1
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di Franco F, Rosuel N, Gallin-Martel L, Gallin-Martel ML, Ghafooryan-Sangchooli M, Keshmiri S, Motte JF, Muraz JF, Pellicioli P, Ruat M, Serduc R, Verry C, Dauvergne D, Adam JF. Monocrystalline diamond detector for online monitoring during synchrotron microbeam radiotherapy. JOURNAL OF SYNCHROTRON RADIATION 2023; 30:1076-1085. [PMID: 37815374 PMCID: PMC10624038 DOI: 10.1107/s160057752300752x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 08/28/2023] [Indexed: 10/11/2023]
Abstract
Microbeam radiation therapy (MRT) is a radiotherapy technique combining spatial fractionation of the dose distribution on a micrometric scale, X-rays in the 50-500 keV range and dose rates up to 16 × 103 Gy s-1. Nowadays, in vivo dosimetry remains a challenge due to the ultra-high radiation fluxes involved and the need for high-spatial-resolution detectors. The aim here was to develop a striped diamond portal detector enabling online microbeam monitoring during synchrotron MRT treatments. The detector, a 550 µm bulk monocrystalline diamond, is an eight-strip device, of height 3 mm, width 178 µm and with 60 µm spaced strips, surrounded by a guard ring. An eight-channel ASIC circuit for charge integration and digitization has been designed and tested. Characterization tests were performed at the ID17 biomedical beamline of the European Synchrotron Radiation Facility (ESRF). The detector measured direct and attenuated microbeams as well as interbeam fluxes with a precision level of 1%. Tests on phantoms (RW3 and anthropomorphic head phantoms) were performed and compared with simulations. Synchrotron radiation measurements were performed on an RW3 phantom for strips facing a microbeam and for strips facing an interbeam area. A 2% difference between experiments and simulations was found. In more complex geometries, a preliminary study showed that the absolute differences between simulated and recorded transmitted beams were within 2%. Obtained results showed the feasibility of performing MRT portal monitoring using a microstriped diamond detector. Online dosimetric measurements are currently ongoing during clinical veterinary trials at ESRF, and the next 153-strip detector prototype, covering the entire irradiation field, is being finalized at our institution.
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Affiliation(s)
- Francesca di Franco
- Université Grenoble-Alpes, CNRS, Grenoble INP, LPSC UMR5821, 38000 Grenoble, France
| | - Nicolas Rosuel
- Université Grenoble-Alpes, CNRS, Grenoble INP, LPSC UMR5821, 38000 Grenoble, France
| | | | | | | | - Sarvenaz Keshmiri
- Université Grenoble-Alpes, UGA/INSERM UA7 STROBE, 2280 Rue de la Piscine, 38400 Saint-Martin d’Hères, France
| | - Jean-François Motte
- Université Grenoble-Alpes, Institut Néel, CNRS, Grenoble-INP, Grenoble, France
| | - Jean-François Muraz
- Université Grenoble-Alpes, CNRS, Grenoble INP, LPSC UMR5821, 38000 Grenoble, France
| | | | | | - Raphael Serduc
- Université Grenoble-Alpes, UGA/INSERM UA7 STROBE, 2280 Rue de la Piscine, 38400 Saint-Martin d’Hères, France
- Centre Hospitalier Universitaire Grenoble-Alpes, CS10217, 38043 Grenoble, France
| | - Camille Verry
- Centre Hospitalier Universitaire Grenoble-Alpes, CS10217, 38043 Grenoble, France
| | - Denis Dauvergne
- Université Grenoble-Alpes, CNRS, Grenoble INP, LPSC UMR5821, 38000 Grenoble, France
| | - Jean-François Adam
- Université Grenoble-Alpes, UGA/INSERM UA7 STROBE, 2280 Rue de la Piscine, 38400 Saint-Martin d’Hères, France
- Centre Hospitalier Universitaire Grenoble-Alpes, CS10217, 38043 Grenoble, France
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2
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Gobet F, Barberet P, Delville MH, Devès G, Guérin T, Liénard R, Tran HN, Vecco-Garda C, Würger A, Zein S, Seznec H. Electric Fields in Liquid Water Irradiated with Protons at Ultrahigh Dose Rates. PHYSICAL REVIEW LETTERS 2023; 131:178001. [PMID: 37955497 DOI: 10.1103/physrevlett.131.178001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 09/21/2023] [Indexed: 11/14/2023]
Abstract
We study the effects of irradiating water with 3 MeV protons at high doses by observing the motion of charged polystyrene beads outside the proton beam. By single-particle tracking, we measure a radial velocity of the order of microns per second. Combining electrokinetic theory with simulations of the beam-generated reaction products and their outward diffusion, we find that the bead motion is due to electrophoresis in the electric field induced by the mobility contrast of cations and anions. This work sheds light on the perturbation of biological systems by high-dose radiations and paves the way for the manipulation of colloid or macromolecular dispersions by radiation-induced diffusiophoresis.
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Affiliation(s)
- F Gobet
- University of Bordeaux, CNRS, LP2I, UMR 5797, F-33170 Gradignan, France
| | - P Barberet
- University of Bordeaux, CNRS, LP2I, UMR 5797, F-33170 Gradignan, France
| | - M-H Delville
- University of Bordeaux, CNRS, ICMCB, UMR 5026, F-33608 Pessac, France
| | - G Devès
- University of Bordeaux, CNRS, LP2I, UMR 5797, F-33170 Gradignan, France
| | - T Guérin
- University of Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France
| | - R Liénard
- University of Bordeaux, CNRS, LP2I, UMR 5797, F-33170 Gradignan, France
| | - H N Tran
- University of Bordeaux, CNRS, LP2I, UMR 5797, F-33170 Gradignan, France
| | - C Vecco-Garda
- University of Bordeaux, CNRS, ICMCB, UMR 5026, F-33608 Pessac, France
| | - A Würger
- University of Bordeaux, CNRS, LOMA, UMR 5798, F-33400 Talence, France
| | - S Zein
- University of Bordeaux, CNRS, LP2I, UMR 5797, F-33170 Gradignan, France
| | - H Seznec
- University of Bordeaux, CNRS, LP2I, UMR 5797, F-33170 Gradignan, France
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3
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Shukla S, Saha T, Rama N, Acharya A, Le T, Bian F, Donovan J, Tan LA, Vatner R, Kalinichenko V, Mascia A, Perentesis JP, Kalin TV. Ultra-high dose-rate proton FLASH improves tumor control. Radiother Oncol 2023; 186:109741. [PMID: 37315577 PMCID: PMC10527231 DOI: 10.1016/j.radonc.2023.109741] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 06/04/2023] [Accepted: 06/05/2023] [Indexed: 06/16/2023]
Abstract
BACKGROUND AND PURPOSE Proton radiotherapy (PRT) offers potential benefits over other radiation modalities, including photon and electron radiotherapy. Increasing the rate at which proton radiation is delivered may provide a therapeutic advantage. Here, we compared the efficacy of conventional proton therapy (CONVpr) to ultrahigh dose-rate proton therapy, FLASHpr, in a mouse model of non-small cell lung cancers (NSCLC). MATERIALS AND METHODS Mice bearing orthotopic lung tumors received thoracic radiation therapy using CONVpr (<0.05 Gy/s) and FLASHpr (>60 Gy/s) dose rates. RESULTS Compared to CONVpr, FLASHpr was more effective in reducing tumor burden and decreasing tumor cell proliferation. Furthermore, FLASHpr was more efficient in increasing the infiltration of cytotoxic CD8+ T-lymphocytes inside the tumor while simultaneously reducing the percentage of immunosuppressive regulatory T-cells (Tregs) among T-lymphocytes. Also, compared to CONVpr, FLASHpr was more effective in decreasing pro-tumorigenic M2-like macrophages in lung tumors, while increasing infiltration of anti-tumor M1-like macrophages. Finally, FLASHpr treatment reduced expression of checkpoint inhibitors in lung tumors, indicating reduced immune tolerance. CONCLUSIONS Our results suggest that FLASH dose-rate proton delivery modulates the immune system to improve tumor control and might thus be a promising new alternative to conventional dose rates for NSCLC treatment.
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Affiliation(s)
- Samriddhi Shukla
- Division of Pulmonary Biology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States
| | - Taniya Saha
- Division of Pulmonary Biology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States
| | - Nihar Rama
- Division of Pulmonary Biology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States
| | - Anusha Acharya
- Division of Pulmonary Biology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States
| | - Tien Le
- Division of Pulmonary Biology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States
| | - Fenghua Bian
- Division of Pulmonary Biology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States
| | - Johnny Donovan
- Division of Pulmonary Biology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States
| | - Lin Abigail Tan
- Division of Pulmonary Biology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States
| | - Ralph Vatner
- Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, OH, USA, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Vladimir Kalinichenko
- Division of Pulmonary Biology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States; Neonatology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States; Center for Lung Regenerative Medicine, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States
| | - Anthony Mascia
- Department of Radiation Oncology, University of Cincinnati College of Medicine, Cincinnati, OH, USA, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - John P Perentesis
- Cincinnati Children's Hospital Medical Center, Division of Oncology, Division of Experimental Hematology, Division of Biomedical Informatics, Cincinnati, OH 45229, USA
| | - Tanya V Kalin
- Division of Pulmonary Biology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States; Neonatology, the Perinatal Institute of Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH 45229, United States.
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4
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Vozenin MC, Bourhis J, Durante M. Towards clinical translation of FLASH radiotherapy. Nat Rev Clin Oncol 2022; 19:791-803. [DOI: 10.1038/s41571-022-00697-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2022] [Indexed: 11/09/2022]
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5
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Towards neuro-oncologic clinical trials of high dose rate synchrotron Microbeam Radiation Therapy: first treatment of a spontaneous canine brain tumor. Int J Radiat Oncol Biol Phys 2022; 113:967-973. [DOI: 10.1016/j.ijrobp.2022.04.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/13/2022] [Accepted: 04/16/2022] [Indexed: 11/22/2022]
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6
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Keshmiri S, Brocard S, Serduc R, Adam JF. A high resolution dose calculation engine for x-ray microbeams radiation therapy. Med Phys 2022; 49:3999-4017. [PMID: 35342953 PMCID: PMC9322281 DOI: 10.1002/mp.15637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 03/04/2022] [Accepted: 03/08/2022] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Microbeam radiation therapy (MRT) is a treatment modality based on spatial fractionation of synchrotron generated x-rays into parallel, high dose, microbeams of a few microns width. MRT is still an under-development radiosurgery technique for which, promising preclinical results on brain tumors and epilepsy encourages its clinical transfer. PURPOSE A safe clinical transfer of MRT needs a specific treatment planning system (TPS) that provides accurate dose calculations in human patients, taking into account the MRT beams properties (high dose gradients, spatial fractionation, polarization effects). So far, the most advanced MRT treatment planning system, based on a hybrid dose calculation algorithm, is limited to a macroscopic rendering of the dose and does not account for the complex dose distribution inherent to MRT if delivered as conformal irradiations with multiple incidences. For overcoming these limitations, a multi-scale full Monte-Carlo calculation engine called penMRT has been developed and benchmarked against two general purpose Monte Carlo codes: penmain based on PENELOPE and Gate based on Geant4. METHODS PenMRT, is based on the PENELOPE (2018) Monte Carlo (MC) code, modified to take into account the voxelized geometry of the patients (CT-scans) and offering an adaptive micrometric dose calculation grid independent to the CT size, location and orientation. The implementation of the dynamic memory allocation in penMRT, makes the simulations feasible within a huge number of dose scoring bins. The possibility of using a source replication approach to simulate arrays of microbeams, and the parallelization using OpenMPI have been added to penMRT in order to increase the calculation speed for clinical usages. This engine can be implemented in a TPS as a dose calculation core. RESULTS The performance tests highlight the reliability of penMRT to be used for complex irradiation conditions in MRT. The benchmarking against a standard PENELOPE code did not show any significant difference for calculations in centimetric beams, for a single microbeam and for a microbeam array. The comparisons between penMRT and Gate as an independent MC code did not show any difference in the beam paths, whereas in valley regions, relative differences between the two codes rank from 1 to 7.5% which are probably due to the differences in physics lists that are used in these two codes. The reliability of the source replication approach has also been tested and validated with an underestimation of no more than 0.6% in low dose areas. CONCLUSIONS Good agreements (a relative difference between 0 to 8%) were found when comparing calculated peak to valley dose ratio (PVDR) values using penMRT, for irradiations with a full microbeam array, with calculated values in the literature. The high-resolution calculated dose maps obtained with penMRT are used to extract differential and cumulative dose-volume histograms (DVHs) and analyze treatment plans with much finer metrics regarding the irradiation complexity. To our knowledge, these are the first high-resolution dose maps and associated DVHs ever obtained for cross-fired microbeams irradiation, which is bringing a significant added value to the field of treatment planning in spatially fractionated radiation therapy. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Sylvan Brocard
- Univ. Grenoble Alpes, INSERM, UA07 STROBE, Grenoble, 38000, France
| | - Raphaël Serduc
- Univ. Grenoble Alpes, INSERM, UA07 STROBE, Grenoble, 38000, France.,Centre Hospitalier Universitaire de Grenoble, Grenoble, 38000, France
| | - Jean-François Adam
- Univ. Grenoble Alpes, INSERM, UA07 STROBE, Grenoble, 38000, France.,Centre Hospitalier Universitaire de Grenoble, Grenoble, 38000, France
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7
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Non-Targeted Effects of Synchrotron Radiation: Lessons from Experiments at the Australian and European Synchrotrons. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12042079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Studies have been conducted at synchrotron facilities in Europe and Australia to explore a variety of applications of synchrotron X-rays in medicine and biology. We discuss the major technical aspects of the synchrotron irradiation setups, paying specific attention to the Australian Synchrotron (AS) and the European Synchrotron Radiation Facility (ESRF) as those best configured for a wide range of biomedical research involving animals and future cancer patients. Due to ultra-high dose rates, treatment doses can be delivered within milliseconds, abiding by FLASH radiotherapy principles. In addition, a homogeneous radiation field can be spatially fractionated into a geometric pattern called microbeam radiotherapy (MRT); a coplanar array of thin beams of microscopic dimensions. Both are clinically promising radiotherapy modalities because they trigger a cascade of biological effects that improve tumor control, while increasing normal tissue tolerance compared to conventional radiation. Synchrotrons can deliver high doses to a very small volume with low beam divergence, thus facilitating the study of non-targeted effects of these novel radiation modalities in both in-vitro and in-vivo models. Non-targeted radiation effects studied at the AS and ESRF include monitoring cell–cell communication after partial irradiation of a cell population (radiation-induced bystander effect, RIBE), the response of tissues outside the irradiated field (radiation-induced abscopal effect, RIAE), and the influence of irradiated animals on non-irradiated ones in close proximity (inter-animal RIBE). Here we provide a summary of these experiments and perspectives on their implications for non-targeted effects in biomedical fields.
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8
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Abstract
AbstractSpatially fractionated radiation therapy (SFRT) challenges some of the classical dogmas in conventional radiotherapy. The highly modulated spatial dose distributions in SFRT have been shown to lead, both in early clinical trials and in small animal experiments, to a significant increase in normal tissue dose tolerances. Tumour control effectiveness is maintained or even enhanced in some configurations as compared with conventional radiotherapy. SFRT seems to activate distinct radiobiological mechanisms, which have been postulated to involve bystander effects, microvascular alterations and/or immunomodulation. Currently, it is unclear which is the dosimetric parameter which correlates the most with both tumour control and normal tissue sparing in SFRT. Additional biological experiments aiming at parametrizing the relationship between the irradiation parameters (beam width, spacing, peak-to-valley dose ratio, peak and valley doses) and the radiobiology are needed. A sound knowledge of the interrelation between the physical parameters in SFRT and the biological response would expand its clinical use, with a higher level of homogenisation in the realisation of clinical trials. This manuscript reviews the state of the art of this promising therapeutic modality, the current radiobiological knowledge and elaborates on future perspectives.
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9
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Laissue JA, Barré S, Bartzsch S, Blattmann H, Bouchet AM, Djonov VG, Haberthür D, Hlushchuk R, Kaser-Hotz B, Laissue PP, LeDuc G, Reding SO, Serduc R. Tolerance of Normal Rabbit Facial Bones and Teeth to Synchrotron X-Ray Microbeam Irradiation. Radiat Res 2021; 197:233-241. [PMID: 34755190 DOI: 10.1667/rade-21-00032.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 09/30/2021] [Indexed: 11/03/2022]
Abstract
Microbeam radiation therapy, an alternative radiosurgical treatment under preclinical investigation, aims to safely treat muzzle tumors in pet animals. This will require data on the largely unknown radiation toxicity of microbeam arrays for bones and teeth. To this end, the muzzle of six young adult New Zealand rabbits was irradiated by a lateral array of microplanar beamlets with peak entrance doses of 200, 330 or 500 Gy. The muzzles were examined 431 days postirradiation by computed microtomographic imaging (micro-CT) ex vivo, and extensive histopathology. The boundaries of the radiation field were identified histologically by microbeam tracks in cartilage and other tissues. There was no radionecrosis of facial bones in any rabbit. Conversely, normal incisor teeth exposed to peak entrance doses of 330 Gy or 500 Gy developed marked caries-like damage, whereas the incisors of the two rabbits exposed to 200 Gy remained unscathed. A single, unidirectional array of microbeams with a peak entrance dose ≤200 Gy (valley dose14 Gy) did not damage normal bone, teeth and soft tissues of the muzzle of normal rabbits longer than one year after irradiation. Because of that, Microbeam radiation therapy of muzzle tumors in pet animals is unlikely to cause sizeable damage to normal teeth, bone and soft tissues, if a single array as used here delivers a limited entrance dose of 200 Gy and a valley dose of ≤14 Gy.
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Affiliation(s)
- Jean Albert Laissue
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH -3012 Bern, Switzerland
| | - Sébastien Barré
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH -3012 Bern, Switzerland
| | - Stefan Bartzsch
- Department of Radiation Oncology, Klinikum rechts der Isar - TU Munich, Germany
| | - Hans Blattmann
- Niederwiesstrasse 13C, CH-5417 Untersiggenthal, Switzerland
| | - Audrey M Bouchet
- INSERM UA8, "Radiations : Défense, Santé, Environnement," 69008 Lyon, France
| | | | - David Haberthür
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH -3012 Bern, Switzerland
| | - Ruslan Hlushchuk
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH -3012 Bern, Switzerland
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10
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Wright MD, Romanelli P, Bravin A, Le Duc G, Brauer-Krisch E, Requardt H, Bartzsch S, Hlushchuk R, Laissue JA, Djonov V. Non-conventional Ultra-High Dose Rate (FLASH) Microbeam Radiotherapy Provides Superior Normal Tissue Sparing in Rat Lung Compared to Non-conventional Ultra-High Dose Rate (FLASH) Radiotherapy. Cureus 2021; 13:e19317. [PMID: 35223216 PMCID: PMC8864723 DOI: 10.7759/cureus.19317] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2021] [Indexed: 12/12/2022] Open
Abstract
Conventional radiotherapy is a widely used non-invasive form of treatment for many types of cancer. However, due to a low threshold in the lung for radiation-induced normal tissue damage, it is of less utility in treating lung cancer. For this reason, surgery is the preferred treatment for lung cancer, which has the detriment of being highly invasive. Non-conventional ultra-high dose rate (FLASH) radiotherapy is currently of great interest in the radiotherapy community due to demonstrations of reduced normal tissue toxicity in lung and other anatomy. This study investigates the effects of FLASH microbeam radiotherapy, which in addition to ultra-high dose rate incorporates a spatial segmentation of the radiation field, on the normal lung tissue of rats. With a focus on fibrotic damage, this work demonstrates that FLASH microbeam radiotherapy provides an order of magnitude increase in normal tissue radio-resistance compared to FLASH radiotherapy. This result suggests FLASH microbeam radiotherapy holds promise for much improved non-invasive control of lung cancer.
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Affiliation(s)
- Michael D Wright
- Ginzton Technology Center, Varian Medical Systems, Palo Alto, USA.,Research & Development Center, Avail Medical Devices, Roseville, USA
| | | | - Alberto Bravin
- Biomedical Beamline, European Synchrotron Radiation Facility, Grenoble, FRA
| | - Geraldine Le Duc
- Biomedical Beamline, European Synchrotron Radiation Facility, Grenoble, FRA.,Pharmaceutics, NH TherAguix, Lyon, FRA
| | - Elke Brauer-Krisch
- Biomedical Beamline, European Synchrotron Radiation Facility, Grenoble, FRA
| | - Herwig Requardt
- Biomedical Beamline, European Synchrotron Radiation Facility, Grenoble, FRA
| | - Stefan Bartzsch
- Department of Radiation Oncology, School of Medicine, Technical University of Munich, Munich, DEU.,Institute for Radiation Medicine, Helmholtz Centre Munich, Munich, DEU
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11
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Zverev D, Snigireva I, Sorokovikov M, Yunkin V, Kuznetsov S, Snigirev A. Coherent X-ray beam expander based on a multilens interferometer. OPTICS EXPRESS 2021; 29:35038-35053. [PMID: 34808948 DOI: 10.1364/oe.434656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
A coherent X-ray beam expander based on a multilens interferometer is proposed in this paper. The multilens interferometer allows efficient generation of a highly diverging coherent beam up to several milliradians in the hard X-ray energy range. The optical properties of the interferometer were experimentally demonstrated at the ESRF ID13 undulator beamline (Grenoble, France), using 12.4 keV X-rays. The beam expander allowed us to control the angular size and photon flux density of the formed beam and enabled operation in both coherent and incoherent modes. The experimental results were fully consistent with the theoretical concepts and appropriate computer simulations. Future design improvements and related applications are also discussed.
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12
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Zakaria AM, Colangelo NW, Meesungnoen J, Jay-Gerin JP. Transient hypoxia in water irradiated by swift carbon ions at ultra-high dose rates: implication for FLASH carbon-ion therapy. CAN J CHEM 2021. [DOI: 10.1139/cjc-2021-0110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Large doses of ionizing radiation delivered to tumors at ultra-high dose rates (i.e., in a few milliseconds) paradoxically spare the surrounding healthy tissue while preserving anti-tumor activity (compared with conventional radiotherapy delivered at much lower dose rates). This new modality is known as “FLASH radiotherapy” (FLASH-RT). Although the molecular mechanisms underlying FLASH-RT are not yet fully understood, it has been suggested that radiation delivered at high dose rates spares normal tissue via oxygen depletion followed by subsequent radioresistance of the irradiated tissue. To date, FLASH-RT has been studied using electrons, photons, and protons in various basic biological experiments, pre-clinical studies, and recently in a human patient. However, the efficacy of heavy ions, such as energetic carbon ions, under FLASH-RT conditions remains unclear. Given that living cells and tissues consist mainly of water, we set out to study, from a pure radiation chemistry perspective, the effects of ultra-high dose rates on the transient yields and concentrations of radiolytic species formed in water irradiated by 300-MeV per nucleon carbon ions (LET ∼ 11.6 keV/µm). This mimics irradiation in the “plateau” region of the depth–dose distribution of ions, i.e., in the “normal” tissue region in which the LET is rather low. We used Monte Carlo simulations of multiple, simultaneously interacting radiation tracks together with an “instantaneous pulse” irradiation model. Our calculations show a pronounced oxygen depletion around 0.2 μs, strongly suggesting, as with electrons, photons, and protons, that irradiation with energetic carbon ions at ultra-high dose rates is suitable for FLASH-RT.
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Affiliation(s)
- Abdullah Muhammad Zakaria
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12ème Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Nicholas W. Colangelo
- Department of Radiation Oncology, NYU Grossman School of Medicine, New York, NY, USA
| | - Jintana Meesungnoen
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12ème Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Jean-Paul Jay-Gerin
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12ème Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
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13
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Montay-Gruel P, Corde S, Laissue JA, Bazalova-Carter M. FLASH radiotherapy with photon beams. Med Phys 2021; 49:2055-2067. [PMID: 34519042 DOI: 10.1002/mp.15222] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 08/12/2021] [Accepted: 08/30/2021] [Indexed: 12/16/2022] Open
Abstract
Ultra-high-dose rate "FLASH" radiotherapy (FLASH-RT) has been shown to drastically reduce normal tissue toxicities while being as efficacious as conventional dose rate radiotherapy to treat tumors. A large number of preclinical studies describing this so-called FLASH effect have led to the clinical translation of FLASH-RT using ultra-high-dose rate electron and proton beams. Although the vast majority of radiation therapy treatments are delivered using X-rays, few preclinical data using ultra-high-dose rate X-ray irradiation have been published. This review focuses on different methods that can be used to generate ultra-high-dose rate X-rays and their beam characteristics along with their effect on the biological tissues and the perspectives for the development of FLASH-RT with X-rays.
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Affiliation(s)
- Pierre Montay-Gruel
- Department of Radiation Oncology, University of California, Irvine, California, USA.,Department of Radiotherapy, Iridium Network, Antwerp, Belgium
| | - Stéphanie Corde
- Department of Radiation Oncology, Prince of Wales Hospital, Randwick, NSW, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia.,Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Jean A Laissue
- Institute of Pathology, University of Bern, Bern, Switzerland
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A Brief Overview of the Preclinical and Clinical Radiobiology of Microbeam Radiotherapy. Clin Oncol (R Coll Radiol) 2021; 33:705-712. [PMID: 34454806 DOI: 10.1016/j.clon.2021.08.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/27/2021] [Accepted: 08/17/2021] [Indexed: 11/23/2022]
Abstract
Microbeam radiotherapy (MRT) is the delivery of spatially fractionated beams that have the potential to offer significant improvements in the therapeutic ratio due to the delivery of micron-sized high dose and dose rate beams. They build on longstanding clinical experience of GRID radiotherapy and more recently lattice-based approaches. Here we briefly overview the preclinical evidence for MRT efficacy and highlight the challenges for bringing this to clinical utility. The biological mechanisms underpinning MRT efficacy are still unclear, but involve vascular, bystander, stem cell and potentially immune responses. There is probably significant overlap in the mechanisms underpinning MRT responses and FLASH radiotherapy that needs to be further defined.
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15
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Trappetti V, Fazzari JM, Fernandez-Palomo C, Scheidegger M, Volarevic V, Martin OA, Djonov VG. Microbeam Radiotherapy-A Novel Therapeutic Approach to Overcome Radioresistance and Enhance Anti-Tumour Response in Melanoma. Int J Mol Sci 2021; 22:7755. [PMID: 34299373 PMCID: PMC8303317 DOI: 10.3390/ijms22147755] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/15/2021] [Accepted: 07/17/2021] [Indexed: 12/19/2022] Open
Abstract
Melanoma is the deadliest type of skin cancer, due to its invasiveness and limited treatment efficacy. The main therapy for primary melanoma and solitary organ metastases is wide excision. Adjuvant therapy, such as chemotherapy and targeted therapies are mainly used for disseminated disease. Radiotherapy (RT) is a powerful treatment option used in more than 50% of cancer patients, however, conventional RT alone is unable to eradicate melanoma. Its general radioresistance is attributed to overexpression of repair genes in combination with cascades of biochemical repair mechanisms. A novel sophisticated technique based on synchrotron-generated, spatially fractionated RT, called Microbeam Radiation Therapy (MRT), has been shown to overcome these treatment limitations by allowing increased dose delivery. With MRT, a collimator subdivides the homogeneous radiation field into an array of co-planar, high-dose microbeams that are tens of micrometres wide and spaced a few hundred micrometres apart. Different preclinical models demonstrated that MRT has the potential to completely ablate tumours, or significantly improve tumour control while dramatically reducing normal tissue toxicity. Here, we discuss the role of conventional RT-induced immunity and the potential for MRT to enhance local and systemic anti-tumour immune responses. Comparative gene expression analysis from preclinical tumour models indicated a specific gene signature for an 'MRT-induced immune effect'. This focused review highlights the potential of MRT to overcome the inherent radioresistance of melanoma which could be further enhanced for future clinical use with combined treatment strategies, in particular, immunotherapy.
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Affiliation(s)
- Verdiana Trappetti
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (V.T.); (J.M.F.); (C.F.-P.); (M.S.); (O.A.M.)
| | - Jennifer M. Fazzari
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (V.T.); (J.M.F.); (C.F.-P.); (M.S.); (O.A.M.)
| | - Cristian Fernandez-Palomo
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (V.T.); (J.M.F.); (C.F.-P.); (M.S.); (O.A.M.)
| | - Maximilian Scheidegger
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (V.T.); (J.M.F.); (C.F.-P.); (M.S.); (O.A.M.)
| | - Vladislav Volarevic
- Department of Genetics, Department of Microbiology and Immunology, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia;
| | - Olga A. Martin
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (V.T.); (J.M.F.); (C.F.-P.); (M.S.); (O.A.M.)
- Peter MacCallum Cancer Centre, Division of Radiation Oncology, Melbourne, VIC 3000, Australia
- University of Melbourne, Parkville, VIC 3010, Australia
| | - Valentin G. Djonov
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (V.T.); (J.M.F.); (C.F.-P.); (M.S.); (O.A.M.)
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16
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Laissue JA. Elke Bräuer-Krisch: dedication, creativity and generosity: May 17, 1961-September 10, 2018. Int J Radiat Biol 2021; 98:280-287. [PMID: 34129423 DOI: 10.1080/09553002.2021.1941385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE This extraordinary woman worked her professional way from a radiation protection engineer to become the successful principal investigator of a prestigious international European project for a new radiation therapy (ERC Synergy grant, HORIZON 2020). The evaluation of the submitted proposal was very positive. The panel proposed that it be funded. Elke tragically passed away a few days before this conclusion of the panel. The present account describes her gradual career development; it includes many episodes that Elke personally chronicled in her curriculum of 2017. METHODS An internet literature search was performed using Google Scholar and other sources to assist in the writing of this narrative review and account. CONCLUSIONS In parallel to the development of the new Biomedical Beamline ID17 at the European Synchrotron Radiation Facility in Grenoble in the late nineties, Elke focused her interest and her personal and professional priorities on MRT, particularly on its clinical goals. She outlined her main objectives in several documents: (1) develop a new paradigm of cancer care by broadening the foundation for MRT. (2) Filling the gaps in basic biological knowledge about the mechanisms of MRT effects on normal and neoplastic tissues. (3) Broaden the preclinical level of evidence for the low normal organ toxicity of MRT versus standard X-ray irradiations; preclinical experiments involved the application of MRT to animal tumor patients, to animals of larger size than laboratory rodents, using larger radiation field sizes, and irradiating in a real-time scenario comparable to the one planned for human patients. (4) To foster the specific purpose of radiosurgical MRT of tumor patients at the ESRF that required development of new, specific state of the art modalities and tools for treatment planning, dosimetry, dose calculation, patient positioning and, of particular importance, redundant levels of patient safety. Just as she was about to take responsibility as principal investigator for a prestigious international European project on a new radiation therapy, death called Elke in.
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Affiliation(s)
- Jean A Laissue
- Institute of Pathology, University of Bern, Bern, Switzerland
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17
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Rahman M, Ashraf MR, Zhang R, Bruza P, Dexter CA, Thompson L, Cao X, Williams BB, Hoopes PJ, Pogue BW, Gladstone DJ. Electron FLASH Delivery at Treatment Room Isocenter for Efficient Reversible Conversion of a Clinical LINAC. Int J Radiat Oncol Biol Phys 2021; 110:872-882. [PMID: 33444695 PMCID: PMC10416223 DOI: 10.1016/j.ijrobp.2021.01.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/02/2020] [Accepted: 01/07/2021] [Indexed: 12/21/2022]
Abstract
PURPOSE In this study, procedures were developed to achieve efficient reversible conversion of a clinical linear accelerator (LINAC) and deliver ultrahigh-dose-rate (UHDR) electron or conventional beams to the treatment room isocenter for FLASH radiation therapy. METHODS AND MATERIALS The LINAC was converted to deliver UHDR beam within 20 minutes by retracting the x-ray target from the beam's path, positioning the carousel on an empty port, and selecting 10 MV photon beam energy in the treatment console. Dose rate surface and depth dose profiles were measured in solid water phantom at different field sizes with Gafchromic film and an optically stimulated luminescent dosimeter (OSLD). A pulse controller counted the pulses via scattered radiation signal and gated the delivery for a preset pulse count. A fast photomultiplier tube-based Cherenkov detector measured the per pulse beam output at a 2-ns sampling rate. After conversion back to clinical mode, conventional beam output, flatness, symmetry, field size, and energy were measured for all clinically commissioned energies. RESULTS The surface average dose rates at the isocenter for 1-cm diameter and 1.5-in diameter circular fields and for a jaws-wide-open field were 238 ± 5 Gy/s, 262 ± 5 Gy/s, and 290 ± 5 Gy/s, respectively. The radial symmetry of the beams was within 2.4%, 0.5%, and 0.2%, respectively. The doses from simultaneous irradiation of film and OSLD were within 1%. The photomultiplier tube showed the LINAC required ramp up time in the first 4 to 6 pulses before the output stabilized, after which its stability was within 3%. CONCLUSIONS At the isocenter of the treatment room, 10 MeV UHDR beams were achieved. The beam output was reproducible but requires further investigation of the ramp up time, equivalent to ∼1 Gy, requiring dose monitoring. The UHDR beam can irradiate both small and large subjects to investigate potential FLASH radiobiological effects in minimally modified clinical settings, and the dose rate can be further increased by reducing the source-to-surface distance.
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Affiliation(s)
- Mahbubur Rahman
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire.
| | - M Ramish Ashraf
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Rongxiao Zhang
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Petr Bruza
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Chad A Dexter
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Lawrence Thompson
- Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Xu Cao
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire
| | - Benjamin B Williams
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - P Jack Hoopes
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; Department of Surgery, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire
| | - David J Gladstone
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire; Department of Medicine, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
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18
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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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19
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Unexpected Benefits of Multiport Synchrotron Microbeam Radiation Therapy for Brain Tumors. Cancers (Basel) 2021; 13:cancers13050936. [PMID: 33668110 PMCID: PMC7956531 DOI: 10.3390/cancers13050936] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary We unveiled the potential of an innovative irradiation technique that ablates brain cancer while sparing normal tissues. Spatially fractionating the incident beam into arrays of micrometer-wide beamlets of X-rays (MRT for Microbeam Radiation Therapy) has led to significantly increased survival and tumor control in preclinical studies. Multiport MRT versus conventional irradiations, for the same background continuous dose, resulted in unexpectedly high equivalent biological effects in rats that have not been achieved with any other radiotherapeutic method. These hallmarks of multiport MRT, i.e., minimal impact on normal tissues and exceptional tumor control, may promote this method towards clinical applications, possibly increasing survival and improving long-term outcomes in neuro-oncology patients. Abstract Delivery of high-radiation doses to brain tumors via multiple arrays of synchrotron X-ray microbeams permits huge therapeutic advantages. Brain tumor (9LGS)-bearing and normal rats were irradiated using a conventional, homogeneous Broad Beam (BB), or Microbeam Radiation Therapy (MRT), then studied by behavioral tests, MRI, and histopathology. A valley dose of 10 Gy deposited between microbeams, delivered by a single port, improved tumor control and median survival time of tumor-bearing rats better than a BB isodose. An increased number of ports and an accumulated valley dose maintained at 10 Gy delayed tumor growth and improved survival. Histopathologically, cell death, vascular damage, and inflammatory response increased in tumors. At identical valley isodose, each additional MRT port extended survival, resulting in an exponential correlation between port numbers and animal lifespan (r2 = 0.9928). A 10 Gy valley dose, in MRT mode, delivered through 5 ports, achieved the same survival as a 25 Gy BB irradiation because of tumor dose hot spots created by intersecting microbeams. Conversely, normal tissue damage remained minimal in all the single converging extratumoral arrays. Multiport MRT reached exceptional ~2.5-fold biological equivalent tumor doses. The unique normal tissue sparing and therapeutic index are eminent prerequisites for clinical translation.
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20
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Snyder M, Vadas J, Musselwhite J, Halford R, Wilson G, Stevens C, Yan D. Technical Note: FLASH radiotherapy monitor chamber signal conditioning. Med Phys 2020; 48:791-795. [PMID: 33296516 DOI: 10.1002/mp.14650] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/11/2020] [Accepted: 11/30/2020] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Recent studies of ultra-high dose rate FLASH radiotherapy show a substantial reduction of damage to normal tissue cells when compared with conventional radiotherapy. Most, if not all, of these FLASH studies have taken place using either custom research equipment or heavily modified linacs with external dosimetric control. To simplify our preclinical research efforts, we wish to deliver FLASH with a minimally modified linac using the internal dosimetric system. METHODS To enable the built-in monitor chambers to terminate a FLASH beam, we reversibly modified an Elekta linear accelerator previously fit with a high dose rate electron (HDRE) system to include additional resistance in the signal path from the monitor chambers to the dose control system. To produce the FLASH beam, we altered the energy calibration tables of a decommissioned HDRE beam to functionally produce a photon mode beam current exiting through the electron window of the linac. We then used the machine modifications to assist in beam tuning and to calibrate the monitor chambers for FLASH delivery. We employed a radiochromic film for external dosimetry and preliminary tests of monitor chamber dosimetric stability. RESULTS We identified attenuation values and distributions that reduced the overall signal from the monitor chambers to the dose control system such that the system could terminate the beam without input from external monitoring circuits. Calibration of the control system resulted in 12 MU per second, constituting roughly 180 Gy at the mylar window. Preliminary tests indicate a linear MU to dose relationship at FLASH dose rates, but we encountered challenges in both dose resolution and repeatability of beam termination. CONCLUSIONS The addition of attenuation in the control system path from the monitor chambers is fundamentally identical to current HDRE system design and was achieved without significant modification of the accelerator. Preliminary results indicate that current-generation monitor chambers could potentially govern FLASH radiotherapy, but overall beam and monitor chamber stability issues may necessitate machine modifications to achieve desired dosimetric accuracy.
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Affiliation(s)
- Michael Snyder
- Department of Radiation Oncology, Beaumont Health, Royal Oak, MI, USA.,Oakland University William Beaumont School of Medicine, Rochester, MI, USA
| | - Jessica Vadas
- Department of Radiation Oncology, Beaumont Health, Royal Oak, MI, USA
| | - John Musselwhite
- Department of Radiation Oncology, Beaumont Health, Royal Oak, MI, USA
| | - Robert Halford
- Department of Radiation Oncology, Beaumont Health, Royal Oak, MI, USA
| | - George Wilson
- Department of Radiation Oncology, Beaumont Health, Royal Oak, MI, USA.,Oakland University William Beaumont School of Medicine, Rochester, MI, USA
| | - Craig Stevens
- Department of Radiation Oncology, Beaumont Health, Royal Oak, MI, USA.,Oakland University William Beaumont School of Medicine, Rochester, MI, USA
| | - Di Yan
- Department of Radiation Oncology, Beaumont Health, Royal Oak, MI, USA.,Oakland University William Beaumont School of Medicine, Rochester, MI, USA
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21
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Hainfeld JF, Ridwan SM, Stanishevskiy FY, Smilowitz HM. Iodine nanoparticle radiotherapy of human breast cancer growing in the brains of athymic mice. Sci Rep 2020; 10:15627. [PMID: 32973267 PMCID: PMC7515899 DOI: 10.1038/s41598-020-72268-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/18/2020] [Indexed: 12/16/2022] Open
Abstract
About 30% of breast cancers metastasize to the brain; those widely disseminated are fatal typically in 3-4 months, even with the best available treatments, including surgery, drugs, and radiotherapy. To address this dire situation, we have developed iodine nanoparticles (INPs) that target brain tumors after intravenous (IV) injection. The iodine then absorbs X-rays during radiotherapy (RT), creating free radicals and local tumor damage, effectively boosting the local RT dose at the tumor. Efficacy was tested using the very aggressive human triple negative breast cancer (TNBC, MDA-MB-231 cells) growing in the brains of athymic nude mice. With a well-tolerated non-toxic IV dose of the INPs (7 g iodine/kg body weight), tumors showed a heavily iodinated rim surrounding the tumor having an average uptake of 2.9% iodine by weight, with uptake peaks at 4.5%. This is calculated to provide a dose enhancement factor of approximately 5.5 (peaks at 8.0), the highest ever reported for any radiation-enhancing agents. With RT alone (15 Gy, single dose), all animals died by 72 days; INP pretreatment resulted in longer-term remissions with 40% of mice surviving 150 days and 30% surviving > 280 days.
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Affiliation(s)
- James F Hainfeld
- Nanoprobes, Inc., 95 Horseblock Rd., Unit 1, Yaphank, NY, 11980, USA.
| | - Sharif M Ridwan
- Department of Cell Biology, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT, 06030, USA
| | | | - Henry M Smilowitz
- Department of Cell Biology, University of Connecticut Health Center, 263 Farmington Ave., Farmington, CT, 06030, USA
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22
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Alanazi A, Meesungnoen J, Jay-Gerin JP. Linear energy transfer dependence of transient yields in water irradiated by 150 keV – 500 MeV protons in the limit of low dose rates. CAN J CHEM 2020. [DOI: 10.1139/cjc-2020-0113] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
FLASH radiotherapy is a new irradiation method in which large doses of ionizing radiation are delivered to tumors almost instantly (a few milliseconds), paradoxically sparing healthy tissue while preserving anti-tumor activity. Although this technique is primarily studied in the context of electron and photon therapies, proton delivery at high dose rates can also reduce the adverse side effects on normal cells. So far, no definitive mechanism has been proposed to explain the differences in the responses to radiation between tumor and normal tissues. Given that living cells and tissues consist mainly of water, we set out to study the effects of high dose rates on the radiolysis of water by protons in the energy range of 150 keV – 500 MeV (i.e., for linear energy transfer (LET) values between ∼72.2 and 0.23 keV/μm, respectively) using Monte Carlo simulations. To validate our methodology, however, we, first, report here the results of our calculations of the yields (G values) of the radiolytically produced species, namely the hydrated electron ([Formula: see text]), •OH, H•, H2, and H2O2, for low dose rates. Overall, our simulations agree very well with the experiment. In the presence of oxygen, [Formula: see text] and H• atoms are rapidly converted into superoxide anion or hydroperoxyl radicals, with a well-defined maximum of [Formula: see text] at ∼1 μs. This maximum decreases substantially when going from low-LET 500 MeV to high-LET 150 keV irradiating protons. Differences in the geometry of the proton track structure with increasing LET readily explain this diminution in [Formula: see text] radicals.
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Affiliation(s)
- Ahmed Alanazi
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Jintana Meesungnoen
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Jean-Paul Jay-Gerin
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
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Conventional dose rate spatially-fractionated radiation therapy (SFRT) treatment response and its association with dosimetric parameters-A preclinical study in a Fischer 344 rat model. PLoS One 2020; 15:e0229053. [PMID: 32569277 PMCID: PMC7307781 DOI: 10.1371/journal.pone.0229053] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/21/2020] [Indexed: 12/15/2022] Open
Abstract
Purpose To identify key dosimetric parameters that have close associations with tumor treatment response and body weight change in SFRT treatments with a large range of spatial-fractionation scale at dose rates of several Gy/min. Methods Six study arms using uniform tumor radiation, half-tumor radiation, 2mm beam array radiation, 0.3mm minibeam radiation, and an untreated arm were used. All treatments were delivered on a 320kV x-ray irradiator. Forty-two female Fischer 344 rats with fibrosarcoma tumor allografts were used. Dosimetric parameters studied are peak dose and width, valley dose and width, peak-to-valley-dose-ratio (PVDR), volumetric average dose, percentage volume directly irradiated, and tumor- and normal-tissue EUD. Animal survival, tumor volume change, and body weight change (indicative of treatment toxicity) are tested for association with the dosimetric parameters using linear regression and Cox Proportional Hazards models. Results The dosimetric parameters most closely associated with tumor response are tumor EUD (R2 = 0.7923, F-stat = 15.26*; z-test = -4.07***), valley (minimum) dose (R2 = 0.7636, F-stat = 12.92*; z-test = -4.338***), and percentage tumor directly irradiated (R2 = 0.7153, F-stat = 10.05*; z-test = -3.837***) per the linear regression and Cox Proportional Hazards models, respectively. Tumor response is linearly proportional to valley (minimum) doses and tumor EUD. Average dose (R2 = 0.2745, F-stat = 1.514 (no sig.); z-test = -2.811**) and peak dose (R2 = 0.04472, F-stat = 0.6874 (not sig.); z-test = -0.786 (not sig.)) show the weakest associations to tumor response. Only the uniform radiation arm did not gain body weight post-radiation, indicative of treatment toxicity; however, body weight change in general shows weak association with all dosimetric parameters except for valley (minimum) dose (R2 = 0.3814, F-stat = 13.56**), valley width (R2 = 0.2853, F-stat = 8.783**), and peak width (R2 = 0.2759, F-stat = 8.382**). Conclusions For a single-fraction SFRT at conventional dose rates, valley, not peak, dose is closely associated with tumor treatment response and thus should be used for treatment prescription. Tumor EUD, valley (minimum) dose, and percentage tumor directly irradiated are the top three dosimetric parameters that exhibited close associations with tumor response.
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Jay-Gerin JP. Ultra-high dose-rate (FLASH) radiotherapy: Generation of early, transient, strongly acidic spikes in the irradiated tumor environment. Cancer Radiother 2020; 24:332-334. [PMID: 32446537 DOI: 10.1016/j.canrad.2019.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 11/05/2019] [Accepted: 11/13/2019] [Indexed: 10/24/2022]
Abstract
Monte Carlo simulations of γ/fast electron-radiolysis of water show that the in situ formation of H3O+ temporarily renders each "native" isolated spur/track region very acidic. For pulsed (FLASH) irradiation with high dose rate, this early time, transient "acid-spike" response is shown to extend evenly across the entire irradiated volume. Since pH controls many cellular processes, this study highlights the need to consider these spikes of acidity in understanding the fundamental mechanisms underlying FLASH radiotherapy.
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Affiliation(s)
- J-P Jay-Gerin
- Département de médecine nucléaire et de radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12(e) Avenue Nord, Sherbrooke, Québec, J1H 5N4, Canada.
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25
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Tubin S, Yan W, Mourad WF, Fossati P, Khan MK. The future of radiation-induced abscopal response: beyond conventional radiotherapy approaches. Future Oncol 2020; 16:1137-1151. [PMID: 32338046 DOI: 10.2217/fon-2020-0063] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Advances in the immunological pharmaceuticals, such as checkpoint inhibitors and agonists, have positive implications for the future of the radiotherapy abscopal response. A once rare phenomenon, whereby distant nonirradiated tumor sites regressed after radiotherapy alone, may become more common when combined with the immune modulating agents. Radiotherapy can increase neoantigen expression, increased tumor PD-L1 expression, increase MHC class I expression, reverse exhausted CD8 T cells and increase tumor-infiltrating tumors within the tumor microenvironment. These changes in the tumor and the tumor microenvironment after radiotherapy could potentiate responses to anti-CTL-4, anti-PD-L1/PD-1 and other immunotherapy agents. Thus, advances in checkpoint inhibitors have increased interest in re-evaluation of the role of conventional radiotherapy approaches on the immune system. We reviewed newer nonconventional approaches such as SBRT-PATHY, GRID, FLASH, carbon ion and proton therapy and their role in eliciting immune responses. We believe that combining these novel radiation methods may enhance the outcome with the newly US FDA approved immune modulating agents.
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Affiliation(s)
- Slavisa Tubin
- MedAustron Center for Ion Therapy and Research, Marie Curie Strasse 5, A-2700 Wiener Neustadt, Austria
| | - Weisi Yan
- Department of Radiation Oncology, Thomas Jefferson University, 11th St, Philadelphia, PA 19107, USA
| | - Waleed F Mourad
- Department of Radiation Medicine, Markey Cancer Center, University of Kentucky, Medical Center, MN 150 - Lexington, KY 40536-0298, USA
| | - Piero Fossati
- MedAustron Center for Ion Therapy and Research, Marie Curie Strasse 5, A-2700 Wiener Neustadt, Austria
| | - Mohammad K Khan
- Department of Radiation Oncology, Emory University School of Medicine, Winship Cancer Institute, 1365-C Clifton Road, Atlanta, GA 30322, USA
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26
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Fernandez-Palomo C, Fazzari J, Trappetti V, Smyth L, Janka H, Laissue J, Djonov V. Animal Models in Microbeam Radiation Therapy: A Scoping Review. Cancers (Basel) 2020; 12:cancers12030527. [PMID: 32106397 PMCID: PMC7139755 DOI: 10.3390/cancers12030527] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 02/19/2020] [Accepted: 02/21/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Microbeam Radiation Therapy (MRT) is an innovative approach in radiation oncology where a collimator subdivides the homogeneous radiation field into an array of co-planar, high-dose beams which are tens of micrometres wide and separated by a few hundred micrometres. OBJECTIVE This scoping review was conducted to map the available evidence and provide a comprehensive overview of the similarities, differences, and outcomes of all experiments that have employed animal models in MRT. METHODS We considered articles that employed animal models for the purpose of studying the effects of MRT. We searched in seven databases for published and unpublished literature. Two independent reviewers screened citations for inclusion. Data extraction was done by three reviewers. RESULTS After screening 5688 citations and 159 full-text papers, 95 articles were included, of which 72 were experimental articles. Here we present the animal models and pre-clinical radiation parameters employed in the existing MRT literature according to their use in cancer treatment, non-neoplastic diseases, or normal tissue studies. CONCLUSIONS The study of MRT is concentrated in brain-related diseases performed mostly in rat models. An appropriate comparison between MRT and conventional radiotherapy (instead of synchrotron broad beam) is needed. Recommendations are provided for future studies involving MRT.
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Affiliation(s)
| | - Jennifer Fazzari
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (C.F.-P.); (J.F.); (V.T.); (J.L.)
| | - Verdiana Trappetti
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (C.F.-P.); (J.F.); (V.T.); (J.L.)
| | - Lloyd Smyth
- Department of Obstetrics & Gynaecology, University of Melbourne, 3057 Parkville, Australia;
| | - Heidrun Janka
- Medical Library, University Library Bern, University of Bern, 3012 Bern, Switzerland;
| | - Jean Laissue
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (C.F.-P.); (J.F.); (V.T.); (J.L.)
| | - Valentin Djonov
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (C.F.-P.); (J.F.); (V.T.); (J.L.)
- Correspondence: ; Tel.: +41-31-631-8432
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27
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Mazal A, Prezado Y, Ares C, de Marzi L, Patriarca A, Miralbell R, Favaudon V. FLASH and minibeams in radiation therapy: the effect of microstructures on time and space and their potential application to protontherapy. Br J Radiol 2020; 93:20190807. [PMID: 32003574 PMCID: PMC7066940 DOI: 10.1259/bjr.20190807] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
After years of lethargy, studies on two non-conventional microstructures in time and space of the beams used in radiation therapy are enjoying a huge revival. The first effect called “FLASH” is based on very high dose-rate irradiation (pulse amplitude ≥106 Gy/s), short beam-on times (≤100 ms) and large single doses (≥10 Gy) as experimental parameters established so far to give biological and potential clinical effects. The second effect relies on the use of arrays of minibeams (e.g., 0.5–1 mm, spaced 1–3.5 mm). Both approaches have been shown to protect healthy tissues as an endpoint that must be clearly specified and could be combined with each other (e.g., minibeams under FLASH conditions). FLASH depends on the presence of oxygen and could proceed from the chemistry of peroxyradicals and a reduced incidence on DNA and membrane damage. Minibeams action could be based on abscopal effects, cell signalling and/or migration of cells between “valleys and hills” present in the non-uniform irradiation field as well as faster repair of vascular damage. Both effects are expected to maintain intact the tumour control probability and might even preserve antitumoural immunological reactions. FLASH in vivo experiments involving Zebrafish, mice, pig and cats have been done with electron beams, while minibeams are an intermediate approach between X-GRID and synchrotron X-ray microbeams radiation. Both have an excellent rationale to converge and be applied with proton beams, combining focusing properties and high dose rates in the beam path of pencil beams, and the inherent advantage of a controlled limited range. A first treatment with electron FLASH (cutaneous lymphoma) has recently been achieved, but clinical trials have neither been presented for FLASH with protons, nor under the minibeam conditions. Better understanding of physical, chemical and biological mechanisms of both effects is essential to optimize the technical developments and devise clinical trials.
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Affiliation(s)
| | - Yolanda Prezado
- IMNC, University Paris-Sud and Paris-Saclay, CNRS/IN2P3, Orsay, France
| | - Carme Ares
- Centro de Protonterapia Quironsalud, Madrid, Spain
| | - Ludovic de Marzi
- Institut Curie, Institut Curie, PSL Research University, Centre de protonthérapie d'Orsay, Campus universitaire, bâtiment 101, Orsay 91898, France.,Institut Curie, Inserm U 1021-CNRS UMR 3347, Paris-Saclay and PSL Research Universities, Orsay, France
| | - Annalisa Patriarca
- Institut Curie, Institut Curie, PSL Research University, Centre de protonthérapie d'Orsay, Campus universitaire, bâtiment 101, Orsay 91898, France
| | | | - Vincent Favaudon
- Institut Curie, Inserm U 1021-CNRS UMR 3347, Paris-Saclay and PSL Research Universities, Orsay, France
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28
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Yan W, Khan MK, Wu X, Simone CB, Fan J, Gressen E, Zhang X, Limoli CL, Bahig H, Tubin S, Mourad WF. Spatially fractionated radiation therapy: History, present and the future. Clin Transl Radiat Oncol 2020; 20:30-38. [PMID: 31768424 PMCID: PMC6872856 DOI: 10.1016/j.ctro.2019.10.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/14/2019] [Accepted: 10/17/2019] [Indexed: 12/30/2022] Open
Affiliation(s)
- Weisi Yan
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Mohammad K. Khan
- Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, GA, USA
| | | | - Charles B. Simone
- New York Proton Center, Department of Radiation Oncology, New York, NY, USA
| | - Jiajin Fan
- Radiation Oncology, Inova Schar Cancer Institute, Inova Health System, USA
| | - Eric Gressen
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Xin Zhang
- Boston University School of Medicine, Boston, MA, USA
| | - Charles L. Limoli
- Department of Radiation Oncology, University of California, Ivine 92697-2695, USA
| | - Houda Bahig
- Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada
| | - Slavisa Tubin
- KABEG Klinikum Klagenfurt, Institute of Radiation Oncology, Feschnigstraße 11, 9020 Klagenfurt am Wörthersee, Austria
| | - Waleed F. Mourad
- Department of Radiation Medicine, Markey Cancer Center, University of Kentucky – College of Medicine, USA
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29
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Flynn S, Price T, Allport PP, Silvestre Patallo I, Thomas R, Subiel A, Bartzsch S, Treibel F, Ahmed M, Jacobs-Headspith J, Edwards T, Jones I, Cathie D, Guerrini N, Sedgwick I. Evaluation of a pixelated large format CMOS sensor for x-ray microbeam radiotherapy. Med Phys 2019; 47:1305-1316. [PMID: 31837272 PMCID: PMC7078942 DOI: 10.1002/mp.13971] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/06/2019] [Accepted: 12/06/2019] [Indexed: 01/15/2023] Open
Abstract
PURPOSE Current techniques and procedures for dosimetry in microbeams typically rely on radiochromic film or small volume ionization chambers for validation and quality assurance in 2D and 1D, respectively. Whilst well characterized for clinical and preclinical radiotherapy, these methods are noninstantaneous and do not provide real time profile information. The objective of this work is to determine the suitability of the newly developed vM1212 detector, a pixelated CMOS (complementary metal-oxide-semiconductor) imaging sensor, for in situ and in vivo verification of x-ray microbeams. METHODS Experiments were carried out on the vM1212 detector using a 220 kVp small animal radiation research platform (SARRP) at the Helmholtz Centre Munich. A 3 x 3 cm2 square piece of EBT3 film was placed on top of a marked nonfibrous card overlaying the sensitive silicon of the sensor. One centimeter of water equivalent bolus material was placed on top of the film for build-up. The response of the detector was compared to an Epson Expression 10000XL flatbed scanner using FilmQA Pro with triple channel dosimetry. This was also compared to a separate exposure using 450 µm of silicon as a surrogate for the detector and a Zeiss Axio Imager 2 microscope using an optical microscopy method of dosimetry. Microbeam collimator slits with range of nominal widths of 25, 50, 75, and 100 µm were used to compare beam profiles and determine sensitivity of the detector and both film measurements to different microbeams. RESULTS The detector was able to measure peak and valley profiles in real-time, a significant reduction from the 24 hr self-development required by the EBT3 film. Observed full width at half maximum (FWHM) values were larger than the nominal slit widths, ranging from 130 to 190 µm due to divergence. Agreement between the methods was found for peak-to-valley dose ratio (PVDR), peak to peak separation and FWHM, but a difference in relative intensity of the microbeams was observed between the detectors. CONCLUSIONS The investigation demonstrated that pixelated CMOS sensors could be applied to microbeam radiotherapy for real-time dosimetry in the future, however the relatively large pixel pitch of the vM1212 detector limit the immediate application of the results.
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Affiliation(s)
- Samuel Flynn
- School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK.,Medical Physics Department, National Physical Laboratory, Teddington, TW11 0LW, UK
| | - Tony Price
- School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK.,Medical Physics Department, National Physical Laboratory, Teddington, TW11 0LW, UK
| | - Philip P Allport
- School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Ileana Silvestre Patallo
- Medical Physics Department, National Physical Laboratory, Teddington, TW11 0LW, UK.,UCL Cancer Institute, University College London, London, WC1E 6AG, UK
| | - Russell Thomas
- Medical Physics Department, National Physical Laboratory, Teddington, TW11 0LW, UK
| | - Anna Subiel
- Medical Physics Department, National Physical Laboratory, Teddington, TW11 0LW, UK
| | - Stefan Bartzsch
- Helmholtz Centre Munich, Institute for Radiation Medicine, Munich, 85764, Germany.,School of Medicine, Klinikum rechts der Isar, Department of Radiation Oncology, Technical University of Munich, Munich, 80333, Germany
| | - Franziska Treibel
- School of Medicine, Klinikum rechts der Isar, Department of Radiation Oncology, Technical University of Munich, Munich, 80333, Germany
| | - Mabroor Ahmed
- School of Medicine, Klinikum rechts der Isar, Department of Radiation Oncology, Technical University of Munich, Munich, 80333, Germany
| | | | | | | | | | | | - Iain Sedgwick
- Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
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30
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FLASH radiotherapy International Workshop. Radiother Oncol 2019; 139:1-3. [DOI: 10.1016/j.radonc.2019.07.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 07/15/2019] [Indexed: 11/30/2022]
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