models and even in a first patient with T-cell cutaneous lymphoma. However, the biological mechanisms responsible for the differential effect produced by FLASH irradiation in normal and cancer cells remain to be elucidated. This is of great importance because a good understanding of the underlying radiobiological mechanisms and characterization of the specific beam parameters is required for a successful clinical translation of FLASH radiotherapy. In this review, we summarize the FLASH investigations performed so far and critically evaluate the current hypotheses explaining the FLASH effect, including oxygen depletion, the production of reactive oxygen species, and an altered immune response. We also propose a new theory that assumes an important role of mitochondria in mediating the normal tissue and tumor response to FLASH dose rates.
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22
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Xie DH, Li YC, Ma S, Yang X, Lan RM, Chen AQ, Zhu HY, Mei Y, Peng LX, Li ZF, Huang BJ, Chen Y, Huang XY, Qian CN. Electron Ultra-High Dose Rate FLASH irradiation Study Using a Clinical Linac: Linac Modification, Dosimetry and Radiobiological outcome. Med Phys 2022; 49:6728-6738. [PMID: 35959736 DOI: 10.1002/mp.15920] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 05/24/2022] [Accepted: 08/02/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Ultra-high dose rate FLASH irradiation (FLASH-IR) has been shown to cause less normal tissue damage compared with conventional irradiation (CONV-IR), this is known as the "FLASH effect". It has attracted immense research interest because its underlying mechanism is scarcely known. The purpose of this study was to determine whether FLASH-IR and CONV-IR induce differential inflammatory cytokine expression using a modified clinical linac. MATERIALS AND METHODS An Elekta Synergy linac was used to deliver 6 MeV CONV-IR and modified to deliver FLASH-IR. Female FvB mice were randomly assigned to three different groups: a non-irradiated control, CONV-IR, or FLASH-IR. The FLASH-IR beam was produced by single pulses repeated manually with a 20-second interval (Strategy 1), or single-trigger multiple pulses with a 10 millisecond (ms) interval (Strategy 2). Mice were immobilized in the prone position in a custom-designed applicator with Gafchromic films positioned under the body. The prescribed doses for the mice were 6 to 18 Gy and verified using Gafchromic films. Cytokine expression of three pro-inflammatory cytokines [tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-6 (IL-6)] and one anti-inflammatory cytokine (IL-10) in serum samples and skin tissue were examined within 1- month post-IR. RESULTS The modified linac delivered radiation at an intra-pulse dose rate of around 1×106 Gy/s and a dose per pulse over 2 Gy at a source-to-surface distance (SSD) of 13 to 15 cms. The achieved dose coverage was 90 - 105% of the maximum dose within -20 ∼ 20 mm in the X direction and 95% within -30 ∼ 30 mm in the Y direction. The absolute deviations between the prescribed dose and the actual dose were 2.21, 6.04, 2.09 and 2.73% for 6, 9, 12 and 15 Gy as measured by EBT3 films, respectively; and 4.00, 4.49 and 2.30% for 10, 14 and 18 Gy as measured by the EBT XD films, respectively. The reductions in the CONV-IR versus the FLASH-IR group were 4.89, 10.28, -7.8 and -22.17 % for TNF-α, IFN-γ, IL-6 and IL-10 in the serum on D6, respectively; 37.26, 67.16, 56.68 and -18.95% in the serum on D31, respectively; and 62.67, 35.65, 37.75 and -12.20% for TNF-α, IFN-γ, IL-6 and IL-10 in the skin tissue, respectively. CONCLUSIONS Ultra-high dose rate electron FLASH caused lower pro-inflammatory cytokine levels in serum and skin tissue which might mediate differential tissue damage between FLASH-IR and CONV-IR. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- De-Huan Xie
- Department of Nasopharyngeal Carcinoma, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine
| | | | - Sai Ma
- Elekta Instrument Ltd. Beijing Branch
| | - Xin Yang
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine
| | - Ruo-Ming Lan
- School of Physics and Electronics, Shandong Normal University
| | - Ao-Qiang Chen
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine
| | - Hong-Yu Zhu
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine
| | - Yan Mei
- Department of Pathology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Li-Xia Peng
- Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine
| | | | - Bi-Jun Huang
- Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine
| | - Yan Chen
- Elekta Instrument Ltd. Beijing Branch
| | - Xiao-Yan Huang
- Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine
| | - Chao-Nan Qian
- Department of Nasopharyngeal Carcinoma, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in Southern China, Collaborative Innovation Center for Cancer Medicine.,Guangzhou Concord Cancer Center
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23
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Wei S, Lin H, Shi C, Xiong W, Chen CC, Huang S, Press RH, Hasan S, Chhabra AM, Choi JI, Simone CB, Kang M. Use of single-energy proton pencil beam scanning Bragg peak for intensity-modulated proton therapy FLASH treatment planning in liver hypofractionated radiation therapy. Med Phys 2022; 49:6560-6574. [PMID: 35929404 DOI: 10.1002/mp.15894] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 06/09/2022] [Accepted: 07/20/2022] [Indexed: 11/11/2022] Open
Abstract
PURPOSE The transmission proton FLASH technique delivers high doses to the normal tissue distal to the target, which is less conformal compared to the Bragg peak technique. To investigate FLASH RT planning using single-energy Bragg peak beams with a similar beam arrangement as clinical intensity-modulated proton therapy (IMPT) in liver stereotactic body radiation therapy (SBRT) and to characterize the plan quality, dose sparing of organs-at-risk (OARs), and FLASH dose rate percentage. MATERIALS AND METHODS An in-house platform was developed to enable inverse IMPT-FLASH planning using single-energy Bragg peaks. A universal range shifter and range compensators were utilized to effectively align the Bragg peak to the distal edge of the target. Two different minimum MU settings of 400 and 800 MU/spot (Bragg-400MU and Bragg-800MU) plans were investigated on 10 consecutive hepatocellular carcinoma patients previously treated by IMPT-SBRT to evaluate the FLASH dose and dose rate coverage for OARs. The IMPT-FLASH using single-energy Bragg peaks delivered 50 Gy in 5 fractions with similar or identical beam arrangement to the clinical IMPT-SBRT plans. NRG GI003 dose constraint metrics were used. Three dose rate calculation methods, including average dose rate (ADR), dose threshold dose rate (DTDR), and dose-averaged dose rate (DADR), were all studied. RESULTS The novel spot map optimization can fulfill the inverse planning using single-energy Bragg peaks. All the Bragg peak FLASH plans achieved similar results for the liver-GTV Dmean and heart D0.5cc , compared to SBRT-IMPT. The Bragg-800MU plans resulted in 18.3% higher CTV D2cc compared with SBRT (p < 0.05), and no significant difference was found between Bragg-400MU and SBRT plans. For the CTV Dmax , SBRT plans resulted in 10.3% (p<0.01) less than Bragg-400MU plans and 16.6% (p<0.01) less than Bragg-800MU plans. The Bragg-800MU plans generally achieved higher ADR, DADR, and DTDR dose rates than Bragg-400MU plans, and DADR mostly led to the highest V40Gy/s compared to other dose rate calculation methods, whereas ADR led to the lowest. The lower dose rate portions in certain OARs are related to the lower dose deposited due to the farther distances from targets, especially in the penumbra of the beams. CONCLUSION Single-energy Bragg peak IMPT-FLASH plans eliminate the exit dose in normal tissues, maintaining comparable dose metrics to the conventional IMPT-SBRT plans while achieving a sufficient FLASH dose rate for liver cancers. This study demonstrates the feasibility of and sufficiently high dose rate when applying Bragg peak FLASH treatment for liver cancer hypofractionated FLASH therapy. The advancement of this novel method has the potential to optimize treatment for liver cancer patients. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Shouyi Wei
- New York Proton Center, New York, NY, USA
| | - Haibo Lin
- New York Proton Center, New York, NY, USA
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24
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Yang Y, Shi C, Chen CC, Tsai P, Kang M, Huang S, Lin CH, Chang FX, Chhabra AM, Choi JI, Tome WA, Ii CBS, Lin H. A high spatiotemporal resolution 2D strip ionization chamber array for proton pencil beam scanning FLASH radiotherapy. Med Phys 2022; 49:5464-5475. [PMID: 35593052 DOI: 10.1002/mp.15706] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/18/2022] [Accepted: 05/02/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Experimental measurements of 2D dose rate distributions in proton pencil beam scanning (PBS) FLASH radiation therapy (RT) are currently lacking. In this study, we characterize a newly designed 2D strip-segmented ionization chamber array (SICA) with high spatial and temporal resolution and demonstrate its applications in a modern proton PBS delivery system at both conventional and ultra-high dose rates. METHODS A dedicated research beamline of the Varian ProBeam system was employed to deliver a 250 MeV proton PBS beam with nozzle currents up to 215 nA. In the research and clinical beamlines, the spatial, temporal, and dosimetric performance of the SICA was characterized and compared with measurements using parallel-plate ion chambers (IBA PPC05 and PTW Advanced Markus chamber), a 2D scintillator camera (IBA Lynx), Gafchromic films (EBT-XD), and a Faraday Cup. A novel reconstruction approach was proposed to enable the measurement of 2D dose and dose rate distributions using such a strip-type detector. RESULTS The SICA demonstrated a position accuracy of 0.12 ± 0.02 mm at a 20 kHz sampling rate (50 μs per event) and a linearity of R2 > 0.99 for both dose and dose rate with nozzle beam currents ranging from 1 nA to 215 nA. The 2D dose comparison to the film measurement resulted in a gamma passing rate of 99.8% (2 mm/2%). A measurement-based proton PBS 2D FLASH dose rate distribution was compared to simulation results and showed a gamma passing rate of 97.3% (2 mm/2%). CONCLUSIONS The newly designed SICA demonstrated excellent spatial, temporal, and dosimetric performance and is well suited for commissioning, quality assurance (QA), and a wide range of clinical applications in proton PBS clinical and FLASH radiotherapy. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - J Isabelle Choi
- New York Proton Center, New York, NY, USA.,Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Wolfgang A Tome
- Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York, USA
| | - Charles B Simone Ii
- New York Proton Center, New York, NY, USA.,Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Haibo Lin
- New York Proton Center, New York, NY, USA.,Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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25
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Tashiro M, Yoshida Y, Oike T, Nakao M, Yusa K, Hirota Y, Ohno T. First Human Cell Experiments With FLASH Carbon Ions. Anticancer Res 2022; 42:2469-2477. [PMID: 35489744 DOI: 10.21873/anticanres.15725] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 11/10/2022]
Abstract
BACKGROUND/AIM This study aimed to establish a setup for ultra-high-dose-rate (FLASH) carbon-ion irradiation, and to conduct the first human cell experiments using FLASH carbon ions. MATERIALS AND METHODS A system for FLASH carbon-ion irradiation (1-3 Gy at 13 or 50 keV/μm) was developed. The growth and senescence of HFL1 lung fibroblasts were assessed by crystal violet staining assays and senescence-associated β-galactosidase staining, respectively. Survival of HSGc-C5 cancer cells was assessed by clonogenic assays. RESULTS The dose rates of carbon ions ranged from 96-195 Gy/s, meeting the definition of FLASH. With both 13 and 50 keV/μm beams, no FLASH sparing effect was observed on the growth suppression and senescence of HFL1 cells, nor on the survival of HSGc-C5 cells. CONCLUSION We successfully conducted the first human cell experiments with FLASH carbon ions. No FLASH effect was observed under the conditions examined.
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Affiliation(s)
| | | | - Takahiro Oike
- Gunma University Heavy Ion Medical Center, Gunma, Japan.,Department of Radiation Oncology, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Masao Nakao
- Gunma University Heavy Ion Medical Center, Gunma, Japan
| | - Ken Yusa
- Gunma University Heavy Ion Medical Center, Gunma, Japan
| | - Yuka Hirota
- Department of Radiation Oncology, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Tatsuya Ohno
- Gunma University Heavy Ion Medical Center, Gunma, Japan.,Department of Radiation Oncology, Gunma University Graduate School of Medicine, Gunma, Japan
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Taylor PA, Moran JM, Jaffray DA, Buchsbaum JC. A roadmap to clinical trials for FLASH. Med Phys 2022; 49:4099-4108. [PMID: 35366339 PMCID: PMC9321729 DOI: 10.1002/mp.15623] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 02/17/2022] [Accepted: 03/17/2022] [Indexed: 11/29/2022] Open
Abstract
While FLASH radiation therapy is inspiring enthusiasm to transform the field, it is neither new nor well understood with respect to the radiobiological mechanisms. As FLASH clinical trials are designed, it will be important to ensure we can deliver dose consistently and safely to every patient. Much like hyperthermia and proton therapy, FLASH is a promising new technology that will be complex to implement in the clinic and similarly will require customized credentialing for multi‐institutional clinical trials. There is no doubt that FLASH seems promising, but many technologies that we take for granted in conventional radiation oncology, such as rigorous dosimetry, 3D treatment planning, volumetric image guidance, or motion management, may play a major role in defining how to use, or whether to use, FLASH radiotherapy. Given the extended time frame for patients to experience late effects, we recommend moving deliberately but cautiously forward toward clinical trials. In this paper, we review the state of quality assurance and safety systems in FLASH, identify critical pre‐clinical data points that need to be defined, and suggest how lessons learned from previous technological advancements will help us close the gaps and build a successful path to evidence‐driven FLASH implementation.
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Affiliation(s)
- Paige A Taylor
- The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jean M Moran
- Memorial Sloan Kettering Cancer, New York, New York
| | - David A Jaffray
- The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jeffrey C Buchsbaum
- Radiation Research Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
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Liew H, Mein S, Tessonnier T, Abdollahi A, Debus J, Dokic I, Mairani A. The Impact of Sub-Millisecond Damage Fixation Kinetics on the In Vitro Sparing Effect at Ultra-High Dose Rate in UNIVERSE. Int J Mol Sci 2022; 23:ijms23062954. [PMID: 35328377 PMCID: PMC8954991 DOI: 10.3390/ijms23062954] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/28/2022] [Accepted: 03/07/2022] [Indexed: 02/04/2023] Open
Abstract
The impact of the exact temporal pulse structure on the potential cell and tissue sparing of ultra-high dose-rate irradiation applied in FLASH studies has gained increasing attention. A previous version of our biophysical mechanistic model (UNIVERSE: UNIfied and VERSatile bio response Engine), based on the oxygen depletion hypothesis, has been extended in this work by considering oxygen-dependent damage fixation dynamics on the sub-milliseconds scale and introducing an explicit implementation of the temporal pulse structure. The model successfully reproduces in vitro experimental data on the fast kinetics of the oxygen effect in irradiated mammalian cells. The implemented changes result in a reduction in the assumed amount of oxygen depletion. Furthermore, its increase towards conventional dose-rates is parameterized based on experimental data from the literature. A recalculation of previous benchmarks shows that the model retains its predictive power, while the assumed amount of depleted oxygen approaches measured values. The updated UNIVERSE could be used to investigate the impact of different combinations of pulse structure parameters (e.g., dose per pulse, pulse frequency, number of pulses, etc.), thereby aiding the optimization of potential clinical application and the development of suitable accelerators.
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Affiliation(s)
- Hans Liew
- Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany; (H.L.); (J.D.)
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
- Faculty of Physics and Astronomy, Heidelberg University, 69120 Heidelberg, Germany
| | - Stewart Mein
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
| | - Thomas Tessonnier
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
| | - Amir Abdollahi
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
| | - Jürgen Debus
- Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany; (H.L.); (J.D.)
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
- Faculty of Physics and Astronomy, Heidelberg University, 69120 Heidelberg, Germany
| | - Ivana Dokic
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
| | - Andrea Mairani
- Division of Molecular and Translational Radiation Oncology, National Center for Tumor Diseases (NCT), Heidelberg University Hospital, 69120 Heidelberg, Germany; (S.M.); (A.A.); (I.D.)
- Heidelberg Institute of Radiation Oncology (HIRO), German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
- German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Heidelberg Ion-Beam Therapy Center (HIT), 69120 Heidelberg, Germany;
- Correspondence: ; Tel.: +49-0-6221-56-37535
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28
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Abstract
PURPOSE Hypoxia (low oxygen) is a common feature of solid tumors that has been intensely studied for more than six decades. Here we review the importance of hypoxia to radiotherapy with a particular focus on the contribution of hypoxia to immune responses, metastatic potential and FLASH radiotherapy, active areas of research by leading women in the field. CONCLUSION Although hypoxia-driven metastasis and immunosuppression can negatively impact clinical outcome, understanding these processes can also provide tumor-specific vulnerabilities that may be therapeutically exploited. The different oxygen tensions present in tumors and normal tissues may underpin the beneficial FLASH sparing effect seen in normal tissue and represents a perfect example of advances in the field that can leverage tumor hypoxia to improve future radiotherapy treatments.
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Affiliation(s)
- Eui Jung Moon
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK,Equal Contribution and to whom correspondence should be addressed. ; :
| | - Kristoffer Petersson
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK,Radiation Physics, Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Sweden,Equal Contribution and to whom correspondence should be addressed. ; :
| | - Monica M. Oleina
- MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK,Equal Contribution and to whom correspondence should be addressed. ; :
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Wei S, Lin H, Choi JI, Simone CB, Kang M. A Novel Proton Pencil Beam Scanning FLASH RT Delivery Method Enables Optimal OAR Sparing and Ultra-High Dose Rate Delivery: A Comprehensive Dosimetry Study for Lung Tumors. Cancers (Basel) 2021; 13:5790. [PMID: 34830946 PMCID: PMC8616118 DOI: 10.3390/cancers13225790] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/13/2021] [Accepted: 11/15/2021] [Indexed: 12/25/2022] Open
Abstract
PURPOSE While transmission proton beams have been demonstrated to achieve ultra-high dose rate FLASH therapy delivery, they are unable to spare normal tissues distal to the target. This study aims to compare FLASH treatment planning using single energy Bragg peak proton beams versus transmission proton beams in lung tumors and to evaluate Bragg peak plan optimization, characterize plan quality, and quantify organ-at-risk (OAR) sparing. MATERIALS AND METHODS Both Bragg peak and transmission plans were optimized using an in-house platform for 10 consecutive lung patients previously treated with proton stereotactic body radiation therapy (SBRT). To bring the dose rate up to the FLASH-RT threshold, Bragg peak plans with a minimum MU/spot of 1200 and transmission plans with a minimum MU/spot of 400 were developed. Two common prescriptions, 34 Gy in 1 fraction and 54 Gy in 3 fractions, were studied with the same beam arrangement for both Bragg peak and transmission plans (n = 40 plans). RTOG 0915 dosimetry metrics and dose rate metrics based on different dose rate calculations, including average dose rate (ADR), dose-averaged dose rate (DADR), and dose threshold dose rate (DTDR), were investigated. We then evaluated the effect of beam angular optimization on the Bragg peak plans to explore the potential for superior OAR sparing. RESULTS Bragg peak plans significantly reduced doses to several OAR dose parameters, including lung V7.4Gy and V7Gy by 32.0% (p < 0.01) and 30.4% (p < 0.01) for 34Gy/fx plans, respectively; and by 40.8% (p < 0.01) and 41.2% (p < 0.01) for 18Gy/fx plans, respectively, compared with transmission plans. Bragg peak plans have ~3% less in DADR and ~10% differences in mean OARs in DTDR and DADR relative to transmission plans due to the larger portion of lower dose regions of Bragg peak plans. With angular optimization, optimized Bragg peak plans can further reduce the lung V7Gy by 20.7% (p < 0.01) and V7.4Gy by 19.7% (p < 0.01) compared with Bragg peak plans without angular optimization while achieving a similar 3D dose rate distribution. CONCLUSION The single-energy Bragg peak plans achieve superior dosimetry performances in OARs to transmission plans with comparable dose rate performances for lung cancer FLASH therapy. Beam angle optimization can further improve the OAR dosimetry parameters with similar 3D FLASH dose rate coverage.
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Affiliation(s)
| | | | | | | | - Minglei Kang
- New York Proton Center, New York, NY 10035, USA; (S.W.); (H.L.); (J.I.C.); (C.B.S.II)
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30
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Oesterle R, Gonçalves Jorge P, Grilj V, Bourhis J, Vozenin M, Germond J, Bochud F, Bailat C, Moeckli R. Implementation and validation of a beam-current transformer on a medical pulsed electron beam LINAC for FLASH-RT beam monitoring. J Appl Clin Med Phys 2021; 22:165-171. [PMID: 34609051 PMCID: PMC8598141 DOI: 10.1002/acm2.13433] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/28/2021] [Accepted: 09/13/2021] [Indexed: 12/18/2022] Open
Abstract
PURPOSE To implement and validate a beam current transformer as a passive monitoring device on a pulsed electron beam medical linear accelerator (LINAC) for ultra-high dose rate (UHDR) irradiations in the operational range of at least 3 Gy to improve dosimetric procedures currently in use for FLASH radiotherapy (FLASH-RT) studies. METHODS Two beam current transformers (BCTs) were placed at the exit of a medical LINAC capable of UHDR irradiations. The BCTs were validated as monitoring devices by verifying beam parameters consistency between nominal values and measured values, determining the relationship between the charge measured and the absorbed dose, and checking the short- and long-term stability of the charge-absorbed dose ratio. RESULTS The beam parameters measured by the BCTs coincide with the nominal values. The charge-dose relationship was found to be linear and independent of pulse width and frequency. Short- and long-term stabilities were measured to be within acceptable limits. CONCLUSIONS The BCTs were implemented and validated on a pulsed electron beam medical LINAC, thus improving current dosimetric procedures and allowing for a more complete analysis of beam characteristics. BCTs were shown to be a valid method for beam monitoring for UHDR (and therefore FLASH) experiments.
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Affiliation(s)
- Roxane Oesterle
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Patrik Gonçalves Jorge
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Veljko Grilj
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Jean Bourhis
- Radiation Oncology DepartmentLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Marie‐Catherine Vozenin
- Radiation Oncology DepartmentLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Jean‐François Germond
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - François Bochud
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Claude Bailat
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
| | - Raphaël Moeckli
- Institute of Radiation PhysicsLausanne University Hospital and Lausanne UniversityLausanneSwitzerland
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31
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Chua KLM, Chu PL, Tng DJH, Soo KC, Chua MLK. Repurposing Proton Beam Therapy through Novel Insights into Tumour Radioresistance. Clin Oncol (R Coll Radiol) 2021; 33:e469-e481. [PMID: 34509347 DOI: 10.1016/j.clon.2021.08.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/02/2021] [Accepted: 08/25/2021] [Indexed: 12/11/2022]
Abstract
Despite improvements in radiotherapy, radioresistance remains an important clinical challenge. Radioresistance can be mediated through enhanced DNA damage response mechanisms within the tumour or through selective pressures exerted by the tumour microenvironment (TME). The effects of the TME have in recent times gained increased attention, in part due to the success of immune modulating strategies, but also through improved understanding of the downstream effects of hypoxia and dysregulated wound healing processes on mediating radioresistance. Although we have a better appreciation of these molecular mechanisms, efforts to address them through novel combination approaches have been scarce, owing to limitations of photon therapy and concerns over toxicity. At the same time, proton beam therapy (PBT) represents an advancement in radiotherapy technologies. However, early clinical results have been mixed and the clinical strategies around optimal use and patient selection for PBT remain unclear. Here we highlight the role that PBT can play in addressing radioresistance, through better patient selection, and by providing an improved toxicity profile for integration with novel agents. We will also describe the developments around FLASH PBT. Through close examination of its normal tissue-sparing effects, we will highlight how FLASH PBT can facilitate combination strategies to tackle radioresistance by further improving toxicity profiles and by directly mediating the mechanisms of radioresistance.
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Affiliation(s)
- K L M Chua
- Oncology Academic Clinical Programme, Duke-NUS Medical School, Singapore; Division of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | - P L Chu
- Oncology Academic Clinical Programme, Duke-NUS Medical School, Singapore
| | - D J H Tng
- Division of Radiation Oncology, National Cancer Centre Singapore, Singapore
| | - K C Soo
- Division of Medical Sciences, National Cancer Centre Singapore, Singapore; Division of Surgical Oncology, National Cancer Centre Singapore, Singapore
| | - M L K Chua
- Oncology Academic Clinical Programme, Duke-NUS Medical School, Singapore; Division of Radiation Oncology, National Cancer Centre Singapore, Singapore; Division of Medical Sciences, National Cancer Centre Singapore, Singapore.
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32
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Darafsheh A, Hao Y, Zhao X, Zwart T, Wagner M, Evans T, Reynoso F, Zhao T. Spread-out Bragg peak proton FLASH irradiation using a clinical synchrocyclotron: Proof of concept and ion chamber characterization. Med Phys 2021; 48:4472-4484. [PMID: 34077590 DOI: 10.1002/mp.15021] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE The purpose of this work is to (a) demonstrate the feasibility of delivering a spread-out Bragg peak (SOBP) proton beam in ultra-high dose rate (FLASH) using a proton therapy synchrocyclotron as a major step toward realizing an experimental platform for preclinical studies, and (b) evaluate the response of four models of ionization chambers in such a radiation field. METHODS A clinical Mevion HYPERSCAN® synchrocyclotron was adjusted for ultra-high dose rate proton delivery. Protons with nominal energy of 230 MeV were delivered in pulses with temporal width ranging from 12.5 μs to 24 μs spanning from conventional to FLASH dose rates. A boron carbide absorber and a range modulator block were placed in the beam path for range modulation and creating an SOBP dose profile. The radiation field was defined by a brass aperture with 11 mm diameter. Two Faraday cups were used to determine the number of protons per pulse at various dose rates. The dosimetric response of two cylindrical (IBA CC04 and CC13) and two plane-parallel (IBA PPC05 and PTW Advanced Markus® ) ionization chambers were evaluated. The dose rate was measured using the plane-parallel ionization chambers. The integral depth dose (IDD) was measured with a PTW Bragg Peak® ionization chamber. The lateral beam profile was measured with EBT-XD radiochromic film. Monte Carlo simulation was performed in TOPAS as the secondary check for the measurements and as a tool for further optimization of the range modulators' design. RESULTS Faraday cups measurement showed that the maximum protons per pulse is 39.9 pC at 24 μs pulse width. A good agreement between the measured and simulated IDD and lateral beam profiles was observed. The cylindrical ionization chambers showed very high ion recombination and deemed not suitable for absolute dosimetry at ultra-high dose rates. The average dose rate measured using the PPC05 ionization chamber was 163 Gy/s at the pristine Bragg peak and 126 Gy/s at 1 cm depth for the SOBP beam. The SOBP beam range and modulation were measured 24.4 mm and 19 mm, respectively. The pristine Bragg peak beam had 25.6 mm range. Simulation results showed that the IDD and profile flatness can be improved by the cavity diameter of the range modulator and the number of scanned spots, respectively. CONCLUSIONS Feasibility of delivering protons in an SOBP pattern with >100 Gy/s average dose rate using a clinical synchrocyclotron was demonstrated. The dose heterogeneity can be improved through optimization of the range modulator and number of delivered spots. Plane-parallel chambers with smaller gap between electrodes are more suitable for FLASH dosimetry compared to the other ion chambers used in this work.
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Affiliation(s)
- Arash Darafsheh
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yao Hao
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Xiandong Zhao
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | | | | | | | - Francisco Reynoso
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
| | - Tianyu Zhao
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
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Winterhalter C, Togno M, Nesteruk KP, Emert F, Psoroulas S, Vidal M, Meer D, Weber DC, Lomax A, Safai S. Faraday cup for commissioning and quality assurance for proton pencil beam scanning beams at conventional and ultra-high dose rates. Phys Med Biol 2021; 66. [PMID: 33906166 DOI: 10.1088/1361-6560/abfbf2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/27/2021] [Indexed: 11/11/2022]
Abstract
Recently, proton therapy treatments delivered with ultra-high dose rates have been of high scientific interest, and the Faraday cup (FC) is a promising dosimetry tool for such experiments. Different institutes use different FC designs, and either a high voltage guard ring, or the combination of an electric and a magnetic field is employed to minimize the effect of secondary electrons. The authors first investigate these different approaches for beam energies of 70, 150, 230 and 250 MeV, magnetic fields between 0 and 24 mT and voltages between -1000 and 1000 V. When applying a magnetic field, the measured signal is independent of the guard ring voltage, indicating that this setting minimizes the effect of secondary electrons on the reading of the FC. Without magnetic field, applying the negative voltage however decreases the signal by an energy dependent factor up to 1.3% for the lowest energy tested and 0.4% for the highest energy, showing an energy dependent response. Next, the study demonstrates the application of the FC up to ultra-high dose rates. FC measurements with cyclotron currents up to 800 nA (dose rates of up to approximately 1000 Gy s-1) show that the FC is indeed dose rate independent. Then, the FC is applied to commission the primary gantry monitor for high dose rates. Finally, short-term reproducibility of the monitor calibration is quantified within single days, showing a standard deviation of 0.1% (one sigma). In conclusion, the FC is a promising, dose rate independent tool for dosimetry up to ultra-high dose rates. Caution is however necessary when using a FC without magnetic field, as a guard ring with high voltage alone can introduce an energy dependent signal offset.
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Affiliation(s)
- C Winterhalter
- Centre for Proton Therapy, Paul Scherrer Institute, Switzerland.,Physics Department, ETH Zurich, Switzerland
| | - M Togno
- Centre for Proton Therapy, Paul Scherrer Institute, Switzerland
| | - K P Nesteruk
- Centre for Proton Therapy, Paul Scherrer Institute, Switzerland
| | - F Emert
- Centre for Proton Therapy, Paul Scherrer Institute, Switzerland
| | - S Psoroulas
- Centre for Proton Therapy, Paul Scherrer Institute, Switzerland
| | - M Vidal
- Institut Mediterraneen de Protontherapie, Centre Antoine Lacassagne, Nice, France
| | - D Meer
- Centre for Proton Therapy, Paul Scherrer Institute, Switzerland
| | - D C Weber
- Centre for Proton Therapy, Paul Scherrer Institute, Switzerland.,Radiation Oncology Department of the University Hospital of Bern, Switzerland.,Radiation Oncology Department of the University Hospital of Zürich, Switzerland
| | - A Lomax
- Centre for Proton Therapy, Paul Scherrer Institute, Switzerland.,Physics Department, ETH Zurich, Switzerland
| | - S Safai
- Centre for Proton Therapy, Paul Scherrer Institute, Switzerland
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34
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Szpala S, Huang V, Zhao Y, Kyle A, Minchinton A, Karan T, Kohli K. Dosimetry with a clinical linac adapted to FLASH electron beams. J Appl Clin Med Phys 2021; 22:50-59. [PMID: 34028969 PMCID: PMC8200504 DOI: 10.1002/acm2.13270] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/03/2021] [Accepted: 04/10/2021] [Indexed: 11/21/2022] Open
Abstract
Purpose To assess dosimetric properties and identify required updates to commonly used protocols (including use of film and ionization chamber) pertaining to a clinical linac configured into FLASH (ultra‐high dose rate) electron mode. Methods An 18MV photon beam of a Varian iX linac was converted to FLASH electron beam by replacing the target and the flattening filter with an electron scattering foil. The dose was prescribed by entering the MUs through the console. Fundamental beam properties, including energy, dose rate, dose reproducibility, field size, and dose rate dependence on the SAD, were examined in preparation for radiobiological experiments. Gafchromic EBT‐XD film was evaluated for usability in measurements at ultra‐high dose rates by comparing the measured dose to the inverse square model. Selected previously reported models of chamber efficiencies were fitted to measurements in a broad range of dose rates. Results The performance of the modified linac was found adequate for FLASH radiobiological experiments. With exception of the increase in the dose per MU on increase in the repetition rate, all fundamental beam properties proved to be in line with expectations developed with conventional linacs. The field size followed the theorem of similar triangles. The highest average dose rate (2 × 104 Gy/s) was found next to the internal monitor chamber, with the field size of FWHM = 1.5 cm. Independence of the dose readings on the dose rate (up to 2 × 104 Gy/s) was demonstrated for the EBT‐XD film. A model of recombination in an ionization chamber was identified that provided good agreement with the measured chamber efficiencies for the average dose rates up to at least 2 × 103 Gy/s. Conclusion Dosimetric measurements were performed to characterize a linac converted to FLASH dose rates. Gafchromic EBT‐XD film and dose rate‐corrected cc13 ionization chamber were demonstrated usable at FLASH dose rates.
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Affiliation(s)
| | - Vicky Huang
- BC Cancer, Surrey Centre, Surrey, BC, Canada
| | - Yingli Zhao
- BC Cancer, Surrey Centre, Surrey, BC, Canada
| | | | | | - Tania Karan
- BC Cancer, Vancouver Centre, Vancouver, BC, Canada
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35
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Moeckli R, Gonçalves Jorge P, Grilj V, Oesterle R, Cherbuin N, Bourhis J, Vozenin MC, Germond JF, Bochud F, Bailat C. Commissioning of an ultra-high dose rate pulsed electron beam medical LINAC for FLASH RT preclinical animal experiments and future clinical human protocols. Med Phys 2021; 48:3134-3142. [PMID: 33866565 DOI: 10.1002/mp.14885] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/11/2020] [Accepted: 03/31/2021] [Indexed: 11/05/2022] Open
Abstract
PURPOSE To present the acceptance and the commissioning, to define the reference dose, and to prepare the reference data for a quality assessment (QA) program of an ultra-high dose rate (UHDR) electron device in order to validate it for preclinical animal FLASH radiotherapy (FLASH RT) experiments and for FLASH RT clinical human protocols. METHODS The Mobetron® device was evaluated with electron beams of 9 MeV in conventional (CONV) mode and of 6 and 9 MeV in UHDR mode (nominal energy). The acceptance was performed according to the acceptance protocol of the company. The commissioning consisted of determining the short- and long-term stability of the device, the measurement of percent depth dose curves (PDDs) and profiles at two different positions (with two different dose per pulse regimen) and for different collimator sizes, and the evaluation of the variability of these parameters when changing the pulse width and pulse repetition frequency. Measurements were performed using a redundant and validated dosimetric strategy with alanine and radiochromic films, as well as Advanced Markus ionization chamber for some measurements. RESULTS The acceptance tests were all within the tolerances of the company's acceptance protocol. The linearity with pulse width was within 1.5% in all cases. The pulse repetition frequency did not affect the delivered dose more than 2% in all cases but 90 Hz, for which the larger difference was 3.8%. The reference dosimetry showed a good agreement within the alanine and films with variations of 2.2% or less. The short-term (resp. long-term) stability was less than 1.0% (resp. 1.8%) and was the same in both CONV and UHDR modes. PDDs, profiles, and reference dosimetry were measured at two positions, providing data for two specific dose rates (about 9 Gy/pulse and 3 Gy/pulse). Maximal beam size was 4 and 6 cm at 90% isodose in the two positions tested. There was no difference between CONV and UHDR mode in the beam characteristics tested. CONCLUSIONS The device is commissioned for FLASH RT preclinical biological experiments as well as FLASH RT clinical human protocols.
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Affiliation(s)
- Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Patrik Gonçalves Jorge
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Veljko Grilj
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Roxane Oesterle
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Nicolas Cherbuin
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Jean Bourhis
- Radio-Oncology Department, Lausanne University Hospital and Lausanne University, Rue du Bugnon 46, Lausanne, CH-1011, Switzerland
| | - Marie-Catherine Vozenin
- Radio-Oncology Department, Lausanne University Hospital and Lausanne University, Rue du Bugnon 46, Lausanne, CH-1011, Switzerland
| | - Jean-François Germond
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - François Bochud
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Rue du Grand-Pré 1, Lausanne, CH-1007, Switzerland
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Konradsson E, Arendt ML, Bastholm Jensen K, Børresen B, Hansen AE, Bäck S, Kristensen AT, Munck Af Rosenschöld P, Ceberg C, Petersson K. Establishment and Initial Experience of Clinical FLASH Radiotherapy in Canine Cancer Patients. Front Oncol 2021; 11:658004. [PMID: 34055624 PMCID: PMC8155542 DOI: 10.3389/fonc.2021.658004] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 04/26/2021] [Indexed: 01/19/2023] Open
Abstract
FLASH radiotherapy has emerged as a treatment technique with great potential to increase the differential effect between normal tissue toxicity and tumor response compared to conventional radiotherapy. To evaluate the feasibility of FLASH radiotherapy in a relevant clinical setting, we have commenced a feasibility and safety study of FLASH radiotherapy in canine cancer patients with spontaneous superficial solid tumors or microscopic residual disease, using the electron beam of our modified clinical linear accelerator. The setup for FLASH radiotherapy was established using a short electron applicator with a nominal source-to-surface distance of 70 cm and custom-made Cerrobend blocks for collimation. The beam was characterized by measuring dose profiles and depth dose curves for various field sizes. Ten canine cancer patients were included in this initial study; seven patients with nine solid superficial tumors and three patients with microscopic disease. The administered dose ranged from 15 to 35 Gy. To ensure correct delivery of the prescribed dose, film measurements were performed prior to and during treatment, and a Farmer-type ion-chamber was used for monitoring. Treatments were found to be feasible, with partial response, complete response or stable disease recorded in 11/13 irradiated tumors. Adverse events observed at follow-up ranging from 3-6 months were mild and consisted of local alopecia, leukotricia, dry desquamation, mild erythema or swelling. One patient receiving a 35 Gy dose to the nasal planum, had a grade 3 skin adverse event. Dosimetric procedures, safety and an efficient clincal workflow for FLASH radiotherapy was established. The experience from this initial study will be used as a basis for a veterinary phase I/II clinical trial with more specific patient inclusion selection, and subsequently for human trials.
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Affiliation(s)
- Elise Konradsson
- Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Maja L Arendt
- Department of Veterinary Clinical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | | | - Betina Børresen
- Department of Veterinary Clinical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Anders E Hansen
- Department of Biotherapeutic Engineering and Drug Targeting, DTU Health Tech, Kgs, Technical University of Denmark, Lyngby, Denmark
| | - Sven Bäck
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Annemarie T Kristensen
- Department of Veterinary Clinical Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Per Munck Af Rosenschöld
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Crister Ceberg
- Medical Radiation Physics, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Kristoffer Petersson
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden.,Department of Oncology, Oxford Institute for Radiation Oncology, University of Oxford, Oxford, United Kingdom
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37
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Christensen JB, Togno M, Nesteruk KP, Psoroulas S, Meer D, Weber DC, Lomax T, Yukihara EG, Safai S. Al 2O 3:C optically stimulated luminescence dosimeters (OSLDs) for ultra-high dose rate proton dosimetry. Phys Med Biol 2021; 66. [PMID: 33571973 DOI: 10.1088/1361-6560/abe554] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 02/11/2021] [Indexed: 11/11/2022]
Abstract
The response of Al2O3:C optically stimulated luminescence detectors (OSLDs) was investigated in a 250 MeV pencil proton beam. The OSLD response was mapped for a wide range of average dose rates up to 9000 Gy s-1, corresponding to a ∼150 kGy s-1instantaneous dose rate in each pulse. Two setups for ultra-high dose rate (FLASH) experiments are presented, which enable OSLDs or biological samples to be irradiated in either water-filled vials or cylinders. The OSLDs were found to be dose rate independent for all dose rates, with an average deviation <1% relative to the nominal dose for average dose rates of (1-1000) Gy s-1when irradiated in the two setups. A third setup for irradiations in a 9000 Gy s-1pencil beam is presented, where OSLDs are distributed in a 3 × 4 grid. Calculations of the signal averaging of the beam over the OSLDs were in agreement with the measured response at 9000 Gy s-1. Furthermore, a new method was presented to extract the beam spot size of narrow pencil beams, which is in agreement within a standard deviation with results derived from radiochromic films. The Al2O3:C OSLDs were found applicable to support radiobiological experiments in proton beams at ultra-high dose rates.
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Affiliation(s)
| | - Michele Togno
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland
| | | | | | - David Meer
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland
| | - Damien Charles Weber
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland.,Department of Radiation Oncology, University Hospital Zurich, Switzerland.,Department of Radiation Oncology, University Hospital Bern, Switzerland
| | - Tony Lomax
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland.,Department of Physics, ETH Zurich, Switzerland
| | - Eduardo G Yukihara
- Department of Radiation Safety and Security, Paul Scherrer Institute, Switzerland
| | - Sairos Safai
- Center for Proton Therapy, Paul Scherrer Institute, Switzerland
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38
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Cunningham S, McCauley S, Vairamani K, Speth J, Girdhani S, Abel E, Sharma RA, Perentesis JP, Wells SI, Mascia A, Sertorio M. FLASH Proton Pencil Beam Scanning Irradiation Minimizes Radiation-Induced Leg Contracture and Skin Toxicity in Mice. Cancers (Basel) 2021; 13:cancers13051012. [PMID: 33804336 PMCID: PMC7957631 DOI: 10.3390/cancers13051012] [Citation(s) in RCA: 97] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/18/2021] [Accepted: 02/22/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Dose and efficacy of radiation therapy are limited by the toxicity to normal tissue adjacent to the treated tumor region. Recently, ultra-high dose rate radiotherapy (FLASH radiotherapy) has shown beneficial reduction of normal tissue damage while preserving similar tumor efficacy with electron, photon and scattered proton beam irradiation in preclinical models. Proton therapy is increasingly delivered by pencil beam scanning (PBS) technology, and we therefore set out to test PBS FLASH radiotherapy on normal tissue toxicity and tumor control in vivo in mouse using a clinical proton delivery system. This validation of the FLASH normal tissue-sparing hypothesis with a clinical delivery system provides supporting data for PBS FLASH radiotherapy and its potential role in improving radiotherapy outcomes. Abstract Ultra-high dose rate radiation has been reported to produce a more favorable toxicity and tumor control profile compared to conventional dose rates that are used for patient treatment. So far, the so-called FLASH effect has been validated for electron, photon and scattered proton beam, but not yet for proton pencil beam scanning (PBS). Because PBS is the state-of-the-art delivery modality for proton therapy and constitutes a wide and growing installation base, we determined the benefit of FLASH PBS on skin and soft tissue toxicity. Using a pencil beam scanning nozzle and the plateau region of a 250 MeV proton beam, a uniform physical dose of 35 Gy (toxicity study) or 15 Gy (tumor control study) was delivered to the right hind leg of mice at various dose rates: Sham, Conventional (Conv, 1 Gy/s), Flash60 (57 Gy/s) and Flash115 (115 Gy/s). Acute radiation effects were quantified by measurements of plasma and skin levels of TGF-β1 and skin toxicity scoring. Delayed irradiation response was defined by hind leg contracture as a surrogate of irradiation-induced skin and soft tissue toxicity and by plasma levels of 13 different cytokines (CXCL1, CXCL10, Eotaxin, IL1-beta, IL-6, MCP-1, Mip1alpha, TNF-alpha, TNF-beta, VEGF, G-CSF, GM-CSF and TGF- β1). Plasma and skin levels of TGF-β1, skin toxicity and leg contracture were all significantly decreased in FLASH compared to Conv groups of mice. FLASH and Conv PBS had similar efficacy with regards to growth control of MOC1 and MOC2 head and neck cancer cells transplanted into syngeneic, immunocompetent mice. These results demonstrate consistent delivery of FLASH PBS radiation from 1 to 115 Gy/s in a clinical gantry. Radiation response following delivery of 35 Gy indicates potential benefits of FLASH versus conventional PBS that are related to skin and soft tissue toxicity.
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Affiliation(s)
- Shannon Cunningham
- Cincinnati Children’s Hospital Medical Center, Division of Oncology, Cincinnati, OH 45229, USA; (S.C.); (S.M.); (K.V.); (J.P.P.); (S.I.W.)
| | - Shelby McCauley
- Cincinnati Children’s Hospital Medical Center, Division of Oncology, Cincinnati, OH 45229, USA; (S.C.); (S.M.); (K.V.); (J.P.P.); (S.I.W.)
| | - Kanimozhi Vairamani
- Cincinnati Children’s Hospital Medical Center, Division of Oncology, Cincinnati, OH 45229, USA; (S.C.); (S.M.); (K.V.); (J.P.P.); (S.I.W.)
| | - Joseph Speth
- Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA; (J.S.); (A.M.)
| | - Swati Girdhani
- Varian Medical Systems, Inc., Palo Alto, CA 94304, USA; (S.G.); (E.A.); (R.A.S.)
| | - Eric Abel
- Varian Medical Systems, Inc., Palo Alto, CA 94304, USA; (S.G.); (E.A.); (R.A.S.)
| | - Ricky A. Sharma
- Varian Medical Systems, Inc., Palo Alto, CA 94304, USA; (S.G.); (E.A.); (R.A.S.)
| | - John P. Perentesis
- Cincinnati Children’s Hospital Medical Center, Division of Oncology, Cincinnati, OH 45229, USA; (S.C.); (S.M.); (K.V.); (J.P.P.); (S.I.W.)
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Susanne I. Wells
- Cincinnati Children’s Hospital Medical Center, Division of Oncology, Cincinnati, OH 45229, USA; (S.C.); (S.M.); (K.V.); (J.P.P.); (S.I.W.)
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Anthony Mascia
- Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA; (J.S.); (A.M.)
| | - Mathieu Sertorio
- Cincinnati Children’s Hospital Medical Center, Division of Oncology, Cincinnati, OH 45229, USA; (S.C.); (S.M.); (K.V.); (J.P.P.); (S.I.W.)
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
- Correspondence:
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Marcu LG, Bezak E, Peukert DD, Wilson P. Translational Research in FLASH Radiotherapy-From Radiobiological Mechanisms to In Vivo Results. Biomedicines 2021; 9:181. [PMID: 33670409 PMCID: PMC7918545 DOI: 10.3390/biomedicines9020181] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 01/18/2023] Open
Abstract
FLASH radiotherapy, or the administration of ultra-high dose rate radiotherapy, is a new radiation delivery method that aims to widen the therapeutic window in radiotherapy. Thus far, most in vitro and in vivo results show a real potential of FLASH to offer superior normal tissue sparing compared to conventionally delivered radiation. While there are several postulations behind the differential behaviour among normal and cancer cells under FLASH, the full spectra of radiobiological mechanisms are yet to be clarified. Currently the number of devices delivering FLASH dose rate is few and is mainly limited to experimental and modified linear accelerators. Nevertheless, FLASH research is increasing with new developments in all the main areas: radiobiology, technology and clinical research. This paper presents the current status of FLASH radiotherapy with the aforementioned aspects in mind, but also to highlight the existing challenges and future prospects to overcome them.
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Affiliation(s)
- Loredana G Marcu
- Faculty of Informatics & Science, Department of Physics, University of Oradea, 410087 Oradea, Romania
- Cancer Research Institute and School of Health Sciences, University of South Australia, Adelaide, SA 5001, Australia
| | - Eva Bezak
- Cancer Research Institute and School of Health Sciences, University of South Australia, Adelaide, SA 5001, Australia
- School of Physical Sciences, Department of Physics, University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
| | - Dylan D Peukert
- School of Civil, Environmental & Mining Engineering, University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
- STEM, University of South Australia, Adelaide, SA 5001, Australia
| | - Puthenparampil Wilson
- STEM, University of South Australia, Adelaide, SA 5001, Australia
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
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40
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Wu C, Song J, Yin B, Zhang G, Lin H, Fang C, Yang T, Qu B, Xu S. [A New Generation of Radiotherapy Technology-Flash Radiotherapy]. Zhongguo Yi Liao Qi Xie Za Zhi 2020; 44:508-512. [PMID: 33314859 DOI: 10.3969/j.issn.1671-7104.2020.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Flash radiotherapy is a kind of radiotherapy method using ultra-high dose rate radiation. Compared with the traditional dose rate radiotherapy, it has unique radiobiological advantages. In this paper, the principle of flash radiotherapy, the process and results of biological experiments are summarized. At the same time, the advantages and challenges of flash radiotherapy are analyzed, and the future clinical application is prospected.
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Affiliation(s)
- Cheng Wu
- School of Physics, Beijing University of Aeronautics and Astronautics, Beijing, 100191
| | - Jia Song
- School of Physics, Beijing University of Aeronautics and Astronautics, Beijing, 100191
| | - Bin Yin
- School of Physics, Beijing University of Aeronautics and Astronautics, Beijing, 100191
| | - Gaolong Zhang
- School of Physics, Beijing University of Aeronautics and Astronautics, Beijing, 100191
- Precision Medical Advanced Innovation Center, Beijing University of Aeronautics and Astronautics, Beijing, 100083
| | - Haibo Lin
- Department of Radiotherapy, New York Proton Center, NY USA, 10035
| | - Chunfeng Fang
- Department of Radiotherapy, Yizhou Tumor Hospital, Zhuozhou, 072750
| | - Tao Yang
- Department of Radiotherapy, PLA General Hospital, Beijing, 100853
| | - Baolin Qu
- Precision Medical Advanced Innovation Center, Beijing University of Aeronautics and Astronautics, Beijing, 100083
- Department of Radiotherapy, PLA General Hospital, Beijing, 100853
| | - Shouping Xu
- Precision Medical Advanced Innovation Center, Beijing University of Aeronautics and Astronautics, Beijing, 100083
- Department of Radiotherapy, Yizhou Tumor Hospital, Zhuozhou, 072750
- Department of Radiotherapy, PLA General Hospital, Beijing, 100853
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