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Fenwick JD, Kumar S, Pardo-Montero J. Collection efficiencies of cylindrical and plane parallel ionization chambers: analytical and numerical results and implications for experimentally determined correction factors. Phys Med Biol 2024; 69:155023. [PMID: 39013400 DOI: 10.1088/1361-6560/ad63ed] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 07/16/2024] [Indexed: 07/18/2024]
Abstract
Objectives.To derive a collection efficiency formula,fGauss, for cylindrical ionization chambers in pulsed radiation beams from a volume recombination model of Boaget al(1996Phys. Med. Biol.41885-97) including free electrons. To validatefGaussand a parallel plate chamber formulafexpusing an ion transport code and calculate changes in collection efficiencies caused by electric field charge screening at 0.1-100 mGy doses-per-pulse. And to determine collection efficienciesCE∞predicted at infinite voltage in the absence of avalanche effects by fitting scaled formulae to efficiencies computed for 100-400 V chamber voltages and 10 and 100 mGy doses-per-pulse.Approach.Calculations were performed for an idealized parallel plate chamber with 2 mm electrode separationd, and for an idealized cylindrical chamber with 0.5 and 2.333 mm inner and electrode radiirinandrout.Main results.fGaussandfexppredict the same collection efficiencies for cylindrical and parallel plate chambers satisfyingd2=(rout2-rin2)ln(rout/rin)/2, an equivalence condition met by the chambers studied. Without charge screening, efficiencies computed using the code equalledfGaussandfexp. With screening, efficiencies changed by ⩽0.03%, ⩽1.1% and ⩽21.3% at 1, 10 and 100 mGy doses-per-pulse, and differed between the chambers by ⩽0.9% and ⩽19.6% at ⩽10 and 100 mGy dose-per-pulse. For fits offexpandfGauss,CE∞values were ⩽1.2% and ⩽17.6% from unity at 10 and 100 mGy per pulse respectively, closer than for other formulae tested.Significance.Allowing for screening,fGaussandfexpdescribed computed collection efficiencies to within 0.03%, 1.1% and 21.3% at doses-per-pulse ⩽1, 10 and 100 mGy. Equivalence of the two chambers broke down at 100 mGy per pulse. Departures ofCE∞values from unity suggest that collection efficiencies determined experimentally by fittingfGaussorfexpto readings made at multiple voltages will be accurate to within 1.2% and 17.6% at 10 and 100 mGy per pulse respectively.
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Affiliation(s)
- John D Fenwick
- Department of Medical Physics and Bioengineering, 8th Floor, Malet Place Engineering Building, University College London, Gower Street, London WC1E 6BT, England, United Kingdom
| | - Sudhir Kumar
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CT & CRS Building, Anushaktinagar, Mumbai 400094, India
| | - Juan Pardo-Montero
- Group of Medical Physics and Biomathematics, Instituto de Investigación Sanitaria de Santiago (IDIS), 15706 Santiago de Compostela, Spain
- Department of Medical Physics, Complexo Hospitalario Universitario de Santiago de Compostela, 15706 Santiago de Compostela, Spain
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Muir B, Davis S, Dhanesar S, Hillman Y, Iakovenko V, Kim GGY, Alves VGL, Lei Y, Lowenstein J, Renaud J, Sarfehnia A, Siebers J, Tantôt L. AAPM WGTG51 Report 385: Addendum to the AAPM's TG-51 protocol for clinical reference dosimetry of high-energy electron beams. Med Phys 2024. [PMID: 38980220 DOI: 10.1002/mp.17277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/29/2024] [Accepted: 06/14/2024] [Indexed: 07/10/2024] Open
Abstract
An Addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water is presented for electron beams with energies between 4 MeV and 22 MeV (1.70 cm ≤ R 50 ≤ 8.70 cm $1.70\nobreakspace {\rm cm} \le R_{\text{50}} \le 8.70\nobreakspace {\rm cm}$ ). This updated formalism allows simplified calibration procedures, including the use of calibrated cylindrical ionization chambers in all electron beams without the use of a gradient correction. Newk Q $k_{Q}$ data are provided for electron beams based on Monte Carlo simulations. Implementation guidance is provided. Components of the uncertainty budget in determining absorbed dose to water at the reference depth are discussed. Specifications for a reference-class chamber in electron beams include chamber stability, settling, ion recombination behavior, and polarity dependence. Progress in electron beam reference dosimetry is reviewed. Although this report introduces some major changes (e.g., gradient corrections are implicitly included in the electron beam quality conversion factors), they serve to simplify the calibration procedure. Results for absorbed dose per linac monitor unit are expected to be up to approximately 2 % higher using this Addendum compared to using the original TG-51 protocol.
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Affiliation(s)
- Bryan Muir
- Metrology Research Centre, National Research Council of Canada, Ottawa, Ontario, Canada
| | - Stephen Davis
- Department of Radiation Oncology, Miami Cancer Institute, Miami, Florida, USA
| | - Sandeep Dhanesar
- Department of Radiation Oncology, Houston Methodist Hospital, Houston, Texa, USA
| | - Yair Hillman
- Department of Radiation Oncology, Sharett Institute of Oncology, Hadassah Medical Center, Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Grace Gwe-Ya Kim
- Department of Radiation Medicine and Applied Sciences, UC San Diego School of Medicine, San Diego, California, USA
| | | | - Yu Lei
- Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Jessica Lowenstein
- Department of Radiation Physics, UT M.D. Anderson Cancer Center, Houston, Texa, USA
| | - James Renaud
- Metrology Research Centre, National Research Council of Canada, Ottawa, Ontario, Canada
| | - Arman Sarfehnia
- Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
- Department of Medical Physics, Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Jeffrey Siebers
- Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia, USA
| | - Laurent Tantôt
- Département de radio-oncologie, CIUSSS de l'Est-de-l'Île-de-Montréal - Hôpital Maisonneuve-Rosemont, Montreal, Quebec, Canada
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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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4
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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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Claessens M, Vanreusel V, Gasparini A, Nascimento LDF, Yalvec B, Reniers B, Verellen D. Automated determination of the ion-recombination correction factor (k sat) in ultra-high dose rate electron radiation therapy. Med Phys 2024; 51:4536-4545. [PMID: 38639653 DOI: 10.1002/mp.17085] [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: 04/03/2023] [Revised: 03/06/2024] [Accepted: 03/13/2024] [Indexed: 04/20/2024] Open
Abstract
BACKGROUND Plane-parallel ionization chambers are the recommended secondary standard systems for clinical reference dosimetry of electrons. Dosimetry in high dose rate and dose-per-pulse (DPP) is challenging as ionization chambers are subject to ion recombination, especially when dose rate and/or DPP is increased beyond the range of conventional radiotherapy. The lack of universally accepted models for correction of ion recombination in UDHR is still an issue as it is, especially in FLASH-RT research, which is crucial in order to be able to accurately measure the dose for a wide range of dose rates and DPPs. PURPOSE The objective of this study was to show the feasibility of developing an Artificial Intelligence model to predict the ion-recombination factor-ksat for a plane-parallel Advanced Markus ionization chamber for conventional and ultra-high dose rate electron beams based on machine parameters. In addition, the predicted ksat of the AI model was compared with the current applied analytical models for this correction factor. METHODS A total number of 425 measurements was collected with a balanced variety in machine parameter settings. The specific ksat values were determined by dividing the output of the reference dosimeter (optically stimulated luminescence [OSL]) by the output of the AM chamber. Subsequently, a XGBoost regression model was trained, which used the different machine parameters as input features and the corresponding ksat value as output. The prediction accuracy of this regression model was characterized by R2-coefficient of determination, mean absolute error and root mean squared error. In addition, the model was compared with the Two-Voltage (TVA) method and empirical Petersson model for 19 different dose-per-pulse values ranging from conventional to UDHR regimes. The Akiake Information criterion (AIC) was calculated for the three different models. RESULTS The XGBoost regression model reached a R2-score of 0.94 on the independent test set with a MAE of 0.067 and RMSE of 0.106. For the additional 19 random data points, the ksat values predicted by the XGBoost model showed to be in agreement, within the uncertainties, with the ones determined by the Petersson model and better than the TVA method for doses per pulse >3.5 Gy with a maximum deviation from the ground truth of 14.2%, 16.7%, and -36.0%, respectively, for DPP >4 Gy. CONCLUSION The proposed method of using AI for ksat determination displays efficiency. For the investigated DPPs, the ksat values obtained with the XGBoost model were in concurrence with the ones obtained with the current available analytical models within the boundaries of uncertainty, certainly for the DPP characterizing UDHR. But the overall performance of the AI model, taking the number of free parameters into account, lacked efficiency. Future research should optimize the determination of the experimental ksat, and investigate the determination the ksat for DPPs higher than the ones investigated in this study, while also evaluating the prediction of the proposed XGBoost model for UDHR machines of different centers.
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Affiliation(s)
- Michaël Claessens
- Department of Radiation Oncology, Iridium Netwerk, Wilrijk, Antwerp, Belgium
- Centre for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Antwerp, Belgium
| | - Verdi Vanreusel
- Department of Radiation Oncology, Iridium Netwerk, Wilrijk, Antwerp, Belgium
- Centre for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Antwerp, Belgium
- Research in Dosimetric Applications (RDA), SCK CEN, Mol, Antwerp, Belgium
| | - Alessia Gasparini
- Department of Radiation Oncology, Iridium Netwerk, Wilrijk, Antwerp, Belgium
- Centre for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Antwerp, Belgium
| | | | - Burak Yalvec
- NuTeC, CMK, Hasselt University, Hasselt, Belgium
| | | | - Dirk Verellen
- Department of Radiation Oncology, Iridium Netwerk, Wilrijk, Antwerp, Belgium
- Centre for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Antwerp, Belgium
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6
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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. [PMID: 38772134 DOI: 10.1002/mp.17172] [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: 11/30/2023] [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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Shaikh S, Escribano-Rodriguez S, Radogna R, Kelleter L, Godden C, Warren M, Attree D, Saakyan R, Mortimer L, Corlett P, Warry A, Gosling A, Baker C, Poynter A, Kacperek A, Jolly S. Spread-out Bragg peak measurements using a compact quality assurance range calorimeter at the Clatterbridge cancer centre. Phys Med Biol 2024; 69:115015. [PMID: 38657625 DOI: 10.1088/1361-6560/ad42fd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
Objective.The superior dose conformity provided by proton therapy relative to conventional x-ray radiotherapy necessitates more rigorous quality assurance (QA) procedures to ensure optimal patient safety. Practically however, time-constraints prevent comprehensive measurements to be made of the proton range in water: a key parameter in ensuring accurate treatment delivery.Approach.A novel scintillator-based device for fast, accurate water-equivalent proton range QA measurements for ocular proton therapy is presented. Experiments were conducted using a compact detector prototype, the quality assurance range calorimeter (QuARC), at the Clatterbridge cancer centre (CCC) in Wirral, UK for the measurement of pristine and spread-out Bragg peaks (SOBPs). The QuARC uses a series of 14 optically-isolated 100 × 100 × 2.85 mm polystyrene scintillator sheets, read out by a series of photodiodes. The detector system is housed in a custom 3D-printed enclosure mounted directly to the nozzle and a numerical model was used to fit measured depth-light curves and correct for scintillator light quenching.Main results.Measurements of the pristine 60 MeV proton Bragg curve found the QuARC able to measure proton ranges accurate to 0.2 mm and reduced QA measurement times from several minutes down to a few seconds. A new framework of the quenching model was deployed to successfully fit depth-light curves of SOBPs with similar range accuracy.Significance.The speed, range accuracy and simplicity of the QuARC make the device a promising candidate for ocular proton range QA. Further work to investigate the performance of SOBP fitting at higher energies/greater depths is warranted.
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Affiliation(s)
- Saad Shaikh
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | | | | | - Laurent Kelleter
- Division of Medical Physics in Radiation Oncology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Connor Godden
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Matthew Warren
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Derek Attree
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Ruben Saakyan
- Department of Physics and Astronomy, University College London, London, United Kingdom
| | - Linda Mortimer
- Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
| | - Peter Corlett
- Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
| | - Alison Warry
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Andrew Gosling
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Colin Baker
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Andrew Poynter
- Proton Beam Therapy Physics, University College London Hospital NHS Foundation Trust, London, United Kingdom
| | - Andrzej Kacperek
- Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Simon Jolly
- Department of Physics and Astronomy, University College London, London, United Kingdom
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8
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Wanstall HC, Burkart F, Dinter H, Kellermeier M, Kuropka W, Mayet F, Vinatier T, Santina E, Chadwick AL, Merchant MJ, Henthorn NT, Köpke M, Stacey B, Jaster-Merz S, Jones RM. First in vitro measurement of VHEE relative biological effectiveness (RBE) in lung and prostate cancer cells using the ARES linac at DESY. Sci Rep 2024; 14:10957. [PMID: 38740830 DOI: 10.1038/s41598-024-60585-7] [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: 12/07/2023] [Accepted: 04/24/2024] [Indexed: 05/16/2024] Open
Abstract
Very high energy electrons (VHEE) are a potential candidate for radiotherapy applications. This includes tumours in inhomogeneous regions such as lung and prostate cancers, due to the insensitivity of VHEE to inhomogeneities. This study explores how electrons in the VHEE range can be used to perform successful in vitro radiobiological studies. The ARES (accelerator research experiment at SINBAD) facility at DESY, Hamburg, Germany was used to deliver 154 MeV electrons to both prostate (PC3) and lung (A549) cancer cells in suspension. Dose was delivered to samples with repeatability and uniformity, quantified with Gafchromic film. Cell survival in response to VHEE was measured using the clonogenic assay to determine the biological effectiveness of VHEE in cancer cells for the first time using this method. Equivalent experiments were performed using 300 kVp X-rays, to enable VHEE irradiated cells to be compared with conventional photons. VHEE irradiated cancer cell survival was fitted to the linear quadratic (LQ) model (R2 = 0.96-0.97). The damage from VHEE and X-ray irradiated cells at doses between 1.41 and 6.33 Gy are comparable, suggesting similar relative biological effectiveness (RBE) between the two modalities. This suggests VHEE is as damaging as photon radiotherapy and therefore could be used to successfully damage cancer cells during radiotherapy. The RBE of VHEE was quantified as the relative doses required for 50% (D0.5) and 10% (D0.1) cell survival. Using these values, VHEE RBE was measured as 0.93 (D0.5) and 0.99 (D0.1) for A549 and 0.74 (D0.5) and 0.93 (D0.1) for PC3 cell lines respectively. For the first time, this study has shown that 154 MeV electrons can be used to effectively kill lung and prostate cancer cells, suggesting that VHEE would be a viable radiotherapy modality. Several studies have shown that VHEE has characteristics that would offer significant improvements over conventional photon radiotherapy for example, electrons are relatively easy to steer and can be used to deliver dose rapidly and with high efficiency. Studies have shown improved dose distribution with VHEE in treatment plans, in comparison to VMAT, indicating that VHEE can offer improved and safer treatment plans with reduced side effects. The biological response of cancer cells to VHEE has not been sufficiently studied as of yet, however this initial study provides some initial insights into cell damage. VHEE offers significant benefits over photon radiotherapy and therefore more studies are required to fully understand the biological effectiveness of VHEE.
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Affiliation(s)
- Hannah C Wanstall
- Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
- Manchester Academic Health Science Centre, The Christie NHS Foundation Trust, Wilmslow Road, Manchester, M20 4BX, UK.
- Daresbury Laboratory, The Cockcroft Institute, Daresbury, Warrington, WA4 4AD, UK.
| | - Florian Burkart
- Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, 22607, Hamburg, Germany
| | - Hannes Dinter
- Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, 22607, Hamburg, Germany
| | - Max Kellermeier
- Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, 22607, Hamburg, Germany
| | - Willi Kuropka
- Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, 22607, Hamburg, Germany
| | - Frank Mayet
- Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, 22607, Hamburg, Germany
| | - Thomas Vinatier
- Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, 22607, Hamburg, Germany
| | - Elham Santina
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Amy L Chadwick
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Michael J Merchant
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Nicholas T Henthorn
- Division of Cancer Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Michael Köpke
- Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, 22607, Hamburg, Germany
| | - Blae Stacey
- Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, 22607, Hamburg, Germany
| | - Sonja Jaster-Merz
- Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, 22607, Hamburg, Germany
| | - Roger M Jones
- Department of Physics and Astronomy, Faculty of Science and Engineering, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK
- Daresbury Laboratory, The Cockcroft Institute, Daresbury, Warrington, WA4 4AD, UK
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9
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Vidal M, Gérard A, Floquet V, Forthomme J, Christensen JB, Almhagen E, Grusell E, Heymans V, Rossomme S, Dumas S, Trimaud R, Hérault J. Beam monitor chamber calibration of a synchro-cyclotron high dose rate per pulse pulsed scanned proton beam. Phys Med Biol 2024; 69:085016. [PMID: 38252970 DOI: 10.1088/1361-6560/ad2123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 01/22/2024] [Indexed: 01/24/2024]
Abstract
Objective. Ionization chambers, mostly used for beam calibration and for reference dosimetry, can show high recombination effects in pulsed high dose rate proton beams. The aims of this paper are: first, to characterize the linearity response of newly designed asymmetrical beam monitor chambers (ABMC) in a 100-226 MeV pulsed high dose rate per pulse scanned proton beam; and secondly, to calibrate the ABMC with a PPC05 (IBA Dosimetry) plane parallel ionization chamber and compare to calibration with a home-made Faraday cup (FC).Approach. The ABMC response linearity was evaluated with both the FC and a PTW 60019 microDiamond detector. Regarding ionometry-based ABMC calibration, recombination factors were evaluated theoretically, then numerically, and finally experimentally measured in water for a plane parallel ionization chamber PPC05 (IBA Dosimetry) throughkssaturation curves. Finally, ABMC calibration was also achieved with FC and compared to the ionometry method for 7 energies.Main results. Linearity measurements showed that recombination losses in the new ABMC design were well taken into account for the whole range of the machine dose rates. The two-voltage-method was not suitable for recombination correction, but Jaffé's plots analysis was needed, emphasizing the current IAEA TRS-398 reference protocol limitations. Concerning ABMC calibration, FC based absorbed dose estimation and PPC05-based absorbed dose estimation differ by less than 6.3% for the investigated energies.Significance.So far, no update on reference dosimetry protocols is available to estimate the absorbed dose in ionization chambers for clinical high dose rate per pulse pulsed scanned proton beams. This work proposes a validation of the new ABMC design, a method to take into account the recombination effect for ionometry-based ABMC calibration and a comparison with FC dose estimation in this type of proton beams.
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Affiliation(s)
- Marie Vidal
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
| | - Anaïs Gérard
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
| | - Vincent Floquet
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
| | | | - Jeppe Brage Christensen
- DTU Health Tech, Technical University of Denmark, Roskilde, Denmark
- Department of Radiation Safety and Security, Paul Scherrer Institute, PSI Villigen, Switzerland
| | - Erik Almhagen
- Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science-Skandion Clinics Uppsala, Sweden
| | - Erik Grusell
- Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medical Radiation Science-Skandion Clinics Uppsala, Sweden
| | | | | | - Serge Dumas
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
| | - Richard Trimaud
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
| | - Joël Hérault
- Institut Méditerranéen de Protonthérapie-Centre Antoine Lacassagne, Fédération Claude Lalanne, Nice, France
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10
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Bateman JJ, Buchanan E, Corsini R, Farabolini W, Korysko P, Garbrecht Larsen R, Malyzhenkov A, Ortega Ruiz I, Rieker V, Gerbershagen A, Dosanjh M. Development of a novel fibre optic beam profile and dose monitor for very high energy electron radiotherapy at ultrahigh dose rates. Phys Med Biol 2024; 69:085006. [PMID: 38478998 DOI: 10.1088/1361-6560/ad33a0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 03/13/2024] [Indexed: 04/04/2024]
Abstract
Objective. Very high energy electrons (VHEE) in the range of 50-250 MeV are of interest for treating deep-seated tumours with FLASH radiotherapy (RT). This approach offers favourable dose distributions and the ability to deliver ultra-high dose rates (UHDR) efficiently. To make VHEE-based FLASH treatment clinically viable, a novel beam monitoring technology is explored as an alternative to transmission ionisation monitor chambers, which have non-linear responses at UHDR. This study introduces the fibre optic flash monitor (FOFM), which consists of an array of silica optical fibre-based Cherenkov sensors with a photodetector for signal readout.Approach. Experiments were conducted at the CLEAR facility at CERN using 200 MeV and 160 MeV electrons to assess the FOFM's response linearity to UHDR (characterised with radiochromic films) required for FLASH radiotherapy. Beam profile measurements made on the FOFM were compared to those using radiochromic film and scintillating yttrium aluminium garnet (YAG) screens.Main results. A range of photodetectors were evaluated, with a complementary-metal-oxide-semiconductor (CMOS) camera being the most suitable choice for this monitor. The FOFM demonstrated excellent response linearity from 0.9 Gy/pulse to 57.4 Gy/pulse (R2= 0.999). Furthermore, it did not exhibit any significant dependence on the energy between 160 MeV and 200 MeV nor the instantaneous dose rate. Gaussian fits applied to vertical beam profile measurements indicated that the FOFM could accurately provide pulse-by-pulse beam size measurements, agreeing within the error range of radiochromic film and YAG screen measurements, respectively.Significance. The FOFM proves to be a promising solution for real-time beam profile and dose monitoring for UHDR VHEE beams, with a linear response in the UHDR regime. Additionally it can perform pulse-by-pulse beam size measurements, a feature currently lacking in transmission ionisation monitor chambers, which may become crucial for implementing FLASH radiotherapy and its associated quality assurance requirements.
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Affiliation(s)
- Joseph J Bateman
- John Adams Institute for Accelerator Science, Department of Physics, University of Oxford, Oxford, OX1 3RH, United Kingdom
| | - Emma Buchanan
- European Organization for Nuclear Research (CERN), Meyrin, 1211, Geneva, Switzerland
| | - Roberto Corsini
- European Organization for Nuclear Research (CERN), Meyrin, 1211, Geneva, Switzerland
| | - Wilfrid Farabolini
- European Organization for Nuclear Research (CERN), Meyrin, 1211, Geneva, Switzerland
| | - Pierre Korysko
- John Adams Institute for Accelerator Science, Department of Physics, University of Oxford, Oxford, OX1 3RH, United Kingdom
- European Organization for Nuclear Research (CERN), Meyrin, 1211, Geneva, Switzerland
| | - Robert Garbrecht Larsen
- European Organization for Nuclear Research (CERN), Meyrin, 1211, Geneva, Switzerland
- Particle Therapy Research Centre (PARTREC), Department of Radiation Oncology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Alexander Malyzhenkov
- European Organization for Nuclear Research (CERN), Meyrin, 1211, Geneva, Switzerland
| | - Iñaki Ortega Ruiz
- European Organization for Nuclear Research (CERN), Meyrin, 1211, Geneva, Switzerland
| | - Vilde Rieker
- European Organization for Nuclear Research (CERN), Meyrin, 1211, Geneva, Switzerland
- Department of Physics, University of Oslo, NO-0316 Blindern, Oslo, Norway
| | - Alexander Gerbershagen
- Particle Therapy Research Centre (PARTREC), Department of Radiation Oncology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Manjit Dosanjh
- John Adams Institute for Accelerator Science, Department of Physics, University of Oxford, Oxford, OX1 3RH, United Kingdom
- European Organization for Nuclear Research (CERN), Meyrin, 1211, Geneva, Switzerland
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11
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Grandvillain M, Vidal M, Hérault J, Benabdesselam M, Hofverberg P, Mady F. Silica-based scintillators: basic properties of radioluminescence kinetics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:245701. [PMID: 38447159 DOI: 10.1088/1361-648x/ad3094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 03/06/2024] [Indexed: 03/08/2024]
Abstract
Radioluminescent silica-based fiber dosimeters offer great advantages for designing miniaturized realtime sensors for high dose-rate dosimetry. Rise and fall kinetics of their response must be properly understood to better assess their performances in terms of measurement speed and repeatability. A standard model of radioluminescence (RL) has already been quantitatively validated for doped silica glasses, but beyond conclusive comparisons with specific experiments, a comprehensive understanding of the processes and parameters determining transient and equilibrium kinetics of RL is still lacking. We analyze in detail the kinetics inherent in the standard RL model. Several asymptotical regimes in the RL growth are demonstrated in the case of a pristine sample (succesive quadratic, linear and power-law time dependencies before the plateau is reached). We show how this situation is modified when a pre-irradiation partly fills traps beforehand. RL growth is then greatly accelerated because of the pre-formation of recombination centers (RCs) from dopant ions, but not due to pre-filling of trapping levels. In all cases, the RL intensity eventually tends to a constant level equal to the pair generation rate, long before all carrier densities themselves reach equilibrium. This occurs late under irradiation, when deep traps get to saturation. The fraction of dopants converted into RCs is then 'frozen' at a lower level the smaller the density of deep traps. Controlling RL kinetics through the engineering of material traps is not an option. Pre-irradiation appears to be the simplest way to obtain accelerated and repeatable kinetics.
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Affiliation(s)
- Marjorie Grandvillain
- Université Côte d'Azur, Fédération de recherche Claude Lalanne, Institut de Physique de Nice, CNRS UMR7010, 17 rue Julien Lauprêtre, 06200 Nice, France
| | - Marie Vidal
- Centre Antoine Lacassagne, Fédération de recherche Claude Lalanne, 227 avenue de la Lanterne, 06200 Nice, France
| | - Joël Hérault
- Centre Antoine Lacassagne, Fédération de recherche Claude Lalanne, 227 avenue de la Lanterne, 06200 Nice, France
| | - Mourad Benabdesselam
- Université Côte d'Azur, Fédération de recherche Claude Lalanne, Institut de Physique de Nice, CNRS UMR7010, 17 rue Julien Lauprêtre, 06200 Nice, France
| | - Petter Hofverberg
- Centre Antoine Lacassagne, Fédération de recherche Claude Lalanne, 227 avenue de la Lanterne, 06200 Nice, France
| | - Franck Mady
- Université Côte d'Azur, Fédération de recherche Claude Lalanne, Institut de Physique de Nice, CNRS UMR7010, 17 rue Julien Lauprêtre, 06200 Nice, France
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12
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Naceur A, Bienvenue C, Romano P, Chilian C, Carrier JF. Extending deterministic transport capabilities for very-high and ultra-high energy electron beams. Sci Rep 2024; 14:2796. [PMID: 38307920 PMCID: PMC11226718 DOI: 10.1038/s41598-023-51143-8] [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: 09/11/2023] [Accepted: 12/31/2023] [Indexed: 02/04/2024] Open
Abstract
Focused Very-High Energy Electron (VHEE, 50-300 MeV) and Ultra-High Energy Electron (UHEE, > 300 MeV) beams can accurately target both large and deeply seated human tumors with high sparing properties, while avoiding the spatial requirements and cost of proton and heavy ion facilities. Advanced testing phases are underway at the CLEAR facilities at CERN (Switzerland), NLCTA at Stanford (USA), and SPARC at INFN (Italy), aiming to accelerate the transition to clinical application. Currently, Monte Carlo (MC) transport is the sole paradigm supporting preclinical trials and imminent clinical deployment. In this paper, we propose an alternative: the first extension of the nuclear-reactor deterministic chain NJOY-DRAGON for VHEE and UHEE applications. We have extended the Boltzmann-Fokker-Planck (BFP) multigroup formalism and validated it using standard radio-oncology benchmarks, complex assemblies with a wide range of atomic numbers, and comprehensive irradiation of the entire periodic table. We report that [Formula: see text] of water voxels exhibit a BFP-MC deviation below [Formula: see text] for electron energies under [Formula: see text]. Additionally, we demonstrate that at least [Formula: see text] of voxels of bone, lung, adipose tissue, muscle, soft tissue, tumor, steel, and aluminum meet the same criterion between [Formula: see text] and [Formula: see text]. For water, the thorax, and the breast intra-operative benchmark, typical average BFP-MC deviations of [Formula: see text] and [Formula: see text] were observed at [Formula: see text] and [Formula: see text], respectively. By irradiating the entire periodic table, we observed similar performance between lithium ([Formula: see text]) and cerium ([Formula: see text]). Deficiencies observed between praseodymium ([Formula: see text]) and einsteinium ([Formula: see text]) have been reported, analyzed, and quantified, offering critical insights for the ongoing development of the Evaluated Nuclear Data File mode in NJOY.
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Affiliation(s)
- Ahmed Naceur
- École Polytechnique, SLOWPOKE Nuclear Reactor Laboratory, Nuclear Engineering Institute, Montréal, H3T1J4, Canada.
- CRCHUM, Centre hospitalier de l'Université de Montréal, Montréal, H2L4M1, Canada.
| | - Charles Bienvenue
- École Polytechnique, Engineering Physics Department, Biomedical Engineering Institute, Montréal, H3T1J4, Canada
| | - Paul Romano
- Computational Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Cornelia Chilian
- École Polytechnique, SLOWPOKE Nuclear Reactor Laboratory, Nuclear Engineering Institute, Montréal, H3T1J4, Canada
| | - Jean-François Carrier
- Department of Physics, Université de Montréal, Montréal, H3T1J4, Canada
- CRCHUM, Centre hospitalier de l'Université de Montréal, Montréal, H2L4M1, Canada
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13
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Motta S, Dal Bello R, Christensen JB, Bossin L, Yukihara EG. Dosimetry of ultra-high dose rate electron beams using thermoluminescence and optically stimulated luminescence detectors. Phys Med Biol 2024; 69:035022. [PMID: 38198704 DOI: 10.1088/1361-6560/ad1cf5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 01/10/2024] [Indexed: 01/12/2024]
Abstract
Objective.The aim of this work is to investigate the dose rate dependence of thermoluminescence and optically stimulated luminescence detectors (TLDs and OSLDs) in a wide uniform ultra-high dose rate electron beam and demonstrate the potential use of TLDs and OSLDs to correct the ion recombination in air-filled ionization chambers. This study avoids previously reported complications related to the field size and homogeneity.Approach.Two types of OSLDs (BeO and Al2O3:C) and three types of TLDs (LiF:Mg,Ti, LiF:Mg,Cu,P, CaF2:Tm) were irradiated simultaneously in a uniform 16 MeV electron beam generated by a clinically decommissioned C-Arm LINAC, modified to deliver doses per pulse between 8.3 × 10-4Gy and 1.255 Gy, corresponding to instantaneous dose rates between 2 × 102Gy s-1and 3 × 105Gy s-1. A prototype ultra-thin parallel plate ionization chamber was employed as reference detector.Main results.Reproducible results were achieved both at conventional (standard deviation of the data <2%) and at the highest dose per pulse (standard deviation of the data <4%). No trend in the dose rate response of the TLDs and OSLDs was observed in the investigated dose per pulse range. The Al2O3:C OSLD was found to be the most precise detector, with a standard deviation of the data <2% at all investigated dose rates and dose levels.Significance.The dose rate independence of the investigated TLDs and OSLDs make them good candidates for dosimetry at ultra-high dose rates, at least up to 3 × 105Gy s-1. A dose rate independent method to measure the dose per pulse is proposed, which can be applied to characterize ultra-high dose rate electron beams and correct for ion recombination in ionization chambers.
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Affiliation(s)
- S Motta
- Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland
- Department of Physics, ETH Zürich, Zürich, Switzerland
| | - R Dal Bello
- Department of Radiation Oncology, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - J B Christensen
- Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - L Bossin
- Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - E G Yukihara
- Department of Radiation Safety and Security, Paul Scherrer Institute, Villigen PSI, Switzerland
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14
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Oh K, Gallagher KJ, Hyun M, Schott D, Wisnoskie S, Lei Y, Hendley S, Wong J, Wang S, Graff B, Jenkins C, Rutar F, Ahmed M, McNeur J, Taylor J, Schmidt M, Senadheera L, Smith W, Umstadter D, Lele SM, Dai R, Jianghu (James) D, Yan Y, Su‐min Z. Initial experience with an electron FLASH research extension (FLEX) for the Clinac system. J Appl Clin Med Phys 2024; 25:e14159. [PMID: 37735808 PMCID: PMC10860433 DOI: 10.1002/acm2.14159] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/04/2023] [Accepted: 08/21/2023] [Indexed: 09/23/2023] Open
Abstract
PURPOSE Radiotherapy delivered at ultra-high-dose-rates (≥40 Gy/s), that is, FLASH, has the potential to effectively widen the therapeutic window and considerably improve the care of cancer patients. The underlying mechanism of the FLASH effect is not well understood, and commercial systems capable of delivering such dose rates are scarce. The purpose of this study was to perform the initial acceptance and commissioning tests of an electron FLASH research product for preclinical studies. METHODS A linear accelerator (Clinac 23EX) was modified to include a non-clinical FLASH research extension (the Clinac-FLEX system) by Varian, a Siemens Healthineers company (Palo Alto, CA) capable of delivering a 16 MeV electron beam with FLASH and conventional dose rates. The acceptance, commissioning, and dosimetric characterization of the FLEX system was performed using radiochromic film, optically stimulated luminescent dosimeters, and a plane-parallel ionization chamber. A radiation survey was conducted for which the shielding of the pre-existing vault was deemed sufficient. RESULTS The Clinac-FLEX system is capable of delivering a 16 MeV electron FLASH beam of approximately 1 Gy/pulse at isocenter and reached a maximum dose rate >3.8 Gy/pulse near the upper accessory mount on the linac gantry. The percent depth dose curves of the 16 MeV FLASH and conventional modes for the 10 × 10 cm2 applicator agreed within 0.5 mm at a range of 50% of the maximum dose. Their respective profiles agreed well in terms of flatness but deviated for field sizes >10 × 10 cm2 . The output stability of the FLASH system exhibited a dose deviation of <1%. Preliminary cell studies showed that the FLASH dose rate (180 Gy/s) had much less impact on the cell morphology of 76N breast normal cells compared to the non-FLASH dose rate (18 Gy/s), which induced large-size cells. CONCLUSION Our studies characterized the non-clinical Clinac-FLEX system as a viable solution to conduct FLASH research that could substantially increase access to ultra-high-dose-rate capabilities for scientists.
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Affiliation(s)
- Kyuhak Oh
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | | | - Megan Hyun
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | - Diane Schott
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | | | - Yu Lei
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | | | - Jeffrey Wong
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | - Shuo Wang
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | - Brendan Graff
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | | | - Frank Rutar
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | - Md Ahmed
- Varian Medical SystemsPalo AltoCaliforniaUSA
| | | | | | | | | | - Wendy Smith
- Varian Medical SystemsPalo AltoCaliforniaUSA
| | | | | | - Ran Dai
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | | | - Ying Yan
- University of Nebraska Medical CenterOmahaNebraskaUSA
| | - Zhou Su‐min
- University of Nebraska Medical CenterOmahaNebraskaUSA
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15
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Liu K, Holmes S, Hooten B, Schüler E, Beddar S. Evaluation of ion chamber response for applications in electron FLASH radiotherapy. Med Phys 2024; 51:494-508. [PMID: 37696271 PMCID: PMC10840726 DOI: 10.1002/mp.16726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 08/08/2023] [Accepted: 08/23/2023] [Indexed: 09/13/2023] Open
Abstract
Ion chambers are required for calibration and reference dosimetry applications in radiation therapy (RT). However, exposure of ion chambers in ultra-high dose rate (UHDR) conditions pertinent to FLASH-RT leads to severe saturation and ion recombination, which limits their performance and usability. The purpose of this study was to comprehensively evaluate a set of commonly used commercially available ion chambers in RT, all with different design characteristics, and use this information to produce a prototype ion chamber with improved performance in UHDR conditions as a first step toward ion chambers specific for FLASH-RT. The Advanced Markus and Exradin A10, A26, and A20 ion chambers were evaluated. The chambers were placed in a water tank, at a depth of 2 cm, and exposed to an UHDR electron beam at different pulse repetition frequency (PRF), pulse width (PW), and pulse amplitude settings on an IntraOp Mobetron. Ion chamber responses were investigated for the various beam parameter settings to isolate their dependence on integrated dose, mean dose rate and instantaneous dose rate, dose-per-pulse (DPP), and their design features such as chamber type, bias voltage, and collection volume. Furthermore, a thin parallel-plate (TPP) prototype ion chamber with reduced collector plate separation and volume was constructed and equally evaluated as the other chambers. The charge collection efficiency of the investigated ion chambers decreased with increasing DPP, whereas the mean dose rate did not affect the response of the chambers (± 1%). The dependence of the chamber response on DPP was found to be solely related to the total dose within the pulse, and not on mean dose rate, PW, or instantaneous dose rate within the ranges investigated. The polarity correction factor (Ppol ) values of the TPP prototype, A10, and Advanced Markus chambers were found to be independent of DPP and dose rate (± 2%), while the A20 and A26 chambers yielded significantly larger variations and dependencies under the same conditions. Ion chamber performance evaluated under different irradiation conditions of an UHDR electron beam revealed a strong dependence on DPP and a negligible dependence on the mean and instantaneous dose rates. These results suggest that modifications to ion chambers design to improve their usability in UHDR beamlines should focus on minimizing DPP effects, with emphasis on optimizing the electric field strength, through the construction of smaller electrode separation and larger bias voltages. This was confirmed through the production and evaluation of a prototype ion chamber specifically designed with these characteristics.
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Affiliation(s)
- Kevin Liu
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
| | | | | | - Emil Schüler
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
| | - Sam Beddar
- Division of Radiation Oncology, Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Graduate School of Biomedical Sciences, The University of Texas, Houston, Texas, USA
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16
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Bourgouin A, Paz-Martín J, Gedik YC, Frei F, Peier P, Rossomme S, Schönfeld AA, Schüller A, Rodriguez FG, Kapsch RP. Charge collection efficiency of commercially available parallel-plate ionisation chambers in ultra-high dose-per-pulse electron beams. Phys Med Biol 2023; 68:235002. [PMID: 37934049 DOI: 10.1088/1361-6560/ad0a58] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/07/2023] [Indexed: 11/08/2023]
Abstract
Objective. This investigation aims to experimentally determine the charge collection efficiency (CCE) of six commercially available parallel-plate ionisation chamber (PPIC) models in ultra-high dose-per-pulse (UHDPP) electron beams.Approach. The CCE of 22 PPICs has been measured in UHDPP electron beams at the National Metrology Institution of Germany (PTB). The CCE was determined for a dose per pulse (DPP) range between 0.1 and 6.4 Gy (pulse duration of 2.5μs). The results obtained with the different PPICs were compared to evaluate the reproducibility, intra- and inter-model variation, and the performance of a CCE empirical model.Main results. The intra-model variation was, on average, 4.0%, which is more than three times the total combined relative standard uncertainty and was found to be greater at higher DPP (up to 20%). The inter-model variation for the PPIC with 2 mm electrode spacing, which was found to be, on average, 10%, was also significant compared to the relative uncertainty and the intra-model variation. The observed CCE variation could not be explained only by the expected deviation of the electrode spacing from the nominal value within the manufacturing tolerance. It should also be noted that a substantial polarity effect, between 0.914(5) and 1.201(3), was observed, and significant intra- and inter-model variation was observed on this effect.Significance. For research and pre-clinical study, the commercially available PPIC with a well-known CCE (directly measured for the specific chamber) and with a small electrode spacing could be used for relative and absolute dosimetry with a lower-limit uncertainty of 1.6% (k= 1) in the best case. However, to use a PPIC as a secondary standard in UHDPP electron beams for clinical purposes would require new model development to reduce the ion recombination, the polarity effect, and the total standard uncertainty on the dose measurement.
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Affiliation(s)
- Alexandra Bourgouin
- Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
| | - Jose Paz-Martín
- Departamento de Física de Partículas, Universidad de Santiago, Santiago de Compostela, Spain
| | - Yunus Can Gedik
- Nuclear Energy Research Institute (NÜKEN), Turkish Energy Nuclear and Mineral Research Agency (TENMAK), Ankara, Turkey
| | - Franziska Frei
- Eidgenössisches Institut für Metrologie (METAS), Bern-Wabern, Switzerland
| | - Peter Peier
- Eidgenössisches Institut für Metrologie (METAS), Bern-Wabern, Switzerland
| | | | - Andreas A Schönfeld
- Sun Nuclear, A Mirion Medical Company, Melbourne, FL, United States of America
| | - Andreas Schüller
- Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
| | | | - Ralf-Peter Kapsch
- Dosimetry for Radiation Therapy and Diagnostic Radiology, Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany
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17
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Horváth D, Grittani G, Precek M, Versaci R, Bulanov SV, Olšovcová V. Time dynamics of the dose deposited by relativistic ultra-short electron beams. Phys Med Biol 2023; 68:22NT01. [PMID: 37797651 DOI: 10.1088/1361-6560/ad00a3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 10/05/2023] [Indexed: 10/07/2023]
Abstract
Ultra-short electron beams are used as ultra-fast radiation source for radiobiology experiments aiming at very high energy electron beams (VHEE) radiotherapy with very high dose rates. Laser plasma accelerators are capable of producing electron beams as short as 1 fs and with tunable energy from few MeV up to multi-GeV with compact footprint. This makes them an attractive source for applications in different fields, where the ultra-short (fs) duration plays an important role. The time dynamics of the dose deposited by electron beams with energies in the range 50-250 MeV have been studied and the results are presented here. The results set a quantitative limit to the maximum dose rate at which the electron beams can impart dose.
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Affiliation(s)
- D Horváth
- ELI Beamlines Facility, The Extreme Light Infrastructure ERIC, Za Radnicí 835, 252 41 Dolní Břežany, Czech Republic
| | - G Grittani
- ELI Beamlines Facility, The Extreme Light Infrastructure ERIC, Za Radnicí 835, 252 41 Dolní Břežany, Czech Republic
| | - M Precek
- ELI Beamlines Facility, The Extreme Light Infrastructure ERIC, Za Radnicí 835, 252 41 Dolní Břežany, Czech Republic
| | - R Versaci
- ELI Beamlines Facility, The Extreme Light Infrastructure ERIC, Za Radnicí 835, 252 41 Dolní Břežany, Czech Republic
| | - S V Bulanov
- ELI Beamlines Facility, The Extreme Light Infrastructure ERIC, Za Radnicí 835, 252 41 Dolní Břežany, Czech Republic
| | - V Olšovcová
- ELI Beamlines Facility, The Extreme Light Infrastructure ERIC, Za Radnicí 835, 252 41 Dolní Břežany, Czech Republic
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18
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Jeon C, Ahn S, Amano D, Kamiguchi N, Cho S, Sheen H, Park HC, Han Y. FLASH dose rate calculation based on log files in proton pencil beam scanning therapy. Med Phys 2023; 50:7154-7166. [PMID: 37431587 DOI: 10.1002/mp.16575] [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: 11/30/2022] [Revised: 06/05/2023] [Accepted: 06/06/2023] [Indexed: 07/12/2023] Open
Abstract
BACKGROUND In radiation therapy, irradiating healthy normal tissues in the beam trajectories is inevitable. This unnecessary dose means that patients undergoing treatment risk developing side effects. Recently, FLASH radiotherapy delivering ultra-high-dose-rate beams has been re-examined because of its normal-tissue-sparing effect. To confirm the mean and instantaneous dose rates of the FLASH beam, stable and accurate dosimetry is required. PURPOSE Detailed verification of the FLASH effect requires dosimeters and a method to measure the average and instantaneous dose rate stably for 2- or 3-dimensional dose distributions. To verify the delivered FLASH beam, we utilized machine log files from the built-in monitor chamber to develop a dosimetry method to calculate the dose and average/instantaneous dose rate distributions in two or three dimensions in a phantom. METHODS To create a spread-out Bragg peak (SOBP) and deliver a uniform dose in a target, a mini-ridge filter was created with a 3D printer. Proton pencil beam line scanning plans of 2 × 2 cm2 , 3 × 3 cm2 , 4 × 4 cm2 , and round shapes with 2.3 cm diameter patterns delivering 230 MeV energy protons were created. The absorbed dose in the solid water phantom of each plan was measured using a PPC05 ionization chamber (IBA Dosimetry, Virginia, USA) in the SOBP region, and the log files for each plan were exported from the treatment control system console. Using these log files, the delivered dose and average dose rate were calculated using two methods: a direct method and a Monte Carlo (MC) simulation method that uses log file information. The computed and average dose rates were compared with the ionization chamber measurements. Additionally, instantaneous dose rates in user-defined volumes were calculated using the MC simulation method with a temporal resolution of 5 ms. RESULTS Compared to ionization chamber dosimetry, 10 of 12 cases using the direct calculation method and 9 of 11 cases using the MC method had a dose difference below ±3%. Nine of 12 cases using the direct calculation method and 8 of 11 cases using the MC method had dose rate differences below ±3%. The average and maximum dose differences for the direct calculation and MC method were-0.17, +0.72%, and -3.15, +3.32%, respectively. For the dose rate difference, the average and maximum for the direct calculation and MC method were +1.26, +1.12%, and +3.75, +3.15%, respectively. In the instantaneous dose rate calculation with the MC simulation, a large fluctuation with a maximum of 163 Gy/s and a minimum of 4.29 Gy/s instantaneous dose rate was observed in a specific position, whereas the mean dose rate was 62 Gy/s. CONCLUSIONS We successfully developed methods in which machine log files are used to calculate the dose and the average and instantaneous dose rates for FLASH radiotherapy and demonstrated the feasibility of verifying the delivered FLASH beams.
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Affiliation(s)
- Chanil Jeon
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea
| | - Sunghwan Ahn
- Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Daizo Amano
- Sumitomo Heavy Industries, Ltd, Tokyo, Japan
| | | | - Sungkoo Cho
- Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Heesoon Sheen
- Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Hee Chul Park
- Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Youngyih Han
- Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul, Republic of Korea
- Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
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Choi DH, Kim JS, Lee R, Ahn SH, Ahn WS. Dosimetric verification of annual quality assurance for a linear accelerator using a transmission type detector. Sci Rep 2023; 13:17994. [PMID: 37865666 PMCID: PMC10590446 DOI: 10.1038/s41598-023-45114-2] [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: 03/24/2023] [Accepted: 10/16/2023] [Indexed: 10/23/2023] Open
Abstract
The purpose of our study is to establish an efficient quality assurance (QA) procedure using a transmission-type detector (IBA, Stealth chamber), a reference signal detector, as a field chamber. Relative dosimetry items, including monitor unit linearity, output constancy based on dose rate and field size, and output factor were measured and compared with results obtained from the Farmer-type chamber (IBA, Wellhofer, FC65-G). Moreover, output for each field size was measured to assess its applicability to small fields. Results using the Stealth chamber were in good agreement with the FC65-G within 1.0%, except for output constancy according to gantry angle, which had a 1.1% error rate for the Stealth chamber and 2.7% for the FC65-G. Differences of up to - 6.26% output factor were observed for the Stealth chamber and up to - 0.56% for the CC-13 ionization chamber (IBA) in the 3 × 3 cm2 field. Our study confirmed the possibility of using Stealth chambers for relative dosimetry measurement in QA.
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Affiliation(s)
- Dong Hyeok Choi
- Department of Medicine, Yonsei University College of Medicine, Seoul, South Korea
- Medical Physics and Biomedical Engineering Lab (MPBEL), Yonsei University College of Medicine, Seoul, South Korea
- Department of Radiation Oncology, Yonsei Cancer Center, Heavy Ion Therapy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Jin Sung Kim
- Department of Medicine, Yonsei University College of Medicine, Seoul, South Korea
- Medical Physics and Biomedical Engineering Lab (MPBEL), Yonsei University College of Medicine, Seoul, South Korea
- Department of Radiation Oncology, Yonsei Cancer Center, Heavy Ion Therapy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Rena Lee
- Department of Biomedical Engineering, School of Medicine, Ewha Womans University, Seoul, South Korea
| | - So Hyun Ahn
- Ewha Medical Research Institute, School of Medicine, Ewha Womans University, Seoul, South Korea.
| | - Woo Sang Ahn
- Department of Radiation Oncology, Gangneung Asan Hospital, University of Ulsan College of Medicine, Gangneung, South Korea.
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20
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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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21
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Cotterill J, Flynn S, Thomas R, Subiel A, Lee N, Shipley D, Palmans H, Lourenço A. Monte Carlo modelling of a prototype small-body portable graphite calorimeter for ultra-high dose rate proton beams. Phys Imaging Radiat Oncol 2023; 28:100506. [PMID: 38045641 PMCID: PMC10692912 DOI: 10.1016/j.phro.2023.100506] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 11/02/2023] [Accepted: 11/02/2023] [Indexed: 12/05/2023] Open
Abstract
Background and purpose Accurate dosimetry in Ultra-High Dose Rate (UHDR) beams is challenging because high levels of ion recombination occur within ionisation chambers used as reference dosimeters. A Small-body Portable Graphite Calorimeter (SPGC) exhibiting a dose-rate independent response was built to offer reduced uncertainty on secondary standard dosimetry in UHDR regimes. The aim of this study was to quantify the effect of the geometry and material properties of the device on the dose measurement. Materials and methods A detailed model of the SPGC was built in the Monte Carlo code TOPAS (v3.6.1) to derive the impurity and gap correction factors, k i m p and k g a p . A dose conversion factor, D w MC / D g MC , was also calculated using FLUKA (v2021.2.0). These factors convert the average dose to its graphite core to the dose-to-water for a 249.7 MeV mono-energetic spot-scanned clinical proton beam. The effect of the surrounding Styrofoam on the dose measurement was examined in the simulations by substituting it for graphite. Results The k i m p and k g a p correction factors were 0.9993 ± 0.0002 and 1.0000 ± 0.0001, respectively when the Styrofoam was not substituted, and 1.0037 ± 0.0002 and 0.9999 ± 0.0001, respectively when substituted for graphite. The dose conversion factor was calculated to be 1.0806 ± 0.0001. All uncertainties are Type A. Conclusions Impurity and gap correction factors, and the dose conversion factor were calculated for the SPGC in a FLASH proton beam. Separating out the effect of scatter from Styrofoam insulation showed this as the dominating correction factor, amounting to 1.0043 ± 0.0002.
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Affiliation(s)
- John Cotterill
- Medical Radiation Science Group, National Physical Laboratory, Teddington TW11 0LW, UK
| | - Sam Flynn
- Medical Radiation Science Group, National Physical Laboratory, Teddington TW11 0LW, UK
- Particle Physics Group, University of Birmingham, Edgbaston B15 2TT, UK
| | - Russell Thomas
- Medical Radiation Science Group, National Physical Laboratory, Teddington TW11 0LW, UK
- University of Surrey, Faculty of Engineering and Physical Science, Guildford GU2 7XH, UK
| | - Anna Subiel
- Medical Radiation Science Group, National Physical Laboratory, Teddington TW11 0LW, UK
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, UK
| | - Nigel Lee
- Medical Radiation Science Group, National Physical Laboratory, Teddington TW11 0LW, UK
| | - David Shipley
- Medical Radiation Science Group, National Physical Laboratory, Teddington TW11 0LW, UK
| | - Hugo Palmans
- Medical Radiation Science Group, National Physical Laboratory, Teddington TW11 0LW, UK
- Medical Physics Group, MedAustron Ion Therapy Center, A-2700 Wiener Neustadt, Austria
| | - Ana Lourenço
- Medical Radiation Science Group, National Physical Laboratory, Teddington TW11 0LW, UK
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, UK
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22
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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: 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: 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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23
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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: 5.0] [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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24
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Bruzzi M, Verroi E. Epitaxial SiC Dosimeters and Flux Monitoring Detectors for Proton Therapy Beams. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16103643. [PMID: 37241270 DOI: 10.3390/ma16103643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 04/25/2023] [Accepted: 05/05/2023] [Indexed: 05/28/2023]
Abstract
The exceptional optoelectronic properties and high radiation resistance of epitaxial silicon carbide make this material attractive for high-energy beam dosimetry and radiation monitoring, especially when strict requirements such as high signal-to-noise ratios, high time and spatial resolutions and low detectivity levels are required. A 4H-SiC Schottky diode has been characterized as a proton-flux-monitoring detector and dosimeter under proton beams for proton therapy. The diode was composed of an epitaxial film grown on 4H-SiC n+-type substrate equipped with a gold Schottky contact. The diode was embedded in a tissue-equivalent epoxy resin and then characterized in terms of capacitance vs. voltage (C-V) and current vs. voltage (I-V) characteristics in the dark in the range of 0-40 V. The dark currents at room temperature are in the order of 1 pA, while the doping and active thicknesses extracted from the C-V are 2.5 × 1015 cm-3 and 2-4 μm, respectively. Proton beam tests have been carried out at the Proton Therapy Center of the Trento Institute for Fundamental Physics and Applications (TIFPA-INFN). They have been carried out with energies and extraction currents of 83-220 MeV and 1-10 nA, respectively, as typical for proton therapy applications, corresponding to dose rates in the range of 5 mGy/s to 2.7 Gy/s. The I-V characteristics measured under proton beam irradiation at the lowest dose rate showed a typical diode photocurrent response and a signal-to-noise ratio well above 10. Investigations with null bias evidenced a very good performance in terms of the diode's sensitivity, fast rise and decay times and response stability. The diode's sensitivity was in agreement with the expected theoretical values, and its response was linear throughout the whole investigated dose rate range.
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Affiliation(s)
- Mara Bruzzi
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, FI, Italy
- I.N.F.N. Sezione di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, FI, Italy
- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Via G. Giusti 9, 50121 Firenze, FI, Italy
| | - Enrico Verroi
- Trento Institute for Fundamental Physics and Applications, National Institute of Nuclear Physics (TIFPA), Via Sommarive, 14, 38123 Povo, TN, Italy
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25
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Oancea C, Granja C, Marek L, Jakubek J, Šolc J, Bodenstein E, Gantz S, Pawelke J, Pivec J. Out-of-field measurements and simulations of a proton pencil beam in a wide range of dose rates using a Timepix3 detector: Dose rate, flux and LET. Phys Med 2023; 106:102529. [PMID: 36657235 DOI: 10.1016/j.ejmp.2023.102529] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 12/22/2022] [Accepted: 01/03/2023] [Indexed: 01/19/2023] Open
Abstract
Stray radiation produced by ultra-high dose-rates (UHDR) proton pencil beams is characterized using ASIC-chip semiconductor pixel detectors. A proton pencil beam with an energy of 220 MeV was utilized to deliver dose rates (DR) ranging from conventional radiotherapy DRs up to 270 Gy/s. A MiniPIX Timepix3 detector equipped with a silicon sensor and integrated readout electronics was used. The chip-sensor assembly and chipboard on water-equivalent backing were detached and immersed in the water-phantom. The deposited energy, particle flux, DR, and the linear energy transfer (LET(Si)) spectra were measured in the silicon sensor at different positions both laterally, at different depths, and behind the Bragg peak. At low-intensity beams, the detector is operated in the event-by-event data-driven mode for high-resolution spectral tracking of individual particles. This technique provides precise energy loss response and LET(Si) spectra with radiation field composition resolving power. At higher beam intensities a rescaling of LET(Si) can be performed as the distribution of the LET(Si) spectra exhibits the same characteristics regardless of the delivered DR. The integrated deposited energy and the absorbed dose can be thus measured in a wide range. A linear response of measured absorbed dose was obtained by gradually increasing the delivered DR to reach UHDR beams. Particle tracking of scattered radiation in data-driven mode could be performed at DRs up to 0.27 Gy/s. In integrated mode, the saturation limits were not reached at the measured out-of-field locations up to the delivered DR of over 270 Gy/s. A good agreement was found between measured and simulated absorbed doses.
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Affiliation(s)
- Cristina Oancea
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic; University of Bucharest, Bucharest, Romania.
| | - Carlos Granja
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic
| | - Lukas Marek
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic; Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - Jan Jakubek
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic
| | - Jaroslav Šolc
- Czech Metrology Institute, Okruzni 31, 638 00 Brno, Czech Republic
| | - Elisabeth Bodenstein
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany; Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany
| | - Sebastian Gantz
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany; Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany
| | - Jörg Pawelke
- OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany; Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany
| | - Jiri Pivec
- ADVACAM, U Pergamenky 12, 170 00 Prague 7, Czech Republic
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Ion recombination correction factors and detector comparison in a very-high dose rate proton scanning beam. Phys Med 2023; 106:102518. [PMID: 36638707 DOI: 10.1016/j.ejmp.2022.102518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 12/09/2022] [Accepted: 12/27/2022] [Indexed: 01/13/2023] Open
Abstract
PURPOSE Accurate dosimetry is paramount to study the FLASH biological effect since dose and dose rate are critical dosimetric parameters governing its underlying mechanisms. With the goal of assessing the suitability of standard clinical dosimeters in a very-high dose rate (VHDR) experimental setup, we evaluated the ion collection efficiency of several commercially available air-vented ionization chambers (IC) in conventional and VHDR proton irradiation conditions. METHODS A cyclotron at the Orsay Proton Therapy Center was used to deliver VHDR pencil beam scanning irradiation. Ion recombination correction factors (ks) were determined for several detectors (Advanced Markus, PPC05, Nano Razor, CC01) at the entrance of the plateau and at the Bragg peak, using the Niatel model, the Two-voltage method and Boag's analytical formula for continuous beams. RESULTS Mean dose rates ranged from 4 Gy/s to 385 Gy/s, and instantaneous dose rates up to 1000 Gy/s were obtained with the experimental set-up. Recombination correction factors below 2 % were obtained for all chambers, except for the Nano Razor, at VHDRs with variations among detectors, while ks values were significantly smaller (0.8 %) for conventional dose rates. CONCLUSIONS While the collection efficiency of the probed ICs in scanned VHDR proton therapy is comparable to those in the conventional regime with recombination coefficiens smaller than 1 % for mean dose rates up to 177 Gy/s, the reduction in collection efficiency for higher dose rates cannot be ignored when measuring the absorbed dose in pre-clinical proton scanned FLASH experiments and clinical trials.
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Fenwick JD, Kumar S. Collection efficiencies of ionization chambers in pulsed radiation beams: an exact solution of an ion recombination model including free electron effects. Phys Med Biol 2022; 68:015016. [PMID: 36571457 DOI: 10.1088/1361-6560/aca74e] [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: 07/28/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022]
Abstract
Objective.Boaget al(1996) formulated a key model of collection efficiency for ionization chambers in pulsed radiation beams, in which some free electrons form negatively charged ions with a density that initially varies exponentially across the chamber. This non-uniform density complicates ion recombination calculations, in comparison with Boag's 1950 work in which a collection efficiency formula,f, was straightforwardly obtained assuming a uniform negative ion cloud. Boaget al(1996) therefore derived collection efficiency formulaef',f″ andf'″ based on three approximate descriptions of the exponentially-varying negative ion cloud, each uniform within a region. Collection efficiencies calculated by Boaget al(1996) using these formulae differed by a maximum of 5.1% relative (at 144 mGy dose-per-pulse with 212 V applied over a 1 mm electrode separation) and all three formulae are often used together. Here an exact solution of the exponentially-varying model is obtained.Approach.The exact solution was derived from a differential equation relating the number of negative ions collected from within some distance of the anode to numbers of ions initially located within that region. Using the resulting formula,fexp, collection efficiencies were calculated for a range of ionization chamber properties and doses-per-pulse, and compared withf,f',f″ andf″' values and results from an ion transport code.Main results.fexpvalues agreed to 5 decimal places with ion transport code results. The maximum relative difference betweenfexpandf″', which was often closest tofexp, was 0.78% for the chamber properties and doses-per-pulse studied by Boaget al(1996), rising to 6.1% at 1 Gy dose-per-pulse and 2 mm electrode separation.Significance.Use offexpshould reduce ambiguities in collection efficiencies calculated using the approximate formulae, although like themfexpdoes not account for electric field distortion, which becomes substantial at doses-per-pulse ≥100 mGy.
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Affiliation(s)
- John D Fenwick
- Department of Molecular and Clinical Cancer Medicine, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, The Sherrington Building, Ashton Street, Liverpool L69 3BX, United Kingdom
| | - Sudhir Kumar
- Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, CT & CRS Building, Anushaktinagar, Mumbai-400094, India
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Ultra-high dose rate FLASH irradiator at the radiological research accelerator facility. Sci Rep 2022; 12:22149. [PMID: 36550150 PMCID: PMC9780319 DOI: 10.1038/s41598-022-19211-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 08/25/2022] [Indexed: 12/24/2022] Open
Abstract
The Radiological Research Accelerator Facility has modified a decommissioned Varian Clinac to deliver ultra-high dose rates: operating in 9 MeV electron mode (FLASH mode), samples can be irradiated at a Source-Surface Distance (SSD) of 20 cm at average dose rates of up to 600 Gy/s (3.3 Gy per 0.13 µs pulse, 180 pulses per second). In this mode multiple pulses are required for most irradiations. By modulating pulse repetition rate and irradiating at SSD = 171 cm, dose rates below 1 Gy/min can be achieved, allowing comparison of FLASH and conventional irradiations with the same beam. Operating in 6 MV photon mode, with the conversion target removed (SuperFLASH mode), samples are irradiated at higher dose rates (0.2-150 Gy per 5 µs pulse, 360 pulses per second) and most irradiations can be performed with a single very high dose rate pulse. In both modes we have seen the expected inverse relation between dose rate and irradiated area, with the highest dose rates obtained for beams with a FWHM of about 2 cm and ± 10% uniformity over 1 cm diameter. As an example of operation of the ultra-high dose rate FLASH irradiator, we present dose rate dependence of dicentric chromosome yields.
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FLASHlab@PITZ: New R&D platform with unique capabilities for electron FLASH and VHEE radiation therapy and radiation biology under preparation at PITZ. Phys Med 2022; 104:174-187. [PMID: 36463582 DOI: 10.1016/j.ejmp.2022.10.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 09/19/2022] [Accepted: 10/31/2022] [Indexed: 12/03/2022] Open
Abstract
At the Photo Injector Test facility at DESY in Zeuthen (PITZ), an R&D platform for electron FLASH and very high energy electron radiation therapy and radiation biology is being prepared (FLASHlab@PITZ). The beam parameters available at PITZ are worldwide unique. They are based on experiences from 20 + years of developing high brightness beam sources and an ultra-intensive THz light source demonstrator for ps scale electron bunches with up to 5 nC bunch charge at MHz repetition rate in bunch trains of up to 1 ms length, currently 22 MeV (upgrade to 250 MeV planned). Individual bunches can provide peak dose rates up to 1014 Gy/s, and 10 Gy can be delivered within picoseconds. Upon demand, each bunch of the bunch train can be guided to a different transverse location, so that either a "painting" with micro beams (comparable to pencil beam scanning in proton therapy) or a cumulative increase of absorbed dose, using a wide beam distribution, can be realized at the tumor. Full tumor treatment can hence be completed within 1 ms, mitigating organ movement issues. With extremely flexible beam manipulation capabilities, FLASHlab@PITZ will cover the current parameter range of successfully demonstrated FLASH effects and extend the parameter range towards yet unexploited short treatment times and high dose rates. A summary of the plans for FLASHlab@PITZ and the status of its realization will be presented.
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Kranzer R, Schüller A, Gómez Rodríguez F, Weidner J, Paz-Martín J, Looe HK, Poppe B. Charge collection efficiency, underlying recombination mechanisms, and the role of electrode distance of vented ionization chambers under ultra-high dose-per-pulse conditions. Phys Med 2022; 104:10-17. [PMID: 36356499 PMCID: PMC9719440 DOI: 10.1016/j.ejmp.2022.10.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 09/23/2022] [Accepted: 10/23/2022] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Investigating and understanding of the underlying mechanisms affecting the charge collection efficiency (CCE) of vented ionization chambers under ultra-high dose rate pulsed electron radiation. This is an important step towards real-time dosimetry with ionization chambers in FLASH radiotherapy. METHODS Parallel-plate ionization chambers (PPIC) with three different electrode distances were build and investigated with electron beams with ultra-high dose-per-pulse (DPP) up to 5.4 Gy. The measurements were compared with simulations. The experimental determination of the CCE was done by comparison against the reference dose based on alanine dosimetry. The numerical solution of a system of partial differential equations taking into account charge creations by the radiation, their transport and reaction in an applied electric field was used for the simulations of the CCE and the underlying effects. RESULTS A good agreement between the experimental results and the simulated CCE could be achieved. The recombination losses found under ultra-high DPP could be attributed to a temporal and spatial charge carrier imbalance and the associated electric field distortion. With ultra-thin electrode distances down to 0.25 mm and a suitable chamber voltage, a CCE greater than 99 % could be achieved under the ultra-high DPP conditions investigated. CONCLUSIONS Well-guarded ultra-thin PPIC are suited for real-time dosimetry under ultra-high DPP conditions. This allows dosimetry also for FLASH RT according to common codes of practice, traceable to primary standards. The numerical approach used allows the determination of appropriate correction factors beyond the DPP ranges where established theories are applicable to account for remaining recombination losses.
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Affiliation(s)
- 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,Corresponding author
| | - Andreas Schüller
- Physikalisch-Technische Bundesanstalt, Braunschweig 38116, Germany
| | - Faustino Gómez Rodríguez
- Departamento de Fisica de Particulas, Universidad de Santiago, Santiago de Compostela, Spain,Laboratorio de Radiofisica, Universidad de Santiago, Santiago de Compostela, Spain
| | | | - Jose Paz-Martín
- Departamento de Fisica de Particulas, Universidad de Santiago, Santiago de Compostela, Spain
| | - Hui Khee Looe
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University Oldenburg, 26121, Germany
| | - Björn Poppe
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University Oldenburg, 26121, Germany
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31
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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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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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34
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Di Martino F, Del Sarto D, Giuseppina Bisogni M, Capaccioli S, Galante F, Gasperini A, Linsalata S, Mariani G, Pacitti M, Paiar F, Ursino S, Vanreusel V, Verellen D, Felici G. A new solution for UHDP and UHDR (Flash) measurements: Theory and conceptual design of ALLS chamber. Phys Med 2022; 102:9-18. [PMID: 36030665 DOI: 10.1016/j.ejmp.2022.08.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 07/27/2022] [Accepted: 08/10/2022] [Indexed: 10/15/2022] Open
Abstract
Ultra-High dose-per-pulse regimens (UHDP), necessary to trigger the "FLASH" effect, still pose serious challenges to dosimetry. Dosimetry plays a crucial role, both to significantly improve the accuracy of the radiobiological experiments necessary to fully understand the mechanisms underlying the effect and its dependencies on the beam parameters, and to be able to translate such effect into clinical practice. The standard ionization chamber in UHDP region is significantly affected by the effects of the electric field generated by the enormous density of charges produced by the dose pulse. This work describes the theory and the conceptual design of a gas chamber (the ALLS chamber) which overcomes the above-mentioned problems.
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Affiliation(s)
- Fabio Di Martino
- Fisica Sanitaria, Azienda Ospedaliero Universitaria Pisa AOUP, ed.18 via Roma 67, Pisa, Italy; Centro Pisano ricerca e implementazione clinica Flash Radiotherapy (CPFR@CISUP), Presidio S. Chiara, ed. 18 via Roma 67, Pisa, Italy; INFN, Sezione di Pisa, Largo B. Pontecorvo 3, I-57127 Pisa, Italy.
| | - Damiano Del Sarto
- Centro Pisano ricerca e implementazione clinica Flash Radiotherapy (CPFR@CISUP), Presidio S. Chiara, ed. 18 via Roma 67, Pisa, Italy
| | - Maria Giuseppina Bisogni
- Centro Pisano ricerca e implementazione clinica Flash Radiotherapy (CPFR@CISUP), Presidio S. Chiara, ed. 18 via Roma 67, Pisa, Italy; Department of Physics, University of Pisa, Largo B. Pontecorvo 3, I-57127 Pisa, Italy; INFN, Sezione di Pisa, Largo B. Pontecorvo 3, I-57127 Pisa, Italy
| | - Simone Capaccioli
- Centro Pisano ricerca e implementazione clinica Flash Radiotherapy (CPFR@CISUP), Presidio S. Chiara, ed. 18 via Roma 67, Pisa, Italy; Department of Physics, University of Pisa, Largo B. Pontecorvo 3, I-57127 Pisa, Italy
| | | | - Alessia Gasperini
- Iridium Kankernetwerk, 2610 Antwerp, Belgium; Antwerp University, Faculty of Medicine and Health Sciences, 2610 Antwerp, Belgium
| | - Stefania Linsalata
- Fisica Sanitaria, Azienda Ospedaliero Universitaria Pisa AOUP, ed.18 via Roma 67, Pisa, Italy
| | | | | | - Fabiola Paiar
- Centro Pisano ricerca e implementazione clinica Flash Radiotherapy (CPFR@CISUP), Presidio S. Chiara, ed. 18 via Roma 67, Pisa, Italy; INFN, Sezione di Pisa, Largo B. Pontecorvo 3, I-57127 Pisa, Italy; Radiation Oncology Unit, Department of Translational Research, University of Pisa, Pisa, Italy
| | - Stefano Ursino
- Centro Pisano ricerca e implementazione clinica Flash Radiotherapy (CPFR@CISUP), Presidio S. Chiara, ed. 18 via Roma 67, Pisa, Italy; INFN, Sezione di Pisa, Largo B. Pontecorvo 3, I-57127 Pisa, Italy; Radiation Oncology Unit, Department of Translational Research, University of Pisa, Pisa, Italy
| | - Verdi Vanreusel
- Iridium Kankernetwerk, 2610 Antwerp, Belgium; Antwerp University, Faculty of Medicine and Health Sciences, 2610 Antwerp, Belgium
| | - Dirk Verellen
- Iridium Kankernetwerk, 2610 Antwerp, Belgium; Antwerp University, Faculty of Medicine and Health Sciences, 2610 Antwerp, Belgium
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35
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Poirier Y, Xu J, Mossahebi S, Therriault‐Proulx F, Sawant A. Technical note: Characterization and practical applications of a novel plastic scintillator for on‐line dosimetry for ultra‐high dose rate (FLASH). Med Phys 2022; 49:4682-4692. [DOI: 10.1002/mp.15671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 03/23/2022] [Accepted: 03/30/2022] [Indexed: 11/06/2022] Open
Affiliation(s)
- Yannick Poirier
- University of Maryland School of Medicine Baltimore MD 21201
- McGill University Montreal QC H3A 2T5 Canada
| | - Junliang Xu
- University of Maryland School of Medicine Baltimore MD 21201
| | - Sina Mossahebi
- University of Maryland School of Medicine Baltimore MD 21201
| | | | - Amit Sawant
- University of Maryland School of Medicine Baltimore MD 21201
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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: 17] [Impact Index Per Article: 8.5] [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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Kranzer R, Schüller A, Bourgouin A, Hackel T, Poppinga D, Lapp M, Looe HK, Poppe B. Response of diamond detectors in ultra-high dose-per-pulse electron beams for dosimetry at FLASH radiotherapy. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac594e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/28/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Objective. With increasing investigation of the so-called FLASH effect, the need for accurate real time dosimetry for ultra-high dose rates is also growing. Considering the ultra-high dose-per-pulse (DPP) necessary to produce the ultra-high dose rates for investigations of the FLASH effect, real time dosimetry is a major challenge. In particular, vented ionization chambers, as used for dosimetry in conventional radiotherapy, show significant deviations from linearity with increasing DPP. This is due to recombination losses in the sensitive air volume. Solid state detectors could be an alternative. Due to their good stability of the response with regard to the accumulated dose, diamond detectors such as the microDiamond could be suitable here. The aims of this work are to investigate the response of microDiamond and adapted microDiamond prototypes in ultra-high DPP electron beams, to understand the underlying effects and to draw conclusions for further detector developments. Approach. For the study, an electron beam with a DPP up to 6.5 Gy and a pulse duration of 2.5 μs was used to fulfill the conditions under which the FLASH effect was observed. As a dose rate-independent reference, alanine dosimeters were used. Main Results. It has been shown that the commercially available microDiamond detectors have limitations in terms of linearity at ultra-high DPP. But this is not an intrinsic limitation of the detector principle. The deviations from linearity were correlated with the series resistance and the sensitivity. It could be shown that the linear range can be extended towards ultra-high DPP range by reducing the sensitivity in combination with a low series resistance of the detectors. Significance. The work shows that synthetic single crystal diamond detectors working as Schottky photodiodes are in principle suitable for FLASH-RT dosimetry at electron linear accelerators.
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38
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McManus M, Romano F, Royle G, Botnariuc D, Shipley D, Palmans H, Subiel A. Determination of beam quality correction factors for the Roos plane-parallel ionisation chamber exposed to very high energy electron (VHEE) beams using Geant4. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac5a94] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 02/28/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Detailed characterisation of the Roos secondary standard plane-parallel ionisation chamber has been conducted in a novel 200 MeV Very High Energy Electron (VHEE) beam with reference to the standard 12 MeV electron calibration beam used in our experimental work. Stopping-power-ratios and perturbation factors have been determined for both beams and used to calculated the beam quality correction factor using the Geant4 general purpose MC code. These factors have been calculated for a variety of charged particle transport parameters available in Geant4 which were found to pass the Fano cavity test. Stopping-power-ratios for the 12 MeV electron calibration beam quality were found to agree within uncertainties to that quoted by current dosimetry protocols. Perturbation factors were found to vary by up-to 4% for the calibration beam depending on the parameter configuration, compared with only 0.8% for the VHEE beam. Beam quality correction factors were found to describe an approximately 10% lower dose than would be originally calculated if a beam quality correction were not accounted for. Moreover, results presented here largely resolve unphysical chamber measurements, such as collection efficiencies greater than 100%, and assist in the accurate determination of absorbed dose and ion recombination in secondary standard ionisation chambers.
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39
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McManus M, Romano F, Royle G, Palmans H, Subiel A. A Geant4 Fano test for novel very high energy electron beams. Phys Med Biol 2021; 66. [PMID: 34844225 DOI: 10.1088/1361-6560/ac3e0f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 11/29/2021] [Indexed: 11/12/2022]
Abstract
Objective.The boundary crossing algorithm available in Geant4 10.07-p01 general purpose Monte Carlo code has been investigated for a 12 and 200 MeV electron source by the application of a Fano cavity test.Approach.Fano conditions were enforced through all simulations whilst varying individual charged particle transport parameters which control particle step size, ionisation and single scattering.Main Results.At 12 MeV, Geant4 was found to return excellent dose consistency within 0.1% even with the default parameter configurations. The 200 MeV case, however, showed significant consistency issues when default physics parameters were employed with deviations from unity of more than 6%. The effect of the inclusion of nuclear interactions was also investigated for the 200 MeV beam and was found to return good consistency for a number of parameter configurations.Significance.The Fano test is a necessary investigation to ensure the consistency of charged particle transport available in Geant4 before detailed detector simulations can be conducted.
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Affiliation(s)
- M McManus
- National Physicsal Laboratory, Hampton Road, Teddington, TW11 0LW, United Kingdom.,University College London, Gower Street, WC1E 6BT, United Kingdom
| | - F Romano
- Instituto Nazionale Di Fisica Nucleare, Sezione Di Catania, Catania, Italy
| | - G Royle
- University College London, Gower Street, WC1E 6BT, United Kingdom
| | - H Palmans
- National Physicsal Laboratory, Hampton Road, Teddington, TW11 0LW, United Kingdom.,MedAustron Ion Therapy Center, Marie-Curie Strasse 5, A-2700 Wiener Neustadt, Austria
| | - A Subiel
- National Physicsal Laboratory, Hampton Road, Teddington, TW11 0LW, United Kingdom
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Ronga MG, Cavallone M, Patriarca A, Leite AM, Loap P, Favaudon V, Créhange G, De Marzi L. Back to the Future: Very High-Energy Electrons (VHEEs) and Their Potential Application in Radiation Therapy. Cancers (Basel) 2021; 13:4942. [PMID: 34638424 PMCID: PMC8507836 DOI: 10.3390/cancers13194942] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 12/14/2022] Open
Abstract
The development of innovative approaches that would reduce the sensitivity of healthy tissues to irradiation while maintaining the efficacy of the treatment on the tumor is of crucial importance for the progress of the efficacy of radiotherapy. Recent methodological developments and innovations, such as scanned beams, ultra-high dose rates, and very high-energy electrons, which may be simultaneously available on new accelerators, would allow for possible radiobiological advantages of very short pulses of ultra-high dose rate (FLASH) therapy for radiation therapy to be considered. In particular, very high-energy electron (VHEE) radiotherapy, in the energy range of 100 to 250 MeV, first proposed in the 2000s, would be particularly interesting both from a ballistic and biological point of view for the establishment of this new type of irradiation technique. In this review, we examine and summarize the current knowledge on VHEE radiotherapy and provide a synthesis of the studies that have been published on various experimental and simulation works. We will also consider the potential for VHEE therapy to be translated into clinical contexts.
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Affiliation(s)
- Maria Grazia Ronga
- Centre de Protonthérapie d’Orsay, Department of Radiation Oncology, Campus Universitaire, Institut Curie, PSL Research University, 91898 Orsay, France; (M.G.R.); (M.C.); (A.P.); (A.M.L.); (P.L.); (G.C.)
- Thales AVS Microwave & Imaging Sub-Systems, 78141 Vélizy-Villacoublay, France
| | - Marco Cavallone
- Centre de Protonthérapie d’Orsay, Department of Radiation Oncology, Campus Universitaire, Institut Curie, PSL Research University, 91898 Orsay, France; (M.G.R.); (M.C.); (A.P.); (A.M.L.); (P.L.); (G.C.)
| | - Annalisa Patriarca
- Centre de Protonthérapie d’Orsay, Department of Radiation Oncology, Campus Universitaire, Institut Curie, PSL Research University, 91898 Orsay, France; (M.G.R.); (M.C.); (A.P.); (A.M.L.); (P.L.); (G.C.)
| | - Amelia Maia Leite
- Centre de Protonthérapie d’Orsay, Department of Radiation Oncology, Campus Universitaire, Institut Curie, PSL Research University, 91898 Orsay, France; (M.G.R.); (M.C.); (A.P.); (A.M.L.); (P.L.); (G.C.)
- INSERM LITO U1288, Campus Universitaire, Institut Curie, PSL Research University, University Paris Saclay, 91898 Orsay, France
| | - Pierre Loap
- Centre de Protonthérapie d’Orsay, Department of Radiation Oncology, Campus Universitaire, Institut Curie, PSL Research University, 91898 Orsay, France; (M.G.R.); (M.C.); (A.P.); (A.M.L.); (P.L.); (G.C.)
| | - Vincent Favaudon
- INSERM U 1021-CNRS UMR 3347, Campus Universitaire, Institut Curie, PSL Research University, University Paris Saclay, 91898 Orsay, France;
| | - Gilles Créhange
- Centre de Protonthérapie d’Orsay, Department of Radiation Oncology, Campus Universitaire, Institut Curie, PSL Research University, 91898 Orsay, France; (M.G.R.); (M.C.); (A.P.); (A.M.L.); (P.L.); (G.C.)
| | - Ludovic De Marzi
- Centre de Protonthérapie d’Orsay, Department of Radiation Oncology, Campus Universitaire, Institut Curie, PSL Research University, 91898 Orsay, France; (M.G.R.); (M.C.); (A.P.); (A.M.L.); (P.L.); (G.C.)
- INSERM LITO U1288, Campus Universitaire, Institut Curie, PSL Research University, University Paris Saclay, 91898 Orsay, France
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Rahman M, Ashraf MR, Zhang R, Gladstone DJ, Cao X, Williams BB, Hoopes PJ, Pogue BW, Bruza P. Spatial and temporal dosimetry of individual electron FLASH beam pulses using radioluminescence imaging. Phys Med Biol 2021; 66:10.1088/1361-6560/ac0390. [PMID: 34015774 PMCID: PMC10468779 DOI: 10.1088/1361-6560/ac0390] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 05/20/2021] [Indexed: 11/11/2022]
Abstract
Purpose.In this study, spatio-temporal beam profiling for electron ultra-high dose rate (UHDR; >40 Gy s-1) radiation via Cherenkov emission and radioluminescence imaging was investigated using intensified complementary metal-oxide-semiconductor cameras.Methods.The cameras, gated to FLASH optimized linear accelerator pulses, imaged radioluminescence and Cherenkov emission incited by single pulses of a UHDR (>40 Gy s-1) 10 MeV electron beam delivered to the isocenter. Surface dosimetry was investigated via imaging Cherenkov emission or scintillation from a solid water phantom or Gd2O2S:Tb screen positioned on top of the phantom, respectively. Projected depth-dose profiles were imaged from a tank filled with water (Cherenkov emission) and a 1 g l-1quinine sulfate solution (scintillation). These optical results were compared with projected lateral dose profiles measured by Gafchromic film at different depths, including the surface.Results.The per-pulse beam output from Cherenkov imaging agreed with the photomultiplier tube Cherenkov output to within 3% after about the first five to seven ramp-up pulses. Cherenkov emission and scintillation were linear with dose (R2 = 0.987 and 0.995, respectively) and independent of dose rate from ∼50 to 300 Gy s-1(0.18-0.91 Gy/pulse). The surface dose distribution from film agreed better with scintillation than with Cherenkov emission imaging (3%/3 mm gamma pass rates of 98.9% and 88.8%, respectively). Using a 450 nm bandpass filter, the quinine sulfate-based water imaging of the projected depth optical profiles agreed with the projected film dose to within 5%.Conclusion.The agreement of surface dosimetry using scintillation screen imaging and Gafchromic film suggests it can verify the consistency of daily beam quality assurance parameters with an accuracy of around 2% or 2 mm. Cherenkov-based surface dosimetry was affected by the target's optical properties, prompting additional calibration. In projected depth-dose profiling, scintillation imaging via spectral suppression of Cherenkov emission provided the best match to film. Both camera-based imaging modalities resolved dose from single UHDR beam pulses of up to 60 Hz repetition rate and 1 mm spatial resolution.
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Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - M. Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - David J. Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Benjamin B. Williams
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - P. Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Radiation Oncology, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 03755 USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
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First theoretical determination of relative biological effectiveness of very high energy electrons. Sci Rep 2021; 11:11242. [PMID: 34045625 PMCID: PMC8160353 DOI: 10.1038/s41598-021-90805-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/17/2021] [Indexed: 02/07/2023] Open
Abstract
Very high energy electrons (VHEEs, E > 70 MeV) present promising clinical advantages over conventional beams due to their increased range, improved penumbra and relative insensitivity to tissue heterogeneities. They have recently garnered additional interest in their application to spatially fractionated radiotherapy or ultra-high dose rate (FLASH) therapy. However, the lack of radiobiological data limits their rapid development. This study aims to provide numerical biologically-relevant information by characterizing VHEE beams (100 and 300 MeV) against better-known beams (clinical energy electrons, photons, protons, carbon and neon ions). Their macro- and microdosimetric properties were compared, using the dose-averaged linear energy transfer ([Formula: see text]) as the macroscopic metric, and the dose-mean lineal energy [Formula: see text] and the dose-weighted lineal energy distribution, yd(y), as microscopic metrics. Finally, the modified microdosimetric kinetic model was used to calculate the respective cell survival curves and the theoretical RBE. From the macrodosimetric point of view, VHEEs presented a potential improved biological efficacy over clinical photon/electron beams due to their increased [Formula: see text]. The microdosimetric data, however, suggests no increased biological efficacy of VHEEs over clinical electron beams, resulting in RBE values of approximately 1, giving confidence to their clinical implementation. This study represents a first step to complement further radiobiological experiments.
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Ashraf M, Rahman M, Zhang R, Cao X, Williams BB, Hoopes PJ, Gladstone DJ, Pogue BW, Bruza P. Technical Note: Single-pulse beam characterization for FLASH-RT using optical imaging in a water tank. Med Phys 2021; 48:2673-2681. [PMID: 33730367 PMCID: PMC10771323 DOI: 10.1002/mp.14843] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 11/07/2022] Open
Abstract
PURPOSE High dose rate conditions, coupled with problems related to small field dosimetry, make dose characterization for FLASH-RT challenging. Most conventional dosimeters show significant dependence on dose rate at ultra-high dose rate conditions or fail to provide sufficiently fast temporal data for pulse to pulse dosimetry. Here fast 2D imaging of radioluminescence from a water and quinine phantom was tested for dosimetry of individual 4 μs linac pulses. METHODS A modified clinical linac delivered an electron FLASH beam of >50 Gy/s to clinical isocenter. This modification removed the x-ray target and flattening filter, leading to a beam that was symmetric and gaussian, as verified with GafChromic EBT-XD film. Lateral projected 2D dose distributions for each linac pulse were imaged in a quinine-doped water tank using a gated intensified camera, and an inverse Abel transform reconstruction provided 3D images for on-axis depth dose values. A total of 20 pulses were delivered with a 10 MeV, 1.5 cm circular beam, and beam with jaws wide open (40 × 40 cm2 ), and a 3D dose distribution was recovered for each pulse. Beam output was analyzed on a pulse by pulse basis. RESULTS The Rp , Dmax , and the R50 measured with film and optical methods agreed to within 1 mm for the 1.5 cm circular beam and the beam with jaws wide open. Cross beam profiles for both beams agreed with film data with >95% passing rate (2%/2 mm gamma criteria). The optical central axis depth dose agreed with film data, except for near the surface. A temporal pulse analysis revealed a ramp-up period where the dose per pulse increased for the first few pulses and then stabilized. CONCLUSIONS Optical imaging of radioluminescence was presented as a valuable tool for establishing a baseline for the recently initiated electron FLASH beam at our institution.
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Affiliation(s)
- M.Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
| | - Benjamin B. Williams
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - P. Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 0375 USA
| | - David J. Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Department of Medicine, Geisel School of Medicine, Dartmouth College Hanover NH 03755 USA
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Brian W. Pogue
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
- Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover NH 0375 USA
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover NH 03755, US
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Marcu LG, Bezak E, Peukert DD, Wilson P. Translational Research in FLASH Radiotherapy-From Radiobiological Mechanisms to In Vivo Results. Biomedicines 2021; 9:181. [PMID: 33670409 PMCID: PMC7918545 DOI: 10.3390/biomedicines9020181] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 01/18/2023] Open
Abstract
FLASH radiotherapy, or the administration of ultra-high dose rate radiotherapy, is a new radiation delivery method that aims to widen the therapeutic window in radiotherapy. Thus far, most in vitro and in vivo results show a real potential of FLASH to offer superior normal tissue sparing compared to conventionally delivered radiation. While there are several postulations behind the differential behaviour among normal and cancer cells under FLASH, the full spectra of radiobiological mechanisms are yet to be clarified. Currently the number of devices delivering FLASH dose rate is few and is mainly limited to experimental and modified linear accelerators. Nevertheless, FLASH research is increasing with new developments in all the main areas: radiobiology, technology and clinical research. This paper presents the current status of FLASH radiotherapy with the aforementioned aspects in mind, but also to highlight the existing challenges and future prospects to overcome them.
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Affiliation(s)
- Loredana G Marcu
- Faculty of Informatics & Science, Department of Physics, University of Oradea, 410087 Oradea, Romania
- Cancer Research Institute and School of Health Sciences, University of South Australia, Adelaide, SA 5001, Australia
| | - Eva Bezak
- Cancer Research Institute and School of Health Sciences, University of South Australia, Adelaide, SA 5001, Australia
- School of Physical Sciences, Department of Physics, University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
| | - Dylan D Peukert
- School of Civil, Environmental & Mining Engineering, University of Adelaide, North Terrace, Adelaide, SA 5005, Australia
- STEM, University of South Australia, Adelaide, SA 5001, Australia
| | - Puthenparampil Wilson
- STEM, University of South Australia, Adelaide, SA 5001, Australia
- Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
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Poppinga D, Kranzer R, Farabolini W, Gilardi A, Corsini R, Wyrwoll V, Looe HK, Delfs B, Gabrisch L, Poppe B. VHEE beam dosimetry at CERN Linear Electron Accelerator for Research under ultra-high dose rate conditions. Biomed Phys Eng Express 2020; 7. [PMID: 34037536 DOI: 10.1088/2057-1976/abcae5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 11/16/2020] [Indexed: 01/28/2023]
Abstract
The aim of this work is the dosimetric characterization of a plane parallel ionization chamber under defined beam setups at the CERN Linear Electron Accelerator for Research (CLEAR). A laser driven electron beam with energy of 200 MeV at two different field sizes of approximately 3.5 mm FWHM and approximately 7 mm FWHM were used at different pulse structures. Thereby the dose-per-pulse range varied between approximately 0.2 and 12 Gy per pulse. This range represents approximately conventional dose rate range beam conditions up to ultra-high dose rate (UHDR) beam conditions. The experiment was based on a water phantom which was integrated into the horizontal beamline and radiochromic films and an Advanced Markus ionization chamber was positioned in the water phantom. In addition, the experimental setup were modelled in the Monte Carlo simulation environment FLUKA. In a first step the radiochromic film measurements were used to verify the beamline setup. Depth dose distributions and dose profiles measured by radiochromic film were compared with Monte Carlo simulations to verify the experimental conditions. Second, the radiochromic films were used for reference dosimetry to characterize the ionization chamber. In particular, polarity effects and the ion collection efficiency of the ionization chamber were investigated for both field sizes and the complete dose rate range. As a result of the study, significant polarity effects and recombination loss of the ionization chamber were shown and characterized. However, the work shows that the behavior of the ionization chamber at the laser driven beam line at the CLEAR facility is comparable to classical high dose-per-pulse electron beams. This allows the use of ionization chambers on the CLEAR system and thus enables active dose measurement during the experiment. Compared to passive dose measurement with film, this is an important step forward in the experimental equipment of the facility.
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Affiliation(s)
| | - Rafael Kranzer
- PTW Freiburg, Freiburg, Germany.,University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | | | - Antonio Gilardi
- Federico II, DIETI, University of Napoli, Napoli, Italy.,CERN, CH1211 Geneva, Switzerland.,National Institute for Nuclear Physics (INFN), Section of Napoli, Italy
| | | | | | - Hui Khee Looe
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Björn Delfs
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Lukas Gabrisch
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
| | - Björn Poppe
- University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany
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Schüller A, Heinrich S, Fouillade C, Subiel A, De Marzi L, Romano F, Peier P, Trachsel M, Fleta C, Kranzer R, Caresana M, Salvador S, Busold S, Schönfeld A, McEwen M, Gomez F, Solc J, Bailat C, Linhart V, Jakubek J, Pawelke J, Borghesi M, Kapsch RP, Knyziak A, Boso A, Olsovcova V, Kottler C, Poppinga D, Ambrozova I, Schmitzer CS, Rossomme S, Vozenin MC. The European Joint Research Project UHDpulse – Metrology for advanced radiotherapy using particle beams with ultra-high pulse dose rates. Phys Med 2020; 80:134-150. [DOI: 10.1016/j.ejmp.2020.09.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 08/17/2020] [Accepted: 09/23/2020] [Indexed: 02/08/2023] Open
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Labate L, Palla D, Panetta D, Avella F, Baffigi F, Brandi F, Di Martino F, Fulgentini L, Giulietti A, Köster P, Terzani D, Tomassini P, Traino C, Gizzi LA. Toward an effective use of laser-driven very high energy electrons for radiotherapy: Feasibility assessment of multi-field and intensity modulation irradiation schemes. Sci Rep 2020; 10:17307. [PMID: 33057078 PMCID: PMC7560873 DOI: 10.1038/s41598-020-74256-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 09/17/2020] [Indexed: 12/30/2022] Open
Abstract
Radiotherapy with very high energy electrons has been investigated for a couple of decades as an effective approach to improve dose distribution compared to conventional photon-based radiotherapy, with the recent intriguing potential of high dose-rate irradiation. Its practical application to treatment has been hindered by the lack of hospital-scale accelerators. High-gradient laser-plasma accelerators (LPA) have been proposed as a possible platform, but no experiments so far have explored the feasibility of a clinical use of this concept. We show the results of an experimental study aimed at assessing dose deposition for deep seated tumours using advanced irradiation schemes with an existing LPA source. Measurements show control of localized dose deposition and modulation, suitable to target a volume at depths in the range from 5 to 10 cm with mm resolution. The dose delivered to the target was up to 1.6 Gy, delivered with few hundreds of shots, limited by secondary components of the LPA accelerator. Measurements suggest that therapeutic doses within localized volumes can already be obtained with existing LPA technology, calling for dedicated pre-clinical studies.
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Affiliation(s)
- Luca Labate
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy.
| | - Daniele Palla
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy
| | - Daniele Panetta
- Consiglio Nazionale delle Ricerche, Istituto di Fisiologia Clinica, Pisa, Italy
| | - Federico Avella
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy
| | - Federica Baffigi
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy
| | - Fernando Brandi
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy
| | - Fabio Di Martino
- Unità Operativa di Fisica Sanitaria, Azienza Ospedaliero-Universitaria Pisana, Pisa, Italy
| | - Lorenzo Fulgentini
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy
| | - Antonio Giulietti
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy
| | - Petra Köster
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy
| | - Davide Terzani
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy
- Lawrence Berkeley National Laboratory, LBL, Berkeley, CA, USA
| | - Paolo Tomassini
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy
| | - Claudio Traino
- Unità Operativa di Fisica Sanitaria, Azienza Ospedaliero-Universitaria Pisana, Pisa, Italy
| | - Leonida A Gizzi
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Pisa, Italy.
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