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Yang XX, Luo H, Zhang JJ, Ge H, Ge L. Clinical translation of ultra-high dose rate flash radiotherapy: Opportunities, challenges, and prospects. World J Radiol 2025; 17:105722. [PMID: 40309475 PMCID: PMC12038406 DOI: 10.4329/wjr.v17.i4.105722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2025] [Revised: 03/09/2025] [Accepted: 03/25/2025] [Indexed: 04/22/2025] Open
Abstract
Ultra-high dose rate flash radiotherapy (FLASH-RT) has attracted wide attention in the field of radiotherapy in recent years. For FLASH-RT, radiation is delivered at a very high dose rate [usually thousands of times compared with conventional radiotherapy (CONV-RT)] in an extremely short time. This novel irradiation technique shows a protective effect on normal tissues, also known as the flash effect. At the same time, FLASH-RT is comparable to CONV-RT in terms of tumor-killing efficacy. As basic research dedicates to uncover the mechanisms by which FLASH-RT reduces radiation-induced normal tissue damage, clinical trials of FLASH-RT have been gradually conducted worldwide. This article systematically reviews the evidence of the feasibility and safety of FLASH-RT in clinical practice and offers insights into the future translation of this technology in clinic.
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Affiliation(s)
- Xiang-Xiang Yang
- Department of Medical Imaging, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou 450001, Henan Province, China
| | - Hui Luo
- Department of Radiation Oncology, Henan Cancer Hospital, Zhengzhou 450003, Henan Province, China
| | - Jia-Jun Zhang
- Department of Medical Imaging, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou 450001, Henan Province, China
| | - Heng Ge
- Department of Oncology, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou 450001, Henan Province, China
| | - Liang Ge
- Department of Medical Imaging, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou 450001, Henan Province, China
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Paz-Martín J, Schüller A, Bourgouin A, Gago-Arias A, González-Castaño DM, Gómez-Fernández N, Pardo-Montero J, Gómez F. Evaluation of the two-voltage method for parallel-plate ionization chambers irradiated with pulsed beams. Med Phys 2025. [PMID: 40219618 DOI: 10.1002/mp.17814] [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: 10/04/2024] [Revised: 03/05/2025] [Accepted: 03/06/2025] [Indexed: 04/14/2025] Open
Abstract
BACKGROUND Air-vented ionization chambers exposed to clinical radiation beams may suffer from recombination during the drift of the charge carriers towards the electrodes. Thus, dosimetry protocols recommend the use of a correction factor, usually denominated saturation factor (k sat $k_{\rm sat}$ ), to correct the ionization chamber readout for the incomplete collection of charge. The two-voltage method (TVM) is the recommended methodology for the calculation of the saturation factor, however, it is based on the early Boag model, which only takes into account the presence of positive and negative ions in the ionization chamber and does not account for the electric field screening or the free electron contribution to the signal. PURPOSE To evaluate the impact of a more realistic approach to the saturation problem that accounts for the free electron fraction. METHODS The saturation factor of four ionization chambers (two Advanced Markus and two PPC05) was experimentally determined in the ultra-high dose per pulse reference beam of the German National Metrology Institute (Physikalisch-Technische Bundesanstalt [PTB]) for voltages ranging from 50 to 400 V and pulse durations between 0.5 and 2.9 μ s $\umu{\rm s}$ . Several analytical models and a recently developed numerical model are used to calculate the saturation factor as a function of the dose per pulse and compare it to the obtained experimental data. Parameterizations of the saturation factor against the ratio of charges at different voltages are given for parallel plate ionization chamber with a distance between electrodes of 0.6 and 1 mm in pulsed beams for different pulse durations. RESULTS The saturation factors calculated using the different Boag analytical models do not agree neither with each other nor with the numerical simulation even at the lowest dose per pulse of the investigated range ( < $<$ 30 mGy). A recently developed analytical model by Fenwick and Kumar agrees with the numerical simulation in the low dose per pulse regime but discrepancies are observed when the dose becomes larger (i.e., > $>$ 40 mGy for Advanced Markus) due to the electric field perturbation. The numerical simulation is in a good agreement with the experimentally determined charge collection efficiency (CCE) with an average discrepancy of 0.7% for the two PPC05 and 0.5% for the two Advanced Markus. The saturation factor obtained with the numerical simulation of the collected charge has been fitted to a third-order polynomial for different voltage ratios and pulse duration. This methodology provides a practical way fork sat $k_{\rm sat}$ evaluation wheneverk sat < 1.05 $k_{\rm sat}<1.05$ . CONCLUSIONS The numerical simulation shows a better agreement with the experimental data than the current analytical theories in terms of CCE. The classical TVM, systematically overestimates the saturation factor, with differences increasing with dose per pulse but also present at low dose per pulse. These results may have implications for the dosimetry with ionization chambers in therapy modalities that use a dose per pulse higher than conventional radiotherapy such as intraoperative radiotherapy but also in conventional dose per pulse for ionization chambers that suffer from significant charge recombination.
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Affiliation(s)
- José Paz-Martín
- Departamento de Física de Partículas, Universidade de Santiago de Compostela, Santiago de Compostela, A Coruña, Spain
| | - Andreas Schüller
- Dosimetry for Radiotherapy, Physikalisch-Technische Bundesanstalt, Braunschweig, Germany
| | - Alexandra Bourgouin
- National Research Council of Canada, Metrology Research Center, Ottawa, ON, Canada
| | - Araceli Gago-Arias
- Departamento de Física de Partículas, Universidade de Santiago de Compostela, Santiago de Compostela, A Coruña, Spain
| | | | - Nicolás Gómez-Fernández
- Laboratorio de Radiofísica, Universidade de Santiago, Santiago de Compostela, A Coruña, Spain
| | - Juan Pardo-Montero
- Group of Medical Physics and Biomathematics, Instituto de Investigacion Sanitaria de Santiago (IDIS), Santiago de Compostela, A Coruña, Spain
- Department of Medical Physics, Complexo Hospitalario Universitario de Santiago de Compostela, Santiago de Compostela, A Coruña, Spain
| | - Faustino Gómez
- Departamento de Física de Partículas, Universidade de Santiago de Compostela, Santiago de Compostela, A Coruña, Spain
- Laboratorio de Radiofísica, Universidade de Santiago, Santiago de Compostela, A Coruña, Spain
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Okpuwe C, Milluzzo G, Coves D, Delaviere T, Del Sarto D, De Napoli M, Di Martino F, Felici G, Lanzanò L, Masturzo L, Pensavalle J, Touzain E, Camarda M, Romano F. Systematic Study of Silicon Carbide Detectors and Beam Current Transformer Signals for UHDR Single Electron Pulse Monitoring. Radiat Res 2025; 203:236-245. [PMID: 39996278 DOI: 10.1667/rade-24-00139.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 08/16/2024] [Indexed: 02/26/2025]
Abstract
The use of ultra-high dose rate beams (UHDR) (> 40 Gy/s) for radiotherapy, despite its advantage of exhibiting the FLASH effect that improves the sparing of healthy tissues, faces challenges in dosimetry and beam monitoring since standard dosimeters like the ionization chamber experience saturation effects at such high dose rates. Silicon carbide (SiC) detectors have recently been demonstrated to be dose-rate independent with low-energy pulsed electron beams up to an instantaneous dose rate of 5.5 MGy/s, and has emerged as a reliable alternative technology for dosimetry in FLASH-RT. This study explored the suitability of using the SiC detector for measuring intra-pulse instantaneous dose rates, which are necessary for monitoring fluctuations within the pulse of UHDR pulsed electron beams. The experiments reported were conducted using UHDR electron beams accelerated at 9 MeV by an ElectronFlash linac and using varying different beam parameters, such as the beam current (i.e., different dose per pulse) and pulse width settings. The temporal single pulse shape signals were measured with a 10 µm thick, 4.5 mm2 area SiC detector for different configurations and compared with a well-characterized AC current transformer (ACCT) (which served as the standard monitoring system of the accelerator), and with a second ACCT placed at the same location as the SiC detector (i.e., after the applicator at the irradiation point). The results show a high level of agreement between the signals of the SiC detector and ACCT placed after the applicator at around the irradiation point. This underscores the potential of the SiC detector and the ACCT to be used for monitoring instantaneous dose rates within a pulse. Furthermore, since use of the SiC detector and ACCT are based on different physical principles, they can provide complementary beam information. A combination of the two has the potential to provide insight about a variety of variables of interest for UHDR beams. However, some discrepancies were observed when comparing the SiC signals with the ACCT installed in the LINAC, which increased linearly with decreasing dose per pulse. Further studies are required to better understand these observations.
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Affiliation(s)
- C Okpuwe
- National Institute of Nuclear Physics (INFN), Catania Division, Catania, Italy
- Department of Physics and Astronomy, University of Catania, Italy
- Department of Physics, Federal University of Technology Owerri (FUTO), Nigeria
| | - G Milluzzo
- National Institute of Nuclear Physics (INFN), Catania Division, Catania, Italy
| | - D Coves
- Bergoz Instrumentation, Saint-Genis-Pouilly, France
| | - T Delaviere
- Bergoz Instrumentation, Saint-Genis-Pouilly, France
| | - D Del Sarto
- Pisano Research and Clinical Implementation Center Flash Radiotherapy (CPFR@CISUP), Pisa, Italy
- Health Physics, Pisa AOUP University Hospital, Pisa, Italy
| | - M De Napoli
- National Institute of Nuclear Physics (INFN), Catania Division, Catania, Italy
| | - F Di Martino
- Pisano Research and Clinical Implementation Center Flash Radiotherapy (CPFR@CISUP), Pisa, Italy
- Health Physics, Pisa AOUP University Hospital, Pisa, Italy
- National Institute of Nuclear Physics (INFN), Pisa Division, Pisa, Italy
| | - G Felici
- S.I.T. - Sordina IORT Technologies S.p.A., Aprilia, Italy
| | - L Lanzanò
- Department of Physics and Astronomy, University of Catania, Italy
| | - L Masturzo
- Pisano Research and Clinical Implementation Center Flash Radiotherapy (CPFR@CISUP), Pisa, Italy
- Health Physics, Pisa AOUP University Hospital, Pisa, Italy
| | - J Pensavalle
- Pisano Research and Clinical Implementation Center Flash Radiotherapy (CPFR@CISUP), Pisa, Italy
- Health Physics, Pisa AOUP University Hospital, Pisa, Italy
- S.I.T. - Sordina IORT Technologies S.p.A., Aprilia, Italy
| | - E Touzain
- Bergoz Instrumentation, Saint-Genis-Pouilly, France
| | | | - F Romano
- National Institute of Nuclear Physics (INFN), Catania Division, Catania, Italy
- Particle Therapy Research Center (PARTREC), Department of Oncology, University Medical Center, Groningen, Netherlands
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Cheng W, Zhao F, Zhang T, He Y, Zhu H. A review of ultra-wide-bandgap semiconductor radiation detector for high-energy particles and photons. NANOTECHNOLOGY 2025; 36:152002. [PMID: 39983238 DOI: 10.1088/1361-6528/adb8f2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2024] [Accepted: 02/21/2025] [Indexed: 02/23/2025]
Abstract
Radiation detectors have gained significant attention due to their extensive applications in high-energy physics, medical diagnostics, aerospace, and nuclear radiation protection. Advances in relevant technologies have made the drawbacks of traditional semiconductor detectors, including high leakage currents and instability, increasingly apparent. Ga2O3, diamond, and BN represent a new generation of semiconductor materials following GaN and SiC, offering wide bandgaps of around 5 eV. These ultra-wide bandgap semiconductors demonstrate excellent properties, including ultra-low dark current, high breakdown fields, and superior radiation tolerance, underscoring their promising potential in radiation detection. In this review, we first discuss the materials and electrical properties of Ga2O3, diamond, and BN, along with the general performance metrics relevant to radiation detectors. Subsequently, the review provides a comprehensive overview of the research progress in x-ray detection, charged particle detection (e.g.αparticles and carbon ions), as well as fast neutron and thermal neutron detection, focusing on aspects such as chip fabrication processes, device architectures, and testing results for radiation detectors based on these three materials.
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Affiliation(s)
- Wenzheng Cheng
- School of Microelectronics, Fudan University, Shanghai 200433, People's Republic of China
| | - Feiyang Zhao
- School of Microelectronics, Fudan University, Shanghai 200433, People's Republic of China
| | - Tianyi Zhang
- School of Microelectronics, Fudan University, Shanghai 200433, People's Republic of China
| | - Yongjie He
- School of Microelectronics, Fudan University, Shanghai 200433, People's Republic of China
| | - Hao Zhu
- School of Microelectronics, Fudan University, Shanghai 200433, People's Republic of China
- Shaoxin Laboratory, Shaoxing, Zhejiang 312000, People's Republic of China
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Schönfeld AA, Hildreth J, Bourgouin A, Flatten V, Kozelka J, Simon W, Schüller A. A 2D detector array for relative dosimetry and beam steering for FLASH radiotherapy with electrons. Med Phys 2025; 52:1845-1857. [PMID: 39688375 PMCID: PMC11880641 DOI: 10.1002/mp.17573] [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: 07/08/2024] [Revised: 11/27/2024] [Accepted: 12/02/2024] [Indexed: 12/18/2024] Open
Abstract
BACKGROUND FLASH radiotherapy is an emerging treatment modality using ultra-high dose rate beams. Much effort has been made to develop suitable dosimeters for reference dosimetry, yet the spatial beam characteristics must also be characterized to enable computerized treatment planning, as well as quality control and service of a treatment delivery device. In conventional radiation therapy, this is commonly achieved by beam profile scans in a water phantom using a point detector. In ultra-high dose rate beams, the delivered dose needed for a set of beam profile scans may exceed the regulatory dose limit specified for a typical treatment room, or degrade components of the scanning system and scanning detector. Point detector scans also cannot quantify the pulse-to-pulse stability of a beam profile. Detector arrays can overcome these challenges, but to date, no detector arrays suitable for ultra-high dose rate beams are commercially available. PURPOSE The study presents the development and characterization of a two-dimensional detector array for measuring pulse-resolved spatial fluence distributions in real-time and temporal structure of intra-pulse dose rate of ultra-high pulsed dose rate (UHPDR) electron beams used in FLASH radiotherapy. METHODS The performance of the SunPoint 1 diode was evaluated by measuring the response of the EDGE Detector in a 20 MeV UHPDR electron beam with a dose per pulse of 0.04 Gy - 6 Gy at a pulse duration of 1 µs or 1.9 µs, and instantaneous dose rates of 0.040 - 3.2 MGy·s-1. Based on the findings regarding a suitable signal acquisition technique, a PROFILER 2 detector array made of SunPoint 1 diodes was then modified by minimizing trace resistance, applying a reverse bias, and implementing an RC component to each diode to optimize the transfer of the collected charge during a pulse. The resultant "FLASH Profiler" was then tested in the same UHPDR electron beam. RESULTS The FLASH Profiler exhibited a linear response within ± 3% deviation over the investigated dose per pulse range. The FLASH Profiler array showed good agreement with the absolute dose measured using a flashDiamond point detector and an integrating current transformer for dose-per-pulse values of up to 6 Gy. The FLASH Profiler was able to measure lateral beam profiles in real-time and on a single-pulse basis. The ability to capture and display the profiles during steering of UHPDR beams was demonstrated. The SunPoint 1 diode was able to measure the pulse duration and the intra-pulse dose rate with a time resolution of 4 ns. CONCLUSION The FLASH Profiler could be used for characterizing UHPDR electron beams and facilitating quality control and beam steering service of electron FLASH irradiators.
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Affiliation(s)
| | - Jeff Hildreth
- Research and DevelopmentSun Nuclear Corp.MelbourneFloridaUSA
| | - Alexandra Bourgouin
- Dosimetry for RadiotherapyPhysikalisch‐Technische BundesanstaltBraunschweig38116Germany
- Present address:
Metrology Research CenterNational Research Council of CanadaOttawaOntarioCanada
| | | | - Jakub Kozelka
- Research and DevelopmentSun Nuclear Corp.MelbourneFloridaUSA
| | - William Simon
- Research and DevelopmentSun Nuclear Corp.MelbourneFloridaUSA
| | - Andreas Schüller
- Dosimetry for RadiotherapyPhysikalisch‐Technische BundesanstaltBraunschweig38116Germany
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Panaino CMV, Piccinini S, Andreassi MG, Bandini G, Borghini A, Borgia M, Di Naro A, Labate LU, Maggiulli E, Portaluri MGA, Gizzi LA. Very High-Energy Electron Therapy Toward Clinical Implementation. Cancers (Basel) 2025; 17:181. [PMID: 39857964 PMCID: PMC11763822 DOI: 10.3390/cancers17020181] [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: 11/11/2024] [Revised: 12/20/2024] [Accepted: 12/31/2024] [Indexed: 01/27/2025] Open
Abstract
The use of very high energy electron (VHEE) beams, with energies between 50 and 400 MeV, has drawn considerable interest in radiotherapy due to their deep tissue penetration, sharp beam edges, and low sensitivity to tissue density. VHEE beams can be precisely steered with magnetic components, positioning VHEE therapy as a cost-effective option between photon and proton therapies. However, the clinical implementation of VHEE therapy (VHEET) requires advances in several areas: developing compact, stable, and efficient accelerators; creating sophisticated treatment planning software; and establishing clinically validated protocols. In addition, the perspective of VHEE to access ultra-high dose-rate regime presents a promising avenue for the practical integration of FLASH radiotherapy of deep tumors and metastases with VHEET (FLASH-VHEET), enhancing normal tissue sparing while maintaining the inherent dosimetric advantages of VHEET. However, FLASH-VHEET systems require validation of time-dependent dose parameters, thus introducing additional technological challenges. Here, we discuss recent progress in VHEET research, focusing on both conventional and FLASH modalities, and covering key aspects including dosimetric properties, radioprotection, accelerator technology, beam focusing, radiobiological effects, and clinical outcomes. Furthermore, we comprehensively analyze initial VHEET in silico studies on coverage across various tumor sites.
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Affiliation(s)
- Costanza Maria Vittoria Panaino
- Intense Laser Irradiation Laboratory, National Institute of Optics, National Research Council of Italy, 56124 Pisa, Italy; (S.P.); (G.B.); (L.U.L.); (L.A.G.)
| | - Simona Piccinini
- Intense Laser Irradiation Laboratory, National Institute of Optics, National Research Council of Italy, 56124 Pisa, Italy; (S.P.); (G.B.); (L.U.L.); (L.A.G.)
| | - Maria Grazia Andreassi
- Institute of Clinical Physiology, National Research Council of Italy, 56124 Pisa, Italy; (M.G.A.); (A.B.)
| | - Gabriele Bandini
- Intense Laser Irradiation Laboratory, National Institute of Optics, National Research Council of Italy, 56124 Pisa, Italy; (S.P.); (G.B.); (L.U.L.); (L.A.G.)
| | - Andrea Borghini
- Institute of Clinical Physiology, National Research Council of Italy, 56124 Pisa, Italy; (M.G.A.); (A.B.)
| | | | - Angelo Di Naro
- ASST Papa Giovanni XXIII Hospital, Radiotherapy, 24127 Bergamo, Italy; (A.D.N.); (M.G.A.P.)
| | - Luca Umberto Labate
- Intense Laser Irradiation Laboratory, National Institute of Optics, National Research Council of Italy, 56124 Pisa, Italy; (S.P.); (G.B.); (L.U.L.); (L.A.G.)
- National Institute for Nuclear Physics, 56127 Pisa, Italy
| | | | | | - Leonida Antonio Gizzi
- Intense Laser Irradiation Laboratory, National Institute of Optics, National Research Council of Italy, 56124 Pisa, Italy; (S.P.); (G.B.); (L.U.L.); (L.A.G.)
- National Institute for Nuclear Physics, 56127 Pisa, Italy
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Oancea C, Sykorova K, Jakubek J, Pivec J, Riemer F, Worm S, Bourgouin A. Dosimetric and temporal beam characterization of individual pulses in FLASH radiotherapy using Timepix3 pixelated detector placed out-of-field. Phys Med 2025; 129:104872. [PMID: 39667142 DOI: 10.1016/j.ejmp.2024.104872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2024] [Revised: 10/12/2024] [Accepted: 11/30/2024] [Indexed: 12/14/2024] Open
Abstract
BACKGROUND FLASH radiotherapy necessitates the development of advanced Quality Assurance methods and detectors for accurate monitoring of the radiation field. This study introduces enhanced time-resolution detection systems and methods used to measure the delivered number of pulses, investigate temporal structure of individual pulses and dose-per-pulse (DPP) based on secondary radiation particles produced in the experimental room. METHODS A 20 MeV electron beam generated from a linear accelerator (LINAC) was delivered to a water phantom. Ultra-high dose-per-pulse electron beams were used with a dose-per-pulse ranging from ̴ 1 Gy to over 7 Gy. The pulse lengths ranged from 1.18 µs to 2.88 µs at a pulse rate frequency of 5 Hz. A semiconductor pixel detector Timepix3 was used to track single secondary particles. Measurements were performed in the air, while the detector was positioned out-of-field at a lateral distance of 200 cm parallel with the LINAC exit window. The dose deposited was measured along with the pulse length and the nanostructure of the pulse. RESULTS The time of arrival (ToA) of single particles was measured with a resolution of 1.56 ns, while the deposited energy was measured with a resolution of several keV based on the Time over Threshold (ToT) value. The pulse count measured by the Timepix3 detector corresponded with the delivered values, which were measured using an in-flange integrating current transformer (ICT). A linear response (R2 = 0.999) was established between the delivered beam current and the measured dose at the detector position (orders of nGy). The difference between the average measured and delivered pulse length was ∼0.003(30) μs. CONCLUSION This simple non-invasive method exhibits no limitations on the delivered DPP within the range used during this investigation.
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Affiliation(s)
| | | | - Jan Jakubek
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic
| | - Jiri Pivec
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic
| | - Felix Riemer
- Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, 15738 Zeuthen, Germany
| | - Steven Worm
- Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, 15738 Zeuthen, Germany
| | - Alexandra Bourgouin
- Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig 38116, Germany; Metrology Research Center, National Research Council of Canada, 1200 Montreal Road, Ottawa, ON, K1A0R6, Canada
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Liu K, Holmes S, Khan AU, Hooten B, DeWerd L, Schüler E, Beddar S. Development of novel ionization chambers for reference dosimetry in electron flash radiotherapy. Med Phys 2024; 51:9275-9289. [PMID: 39311014 DOI: 10.1002/mp.17425] [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: 02/20/2024] [Revised: 08/10/2024] [Accepted: 09/10/2024] [Indexed: 12/20/2024] Open
Abstract
BACKGROUND Reference dosimetry in ultra-high dose rate (UHDR) beamlines is significantly hindered by limitations in conventional ionization chamber design. In particular, conventional chambers suffer from severe charge collection efficiency (CCE) degradation in high dose per pulse (DPP) beams. PURPOSE The aim of this study was to optimize the design and performance of parallel plate ion chambers for use in UHDR dosimetry applications, and evaluate their potential as reference class chambers for calibration purposes. Three chamber designs were produced to determine the influence of the ion chamber response on electrode separation, field strength, and collection volume on the ion chamber response under UHDR and ultra-high dose per pulse (UHDPP) conditions. METHODS Three chambers were designed and produced: the A11-VAR (0.2-1.0 mm electrode gap, 20 mm diameter collector), the A11-TPP (0.3 mm electrode gap, 20 mm diameter collector), and the A30 (0.3 mm electrode gap, 5.4 mm diameter collector). The chambers underwent full characterization using an UHDR 9 MeV electron beam with individually varied beam parameters of pulse repetition frequency (PRF, 10-120 Hz), pulse width (PW, 0.5-4 µs), and pulse amplitude (0.01-9 Gy/pulse). The response of the ion chambers was evaluated as a function of the DPP, PRF, PW, dose rate, electric field strength, and electrode gap. RESULTS The chamber response was found to be dependent on DPP and PW, and these dependencies were mitigated with larger electric field strengths and smaller electrode spacing. At a constant electric field strength, we measured a larger CCE as a function of DPP for ion chambers with a smaller electrode gap in the A11-VAR. For ion chambers with identical electrode gap (A11-TPP and A30), higher electric field strengths were found to yield better CCE at higher DPP. A PW dependence was observed at low electric field strengths (500 V/mm) for DPP values ranging from 1 to 5 Gy at PWs ranging from 0.5 to 4 µs, but at electric field strengths of 1000 V/mm and higher, these effects become negligible. CONCLUSION This study confirmed that the CCE of ion chambers depends strongly on the electrode spacing and the electric field strength, and also on the DPP and the PW of the UHDR beam. A significant finding of this study is that although chamber performance does depend on PW, the effect on the CCE becomes negligible with reduced electrode spacing and increased electric field. A CCE of ≥95% was achieved for DPPs of up to 5 Gy with no observable dependence on PW using the A30 chamber, while still achieving an acceptable performance in conventional dose rate beams, opening up the possibility for this type of chamber to be used as a reference class chamber for calibration purposes of electron FLASH beamlines.
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Affiliation(s)
- Kevin Liu
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, Texas, USA
| | | | - Ahtesham Ullah Khan
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Radiation Oncology, Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Brian Hooten
- Standard Imaging Inc., Middleton, Wisconsin, USA
| | - Larry DeWerd
- Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Emil Schüler
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, Texas, USA
| | - Sam Beddar
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- The University of Texas MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, Texas, USA
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9
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Angelou C, Patallo IS, Doherty D, Romano F, Schettino G. A review of diamond dosimeters in advanced radiotherapy techniques. Med Phys 2024; 51:9230-9249. [PMID: 39221583 PMCID: PMC11656300 DOI: 10.1002/mp.17370] [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: 03/20/2024] [Revised: 07/08/2024] [Accepted: 08/10/2024] [Indexed: 09/04/2024] Open
Abstract
This review article synthesizes key findings from studies on the use of diamond dosimeters in advanced radiotherapy techniques, showcasing their applications, challenges, and contributions to enhancing dosimetric accuracy. The article explores various dosimeters, highlighting synthetic diamond dosimeters as potential candidates especially due to their high spatial resolution and negligible ion recombination effect. The clinically validated commercial dosimeter, PTW microDiamond (mD), faces limitations in small fields, proton and hadron therapy and ultra-high dose per pulse (UHDPP) conditions. Variability in reported values for field sizes < $<$ 2 × $\times$ 2cm 2 ${\rm cm}^2$ is noted, reflecting the competition between volume averaging and density perturbation effects. PTW's introduction of flashDiamond (fD) holds promise for dosimetric measurements in UHDPP conditions and is reliable for commissioning ultra-high dose rate (UHDR) electron beam systems, pending the clinical validation of the device. Other advancements in diamond detectors, such as in 3D configurations and real-time dose per pulse x-ray detectors, are considered valuable in overcoming challenges posed by modern radiotherapy techniques, alongside relative dosimetry and pre-treatment verifications. The studies discussed collectively provide a comprehensive overview of the evolving landscape of diamond dosimetry in the field of radiotherapy, and offer insights into future directions for research and development in the field.
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Affiliation(s)
- Christina Angelou
- Department of PhysicsUniversity of SurreyGuildfordUK
- Radiotherapy and Radiation DosimetryNational Physical Laboratory (NPL)TeddingtonUK
| | | | | | - Francesco Romano
- Istituto Nazionale di Fisica Nucleare (INFN)Sezione di CataniaCataniaItaly
| | - Giuseppe Schettino
- Radiotherapy and Radiation DosimetryNational Physical Laboratory (NPL)TeddingtonUK
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10
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Chaikh A, Édouard M, Huet C, Milliat F, Villagrasa C, Isambert A. Towards clinical application of ultra-high dose rate radiotherapy and the FLASH effect: Challenges and current status. Cancer Radiother 2024; 28:463-473. [PMID: 39304401 DOI: 10.1016/j.canrad.2024.07.001] [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: 05/31/2024] [Revised: 07/05/2024] [Accepted: 07/06/2024] [Indexed: 09/22/2024]
Abstract
Ultra-high dose rate external beam radiotherapy (UHDR-RT) uses dose rates of several tens to thousands of Gy/s, compared with the dose rate of the order of a few Gy/min for conventional radiotherapy techniques, currently used in clinical practice. The use of such dose rate is likely to improve the therapeutic index by obtaining a radiobiological effect, known as the "FLASH" effect. This would maintain tumor control while enhancing tissues protection. To date, this effect has been achieved using beams of electrons, photons, protons, and heavy ions. However, the conditions required to achieve this "FLASH" effect are not well defined, and raise several questions, particularly with regard to the definition of the prescription, including dose fractionation, irradiated volume and the temporal structure of the pulsed beam. In addition, the dose delivered over a very short period induces technical challenges, particularly in terms of detectors, which must be mastered to guarantee safe clinical implementation. IRSN has carried out an in-depth literature review of the UHDR-RT technique, covering various aspects relating to patient radiation protection: the radiobiological mechanisms associated with the FLASH effect, the used temporal structure of the UHDR beams, accelerators and dose control, the properties of detectors to be used with UHDR beams, planning, clinical implementation, and clinical studies already carried out or in progress.
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Affiliation(s)
| | | | | | - Fabien Milliat
- IRSN/PSE-SANTÉ-SERAMED/LRMed, Fontenay-aux-Roses, France
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11
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Gesualdi F, de Marzi L, Dutreix M, Favaudon V, Fouillade C, Heinrich S. A multidisciplinary view of flash irradiation. Cancer Radiother 2024; 28:453-462. [PMID: 39343695 DOI: 10.1016/j.canrad.2024.07.003] [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: 04/15/2024] [Revised: 07/19/2024] [Accepted: 07/19/2024] [Indexed: 10/01/2024]
Abstract
The delivery of ultra-high dose rates of radiation, called flash irradiation or flash-RT, has emerged as a new modality of radiotherapy shaking up the paradigm of proportionality of effect and dose whatever the method of delivery of the radiation. The hallmark of flash-RT is healthy tissue sparing from the side effects of radiation without decrease of the antitumor efficiency in animal models. In this review we will define its specificities, the molecular mechanisms underlying the flash effect and the ongoing developments to bring this new modality to patient treatment.
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Affiliation(s)
- Flavia Gesualdi
- Institut Curie, Hospital Division, centre de protonthérapie d'Orsay, université Paris-Saclay, université PSL, centre universitaire, 91948 Orsay cedex, France
| | - Ludovic de Marzi
- Institut Curie, Hospital Division, centre de protonthérapie d'Orsay, université Paris-Saclay, université PSL, centre universitaire, 91948 Orsay cedex, France; Institut Curie, université PSL, université Paris-Saclay, Inserm Lito U1288, centre universitaire, 91898 Orsay, France
| | - Marie Dutreix
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, université Paris-Saclay, université PSL, centre universitaire, 91401 Orsay cedex, France
| | - Vincent Favaudon
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, université Paris-Saclay, université PSL, centre universitaire, 91401 Orsay cedex, France
| | - Charles Fouillade
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, université Paris-Saclay, université PSL, centre universitaire, 91401 Orsay cedex, France
| | - Sophie Heinrich
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, université Paris-Saclay, université PSL, centre universitaire, 91401 Orsay cedex, France.
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12
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Milluzzo G, De Napoli M, Di Martino F, Amato A, Del Sarto D, D'Oca MC, Marrale M, Masturzo L, Medina E, Okpuwe C, Pensavalle JH, Vignati A, Camarda M, Romano F. Comprehensive dosimetric characterization of novel silicon carbide detectors with UHDR electron beams for FLASH radiotherapy. Med Phys 2024; 51:6390-6401. [PMID: 38772134 DOI: 10.1002/mp.17172] [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: 11/30/2023] [Revised: 04/26/2024] [Accepted: 04/27/2024] [Indexed: 05/23/2024] Open
Abstract
BACKGROUND The extremely fast delivery of doses with ultra high dose rate (UHDR) beams necessitates the investigation of novel approaches for real-time dosimetry and beam monitoring. This aspect is fundamental in the perspective of the clinical application of FLASH radiotherapy (FLASH-RT), as conventional dosimeters tend to saturate at such extreme dose rates. PURPOSE This study aims to experimentally characterize newly developed silicon carbide (SiC) detectors of various active volumes at UHDRs and systematically assesses their response to establish their suitability for dosimetry in FLASH-RT. METHODS SiC PiN junction detectors, recently realized and provided by STLab company, with different active areas (ranging from 4.5 to 10 mm2) and thicknesses (10-20 µm), were irradiated using 9 MeV UHDR pulsed electron beams accelerated by the ElectronFLASH linac at the Centro Pisano for FLASH Radiotherapy (CPFR). The linearity of the SiC response as a function of the delivered dose per pulse (DPP), which in turn corresponds to a specific instantaneous dose rate, was studied under various experimental conditions by measuring the produced charge within the SiC active layer with an electrometer. Due to the extremely high peak currents, an external customized electronic RC circuit was built and used in conjunction with the electrometer to avoid saturation. RESULTS The study revealed a linear response for the different SiC detectors employed up to 21 Gy/pulse for SiC detectors with 4.5 mm2/10 µm active area and thickness. These values correspond to a maximum instantaneous dose rate of 5.5 MGy/s and are indicative of the maximum achievable monitored DPP and instantaneous dose rate of the linac used during the measurements. CONCLUSIONS The results clearly demonstrate that the developed devices exhibit a dose-rate independent response even under extreme instantaneous dose rates and dose per pulse values. A systematic study of the SiC response was also performed as a function of the applied voltage bias, demonstrating the reliability of these dosimeters with UHDR also without any applied voltage. This demonstrates the great potential of SiC detectors for accurate dosimetry in the context of FLASH-RT.
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Affiliation(s)
- Giuliana Milluzzo
- National Institute of Nuclear Physics (INFN), Catania Division, Catania, Italy
| | - Marzio De Napoli
- National Institute of Nuclear Physics (INFN), Catania Division, Catania, Italy
| | - Fabio Di Martino
- Centro Pisano ricerca e implementazione clinica Flash Radiotherapy (CPFR@CISUP), Pisa, Italy
- Fisica Sanitaria, Azienda Ospedaliero Universitaria Pisa AOUP, Pisa, Italy
- National Institute of Nuclear Physics (INFN), Pisa Division, Pisa, Italy
| | - Antonino Amato
- STLab srl, Catania, Italy
- National Institute of Nuclear Physics (INFN), Laboratori Nazionali del Sud, Catania, Italy
| | - Damiano Del Sarto
- Centro Pisano ricerca e implementazione clinica Flash Radiotherapy (CPFR@CISUP), Pisa, Italy
- Fisica Sanitaria, Azienda Ospedaliero Universitaria Pisa AOUP, Pisa, Italy
| | - Maria Cristina D'Oca
- National Institute of Nuclear Physics (INFN), Catania Division, Catania, Italy
- Department of Physics and Chemistry "Emilio Segrè", University of Palermo, Palermo, Italy
| | - Maurizio Marrale
- National Institute of Nuclear Physics (INFN), Catania Division, Catania, Italy
- National Institute of Nuclear Physics (INFN), Laboratori Nazionali del Sud, Catania, Italy
| | - Luigi Masturzo
- Centro Pisano ricerca e implementazione clinica Flash Radiotherapy (CPFR@CISUP), Pisa, Italy
- Fisica Sanitaria, Azienda Ospedaliero Universitaria Pisa AOUP, Pisa, Italy
- SIT-Sordina, Aprilia, Italy
| | - Elisabetta Medina
- Physics Department, University of Torino, Torino, Italy
- National Institute of Nuclear Physics (INFN), Torino Division, Torino, Italy
| | - Chinonso Okpuwe
- National Institute of Nuclear Physics (INFN), Catania Division, Catania, Italy
- Physics Department, University of Catania, Catania, Italy
- Department of Physics, Federal University of Technology Owerri, Owerri, Nigeria
| | - Jake Harold Pensavalle
- Centro Pisano ricerca e implementazione clinica Flash Radiotherapy (CPFR@CISUP), Pisa, Italy
- Fisica Sanitaria, Azienda Ospedaliero Universitaria Pisa AOUP, Pisa, Italy
- SIT-Sordina, Aprilia, Italy
| | - Anna Vignati
- Physics Department, University of Torino, Torino, Italy
- National Institute of Nuclear Physics (INFN), Torino Division, Torino, Italy
| | | | - Francesco Romano
- National Institute of Nuclear Physics (INFN), Catania Division, Catania, Italy
- Particle Therapy Research Center (PARTREC), Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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13
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Portier L, Daira P, Fourmaux B, Heinrich S, Becerra M, Fouillade C, Berthault N, Dutreix M, Londoño-Vallejo A, Verrelle P, Bernoud-Hubac N, Favaudon V. Differential Remodeling of the Oxylipin Pool After FLASH Versus Conventional Dose-Rate Irradiation In Vitro and In Vivo. Int J Radiat Oncol Biol Phys 2024; 119:1481-1492. [PMID: 38340776 DOI: 10.1016/j.ijrobp.2024.01.210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/09/2024] [Accepted: 01/13/2024] [Indexed: 02/12/2024]
Abstract
PURPOSE The products of lipid peroxidation have been implicated in human diseases and aging. This prompted us to investigate the response to conventional (CONV) versus FLASH irradiation of oxylipins, a family of bioactive lipid metabolites derived from omega-3 or omega-6 polyunsaturated fatty acids through oxygen-dependent non-enzymatic as well as dioxygenase-mediated free radical reactions. METHODS AND MATERIALS Ultrahigh performance liquid chromatography coupled to tandem mass spectrometry was used to quantify the expression of 37 oxylipins derived from eicosatetraenoic, eicosapentaenoic and docosahexaenoic acid in mouse lung and in normal or cancer cells exposed to either radiation modality under precise monitoring of the temperature and oxygenation. Among the 37 isomers assayed, 14-16 were present in high enough amount to enable quantitative analysis. The endpoints were the expression of oxylipins as a function of the dose of radiation, normoxia versus hypoxia, temperature and post-irradiation time. RESULTS In normal, normoxic cells at 37°C radiation elicited destruction and neosynthesis of oxylipins acting antagonistically on a background subject to rapid remodeling by oxygenases. Neosynthesis was observed in the CONV mode only, in such a way that the level of oxylipins at 5 minutes after FLASH irradiation was 20-50% lower than in non-irradiated and CONV-irradiated cells. Hypoxia mitigated the differential CONV versus FLASH response in some oxylipins. These patterns were not reproduced in tumor cells. Depression of specific oxylipins following FLASH irradiation was observed in mouse lung at 5 min following irradiation, with near complete recovery in 24 hours and further remodeling at one week and two months post-irradiation. CONCLUSIONS Down-regulation of oxylipins was a hallmark of FLASH irradiation specific of normal cells. Temperature effects suggest that this process occurs via diffusion-controlled, bimolecular recombination of a primary radical species upstream from peroxyl radical formation and evoke a major role of the membrane composition and fluidity in response to the FLASH modality.
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Affiliation(s)
- Lucie Portier
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, Paris-Saclay University, PSL Research University, Centre Universitaire CS 90030, Orsay, France
| | - Patricia Daira
- Univ Lyon, INSA Lyon, CNRS, LaMCoS, UMR 5259, Villeurbanne, France
| | | | - Sophie Heinrich
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, Paris-Saclay University, PSL Research University, Centre Universitaire CS 90030, Orsay, France
| | - Margaux Becerra
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, Paris-Saclay University, PSL Research University, Centre Universitaire CS 90030, Orsay, France
| | - Charles Fouillade
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, Paris-Saclay University, PSL Research University, Centre Universitaire CS 90030, Orsay, France
| | - Nathalie Berthault
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, Paris-Saclay University, PSL Research University, Centre Universitaire CS 90030, Orsay, France
| | - Marie Dutreix
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, Paris-Saclay University, PSL Research University, Centre Universitaire CS 90030, Orsay, France
| | - Arturo Londoño-Vallejo
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, Paris-Saclay University, PSL Research University, Centre Universitaire CS 90030, Orsay, France
| | - Pierre Verrelle
- Institut Curie, Hospital Section, Department of Radiotherapy-Oncology, 26 rue d'Ulm, 75248 Paris Cedex 05, France; Institut Curie, Research Division, Inserm U 1196-CNRS UMR 9187, Paris-Saclay University, PSL Research University, Centre Universitaire CS 90030, Orsay, France
| | | | - Vincent Favaudon
- Institut Curie, Research Division, Inserm U 1021-CNRS UMR 3347, Paris-Saclay University, PSL Research University, Centre Universitaire CS 90030, Orsay, France.
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14
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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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15
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Garibaldi C, Beddar S, Bizzocchi N, Tobias Böhlen T, Iliaskou C, Moeckli R, Psoroulas S, Subiel A, Taylor PA, Van den Heuvel F, Vanreusel V, Verellen D. Minimum and optimal requirements for a safe clinical implementation of ultra-high dose rate radiotherapy: A focus on patient's safety and radiation protection. Radiother Oncol 2024; 196:110291. [PMID: 38648991 DOI: 10.1016/j.radonc.2024.110291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 03/28/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024]
Affiliation(s)
- Cristina Garibaldi
- IEO, Unit of Radiation Research, European Institute of Oncology IRCCS, 20141 Milan, Italy.
| | - Sam Beddar
- The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Nicola Bizzocchi
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland
| | - Till Tobias Böhlen
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Charoula Iliaskou
- Division of Medical Physics, Department of Radiation Oncology, University Medical Center Freiburg, 79106, Germany; German Cancer Consortium (DKTK), Partner Site Freiburg, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Raphaël Moeckli
- Institute of Radiation Physics, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Serena Psoroulas
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland
| | - Anna Subiel
- National Physical Laboratory, Medical Radiation Science, Teddington, UK
| | - Paige A Taylor
- The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Frank Van den Heuvel
- Zuidwest Radiotherapeutisch Institute, Vlissingen, the Netherlands; Dept of Oncology, University of Oxford, Oxford, UK
| | - Verdi Vanreusel
- Iridium Netwerk, Antwerp University (Centre for Oncological Research, CORE), Antwerpen, Belgium; SCK CEN (Research in Dosimetric Applications), Mol, Belgium
| | - Dirk Verellen
- Iridium Netwerk, Antwerp University (Centre for Oncological Research, CORE), Antwerpen, Belgium
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16
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Ciarrocchi E, Ravera E, Cavalieri A, Celentano M, Del Sarto D, Di Martino F, Linsalata S, Massa M, Masturzo L, Moggi A, Morrocchi M, Pensavalle JH, Bisogni MG. Plastic scintillator-based dosimeters for ultra-high dose rate (UHDR) electron radiotherapy. Phys Med 2024; 121:103360. [PMID: 38692114 DOI: 10.1016/j.ejmp.2024.103360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 03/28/2024] [Accepted: 04/19/2024] [Indexed: 05/03/2024] Open
Abstract
This paper reports the development of dosimeters based on plastic scintillating fibers imaged by a charge-coupled device camera, and their performance evaluation through irradiations with the electron Flash research accelerator located at the Centro Pisano Flash Radiotherapy. The dosimeter prototypes were composed of a piece of plastic scintillating fiber optically coupled to a clear optical fiber which transported the scintillation signal to the readout systems (an imaging system and a photodiode). The following properties were tested: linearity, capability to reconstruct the percentage depth dose curve in solid water and to sample in time the single beam pulse. The stem effect contribution was evaluated with three methods, and a proof-of-concept one-dimensional array was developed and tested for online beam profiling. Results show linearity up to 10 Gy per pulse, and good capability to reconstruct both the timing and spatial profiles of the beam, thus suggesting that plastic scintillating fibers may be good candidates for low-energy electron Flash dosimetry.
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Affiliation(s)
- E Ciarrocchi
- University of Pisa, Department of Physics, Pisa, Italy; National Institute of Nuclear Physics, Section of Pisa, Pisa, Italy
| | - E Ravera
- University of Pisa, Department of Physics, Pisa, Italy; National Institute of Nuclear Physics, Section of Pisa, Pisa, Italy
| | - A Cavalieri
- University of Pisa, Department of Physics, Pisa, Italy; National Institute of Nuclear Physics, Section of Pisa, Pisa, Italy
| | - M Celentano
- University of Pisa, Department of Physics, Pisa, Italy; Azienda ospedaliero-universitaria pisana, U.O. Fisica Sanitaria, Pisa, Italy; Centro Pisano ricerca e implementazione clinical Flash Radiotherapy (CPFR-CISUP), Pisa, Italy
| | - D Del Sarto
- National Institute of Nuclear Physics, Section of Pisa, Pisa, Italy; Azienda ospedaliero-universitaria pisana, U.O. Fisica Sanitaria, Pisa, Italy; Centro Pisano ricerca e implementazione clinical Flash Radiotherapy (CPFR-CISUP), Pisa, Italy; University of Pisa, Center for Instrument Sharing of the University of Pisa (CISUP), Pisa, Italy
| | - F Di Martino
- National Institute of Nuclear Physics, Section of Pisa, Pisa, Italy; Azienda ospedaliero-universitaria pisana, U.O. Fisica Sanitaria, Pisa, Italy; Centro Pisano ricerca e implementazione clinical Flash Radiotherapy (CPFR-CISUP), Pisa, Italy
| | - S Linsalata
- Azienda ospedaliero-universitaria pisana, U.O. Fisica Sanitaria, Pisa, Italy
| | - M Massa
- National Institute of Nuclear Physics, Section of Pisa, Pisa, Italy
| | - L Masturzo
- University of Pisa, Department of Physics, Pisa, Italy; Azienda ospedaliero-universitaria pisana, U.O. Fisica Sanitaria, Pisa, Italy; Centro Pisano ricerca e implementazione clinical Flash Radiotherapy (CPFR-CISUP), Pisa, Italy; SIT Sordina IORT Technologies, Aprilia, Italy
| | - A Moggi
- National Institute of Nuclear Physics, Section of Pisa, Pisa, Italy
| | - M Morrocchi
- University of Pisa, Department of Physics, Pisa, Italy; National Institute of Nuclear Physics, Section of Pisa, Pisa, Italy.
| | - J H Pensavalle
- University of Pisa, Department of Physics, Pisa, Italy; Azienda ospedaliero-universitaria pisana, U.O. Fisica Sanitaria, Pisa, Italy; Centro Pisano ricerca e implementazione clinical Flash Radiotherapy (CPFR-CISUP), Pisa, Italy; SIT Sordina IORT Technologies, Aprilia, Italy
| | - M G Bisogni
- University of Pisa, Department of Physics, Pisa, Italy; National Institute of Nuclear Physics, Section of Pisa, Pisa, Italy; Centro Pisano ricerca e implementazione clinical Flash Radiotherapy (CPFR-CISUP), Pisa, Italy
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17
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Fleta C, Pellegrini G, Godignon P, Rodríguez FG, Paz-Martín J, Kranzer R, Schüller A. State-of-the-art silicon carbide diode dosimeters for ultra-high dose-per-pulse radiation at FLASH radiotherapy. Phys Med Biol 2024; 69:095013. [PMID: 38530300 DOI: 10.1088/1361-6560/ad37eb] [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: 07/14/2023] [Accepted: 03/26/2024] [Indexed: 03/27/2024]
Abstract
Objective.The successful implementation of FLASH radiotherapy in clinical settings, with typical dose rates >40 Gy s-1, requires accurate real-time dosimetry.Approach.Silicon carbide (SiC) p-n diode dosimeters designed for the stringent requirements of FLASH radiotherapy have been fabricated and characterized in an ultra-high pulse dose rate electron beam. The circular SiC PiN diodes were fabricated at IMB-CNM (CSIC) in 3μm epitaxial 4H-SiC. Their characterization was performed in PTB's ultra-high pulse dose rate reference electron beam. The SiC diode was operated without external bias voltage. The linearity of the diode response was investigated up to doses per pulse (DPP) of 11 Gy and pulse durations ranging from 3 to 0.5μs. Percentage depth dose measurements were performed in ultra-high dose per pulse conditions. The effect of the total accumulated dose of 20 MeV electrons in the SiC diode sensitivity was evaluated. The temperature dependence of the response of the SiC diode was measured in the range 19 °C-38 °C. The temporal response of the diode was compared to the time-resolved beam current during each electron beam pulse. A diamond prototype detector (flashDiamond) and Alanine measurements were used for reference dosimetry.Main results.The SiC diode response was independent both of DPP and of pulse dose rate up to at least 11 Gy per pulse and 4 MGy s-1, respectively, with tolerable deviation for relative dosimetry (<3%). When measuring the percentage depth dose under ultra-high dose rate conditions, the SiC diode performed comparably well to the reference flashDiamond. The sensitivity reduction after 100 kGy accumulated dose was <2%. The SiC diode was able to follow the temporal structure of the 20 MeV electron beam even for irregular pulse estructures. The measured temperature coefficient was (-0.079 ± 0.005)%/°C.Significance.The results of this study demonstrate for the first time the suitability of silicon carbide diodes for relative dosimetry in ultra-high dose rate pulsed electron beams up to a DPP of 11 Gy per pulse.
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Affiliation(s)
- Celeste Fleta
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Bellaterra, Barcelona, Spain
| | - Giulio Pellegrini
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Bellaterra, Barcelona, Spain
| | - Philippe Godignon
- Instituto de Microelectrónica de Barcelona, IMB-CNM (CSIC), Bellaterra, Barcelona, Spain
| | - Faustino Gómez Rodríguez
- Departamento de Física de Partículas, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
- Laboratorio de Radiofísica, RIAIDT, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - José Paz-Martín
- Departamento de Física de Partículas, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Rafael Kranzer
- PTW-Freiburg (R&D), Freiburg 79115, Germany
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University Oldenburg, 26121, Germany
| | - Andreas Schüller
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
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18
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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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Tessonnier T, Verona-Rinati G, Rank L, Kranzer R, Mairani A, Marinelli M. Diamond detectors for dose and instantaneous dose-rate measurements for ultra-high dose-rate scanned helium ion beams. Med Phys 2024; 51:1450-1459. [PMID: 37742343 PMCID: PMC10922163 DOI: 10.1002/mp.16757] [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: 12/16/2022] [Revised: 07/13/2023] [Accepted: 09/11/2023] [Indexed: 09/26/2023] Open
Abstract
BACKGROUND The possible emergence of the FLASH effect-the sparing of normal tissue while maintaining tumor control-after irradiations at dose-rates exceeding several tens of Gy per second, has recently spurred a surge of studies attempting to characterize and rationalize the phenomenon. Investigating and reporting the dose and instantaneous dose-rate of ultra-high dose-rate (UHDR) particle radiotherapy beams is crucial for understanding and assessing the FLASH effect, towards pre-clinical application and quality assurance programs. PURPOSE The purpose of the present work is to investigate a novel diamond-based detector system for dose and instantaneous dose-rate measurements in UHDR particle beams. METHODS Two types of diamond detectors, a microDiamond (PTW 60019) and a diamond detector prototype specifically designed for operation in UHDR beams (flashDiamond), and two different readout electronic chains, were investigated for absorbed dose and instantaneous dose-rate measurements. The detectors were irradiated with a helium beam of 145.7 MeV/u under conventional and UHDR delivery. Dose-rate delivery records by the monitoring ionization chamber and diamond detectors were studied for single spot irradiations. Dose linearity at 5 cm depth and in-depth dose response from 2 to 16 cm were investigated for both measurement chains and both detectors in a water tank. Measurements with cylindrical and plane-parallel ionization chambers as well as Monte-Carlo simulations were performed for comparisons. RESULTS Diamond detectors allowed for recording the temporal structure of the beam, in good agreement with the one obtained by the monitoring ionization chamber. A better time resolution of the order of few μs was observed as compared to the approximately 50 μs of the monitoring ionization chamber. Both diamonds detectors show an excellent linearity response in both delivery modalities. Dose values derived by integrating the measured instantaneous dose-rates are in very good agreement with the ones obtained by the standard electrometer readings. Bragg peak curves confirmed the consistency of the charge measurements by the two systems. CONCLUSIONS The proposed novel dosimetric system allows for a detailed investigation of the temporal evolution of UHDR beams. As a result, reliable and accurate determinations of dose and instantaneous dose-rate are possible, both required for a comprehensive characterization of UHDR beams and relevant for FLASH effect assessment in clinical treatments.
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Affiliation(s)
- Thomas Tessonnier
- Heidelberg Ion Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- Clinical Cooperation Unit Translational Radiation Oncology, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Luisa Rank
- Heidelberg Ion Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- Faculty of Physics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Rafael Kranzer
- PTW-Freiburg, Freiburg, Germany
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Andrea Mairani
- Heidelberg Ion Beam Therapy Center (HIT), Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany
- Clinical Cooperation Unit Translational Radiation Oncology, German Cancer Consortium (DKTK) Core-Center Heidelberg, National Center for Tumor Diseases (NCT), Heidelberg University Hospital (UKHD) and German Cancer Research Center (DKFZ), Heidelberg, Germany
- Medical Physics department, National Centre of Oncological Hadrontherapy (CNAO), Pavia, Italy
| | - Marco Marinelli
- Industrial Engineering Department, University of Rome Tor Vergata, Rome, Italy
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Verona C, Barna S, Georg D, Hamad Y, Magrin G, Marinelli M, Meouchi C, Verona Rinati G. Diamond based integrated detection system for dosimetric and microdosimetric characterization of radiotherapy ion beams. Med Phys 2024; 51:533-544. [PMID: 37656015 DOI: 10.1002/mp.16698] [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: 01/18/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 09/02/2023] Open
Abstract
BACKGROUND Ion beam therapy allows for a substantial sparing of normal tissues and higher biological efficacy. Synthetic single crystal diamond is a very good material to produce high-spatial-resolution and highly radiation hard detectors for both dosimetry and microdosimetry in ion beam therapy. PURPOSE The aim of this work is the design, fabrication and test of an integrated waterproof detector based on synthetic single crystal diamond able to simultaneously perform dosimetric and microdosimetric characterization of clinical ion beams. METHODS The active elements of the integrated diamond device, that is, dosimeter and microdosimeter, were both realized in a Schottky diode configuration featured by different area, thickness, and shape by means of photolithography technologies for the selective growth of intrinsic and boron-doped CVD diamond. The cross-section of the sensitive volume of the dosimetric element is 4 mm2 and 1 μm-thick, while the microdosimetric one has an active cross-sectional area of 100 × 100 μm2 and a thickness of about 6.2 μm. The dosimetric and microdosimetric performance of the developed device was assessed at different depths in a water phantom at the MedAustron ion beam therapy facility using a monoenergetic uniformly scanned carbon ion beam of 284.7 MeV/u and proton beam of 148.7 MeV. The particle flux in the region of the microdosimeter was 6·107 cm2 /s for both irradiation fields. At each depth, dose and dose distributions in lineal energy were measured simultaneously and the dose mean lineal energy values were then calculated. Monte Carlo simulations were also carried out by using the GATE-Geant4 code to evaluate the relative dose, dose averaged linear energy transfer (LETd ), and microdosimetric spectra at various depths in water for the radiation fields used, by considering the contribution from the secondary particles generated in the ion interaction processes as well. RESULTS Dosimetric and microdosimetric quantities were measured by the developed prototype with relatively low noise (∼2 keV/μm). A good agreement between the measured and simulated dose profiles was found, with discrepancies in the peak to plateau ratio of about 3% and 4% for proton and carbon ion beams respectively, showing a negligible LET dependence of the dosimetric element of the device. The microdosimetric spectra were validated with Monte Carlo simulations and a good agreement between the spectra shapes and positions was found. Dose mean lineal energy values were found to be in close agreement with those reported in the literature for clinical ion beams, showing a sharp increase along the Bragg curve, being also consistent with the calculated LETd for all depths within the experimental error of 10%. CONCLUSIONS The experimental indicate that the proposed device can allow enhanced dosimetry in particle therapy centers, where the absorbed dose measurement is implemented by the microdosimetric characterization of the radiation field, thus providing complementary results. In addition, the proposed device allows for the reduction of the experimental uncertainties associated with detector positioning and could facilitate the partial overcoming of some drawbacks related to the low sensitivity of diamond microdosimeters to low LET radiation.
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Affiliation(s)
- Claudio Verona
- Dipartimento di Ingegneria Industriale, Università di Roma "Tor Vergata", Sez. INFN-Roma2, Roma, Italia, Italy
| | - Sandra Barna
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Dietmar Georg
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
| | - Yasmin Hamad
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
| | - Giulio Magrin
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
| | - Marco Marinelli
- Dipartimento di Ingegneria Industriale, Università di Roma "Tor Vergata", Sez. INFN-Roma2, Roma, Italia, Italy
| | - Cynthia Meouchi
- Institute of Atomic and Subatomic Physics, Vienna University of Technology, Vienna, Austria
| | - Gianluca Verona Rinati
- Dipartimento di Ingegneria Industriale, Università di Roma "Tor Vergata", Sez. INFN-Roma2, Roma, Italia, Italy
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Pettinato S, Felici G, Galluzzo L, Rossi MC, Girolami M, Salvatori S. A readout system for highly sensitive diamond detectors for FLASH dosimetry. Phys Imaging Radiat Oncol 2024; 29:100538. [PMID: 38317851 PMCID: PMC10839766 DOI: 10.1016/j.phro.2024.100538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 02/07/2024] Open
Abstract
Accurate dosimetry of ultra-high dose-rate beams using diamond detectors remains challenging, primarily due to the elevated photocurrent peaks exceeding the input dynamics of precision electrometers. This work aimed at demonstrating the effectiveness of compact gated-integration electronics in conditioning the current peaks (>20 mA) generated by a highly sensitive (S ≃ 26 nC/Gy) custom-made diamond photoconductor under electron FLASH irradiation, as well as in real-time monitoring of beam dose and dose-rate. For the emerging FLASH technology, this study provided a new perspective on using commercially available diamond dosimeters with high sensitivity, currently employed in conventional radiotherapy.
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Affiliation(s)
- Sara Pettinato
- Dept. of Engineering, Niccolò Cusano University, via don Carlo Gnocchi 3, 00166 Rome, Italy
| | - Giuseppe Felici
- SIT – Sordina IORT Technologies S.p.A., Aprilia, Latina, Italy
| | | | - Maria Cristina Rossi
- Dept. of Industrial, Electronic, and Mechanical Engineering, Roma Tre University, Via Vito Volterra 62, 00146 Rome, Italy
| | - Marco Girolami
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche (ISM–CNR), Sede Secondaria di Montelibretti, Strada Provinciale 35/D n. 9, 00010 Montelibretti, Rome, Italy
| | - Stefano Salvatori
- Dept. of Engineering, Niccolò Cusano University, via don Carlo Gnocchi 3, 00166 Rome, Italy
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22
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No HJ, Wu YF, Dworkin ML, Manjappa R, Skinner L, Ashraf MR, Lau B, Melemenidis S, Viswanathan V, Yu ASJ, Surucu M, Schüler E, Graves EE, Maxim PG, Loo BW. Clinical Linear Accelerator-Based Electron FLASH: Pathway for Practical Translation to FLASH Clinical Trials. Int J Radiat Oncol Biol Phys 2023; 117:482-492. [PMID: 37105403 DOI: 10.1016/j.ijrobp.2023.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 03/03/2023] [Accepted: 04/11/2023] [Indexed: 04/29/2023]
Abstract
PURPOSE Ultrahigh-dose-rate (UHDR) radiation therapy (RT) has produced the FLASH effect in preclinical models: reduced toxicity with comparable tumor control compared with conventional-dose-rate RT. Early clinical trials focused on UHDR RT feasibility using specialized devices. We explore the technical feasibility of practical electron UHDR RT on a standard clinical linear accelerator (LINAC). METHODS AND MATERIALS We tuned the program board of a decommissioned electron energy for UHDR electron delivery on a clinical LINAC without hardware modification. Pulse delivery was controlled using the respiratory gating interface. A short source-to-surface distance (SSD) electron setup with a standard scattering foil was configured and tested on an anthropomorphic phantom using circular blocks with 3- to 20-cm field sizes. Dosimetry was evaluated using radiochromic film and an ion chamber profiler. RESULTS UHDR open-field mean dose rates at 100, 80, 70, and 59 cm SSD were 36.82, 59.52, 82.01, and 112.83 Gy/s, respectively. At 80 cm SSD, mean dose rate was ∼60 Gy/s for all collimated field sizes, with an R80 depth of 6.1 cm corresponding to an energy of 17.5 MeV. Heterogeneity was <5.0% with asymmetry of 2.2% to 6.2%. The short SSD setup was feasible under realistic treatment conditions simulating broad clinical indications on an anthropomorphic phantom. CONCLUSIONS Short SSD and tuning for high electron beam current on a standard clinical LINAC can deliver flat, homogenous UHDR electrons over a broad, clinically relevant range of field sizes and depths with practical working distances in a configuration easily reversible to standard clinical use.
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Affiliation(s)
- Hyunsoo Joshua No
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Yufan Fred Wu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Michael Louis Dworkin
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Rakesh Manjappa
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Lawrie Skinner
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - M Ramish Ashraf
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Brianna Lau
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Stavros Melemenidis
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Vignesh Viswanathan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Amy Shu-Jung Yu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Murat Surucu
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California
| | - Emil Schüler
- Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Edward Elliot Graves
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California
| | - Peter Gregor Maxim
- Department of Radiation Oncology, University of California, Irvine, Orange, California
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California; Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California.
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23
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Vanreusel V, Gasparini A, Galante F, Mariani G, Pacitti M, Colijn A, Reniers B, Yalvac B, Vandenbroucke D, Peeters M, Leblans P, Felici G, Verellen D, de Freitas Nascimento L. Optically stimulated luminescence system as an alternative for radiochromic film for 2D reference dosimetry in UHDR electron beams. Phys Med 2023; 114:103147. [PMID: 37804712 DOI: 10.1016/j.ejmp.2023.103147] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 08/18/2023] [Accepted: 09/21/2023] [Indexed: 10/09/2023] Open
Abstract
Radiotherapy is part of the treatment of over 50% of cancer patients. Its efficacy is limited by the radiotoxicity to the healthy tissue. FLASH-RT is based on the biological effect that ultra-high dose rates (UHDR) and very short treatment times strongly reduce normal tissue toxicity, while preserving the anti-tumoral effect. Despite many positive preclinical results, the translation of FLASH-RT to the clinic is hampered by the lack of accurate dosimetry for UHDR beams. To date radiochromic film is commonly used for dose assessment but has the drawback of lengthy and cumbersome read out procedures. In this work, we investigate the equivalence of a 2D OSL system to radiochromic film dosimetry in terms of dose rate independency. The comparison of both systems was done using the ElectronFlash linac. We investigated the dose rate dependence by variation of the (1) modality, (2) pulse repetition frequency, (3) pulse length and (4) source to surface distance. Additionally, we compared the 2D characteristics by field size measurements. The OSL calibration showed transferable between conventional and UHDR modality. Both systems are equally independent of average dose rate, pulse length and instantaneous dose rate. The OSL system showed equivalent in field size determination within 3 sigma. We show the promising nature of the 2D OSL system to serve as alternative for radiochromic film in UHDR electron beams. However, more in depth characterization is needed to assess its full potential.
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Affiliation(s)
- Verdi Vanreusel
- Research in Dosimetric Applications, SCK CEN, Boeretang 200, 2400 Mol, Belgium; CORE, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium; Iridium Netwerk, Oosterveldlaan 22, 2610 Wilrijk, Belgium.
| | - Alessia Gasparini
- CORE, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium; Iridium Netwerk, Oosterveldlaan 22, 2610 Wilrijk, Belgium
| | - Federica Galante
- Sordina IORT Technologies S.p.A., Via dell'Industria, 1/A, 04011 Aprilia, Latina, Italy
| | - Giulia Mariani
- Sordina IORT Technologies S.p.A., Via dell'Industria, 1/A, 04011 Aprilia, Latina, Italy
| | - Matteo Pacitti
- Sordina IORT Technologies S.p.A., Via dell'Industria, 1/A, 04011 Aprilia, Latina, Italy
| | - Arnaud Colijn
- CORE, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Brigitte Reniers
- NuTeC, CMK, Hasselt University, Wetenschapspark 27, 3590 Diepenbeek, Belgium
| | - Burak Yalvac
- NuTeC, CMK, Hasselt University, Wetenschapspark 27, 3590 Diepenbeek, Belgium
| | | | | | - Paul Leblans
- Agfa N.V., Septestraat 27, 2640 Mortsel, Belgium
| | - Giuseppe Felici
- Sordina IORT Technologies S.p.A., Via dell'Industria, 1/A, 04011 Aprilia, Latina, Italy
| | - Dirk Verellen
- CORE, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium; Iridium Netwerk, Oosterveldlaan 22, 2610 Wilrijk, Belgium
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24
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Marinelli M, di Martino F, Del Sarto D, Pensavalle JH, Felici G, Giunti L, De Liso V, Kranzer R, Verona C, Verona Rinati G. A diamond detector based dosimetric system for instantaneous dose rate measurements in FLASH electron beams. Phys Med Biol 2023; 68:175011. [PMID: 37494946 DOI: 10.1088/1361-6560/acead0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/25/2023] [Indexed: 07/28/2023]
Abstract
Objective.A reliable determination of the instantaneous dose rate (I-DR) delivered in FLASH radiotherapy treatments is believed to be crucial to assess the so-called FLASH effect in preclinical and biological studies. At present, no detectors nor real-time procedures are available to do that in ultra high dose rate (UH-DR) electron beams, typically consisting ofμs pulses characterized by I-DRs of the order of MGy/s. A dosimetric system is proposed possibly overcoming the above reported limitation, based on the recently developed flashDiamond (fD) detector (model 60025, PTW-Freiburg, Germany).Approach.A dosimetric system is proposed, based on a flashDiamond detector prototype, properly modified and adapted for very fast signal transmission. It was used in combination with a fast transimpedance amplifier and a digital oscilloscope to record the temporal traces of the pulses delivered by an ElectronFlash linac (SIT S.p.A., Italy). The proposed dosimetric systems was investigated in terms of the temporal characteristics of its response and the capability to measure the absolute delivered dose and instantaneous dose rate (I-DR). A 'standard' flashDiamond was also investigated and its response compared with the one of the specifically designed prototype.Main results. Temporal traces recorded in several UH-DR irradiation conditions showed very good signal to noise ratios and rise and decay times of the order of a few tens ns, faster than the ones obtained by the current transformer embedded in the linac head. By analyzing such signals, a calibration coefficient was derived for the fD prototype and found to be in agreement within 1% with the one obtained under reference60Co irradiation. I-DRs as high as about 2 MGy s-1were detected without any undesired saturation effect. Absolute dose per pulse values extracted by integrating the I-DR signals were found to be linear up to at least 7.13 Gy and in very good agreement with the ones obtained by connecting the fD to a UNIDOS electrometer (PTW-Freiburg, Germany). A good short term reproducibility of the linac output was observed, characterized by a pulse-to-pulse variation coefficient of 0.9%. Negligible differences were observed when replacing the fD prototype with a standard one, with the only exception of a somewhat slower response time for the latter detector type.Significance.The proposed fD-based system was demonstrated to be a suitable tool for a thorough characterization of UH-DR beams, providing accurate and reliable time resolved I-DR measurements from which absolute dose values can be straightforwardly derived.
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Affiliation(s)
- Marco Marinelli
- Dipartimento di Ingegneria Industriale, Università di Roma Tor Vergata, Roma, Italy
| | - Fabio di Martino
- U.O.Fisica Sanitaria, Azienda Universitaria Ospedaliera Pisana, Pisa, Italy
| | - Damiano Del Sarto
- U.O.Fisica Sanitaria, Azienda Universitaria Ospedaliera Pisana, Pisa, Italy
| | | | | | | | | | - Rafael Kranzer
- PTW-Freiburg, Freiburg D-79115, Germany
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University Oldenburg, D-26121 Germany
| | - Claudio Verona
- Dipartimento di Ingegneria Industriale, Università di Roma Tor Vergata, Roma, Italy
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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: 13] [Impact Index Per Article: 6.5] [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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Togno M, Nesteruk KP, Schäfer R, Psoroulas S, Meer D, Grossmann M, Christensen JB, Yukihara EG, Lomax AJ, Weber DC, Safai S. Ultra-high dose rate dosimetry for pre-clinical experiments with mm-small proton fields. Phys Med 2022; 104:101-111. [PMID: 36395638 DOI: 10.1016/j.ejmp.2022.10.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 10/10/2022] [Accepted: 10/23/2022] [Indexed: 11/15/2022] Open
Abstract
PURPOSE To characterize an experimental setup for ultra-high dose rate (UHDR) proton irradiations, and to address the challenges of dosimetry in millimetre-small pencil proton beams. METHODS At the PSI Gantry 1, high-energy transmission pencil beams can be delivered to biological samples and detectors up to a maximum local dose rate of ∼9000 Gy/s. In the presented setup, a Faraday cup is used to measure the delivered number of protons up to ultra-high dose rates. The response of transmission ion-chambers, as well as of different field detectors, was characterized over a wide range of dose rates using the Faraday cup as reference. RESULTS The reproducibility of the delivered proton charge was better than 1 % in the proposed experimental setup. EBT3 films, Al2O3:C optically stimulated luminescence detectors and a PTW microDiamond were used to validate the predicted dose. Transmission ionization chambers showed significant volume ion-recombination (>30 % in the tested conditions) which can be parametrized as a function of the maximum proton current density. Over the considered range, EBT3 films, inorganic scintillator-based screens and the PTW microDiamond were demonstrated to be dose rate independent within ±3 %, ±1.8 % and ±1 %, respectively. CONCLUSIONS Faraday cups are versatile dosimetry instruments that can be used for dose estimation, field detector characterization and on-line dose verification for pre-clinical experiments in UHDR proton pencil beams. Among the tested detectors, the commercial PTW microDiamond was found to be a suitable option to measure real time the dosimetric properties of narrow pencil proton beams for dose rates up to 2.2 kGy/s.
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Affiliation(s)
- M Togno
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland.
| | - K P Nesteruk
- Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, USA
| | - R Schäfer
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland
| | - S Psoroulas
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland
| | - D Meer
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland
| | - M Grossmann
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland
| | - J B Christensen
- Department of Radiation Safety and Security, Paul Scherrer Institut, Villigen, Switzerland
| | - E G Yukihara
- Department of Radiation Safety and Security, Paul Scherrer Institut, Villigen, Switzerland
| | - A J Lomax
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland; Department of Physics, ETH Zurich, Zurich, Switzerland
| | - D C Weber
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland; Department of Radiation Oncology, University Hospital Zurich, Zurich, Switzerland; Department of Radiation Oncology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - S Safai
- Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland
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27
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Numerical modeling of air-vented parallel plate ionization chambers for ultra-high dose rate applications. Phys Med 2022; 103:147-156. [DOI: 10.1016/j.ejmp.2022.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 09/26/2022] [Accepted: 10/07/2022] [Indexed: 11/21/2022] Open
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Di Martino F, Del Sarto D, Barone S, Giuseppina Bisogni M, Capaccioli S, Galante F, Gasparini A, Mariani G, Masturzo L, Montefiori M, Pacitti M, Paiar F, Harold Pensavalle J, Romano F, Ursino S, Vanreusel V, Verellen D, Felici G. A new calculation method for the free electron fraction of an ionization chamber in the ultra-high-dose-per-pulse regimen. Phys Med 2022; 103:175-180. [DOI: 10.1016/j.ejmp.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 10/27/2022] [Accepted: 11/01/2022] [Indexed: 11/11/2022] Open
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29
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Vanreusel V, Gasparini A, Galante F, Mariani G, Pacitti M, Cociorb M, Giammanco A, Reniers B, Reulens N, Shonde TB, Vallet H, Vandenbroucke D, Peeters M, Leblans P, Ma B, Felici G, Verellen D, de Freitas Nascimento L. Point scintillator dosimetry in ultra-high dose rate electron “FLASH” radiation therapy: A first characterization. Phys Med 2022; 103:127-137. [DOI: 10.1016/j.ejmp.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 09/27/2022] [Accepted: 10/07/2022] [Indexed: 11/26/2022] Open
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30
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Rinati GV, Felici G, Galante F, Gasparini A, Kranzer R, Mariani G, Pacitti M, Prestopino G, Schüller A, Vanreusel V, Verellen D, Verona C, Marinelli M. Application of a novel diamond detector for commissioning of FLASH radiotherapy electron beams. Med Phys 2022; 49:5513-5522. [PMID: 35652248 PMCID: PMC9543846 DOI: 10.1002/mp.15782] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/18/2022] [Accepted: 05/23/2022] [Indexed: 11/06/2022] Open
Abstract
Purpose A diamond detector prototype was recently proposed by Marinelli et al. (Medical Physics 2022, https://doi.org/10.1002/mp.15473) for applications in ultrahigh‐dose‐per‐pulse (UH‐DPP) and ultrahigh‐dose‐rate (UH‐DR) beams, as used in FLASH radiotherapy (FLASH‐RT). In the present study, such so‐called flashDiamond (fD) was investigated from the dosimetric point of view, under pulsed electron beam irradiation. It was then used for the commissioning of an ElectronFlash linac (SIT S.p.A., Italy) both in conventional and UH‐DPP modalities. Methods Detector calibration was performed in reference conditions, under 60Co and electron beam irradiation. Its response linearity was investigated in UH‐DPP conditions. For this purpose, the DPP was varied in the 1.2–11.9 Gy range, by changing either the beam applicator or the pulse duration from 1 to 4 μs. Dosimetric validation of the fD detector prototype was then performed in conventional modality, by measuring percentage depth dose (PDD) curves, beam profiles, and output factors (OFs). All such measurements were carried out in a motorized water phantom. The obtained results were compared with the ones from commercially available dosimeters, namely, a microDiamond, an Advanced Markus ionization chamber, a silicon diode detector, and EBT‐XD GAFchromic films. Finally, the fD detector was used to fully characterize the 7 and 9 MeV UH‐DPP electron beams delivered by the ElectronFlash linac. In particular, PDDs, beam profiles, and OFs were measured, for both energies and all the applicators, and compared with the ones from EBT‐XD films irradiated in the same experimental conditions. Results The fD calibration coefficient resulted to be independent from the investigated beam qualities. The detector response was found to be linear in the whole investigated DPP range. A very good agreement was observed among PDDs, beam profiles, and OFs measured by the fD prototype and reference detectors, both in conventional and UH‐DPP irradiation modalities. Conclusions The fD detector prototype was validated from the dosimetric point of view against several commercial dosimeters in conventional beams. It was proved to be suitable in UH‐DPP and UH‐DR conditions, for which no other commercial real‐time active detector is available to date. It was shown to be a very useful tool to perform fast and reproducible beam characterizations in standard clinical motorized water phantom setups. All of the previously mentioned demonstrate the suitability of the proposed detector for the commissioning of UH‐DR linac beams for preclinical FLASH‐RT applications.
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Affiliation(s)
- Gianluca Verona Rinati
- Dipartimento di Ingegneria Industriale, Università di Roma "Tor Vergata,", Roma, 00133, Italy
| | | | | | - Alessia Gasparini
- Iridium Kankernetwerk, Antwerp, 2610, Belgium.,Antwerp University, Faculty of Medicine and Health Sciences, Antwerp, 2610, Belgium
| | - Rafael Kranzer
- PTW-Freiburg, Freiburg, 79115, Germany.,University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, 26121, Germany
| | | | | | - Giuseppe Prestopino
- Dipartimento di Ingegneria Industriale, Università di Roma "Tor Vergata,", Roma, 00133, Italy
| | - Andreas Schüller
- Physikalisch-Technische Bundesanstalt, Braunschweig, 38116, Germany
| | - Verdi Vanreusel
- Iridium Kankernetwerk, Antwerp, 2610, Belgium.,Antwerp University, Faculty of Medicine and Health Sciences, Antwerp, 2610, Belgium
| | - Dirk Verellen
- Iridium Kankernetwerk, Antwerp, 2610, Belgium.,Antwerp University, Faculty of Medicine and Health Sciences, Antwerp, 2610, Belgium
| | - Claudio Verona
- Dipartimento di Ingegneria Industriale, Università di Roma "Tor Vergata,", Roma, 00133, Italy
| | - Marco Marinelli
- Dipartimento di Ingegneria Industriale, Università di Roma "Tor Vergata,", Roma, 00133, Italy
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31
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Rodríguez FG, Gonzalez-Castaño DM, Fernández NG, Pardo-Montero J, Schüller A, Gasparini A, Vanreusel V, Verellen D, Felici G, Kranzer R, Paz-Martín J. Development of an ultra-thin parallel plate ionization chamber for dosimetry in flash radiotherapy. Med Phys 2022; 49:4705-4714. [PMID: 35416306 PMCID: PMC9545838 DOI: 10.1002/mp.15668] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 11/29/2022] Open
Abstract
Background Conventional air ionization chambers (ICs) exhibit ion recombination correction factors that deviate substantially from unity when irradiated with dose per pulse magnitudes higher than those used in conventional radiotherapy. This fact makes these devices unsuitable for the dosimetric characterization of beams in ultra‐high dose per pulse as used for FLASH radiotherapy. Purpose We present the design, development, and characterization of an ultra‐thin parallel plate IC that can be used in ultra‐high dose rate (UHDR) deliveries with minimal recombination. Methods The charge collection efficiency (CCE) of parallel plate ICs was modeled through a numerical solution of the coupled differential equations governing the transport of charged carriers produced by ionizing radiation. It was used to find out the optimal parameters for the purpose of designing an IC capable of exhibiting a linear response with dose (deviation less than 1%) up to 10 Gy per pulse at 4
μs pulse duration. As a proof of concept, two vented parallel plate IC prototypes have been built and tested in different ultra‐high pulse dose rate electron beams. Results It has been found that by reducing the distance between electrodes to a value of 0.25 mm it is possible to extend the dose rate operating range of parallel plate ICs to ultra‐high dose per pulse range, at standard voltage of clinical grade electrometers, well into several Gy per pulse. The two IC prototypes exhibit behavior as predicted by the numerical simulation. One of the so‐called ultra‐thin parallel plate ionization chamber (UTIC) prototypes was able to measure up to 10 Gy per pulse, 4
μs pulse duration, operated at 300 V with no significant deviation from linearity within the uncertainties (ElectronFlash Linac, SIT). The other prototype was tested up to 5.4 Gy per pulse, 2.5
μs pulse duration, operated at 250 V with CCE higher than 98.6% (Metrological Electron Accelerator Facility, MELAF at Physikalisch‐Technische Bundesanstalt, PTB). Conclusions This work demonstrates the ability to extend the dose rate operating range of ICs to ultra‐high dose per pulse range by reducing the spacing between electrodes. The results show that UTICs are suitable for measurement in UHDR electron beams.
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Affiliation(s)
- Faustino Gómez Rodríguez
- Department of Particle Physics, University of Santiago, Santiago de Compostela, Spain.,Radiation Physics Laboratory, University of Santiago, Santiago de Compostela, Spain
| | | | | | - Juan Pardo-Montero
- Group of Medical Physics and Biomathematics, Instituto de Investigación Sanitaria de Santiago (IDIS), Santiago de Compostela, Spain.,Department of Medical Physics, Complexo Hospitalario Universitario de Santiago de Compostela, Spain
| | - Andreas Schüller
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
| | - Alessia Gasparini
- Department of Radiotherapy, Iridium Network, Belgium.,Faculty of Medicine and Health sciences, University of Antwerp, Belgium.,SCK CEN, Research in dosimetric applications, Mol, Belgium
| | - Verdi Vanreusel
- Department of Radiotherapy, Iridium Network, Belgium.,Faculty of Medicine and Health sciences, University of Antwerp, Belgium.,SCK CEN, Research in dosimetric applications, Mol, Belgium
| | - Dirk Verellen
- Department of Radiotherapy, Iridium Network, Belgium.,Faculty of Medicine and Health sciences, University of Antwerp, Belgium
| | | | - Rafael Kranzer
- PTW, Freiburg, Germany.,University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University Oldenburg, Germany
| | - Jose Paz-Martín
- Department of Particle Physics, University of Santiago, Santiago de Compostela, Spain
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