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Subiel A, Bourgouin A, Kranzer R, Peier P, Frei F, Gomez F, Knyziak A, Fleta C, Bailat C, Schüller A. Metrology for advanced radiotherapy using particle beams with ultra-high dose rates. Phys Med Biol 2024; 69:14TR01. [PMID: 38830362 DOI: 10.1088/1361-6560/ad539d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 06/03/2024] [Indexed: 06/05/2024]
Abstract
Dosimetry of ultra-high dose rate beams is one of the critical components which is required for safe implementation of FLASH radiotherapy (RT) into clinical practice. In the past years several national and international programmes have emerged with the aim to address some of the needs that are required for translation of this modality to clinics. These involve the establishment of dosimetry standards as well as the validation of protocols and dosimetry procedures. This review provides an overview of recent developments in the field of dosimetry for FLASH RT, with particular focus on primary and secondary standard instruments, and provides a brief outlook on the future work which is required to enable clinical implementation of FLASH RT.
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Affiliation(s)
- Anna Subiel
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
- University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Alexandra Bourgouin
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
- National Research Council of Canada (NRC), 1200 Montreal Road, Ottawa, ON, K1A0R6, Canada
| | | | - Peter Peier
- Federal Institute of Metrology METAS, Lindenweg 50, 3003 Bern-Wabern, Switzerland
| | - Franziska Frei
- Federal Institute of Metrology METAS, Lindenweg 50, 3003 Bern-Wabern, Switzerland
| | - Faustino Gomez
- University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Adrian Knyziak
- Central Office of Measures (GUM), Elektoralna 2 Str., 00-139 Warsaw, Poland
| | - Celeste Fleta
- Instituto de Microelectrónica de Barcelona, Centro Nacional de Microelectrónica, IMB-CNM (CSIC), Barcelona, Spain
| | - Claude Bailat
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Andreas Schüller
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
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2
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Goddu SM, Hao Y, Ji Z, Setianegara J, Liu F, Green W, Sobotka LG, Zhao T, Perkins S, Darafsheh A. High spatiotemporal resolution scintillation imaging of pulsed pencil beam scanning proton beams produced by a gantry-mounted synchrocyclotron. Med Phys 2024; 51:4996-5006. [PMID: 38748998 DOI: 10.1002/mp.17116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/23/2024] [Accepted: 04/18/2024] [Indexed: 07/10/2024] Open
Abstract
BACKGROUND A dosimeter with high spatial and temporal resolution would be of significant interest for pencil beam scanning (PBS) proton beams' characterization, especially when facing small fields and beams with high temporal dynamics. Optical imaging of scintillators has potential in providing sub-millimeter spatial resolution with pulse-by-pulse basis temporal resolution when the imaging system is capable of operating in synchrony with the beam-producing accelerator. PURPOSE We demonstrate the feasibility of imaging PBS proton beams as they pass through a plastic scintillator detector to simultaneously obtain multiple beam parameters, including proton range, pencil beam's widths at different depths, spot's size, and spot's position on a pulse-by-pulse basis with sub-millimeter resolution. MATERIALS AND METHODS A PBS synchrocyclotron was used for proton irradiation. A BC-408 plastic scintillator block with 30 × 30 × 5 cm3 size, and another block with 30 × 30 × 0.5 cm3 size, positioned in an optically sealed housing, were used sequentially to measure the proton range, and spot size/location, respectively. A high-speed complementary metal-oxide-semiconductor (CMOS) camera system synchronized with the accelerator's pulses through a gating module was used for imaging. Scintillation images, captured with the camera directly facing the 5-cm-thick scintillator, were corrected for background (BG), and ionization quenching of the scintillator to obtain the proton range. Spots' position and size were obtained from scintillation images of the 0.5-cm-thick scintillator when a 45° mirror was used to reflect the scintillation light toward the camera. RESULTS Scintillation images with 0.16 mm/pixel resolution corresponding to all proton pulses were captured. Pulse-by-pulse analysis showed that variations of the range, spots' position, and size were within ± 0.2% standard deviation of their average values. The absolute ranges were within ± 1 mm of their expected values. The average spot-positions were mostly within ± 0.8 mm and spots' sigma agreed within 0.2 mm of the expected values. CONCLUSION Scintillation-imaging PBS beams with high-spatiotemporal resolution is feasible and may help in efficient and cost-effective acceptance testing and commissioning of existing and even emerging technologies such as FLASH, grid, mini-beams, and so forth.
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Affiliation(s)
- S Murty Goddu
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Yao Hao
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Zhen Ji
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Jufri Setianegara
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Fengwei Liu
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Winter Green
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Lee G Sobotka
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Tianyu Zhao
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Stephanie Perkins
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Arash Darafsheh
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
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Yamamoto S, Yamashita T, Yoshino M, Kamada K, Yoshikawa A, Nishio T, Kataoka J. Scintillation of polyester fabric and clothing via proton irradiation and its utilization in surface imaging of proton pencil beams. Sci Rep 2024; 14:13494. [PMID: 38866842 PMCID: PMC11169216 DOI: 10.1038/s41598-024-62456-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Accepted: 05/16/2024] [Indexed: 06/14/2024] Open
Abstract
In the realm of radiation therapy, a conspicuous obstacle lies in the dearth of external observation concerning radiation beams aimed at the patient. While real-time monitoring of such beams on the patient's surface during therapy holds promise, the imaging of particle beams has thus far proven to be a formidable task. Here, we show our discovery of polyester fabrics and cloths as auspicious scintillating materials, ideally suited for the visualization of radiation beams upon the patient's surface. The light output of polyester fabrics ranged from 10 to 20% of that observed in plastic scintillators. When exposed to spot scanning proton beams, clear beam spots emerged on the surface of the polyester cloths. The movement of these scanning beams was effectively captured using a CMOS camera in a light-shield-free with lights-off environment. The resulting images provided a means for evaluating spills of the proton beams. The inherent flexibility of polyester fabrics and clothing enhances their appeal for applications in the intricate landscape of radiation therapy, promising a bright future for surface beam imaging endeavors.
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Affiliation(s)
- Seiichi Yamamoto
- Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
| | | | - Masao Yoshino
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, Japan
| | - Kei Kamada
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, Japan
| | - Akira Yoshikawa
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, Japan
| | - Teiji Nishio
- Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Jun Kataoka
- Faculty of Science and Engineering, Waseda University, Tokyo, Japan
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Rajpurohit YS, Sharma DK, Lal M, Soni I. A perspective on tumor radiation resistance following high-LET radiation treatment. J Cancer Res Clin Oncol 2024; 150:226. [PMID: 38696003 PMCID: PMC11065934 DOI: 10.1007/s00432-024-05757-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 04/22/2024] [Indexed: 05/05/2024]
Abstract
High-linear energy transfer (LET) radiation is a promising alternative to conventional low-LET radiation for therapeutic gain against cancer owing to its ability to induce complex and clustered DNA lesions. However, the development of radiation resistance poses a significant barrier. The potential molecular mechanisms that could confer resistance development are translesion synthesis (TLS), replication gap suppression (RGS) mechanisms, autophagy, epithelial-mesenchymal transition (EMT) activation, release of exosomes, and epigenetic changes. This article will discuss various types of complex clustered DNA damage, their repair mechanisms, mutagenic potential, and the development of radiation resistance strategies. Furthermore, it highlights the importance of careful consideration and patient selection when employing high-LET radiotherapy in clinical settings.
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Affiliation(s)
- Yogendra Singh Rajpurohit
- Molecular Biology Division, Bhabha Atomic Research Centre, 2-46-S, Modular Lab, A-Block, Mumbai, 400085, India.
- Homi Bhabha National Institute, DAE- Deemed University, Mumbai, 400094, India.
| | - Dhirendra Kumar Sharma
- Molecular Biology Division, Bhabha Atomic Research Centre, 2-46-S, Modular Lab, A-Block, Mumbai, 400085, India
| | - Mitu Lal
- Molecular Biology Division, Bhabha Atomic Research Centre, 2-46-S, Modular Lab, A-Block, Mumbai, 400085, India
| | - Ishu Soni
- Homi Bhabha National Institute, DAE- Deemed University, Mumbai, 400094, India
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Vidal M, Gérard A, Floquet V, Forthomme J, Christensen JB, Almhagen E, Grusell E, Heymans V, Rossomme S, Dumas S, Trimaud R, Hérault J. Beam monitor chamber calibration of a synchro-cyclotron high dose rate per pulse pulsed scanned proton beam. Phys Med Biol 2024; 69:085016. [PMID: 38252970 DOI: 10.1088/1361-6560/ad2123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 01/22/2024] [Indexed: 01/24/2024]
Abstract
Objective. Ionization chambers, mostly used for beam calibration and for reference dosimetry, can show high recombination effects in pulsed high dose rate proton beams. The aims of this paper are: first, to characterize the linearity response of newly designed asymmetrical beam monitor chambers (ABMC) in a 100-226 MeV pulsed high dose rate per pulse scanned proton beam; and secondly, to calibrate the ABMC with a PPC05 (IBA Dosimetry) plane parallel ionization chamber and compare to calibration with a home-made Faraday cup (FC).Approach. The ABMC response linearity was evaluated with both the FC and a PTW 60019 microDiamond detector. Regarding ionometry-based ABMC calibration, recombination factors were evaluated theoretically, then numerically, and finally experimentally measured in water for a plane parallel ionization chamber PPC05 (IBA Dosimetry) throughkssaturation curves. Finally, ABMC calibration was also achieved with FC and compared to the ionometry method for 7 energies.Main results. Linearity measurements showed that recombination losses in the new ABMC design were well taken into account for the whole range of the machine dose rates. The two-voltage-method was not suitable for recombination correction, but Jaffé's plots analysis was needed, emphasizing the current IAEA TRS-398 reference protocol limitations. Concerning ABMC calibration, FC based absorbed dose estimation and PPC05-based absorbed dose estimation differ by less than 6.3% for the investigated energies.Significance.So far, no update on reference dosimetry protocols is available to estimate the absorbed dose in ionization chambers for clinical high dose rate per pulse pulsed scanned proton beams. This work proposes a validation of the new ABMC design, a method to take into account the recombination effect for ionometry-based ABMC calibration and a comparison with FC dose estimation in this type of proton beams.
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Affiliation(s)
- Marie Vidal
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
| | - Anaïs Gérard
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
| | - Vincent Floquet
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
| | | | - Jeppe Brage Christensen
- DTU Health Tech, Technical University of Denmark, Roskilde, Denmark
- Department of Radiation Safety and Security, Paul Scherrer Institute, PSI Villigen, Switzerland
| | - Erik Almhagen
- Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science-Skandion Clinics Uppsala, Sweden
| | - Erik Grusell
- Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science-Skandion Clinics Uppsala, Sweden
| | | | | | - Serge Dumas
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
| | - Richard Trimaud
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
| | - Joël Hérault
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
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Cengel KA, Kim MM, Diffenderfer ES, Busch TM. FLASH Radiotherapy: What Can FLASH's Ultra High Dose Rate Offer to the Treatment of Patients With Sarcoma? Semin Radiat Oncol 2024; 34:218-228. [PMID: 38508786 DOI: 10.1016/j.semradonc.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
FLASH is an emerging treatment paradigm in radiotherapy (RT) that utilizes ultra-high dose rates (UHDR; >40 Gy)/s) of radiation delivery. Developing advances in technology support the delivery of UHDR using electron and proton systems, as well as some ion beam units (eg, carbon ions), while methods to achieve UHDR with photons are under investigation. The major advantage of FLASH RT is its ability to increase the therapeutic index for RT by shifting the dose response curve for normal tissue toxicity to higher doses. Numerous preclinical studies have been conducted to date on FLASH RT for murine sarcomas, alongside the investigation of its effects on relevant normal tissues of skin, muscle, and bone. The tumor control achieved by FLASH RT of sarcoma models is indistinguishable from that attained by treatment with standard RT to the same total dose. FLASH's high dose rates are able to mitigate the severity or incidence of RT side effects on normal tissues as evaluated by endpoints ranging from functional sparing to histological damage. Large animal studies and clinical trials of canine patients show evidence of skin sparing by FLASH vs. standard RT, but also caution against delivery of high single doses with FLASH that exceed those safely applied with standard RT. Also, a human clinical trial has shown that FLASH RT can be delivered safely to bone metastasis. Thus, data to date support continued investigations of clinical translation of FLASH RT for the treatment of patients with sarcoma. Toward this purpose, hypofractionated irradiation schemes are being investigated for FLASH effects on sarcoma and relevant normal tissues.
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Affiliation(s)
- Keith A Cengel
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania..
| | - Michele M Kim
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Eric S Diffenderfer
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Theresa M Busch
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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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] [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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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] [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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9
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Liu K, Holmes S, Hooten B, Schüler E, Beddar S. Evaluation of ion chamber response for applications in electron FLASH radiotherapy. Med Phys 2024; 51:494-508. [PMID: 37696271 PMCID: PMC10840726 DOI: 10.1002/mp.16726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 08/08/2023] [Accepted: 08/23/2023] [Indexed: 09/13/2023] Open
Abstract
Ion chambers are required for calibration and reference dosimetry applications in radiation therapy (RT). However, exposure of ion chambers in ultra-high dose rate (UHDR) conditions pertinent to FLASH-RT leads to severe saturation and ion recombination, which limits their performance and usability. The purpose of this study was to comprehensively evaluate a set of commonly used commercially available ion chambers in RT, all with different design characteristics, and use this information to produce a prototype ion chamber with improved performance in UHDR conditions as a first step toward ion chambers specific for FLASH-RT. The Advanced Markus and Exradin A10, A26, and A20 ion chambers were evaluated. The chambers were placed in a water tank, at a depth of 2 cm, and exposed to an UHDR electron beam at different pulse repetition frequency (PRF), pulse width (PW), and pulse amplitude settings on an IntraOp Mobetron. Ion chamber responses were investigated for the various beam parameter settings to isolate their dependence on integrated dose, mean dose rate and instantaneous dose rate, dose-per-pulse (DPP), and their design features such as chamber type, bias voltage, and collection volume. Furthermore, a thin parallel-plate (TPP) prototype ion chamber with reduced collector plate separation and volume was constructed and equally evaluated as the other chambers. The charge collection efficiency of the investigated ion chambers decreased with increasing DPP, whereas the mean dose rate did not affect the response of the chambers (± 1%). The dependence of the chamber response on DPP was found to be solely related to the total dose within the pulse, and not on mean dose rate, PW, or instantaneous dose rate within the ranges investigated. The polarity correction factor (Ppol ) values of the TPP prototype, A10, and Advanced Markus chambers were found to be independent of DPP and dose rate (± 2%), while the A20 and A26 chambers yielded significantly larger variations and dependencies under the same conditions. Ion chamber performance evaluated under different irradiation conditions of an UHDR electron beam revealed a strong dependence on DPP and a negligible dependence on the mean and instantaneous dose rates. These results suggest that modifications to ion chambers design to improve their usability in UHDR beamlines should focus on minimizing DPP effects, with emphasis on optimizing the electric field strength, through the construction of smaller electrode separation and larger bias voltages. This was confirmed through the production and evaluation of a prototype ion chamber specifically designed with these characteristics.
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Affiliation(s)
- Kevin Liu
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
| | | | | | - Emil Schüler
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
| | - Sam Beddar
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
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Tan Y, Zhou S, Haefner J, Chen Q, Mazur TR, Darafsheh A, Zhang T. Simulation study of a novel small animal FLASH irradiator (SAFI) with integrated inverse-geometry CT based on circularly distributed kV X-ray sources. Sci Rep 2023; 13:20181. [PMID: 37978269 PMCID: PMC10656503 DOI: 10.1038/s41598-023-47421-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 11/14/2023] [Indexed: 11/19/2023] Open
Abstract
Ultra-high dose rate (UHDR) radiotherapy (RT) or FLASH-RT can potentially reduce normal tissue toxicity. A small animal irradiator that can deliver FLASH-RT treatments similar to clinical RT treatments is needed for pre-clinical studies of FLASH-RT. We designed and simulated a novel small animal FLASH irradiator (SAFI) based on distributed x-ray source technology. The SAFI system comprises a distributed x-ray source with 51 focal spots equally distributed on a 20 cm diameter ring, which are used for both FLASH-RT and onboard micro-CT imaging. Monte Carlo simulation was performed to estimate the dosimetric characteristics of the SAFI treatment beams. The maximum dose rate, which is limited by the power density of the tungsten target, was estimated based on finite-element analysis (FEA). The maximum DC electron beam current density is 2.6 mA/mm2, limited by the tungsten target's linear focal spot power density. At 160 kVp, 51 focal spots, each with a dimension of [Formula: see text] mm2 and 10° anode angle, can produce up to 120 Gy/s maximum DC irradiation at the center of a cylindrical water phantom. We further demonstrate forward and inverse FLASH-RT planning, as well as inverse-geometry micro-CT with circular source array imaging via numerical simulations.
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Affiliation(s)
- Yuewen Tan
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
- Department of Physics, Washington University in St. Louis, St. Louis, MO, 63130, USA
- Center for Radiological Research, Columbia University, New York, NY, 10032, USA
| | - Shuang Zhou
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Jonathan Haefner
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Qinghao Chen
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Thomas R Mazur
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Arash Darafsheh
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Tiezhi Zhang
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA.
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11
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Siddique S, Ruda HE, Chow JCL. FLASH Radiotherapy and the Use of Radiation Dosimeters. Cancers (Basel) 2023; 15:3883. [PMID: 37568699 PMCID: PMC10417829 DOI: 10.3390/cancers15153883] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 07/27/2023] [Accepted: 07/27/2023] [Indexed: 08/13/2023] Open
Abstract
Radiotherapy (RT) using ultra-high dose rate (UHDR) radiation, known as FLASH RT, has shown promising results in reducing normal tissue toxicity while maintaining tumor control. However, implementing FLASH RT in clinical settings presents technical challenges, including limited depth penetration and complex treatment planning. Monte Carlo (MC) simulation is a valuable tool for dose calculation in RT and has been investigated for optimizing FLASH RT. Various MC codes, such as EGSnrc, DOSXYZnrc, and Geant4, have been used to simulate dose distributions and optimize treatment plans. Accurate dosimetry is essential for FLASH RT, and radiation detectors play a crucial role in measuring dose delivery. Solid-state detectors, including diamond detectors such as microDiamond, have demonstrated linear responses and good agreement with reference detectors in UHDR and ultra-high dose per pulse (UHDPP) ranges. Ionization chambers are commonly used for dose measurement, and advancements have been made to address their response nonlinearities at UHDPP. Studies have proposed new calculation methods and empirical models for ion recombination in ionization chambers to improve their accuracy in FLASH RT. Additionally, strip-segmented ionization chamber arrays have shown potential for the experimental measurement of dose rate distribution in proton pencil beam scanning. Radiochromic films, such as GafchromicTM EBT3, have been used for absolute dose measurement and to validate MC simulation results in high-energy X-rays, triggering the FLASH effect. These films have been utilized to characterize ionization chambers and measure off-axis and depth dose distributions in FLASH RT. In conclusion, MC simulation provides accurate dose calculation and optimization for FLASH RT, while radiation detectors, including diamond detectors, ionization chambers, and radiochromic films, offer valuable tools for dosimetry in UHDR environments. Further research is needed to refine treatment planning techniques and improve detector performance to facilitate the widespread implementation of FLASH RT, potentially revolutionizing cancer treatment.
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Affiliation(s)
- Sarkar Siddique
- Department of Physics, Toronto Metropolitan University, Toronto, ON M5B 2K3, Canada;
| | - Harry E. Ruda
- Centre of Advance Nanotechnology, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON M5S 3E4, Canada;
- Department of Materials Science and Engineering, University of Toronto, Toronto, ON M5S 3E4, Canada
| | - James C. L. Chow
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1X6, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON M5T 1P5, Canada
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12
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Yamamoto S, Yabe T, Akagi T, Yamaguchi M, Kawachi N, Kamada K, Yoshikawa A, Kataoka J. Prompt X-ray imaging during irradiation with spread-out Bragg peak (SOBP) beams of carbon ions. Phys Med 2023; 109:102592. [PMID: 37084677 DOI: 10.1016/j.ejmp.2023.102592] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 04/07/2023] [Accepted: 04/13/2023] [Indexed: 04/23/2023] Open
Abstract
Prompt secondary electron bremsstrahlung X-ray (prompt X-ray) imaging using a low-energy X-ray camera is a promising method for observing a beam shape from outside the subject. However, such imaging has so far been conducted only for pencil beams without a multi-leaf collimator (MLC). The use of spread-out Bragg peak (SOBP) with an MLC may increase the scattered prompt gamma photons and decrease the contrast of the images of prompt X-rays. Consequently, we performed prompt X-ray imaging of SOBP beams formed with an MLC. This imaging was carried out in list mode during irradiation of SOBP beams to a water phantom. An X-ray camera with a 1.5-mm diameter as well as 4-mm-diameter pinhole collimators was used for the imaging. List mode data were sorted to obtain the SOBP beam images as well as energy spectra and time count rate curves. Due to the high background counts from the scattered prompt gamma photons penetrating the tungsten shield of the X-ray camera, the SOBP beam shapes were difficult to observe with a 1.5-mm-diameter pinhole collimator. With the 4-mm-diameter pinhole collimators, images of SOBP beam shapes at clinical dose levels could be obtained with the X-ray camera. The use of a 4-mm-diameter pinhole collimator attached to the X-ray camera is effective for prompt X-ray imaging with high sensitivity and low background counts. This approach makes it possible to image SOBP beams with an MLC when the counts are low and the background levels are high.
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Affiliation(s)
| | - Takuya Yabe
- Takasaki Institute of Advanced Quantum Science, Foundational Quantum Technology Research Directorate, National Institutes for Quantum Science and Technology (QST), Japan
| | | | - Mitsutaka Yamaguchi
- Takasaki Institute of Advanced Quantum Science, Foundational Quantum Technology Research Directorate, National Institutes for Quantum Science and Technology (QST), Japan
| | - Naoki Kawachi
- Takasaki Institute of Advanced Quantum Science, Foundational Quantum Technology Research Directorate, National Institutes for Quantum Science and Technology (QST), Japan
| | - Kei Kamada
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Japan
| | - Akira Yoshikawa
- New Industry Creation Hatchery Center (NICHe), Tohoku University, Japan
| | - Jun Kataoka
- Faculty of Science and Engineering, Waseda University, Japan
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13
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Schulte R, Johnstone C, Boucher S, Esarey E, Geddes CGR, Kravchenko M, Kutsaev S, Loo BW, Méot F, Mustapha B, Nakamura K, Nanni EA, Obst-Huebl L, Sampayan SE, Schroeder CB, Sheng K, Snijders AM, Snively E, Tantawi SG, Van Tilborg J. Transformative Technology for FLASH Radiation Therapy. APPLIED SCIENCES (BASEL, SWITZERLAND) 2023; 13:5021. [PMID: 38240007 PMCID: PMC10795821 DOI: 10.3390/app13085021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2024]
Abstract
The general concept of radiation therapy used in conventional cancer treatment is to increase the therapeutic index by creating a physical dose differential between tumors and normal tissues through precision dose targeting, image guidance, and radiation beams that deliver a radiation dose with high conformality, e.g., protons and ions. However, the treatment and cure are still limited by normal tissue radiation toxicity, with the corresponding side effects. A fundamentally different paradigm for increasing the therapeutic index of radiation therapy has emerged recently, supported by preclinical research, and based on the FLASH radiation effect. FLASH radiation therapy (FLASH-RT) is an ultra-high-dose-rate delivery of a therapeutic radiation dose within a fraction of a second. Experimental studies have shown that normal tissues seem to be universally spared at these high dose rates, whereas tumors are not. While dose delivery conditions to achieve a FLASH effect are not yet fully characterized, it is currently estimated that doses delivered in less than 200 ms produce normal-tissue-sparing effects, yet effectively kill tumor cells. Despite a great opportunity, there are many technical challenges for the accelerator community to create the required dose rates with novel compact accelerators to ensure the safe delivery of FLASH radiation beams.
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Affiliation(s)
- Reinhard Schulte
- Division of Biomedical Engineering Sciences, Loma Linda University, Loma Linda, CA 92350, USA
| | - Carol Johnstone
- Fermi National Accelerator Laboratory, Batavia, IL 60510, USA
| | - Salime Boucher
- RadiaBeam Technologies, LLC, Santa Monica, CA 90404, USA
| | - Eric Esarey
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | | | - Sergey Kutsaev
- RadiaBeam Technologies, LLC, Santa Monica, CA 90404, USA
| | - Billy W. Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - François Méot
- Brookhaven National Laboratory, Upton, NY 11973, USA
| | | | - Kei Nakamura
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Emilio A. Nanni
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | | | - Stephen E. Sampayan
- Lawrence Livermore National Laboratory, Livermore, CA 94551, USA
- Opcondys, Inc., Manteca, CA 95336, USA
| | | | - Ke Sheng
- Department of Radiation Oncology, University of California, San Francisco, CA 94115, USA
| | | | - Emma Snively
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Sami G. Tantawi
- SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
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14
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Ion recombination correction factors and detector comparison in a very-high dose rate proton scanning beam. Phys Med 2023; 106:102518. [PMID: 36638707 DOI: 10.1016/j.ejmp.2022.102518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 12/09/2022] [Accepted: 12/27/2022] [Indexed: 01/13/2023] Open
Abstract
PURPOSE Accurate dosimetry is paramount to study the FLASH biological effect since dose and dose rate are critical dosimetric parameters governing its underlying mechanisms. With the goal of assessing the suitability of standard clinical dosimeters in a very-high dose rate (VHDR) experimental setup, we evaluated the ion collection efficiency of several commercially available air-vented ionization chambers (IC) in conventional and VHDR proton irradiation conditions. METHODS A cyclotron at the Orsay Proton Therapy Center was used to deliver VHDR pencil beam scanning irradiation. Ion recombination correction factors (ks) were determined for several detectors (Advanced Markus, PPC05, Nano Razor, CC01) at the entrance of the plateau and at the Bragg peak, using the Niatel model, the Two-voltage method and Boag's analytical formula for continuous beams. RESULTS Mean dose rates ranged from 4 Gy/s to 385 Gy/s, and instantaneous dose rates up to 1000 Gy/s were obtained with the experimental set-up. Recombination correction factors below 2 % were obtained for all chambers, except for the Nano Razor, at VHDRs with variations among detectors, while ks values were significantly smaller (0.8 %) for conventional dose rates. CONCLUSIONS While the collection efficiency of the probed ICs in scanned VHDR proton therapy is comparable to those in the conventional regime with recombination coefficiens smaller than 1 % for mean dose rates up to 177 Gy/s, the reduction in collection efficiency for higher dose rates cannot be ignored when measuring the absorbed dose in pre-clinical proton scanned FLASH experiments and clinical trials.
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15
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Liu R, Charyyev S, Wahl N, Liu W, Kang M, Zhou J, Yang X, Baltazar F, Palkowitsch M, Higgins K, Dynan W, Bradley J, Lin L. An Integrated Physical Optimization Framework for Proton Stereotactic Body Radiation Therapy FLASH Treatment Planning Allows Dose, Dose Rate, and Linear Energy Transfer Optimization Using Patient-Specific Ridge Filters. Int J Radiat Oncol Biol Phys 2023:S0360-3016(23)00097-4. [PMID: 36736634 DOI: 10.1016/j.ijrobp.2023.01.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 01/04/2023] [Accepted: 01/21/2023] [Indexed: 02/04/2023]
Abstract
PURPOSE Patient-specific ridge filters provide a passive means to modulate proton energy to obtain a conformal dose. Here we describe a new framework for optimization of filter design and spot maps to meet the unique demands of ultrahigh-dose-rate (FLASH) radiation therapy. We demonstrate an integrated physical optimization Intensity-modulated proton therapy (IMPT) (IPO-IMPT) approach for optimization of dose, dose-averaged dose rate (DADR), and dose-averaged linear energy transfer (LETd). METHODS AND MATERIALS We developed an inverse planning software to design patient-specific ridge filters that spread the Bragg peak from a fixed-energy, 250-MeV beam to a proximal beam-specific planning target volume. The software defines patient-specific ridge filter pin shapes and uses a Monte Carlo calculation engine, based on Geant4, to provide dose and LET influence matrices. Plan optimization, using matRAD, accommodates the IPO-IMPT objective function considering dose, dose rate, and LET simultaneously with minimum monitor unit constraints. The framework enables design of both regularly spaced and sparse-optimized ridge filters, from which some pins are omitted to allow faster delivery and selective LET optimization. To demonstrate the framework, we designed ridge filters for 3 example patients with lung cancer and optimized the plans using IPO-IMPT. RESULTS The IPO-IMPT framework selectively spared the organs at risk by reducing LET and increasing dose rate, relative to IMPT planning. Sparse-optimized ridge filters were superior to regularly spaced ridge filters in dose rate. Depending on which parameter is prioritized, volume distributions and histograms for dose, DADR, and LETd, using evaluation structures specific to heart, lung, and esophagus, show high levels of FLASH dose-rate coverage and/or reduced LETd, while maintaining dose coverage within the beam specific planning target volume. CONCLUSIONS This proof-of-concept study demonstrates the feasibility of using an IPO-IMPT framework to accomplish proton FLASH stereotactic body proton therapy, accounting for dose, DADR, and LETd simultaneously.
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Affiliation(s)
- Ruirui Liu
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Serdar Charyyev
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Niklas Wahl
- German Cancer Research Center - DKFZ, Department of Medical Physics in Radiation Oncology, Heidelberg, Germany; Heidelberg Institute for Radiation Oncology - HIRO, Heidelberg, Germany
| | - Wei Liu
- Department of Radiation Oncology, Mayo Clinic, Phoenix, Arizona
| | | | - Jun Zhou
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Xiaofeng Yang
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Filipa Baltazar
- German Cancer Research Center - DKFZ, Department of Medical Physics in Radiation Oncology, Heidelberg, Germany; Instituto SuperiorTécnico, Universidade de Lisboa, Lisbon, Portugal
| | - Martina Palkowitsch
- German Cancer Research Center - DKFZ, Department of Medical Physics in Radiation Oncology, Heidelberg, Germany; Heidelberg Institute for Radiation Oncology - HIRO, Heidelberg, Germany; Atominstitut, TU Wien, Vienna, Austria
| | - Kristin Higgins
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - William Dynan
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Jeffrey Bradley
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Liyong Lin
- Department of Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, Georgia.
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16
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Calvo FA, Ayestaran A, Serrano J, Cambeiro M, Palma J, Meiriño R, Morcillo MA, Lapuente F, Chiva L, Aguilar B, Azcona D, Pedrero D, Pascau J, Delgado JM, Aristu J, Prezado Y. Practice-oriented solutions integrating intraoperative electron irradiation and personalized proton therapy for recurrent or unresectable cancers: Proof of concept and potential for dual FLASH effect. Front Oncol 2022; 12:1037262. [PMID: 36452493 PMCID: PMC9703091 DOI: 10.3389/fonc.2022.1037262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 10/26/2022] [Indexed: 11/15/2022] Open
Abstract
Background Oligo-recurrent disease has a consolidated evidence of long-term surviving patients due to the use of intense local cancer therapy. The latter combines real-time surgical exploration/resection with high-energy electron beam single dose of irradiation. This results in a very precise radiation dose deposit, which is an essential element of contemporary multidisciplinary individualized oncology. Methods Patient candidates to proton therapy were evaluated in Multidisciplinary Tumor Board to consider improved treatment options based on the institutional resources and expertise. Proton therapy was delivered by a synchrotron-based pencil beam scanning technology with energy levels from 70.2 to 228.7 MeV, whereas intraoperative electrons were generated in a miniaturized linear accelerator with dose rates ranging from 22 to 36 Gy/min (at Dmax) and energies from 6 to 12 MeV. Results In a period of 24 months, 327 patients were treated with proton therapy: 218 were adults, 97 had recurrent cancer, and 54 required re-irradiation. The specific radiation modalities selected in five cases included an integral strategy to optimize the local disease management by the combination of surgery, intraoperative electron boost, and external pencil beam proton therapy as components of the radiotherapy management. Recurrent cancer was present in four cases (cervix, sarcoma, melanoma, and rectum), and one patient had a primary unresectable locally advanced pancreatic adenocarcinoma. In re-irradiated patients (cervix and rectum), a tentative radical total dose was achieved by integrating beams of electrons (ranging from 10- to 20-Gy single dose) and protons (30 to 54-Gy Relative Biological Effectiveness (RBE), in 10-25 fractions). Conclusions Individual case solution strategies combining intraoperative electron radiation therapy and proton therapy for patients with oligo-recurrent or unresectable localized cancer are feasible. The potential of this combination can be clinically explored with electron and proton FLASH beams.
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Affiliation(s)
- Felipe A Calvo
- Department of Radiation Oncology, Clinica Universidad de Navarra, Madrid, Spain
| | - Adriana Ayestaran
- Department of Radiation Oncology, Clinica Universidad de Navarra, Madrid, Spain
| | - Javier Serrano
- Department of Radiation Oncology, Clinica Universidad de Navarra, Madrid, Spain
| | - Mauricio Cambeiro
- Department of Radiation Oncology, Clinica Universidad de Navarra, Madrid, Spain
| | - Jacobo Palma
- Department of Radiation Oncology, Clinica Universidad de Navarra, Madrid, Spain
| | - Rosa Meiriño
- Department of Radiation Oncology, Clinica Universidad de Navarra, Madrid, Spain
| | - Miguel A Morcillo
- Medical Applications Unit, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
| | - Fernando Lapuente
- Department of Surgery, Clinica Universidad de Navarra, Madrid, Spain
| | - Luis Chiva
- Department of Gynecology and Obstretics, Clinica Universidad de Navarra, Madrid, Spain
| | - Borja Aguilar
- Department of Medical Physics, Clinica Universidad de Navarra, Madrid, Spain
| | - Diego Azcona
- Department of Medical Physics, Clinica Universidad de Navarra, Madrid, Spain
| | - Diego Pedrero
- Department of Medical Physics, Clinica Universidad de Navarra, Madrid, Spain
| | - Javier Pascau
- Department of Bioengineering and Aerospace Engineering, Universidad Carlos III de Madrid, Madrid, Spain
| | - José Miguel Delgado
- Department of Radiation Oncology, Clinica Universidad de Navarra, Madrid, Spain
| | - Javier Aristu
- Department of Radiation Oncology, Clinica Universidad de Navarra, Madrid, Spain
| | - Yolanda Prezado
- Translational Research Department. Institut Curie, Université PSL, CNRS UMR, Inserm, Signalisation, Radiobiologie et Cancer, Orsay, France.,Université Paris-Saclay, CNRS UMR, Inserm, Signalisation, Radiobiologie et Cancer, Orsay, France
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17
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Schneider T, Fernandez-Palomo C, Bertho A, Fazzari J, Iturri L, Martin OA, Trappetti V, Djonov V, Prezado Y. Combining FLASH and spatially fractionated radiation therapy: The best of both worlds. Radiother Oncol 2022; 175:169-177. [PMID: 35952978 DOI: 10.1016/j.radonc.2022.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/23/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022]
Abstract
FLASH radiotherapy (FLASH-RT) and spatially fractionated radiation therapy (SFRT) are two new therapeutical strategies that use non-standard dose delivery methods to reduce normal tissue toxicity and increase the therapeutic index. Although likely based on different mechanisms, both FLASH-RT and SFRT have shown to elicit radiobiological effects that significantly differ from those induced by conventional radiotherapy. With the therapeutic potential having been established separately for each technique, the combination of FLASH-RT and SFRT could therefore represent a winning alliance. In this review, we discuss the state of the art, advantages and current limitations, potential synergies, and where a combination of these two techniques could be implemented today or in the near future.
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Affiliation(s)
- Tim Schneider
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | | | - Annaïg Bertho
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Jennifer Fazzari
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - Lorea Iturri
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
| | - Olga A Martin
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland; Division of Radiation Oncology, Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia; University of Melbourne, Parkville, VIC 3010, Australia
| | - Verdiana Trappetti
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - Valentin Djonov
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France; Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France.
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18
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Wang Q, Titt U, Mohan R, Guan F, Zhao Y, Yang M, Yepes P. Optimization of FLASH Proton Beams Using a Track-Repeating Algorithm. Med Phys 2022; 49:6684-6698. [PMID: 35900902 DOI: 10.1002/mp.15849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 05/16/2022] [Accepted: 06/23/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Radiation with high dose rate (FLASH) has shown to reduce toxicities to normal tissues around the target and maintain tumor control with the same amount of dose compared to conventional radiation. This phenomenon has been widely studied in electron therapy, which is often used for shallow tumor treatment. Proton therapy is considered as a more suitable treatment modality for deep-seated tumors. The feasibility of FLASH proton therapy has recently been demonstrated by a series of pre- and clinical trials. One of the challenges is to efficiently generate wide enough dose distributions in both lateral and longitudinal directions to cover the entire tumor volume. The goal of this paper is to introduce a set of automatic FLASH proton beam optimization algorithms developed recently. PURPOSE To develop a fast and efficient optimizer for the design of a passive scattering proton FLASH radiotherapy delivery at The University of Texas M. D. Anderson Proton Therapy Center, based on the Fast Dose Calculator (FDC). METHODS A track repeating algorithm, FDC, was validated vs. Geant4 simulations and applied to calculate dose distributions in various beamline setups. The design of the components was optimized to deliver homogeneous fields with well-defined diameters between 11.0 mm and 20.5 mm, as well as a spread-out Bragg peak (SOBP) with modulations between 8.5 and 39.0 mm. A ridge filter, a high-Z material scatterer, and a collimator with range compensator were inserted in the beam path, and their shapes and sizes were optimized to spread out the Bragg peak, widen the beam, and reduce the penumbra. The optimizer was developed and tested using two proton energies (87.0 MeV and 159.5 MeV) in a variety of beam line arrangements. Dose rates of the optimized beams were estimated by scaling their doses to those of unmodified beams. RESULTS The optimized 87.0 MeV beams, with a distance from the beam pipe window to the phantom surface (window-to-surface distance) of 550 mm, produced an 8.5-mm-wide spread-out Bragg peak (proximal 90% to distal 90% of the maximum dose); 14.5 mm, 12.0 mm, and 11.0 mm lateral widths at the 50%, 80%, and 90% dose location, respectively; and a 2.5 mm penumbra from 80% to 20% in the lateral profile. The 159.5 MeV beam had a SOBP of 39.0 mm and lateral widths of 20.5 mm, 15.0 mm, and 12.5 mm at 50%, 80%, and 90% dose location, respectively, when the window-to-surface distance (WSD) was 550 mm. Wider lateral widths were obtained with increased WSD. The SOBP modulations changed when the ridge filters with different characteristics were inserted. Dose rates on the beam central axis for all optimized beams (other than the 87.0 MeV beam with 2000 mm-WSD) were above that needed for the FLASH effect threshold (40 Gy/s) except at the very end of the depth dose profile scaling with a dose rate of 1400 Gy/s at the Bragg peak in the unmodified beams. The optimizer was able to instantly design the individual beamline components for each of the beam line setups, without the need of time intensive iterative simulations. CONCLUSION An efficient system, consisting of an optimizer and a Fast Dose Calculator have been developed and validated in a variety of beam line setups, comprising two proton energies, several WSDs and SOBPs. The set of automatic optimization algorithms produces beam shaping element designs efficiently and with excellent quality. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Qianxia Wang
- Department of Physics and Astronomy, MS 315, Rice University, 6100 Main St., Houston, TX, 77005, United States.,Department of Radiation Physics, Unit 1420, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, United States
| | - Uwe Titt
- Department of Radiation Physics, Unit 1420, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, United States
| | - Radhe Mohan
- Department of Radiation Physics, Unit 1420, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, United States
| | - Fada Guan
- Department of Radiation Physics, Unit 1420, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, United States.,Department of Therapeutic Radiology, Yale School of Medicine, 35 Park St., New Haven, CT, 06511, United States
| | - Yao Zhao
- Department of Radiation Physics, Unit 1420, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, United States.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, 77030, United States
| | - Ming Yang
- Department of Radiation Physics, Unit 1420, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, United States
| | - Pablo Yepes
- Department of Physics and Astronomy, MS 315, Rice University, 6100 Main St., Houston, TX, 77005, United States.,Department of Radiation Physics, Unit 1420, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, United States
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19
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Lee E, Lourenço AM, Speth J, Lee N, Subiel A, Romano F, Thomas R, Amos RA, Zhang Y, Xiao Z, Mascia A. Ultra-high dose rate pencil beam scanning proton dosimetry using ion chambers and a calorimeter in support of first in-human flash clinical trial. Med Phys 2022; 49:6171-6182. [PMID: 35780318 PMCID: PMC9546035 DOI: 10.1002/mp.15844] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 06/20/2022] [Accepted: 06/27/2022] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To provide ultra-high dose rate pencil beam scanning proton dosimetry comparison of clinically used plane-parallel ion chambers, PTW Advanced Markus and IBA PPC05, with a proton graphite calorimeter in support of first in-human proton FLASH clinical trial. METHODS Absolute dose measurement intercomparison of the plane-parallel plate ion chambers and the proton graphite calorimeter was performed at 5 cm water equivalent depth using rectangular 250 MeV single layer treatment plans designed for the first in-human FLASH clinical trial. The dose rate for each field was designed to remain above 60 Gy/s. The ion recombination effects of the plane-parallel plate ion chambers at various bias voltages were also investigated in the range of dose rates between 5 - 60 Gy/s. Two independent model-based extrapolation methods were used to calculate the ion recombination correction factors ks to compare with the two-voltage technique from most widely used clinical protocols. RESULTS The mean measured dose to water with the proton graphite calorimeter across all the pre-defined fields is 7.702 ± 0.037 Gy. The average ratio over the pre-defined fields of the PTW Advanced Markus chamber dose to the calorimeter reference dose is 1.002 ± 0.007 while the IBA PPC05 chamber shows ∼3% higher reading of 1.033 ± 0.007. The relative difference in the ks values determined from between the linear and quadratic extrapolation methods and the two-voltage technique for the PTW Advanced Markus chamber are not statistically significant and the trends of dose rate dependence are similar. The IBA PPC05 shows a flat response in terms of ion recombination effects based on the ks values calculated using the two-voltage technique. Differences in ks values for the PPC05 between the two-voltage technique and other model-based extrapolation methods are not statistically significant at FLASH dose rates. Some of the ks values for the PPC05 that were extrapolated from the three-voltage linear method and the semi-empirical model were reported less than unity possibly due to the charge multiplication effect, which was negligible compared to the volume recombination effect in FLASH dose rates. CONCLUSIONS The absolute dose measurements of both PTW Advanced Markus and IBA PPC05 chambers are in a good agreement with the NPL graphite calorimeter reference dose considering overall uncertainties. Both ion chambers also demonstrate good reproducibility as well as stability as refence dosimeters in ultra-high dose rate pencil beam scanning proton radiotherapy. The dose rate dependency of the ion recombination effects of both ion chambers in cyclotron generated PBS proton beams is acceptable and therefore, both chambers are suitable to use in clinical practice for the range of dose rates between 5 - 60 Gy/s. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Eunsin Lee
- Department of Radiation OncologyUniversity of CincinnatiCincinnatiOhioUSA
- Cincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
| | - Ana Mónica Lourenço
- National Physical LaboratoryMedical Science GroupTeddingtonUK
- Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonUK
| | - Joseph Speth
- University of Cincinnati Medical CenterCincinnatiOhioUSA
| | - Nigel Lee
- National Physical LaboratoryMedical Science GroupTeddingtonUK
| | - Anna Subiel
- National Physical LaboratoryMedical Science GroupTeddingtonUK
| | - Francesco Romano
- Istituto Nazionale di Fisica NucleareSezione di CataniaCataniaItaly
| | - Russell Thomas
- National Physical LaboratoryMedical Science GroupTeddingtonUK
- Faculty of Engineering and Physical ScienceUniversity of SurreyGuildfordSurreyUK
| | - Richard A. Amos
- Department of Medical Physics and Biomedical EngineeringUniversity College LondonLondonUK
| | - Yongbin Zhang
- Department of Radiation OncologyUniversity of CincinnatiCincinnatiOhioUSA
- Cincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
| | - Zhiyan Xiao
- Department of Radiation OncologyUniversity of CincinnatiCincinnatiOhioUSA
- Cincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
| | - Anthony Mascia
- Department of Radiation OncologyUniversity of CincinnatiCincinnatiOhioUSA
- Cincinnati Children's Hospital Medical CenterCincinnatiOhioUSA
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20
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Goddu SM, Westphal GT, Sun B, Wu Y, Bloch CD, Bradley JD, Darafsheh A. Synchronized high-speed scintillation imaging of proton beams, generated by a gantry-mounted synchrocyclotron, on a pulse-by-pulse basis. Med Phys 2022; 49:6209-6220. [PMID: 35760763 DOI: 10.1002/mp.15826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/09/2022] [Accepted: 06/09/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND With the emergence of more complex and novel proton delivery techniques, there is a need for quality assurance (QA) tools with high spatiotemporal resolution to conveniently measure the spatial and temporal properties of the beam. In this context, scintillation-based dosimeters, if synchronized with the radiation beam and corrected for ionization quenching, are appealing. PURPOSE To develop a synchronized high-speed scintillation imaging system for characterization and verification of the proton therapy beams on a pulse-by-pulse basis. MATERIALS AND METHODS A 30 cm × 30 cm × 5 cm block of BC-408 plastic scintillator placed in a light-tight housing was irradiated by proton beams generated by a Mevion S250TM proton therapy synchrocyclotron. A high-speed camera system, placed perpendicular to the beam direction and facing the scintillator, was synchronized to the accelerator's pulses to capture images. Opening and closing of the camera's shutter was controlled by setting a proper time delay and exposure time, respectively. The scintillation signal was recorded as a set of two-dimensional (2D) images. Empirical correction factors were applied to the images to correct for the non-uniformity of the pixel sensitivity and quenching of the scintillator. Proton range and modulation were obtained from the corrected images. RESULTS The camera system was able to capture all data on a pulse-by-pulse basis at a rate of ∼504 frames per second. The applied empirical correction method for ionization quenching was effective and the corrected composite image provided a 2D map of dose distribution. The measured range (depth of distal 90%) through scintillation imaging agreed within 1.2 mm with that obtained from ionization chamber measurement. CONCLUSION A high-speed camera system capable of capturing scintillation signals from individual proton pulses was developed. The scintillation imaging system is promising for rapid proton beam characterization and verification. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- S Murty Goddu
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | | | - Baozhou Sun
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Yu Wu
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Charles D Bloch
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, WA, 98133, USA
| | - Jeffrey D Bradley
- Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA, 30308, USA
| | - Arash Darafsheh
- Department of Radiation Oncology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
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21
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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] [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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22
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Farr J, Grilj V, Malka V, Sudharsan S, Schippers M. Ultra‐High dose rate radiation production and delivery systems intended for FLASH. Med Phys 2022; 49:4875-4911. [PMID: 35403262 PMCID: PMC9544515 DOI: 10.1002/mp.15659] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 02/21/2022] [Accepted: 03/15/2022] [Indexed: 11/05/2022] Open
Abstract
Higher dose rates, a trend for radiotherapy machines, can be beneficial in shortening treatment times for radiosurgery and mitigating the effects of motion. Recently, even higher doses (e.g., 100 times greater) have become targeted because of their potential to generate the FLASH effect (FE). We refer to these physical dose rates as ultra‐high (UHDR). The complete relationship between UHDR and the FE is unknown. But UHDR systems are needed to explore the relationship further and to deliver clinical UHDR treatments, where indicated. Despite the challenging set of unknowns, the authors seek to make reasonable assumptions to probe how existing and developing technology can address the UHDR conditions needed to provide beam generation capable of producing the FE in preclinical and clinical applications. As a preface, this paper discusses the known and unknown relationships between UHDR and the FE. Based on these, different accelerator and ionizing radiation types are then discussed regarding the relevant UHDR needs. The details of UHDR beam production are discussed for existing and potential future systems such as linacs, cyclotrons, synchrotrons, synchrocyclotrons, and laser accelerators. In addition, various UHDR delivery mechanisms are discussed, along with required developments in beam diagnostics and dose control systems.
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Affiliation(s)
- Jonathan Farr
- Applications of Detectors and Accelerators to Medicine Meyrin 1217 Switzerland
| | - Veljko Grilj
- Lausanne University Hospital Lausanne 1011 Switzerland
| | - Victor Malka
- Weizmann Institute of Science Rehovot 7610001 Israel
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23
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Romano F, Bailat C, Jorge PG, Lerch MLF, Darafsheh A. Ultra‐high dose rate dosimetry: challenges and opportunities for FLASH radiation therapy. Med Phys 2022; 49:4912-4932. [PMID: 35404484 PMCID: PMC9544810 DOI: 10.1002/mp.15649] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 02/03/2022] [Accepted: 02/20/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Francesco Romano
- Istituto Nazionale di Fisica Nucleare Sezione di Catania Catania Italy
| | - Claude Bailat
- Institute of Radiation Physics Lausanne University Hospital Lausanne University Switzerland
| | - Patrik Gonçalves Jorge
- Institute of Radiation Physics Lausanne University Hospital Lausanne University Switzerland
- Department of Radiation Oncology Lausanne University Hospital Lausanne Switzerland
- Radio‐Oncology Laboratory DO/CHUV Lausanne University Hospital Lausanne Switzerland
| | | | - Arash Darafsheh
- Department of Radiation Oncology Washington University School of Medicine St. Louis MO 63110 USA
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24
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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] [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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25
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Key biological mechanisms involved in high-LET radiation therapies with a focus on DNA damage and repair. Expert Rev Mol Med 2022; 24:e15. [PMID: 35357290 DOI: 10.1017/erm.2022.6] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
DNA damage and repair studies are at the core of the radiation biology field and represent also the fundamental principles informing radiation therapy (RT). DNA damage levels are a function of radiation dose, whereas the type of damage and biological effects such as DNA damage complexity, depend on radiation quality that is linear energy transfer (LET). Both levels and types of DNA damage determine cell fate, which can include necrosis, apoptosis, senescence or autophagy. Herein, we present an overview of current RT modalities in the light of DNA damage and repair with emphasis on medium to high-LET radiation. Proton radiation is discussed along with its new adaptation of FLASH RT. RT based on α-particles includes brachytherapy and nuclear-RT, that is proton-boron capture therapy (PBCT) and boron-neutron capture therapy (BNCT). We also discuss carbon ion therapy along with combinatorial immune-based therapies and high-LET RT. For each RT modality, we summarise relevant DNA damage studies. Finally, we provide an update of the role of DNA repair in high-LET RT and we explore the biological responses triggered by differential LET and dose.
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26
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Diffenderfer ES, Sørensen BS, Mazal A, Carlson DJ. The current status of preclinical proton FLASH radiation and future directions. Med Phys 2021; 49:2039-2054. [PMID: 34644403 DOI: 10.1002/mp.15276] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 09/12/2021] [Accepted: 09/17/2021] [Indexed: 11/05/2022] Open
Abstract
We review the current status of proton FLASH experimental systems, including preclinical physical and biological results. Technological limitations on preclinical investigation of FLASH biological mechanisms and determination of clinically relevant parameters are discussed. A review of the biological data reveals no reproduced proton FLASH effect in vitro and a significant in vivo FLASH sparing effect of normal tissue toxicity observed with multiple proton FLASH irradiation systems. Importantly, multiple studies suggest little or no difference in tumor growth delay for proton FLASH when compared to conventional dose rate proton radiation. A discussion follows on future areas of development with a focus on the determination of the optimal parameters for maximizing the therapeutic ratio between tumor and normal tissue response and ultimately clinical translation of proton FLASH radiation.
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Affiliation(s)
- Eric S Diffenderfer
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Brita S Sørensen
- Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark.,Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Alejandro Mazal
- Department of Medical Physics, Centro de Protonterapia Quironsalud, Madrid, Spain
| | - David J Carlson
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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27
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Comparison of FLASH Proton Entrance and the Spread-Out Bragg Peak Dose Regions in the Sparing of Mouse Intestinal Crypts and in a Pancreatic Tumor Model. Cancers (Basel) 2021; 13:cancers13164244. [PMID: 34439398 PMCID: PMC8392865 DOI: 10.3390/cancers13164244] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/14/2021] [Accepted: 08/19/2021] [Indexed: 12/15/2022] Open
Abstract
Simple Summary FLASH radiotherapy is a treatment technique of interest that involves radiation delivered at ultra-high dose rates >100 times faster than traditional radiation therapy, which has been shown to spare radiation damage to normal tissue but maintain tumor control capabilities. Proton therapy uses spread-out proton Bragg peaks to reduce radiation dose to normal tissue by directing the highest dose of radiation to the tumor volume. In this study, irradiation of the whole abdomen of mice was performed with proton beams at FLASH dose rates in order to investigate the normal tissue sparing capabilities of the spread-out Bragg peak compared to the entrance region of the proton depth dose curve. Abstract Ultra-high dose rate FLASH proton radiotherapy (F-PRT) has been shown to reduce normal tissue toxicity compared to standard dose rate proton radiotherapy (S-PRT) in experiments using the entrance portion of the proton depth dose profile, while proton therapy uses a spread-out Bragg peak (SOBP) with unknown effects on FLASH toxicity sparing. To investigate, the biological effects of F-PRT using an SOBP and the entrance region were compared to S-PRT in mouse intestine. In this study, 8–10-week-old C57BL/6J mice underwent 15 Gy (absorbed dose) whole abdomen irradiation in four groups: (1) SOBP F-PRT, (2) SOBP S-PRT, (3) entrance F-PRT, and (4) entrance S-PRT. Mice were injected with EdU 3.5 days after irradiation, and jejunum segments were harvested and preserved. EdU-positive proliferating cells and regenerated intestinal crypts were quantified. The SOBP had a modulation (width) of 2.5 cm from the proximal to distal 90%. Dose rates with a SOBP for F-PRT or S-PRT were 108.2 ± 8.3 Gy/s or 0.82 ± 0.14 Gy/s, respectively. In the entrance region, dose rates were 107.1 ± 15.2 Gy/s and 0.83 ± 0.19 Gy/s, respectively. Both entrance and SOBP F-PRT preserved a significantly higher number of EdU + /crypt cells and percentage of regenerated crypts compared to S-PRT. Moreover, tumor growth studies showed no difference between SOBP and entrance for either of the treatment modalities.
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