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Eling L, Verry C, Balosso J, Flandin I, Kefs S, Bouchet A, Adam JF, Laissue JA, Serduc R. Neurologic Changes Induced by Whole-Brain Synchrotron Microbeam Irradiation: 10-Month Behavioral and Veterinary Follow-Up. Int J Radiat Oncol Biol Phys 2024; 120:178-188. [PMID: 38462014 DOI: 10.1016/j.ijrobp.2024.02.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 02/19/2024] [Accepted: 02/25/2024] [Indexed: 03/12/2024]
Abstract
PURPOSE Novel radiation therapy approaches have increased the therapeutic efficacy for malignant brain tumors over the past decades, but the balance between therapeutic gain and radiotoxicity remains a medical hardship. Synchrotron microbeam radiation therapy, an innovative technique, deposes extremely high (peak) doses in micron-wide, parallel microbeam paths, whereas the diffusing interbeam (valley) doses lie in the range of conventional radiation therapy doses. In this study, we evaluated normal tissue toxicity of whole-brain microbeam irradiation (MBI) versus that of a conventional hospital broad beam (hBB). METHODS AND MATERIALS Normal Fischer rats (n = 6-7/group) were irradiated with one of the two modalities, exposing the entire brain to MBI valley/peak doses of 0/0, 5/200, 10/400, 13/520, 17/680, or 25/1000 Gy or to hBB doses of 7, 10, 13, 17, or 25 Gy. Two additional groups of rats received an MBI valley dose of 10 Gy coupled with an hBB dose of 7 or 15 Gy (groups MBI17* and MBI25*). Behavioral parameters were evaluated for 10 months after irradiation combined with veterinary observations. RESULTS MBI peak doses of ≥680 Gy caused acute toxicity and death. Animals exposed to hBB or MBI dose-dependently gained less weight than controls; rats in the hBB25 and MBI25* groups died within 6 months after irradiation. Increasing doses of MBI caused hyperactivity but no other detectable behavioral alterations in our tests. Importantly, no health concerns were seen up to an MBI valley dose of 17 Gy. CONCLUSIONS While acute toxicity of microbeam exposures depends on very high peak doses, late toxicity mainly relates to delivery of high MBI valley doses. MBI seems to have a low impact on normal rat behavior, but further tests are warranted to fully explore this hypothesis. However, high peak and valley doses are well tolerated from a veterinary point of view. This normal tissue tolerance to whole-brain, high-dose MBI reveals a promising avenue for microbeam radiation therapy, that is, therapeutic applications of microbeams that are poised for translation to a clinical environment.
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Affiliation(s)
- Laura Eling
- Université Grenoble Alpes, Institut National de la Santé et de la Recherche Médicale UA7 Synchrotron Radiation for Biomedicine, Saint-Martin d'Hères, France.
| | - Camille Verry
- Centre Hospitalier Universitaire Grenoble Alpes, Maquis du Grésivaudan, La Tronche, France
| | - Jacques Balosso
- Centre Hospitalier Universitaire Grenoble Alpes, Maquis du Grésivaudan, La Tronche, France
| | - Isabelle Flandin
- Centre Hospitalier Universitaire Grenoble Alpes, Maquis du Grésivaudan, La Tronche, France
| | - Samy Kefs
- Centre Hospitalier Universitaire Grenoble Alpes, Maquis du Grésivaudan, La Tronche, France
| | - Audrey Bouchet
- INSERM U1296, Radiation: Defense, Health, Environment, Lyon, France
| | - Jean François Adam
- Université Grenoble Alpes, Institut National de la Santé et de la Recherche Médicale UA7 Synchrotron Radiation for Biomedicine, Saint-Martin d'Hères, France; Centre Hospitalier Universitaire Grenoble Alpes, Maquis du Grésivaudan, La Tronche, France
| | | | - Raphael Serduc
- Université Grenoble Alpes, Institut National de la Santé et de la Recherche Médicale UA7 Synchrotron Radiation for Biomedicine, Saint-Martin d'Hères, France; Centre Hospitalier Universitaire Grenoble Alpes, Maquis du Grésivaudan, La Tronche, France
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Ahmed M, Bicher S, Combs SE, Lindner R, Raulefs S, Schmid TE, Spasova S, Stolz J, Wilkens JJ, Winter J, Bartzsch S. In Vivo Microbeam Radiation Therapy at a Conventional Small Animal Irradiator. Cancers (Basel) 2024; 16:581. [PMID: 38339332 PMCID: PMC11154279 DOI: 10.3390/cancers16030581] [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: 12/30/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 02/12/2024] Open
Abstract
Microbeam radiation therapy (MRT) is a still pre-clinical form of spatially fractionated radiotherapy, which uses an array of micrometer-wide, planar beams of X-ray radiation. The dose modulation in MRT has proven effective in the treatment of tumors while being well tolerated by normal tissue. Research on understanding the underlying biological mechanisms mostly requires large third-generation synchrotrons. In this study, we aimed to develop a preclinical treatment environment that would allow MRT independent of synchrotrons. We built a compact microbeam setup for pre-clinical experiments within a small animal irradiator and present in vivo MRT application, including treatment planning, dosimetry, and animal positioning. The brain of an immobilized mouse was treated with MRT, excised, and immunohistochemically stained against γH2AX for DNA double-strand breaks. We developed a comprehensive treatment planning system by adjusting an existing dose calculation algorithm to our setup and attaching it to the open-source software 3D-Slicer. Predicted doses in treatment planning agreed within 10% with film dosimetry readings. We demonstrated the feasibility of MRT exposures in vivo at a compact source and showed that the microbeam pattern is observable in histological sections of a mouse brain. The platform developed in this study will be used for pre-clinical research of MRT.
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Affiliation(s)
- Mabroor Ahmed
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (M.A.); (S.B.); (S.E.C.); (S.R.); (T.E.S.); (S.S.); (J.S.); (J.J.W.); (J.W.)
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany;
- Department of Physics, School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Sandra Bicher
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (M.A.); (S.B.); (S.E.C.); (S.R.); (T.E.S.); (S.S.); (J.S.); (J.J.W.); (J.W.)
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany;
| | - Stephanie Elisabeth Combs
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (M.A.); (S.B.); (S.E.C.); (S.R.); (T.E.S.); (S.S.); (J.S.); (J.J.W.); (J.W.)
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany;
| | - Rainer Lindner
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany;
| | - Susanne Raulefs
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (M.A.); (S.B.); (S.E.C.); (S.R.); (T.E.S.); (S.S.); (J.S.); (J.J.W.); (J.W.)
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany;
| | - Thomas E. Schmid
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (M.A.); (S.B.); (S.E.C.); (S.R.); (T.E.S.); (S.S.); (J.S.); (J.J.W.); (J.W.)
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany;
| | - Suzana Spasova
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (M.A.); (S.B.); (S.E.C.); (S.R.); (T.E.S.); (S.S.); (J.S.); (J.J.W.); (J.W.)
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany;
- Department of Physics, School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Jessica Stolz
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (M.A.); (S.B.); (S.E.C.); (S.R.); (T.E.S.); (S.S.); (J.S.); (J.J.W.); (J.W.)
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany;
| | - Jan Jakob Wilkens
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (M.A.); (S.B.); (S.E.C.); (S.R.); (T.E.S.); (S.S.); (J.S.); (J.J.W.); (J.W.)
- Department of Physics, School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
| | - Johanna Winter
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (M.A.); (S.B.); (S.E.C.); (S.R.); (T.E.S.); (S.S.); (J.S.); (J.J.W.); (J.W.)
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany;
- Department of Physics, School of Natural Sciences, Technical University of Munich, 85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), 85748 Garching, Germany
| | - Stefan Bartzsch
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; (M.A.); (S.B.); (S.E.C.); (S.R.); (T.E.S.); (S.S.); (J.S.); (J.J.W.); (J.W.)
- Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, Institute of Radiation Medicine, 85764 Neuherberg, Germany;
- Heinz Maier-Leibnitz Zentrum (MLZ), 85748 Garching, Germany
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Effects of Microbeam Irradiation on Rodent Esophageal Smooth Muscle Contraction. Cells 2022; 12:cells12010176. [PMID: 36611969 PMCID: PMC9818134 DOI: 10.3390/cells12010176] [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: 11/16/2022] [Revised: 12/14/2022] [Accepted: 12/27/2022] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND High-dose-rate radiotherapy has shown promising results with respect to normal tissue preservation. We developed an ex vivo model to study the physiological effects of experimental radiotherapy in the rodent esophageal smooth muscle. METHODS We assessed the physiological parameters of the esophageal function in ex vivo preparations of the proximal, middle, and distal segments in the organ bath. High-dose-rate synchrotron irradiation was conducted using both the microbeam irradiation (MBI) technique with peak doses greater than 200 Gy and broadbeam irradiation (BBI) with doses ranging between 3.5-4 Gy. RESULTS Neither MBI nor BBI affected the function of the contractile apparatus. While peak latency and maximal force change were not affected in the BBI group, and no changes were seen in the proximal esophagus segments after MBI, a significant increase in peak latency and a decrease in maximal force change was observed in the middle and distal esophageal segments. CONCLUSION No severe changes in physiological parameters of esophageal contraction were determined after high-dose-rate radiotherapy in our model, but our results indicate a delayed esophageal function. From the clinical perspective, the observed increase in peak latency and decreased maximal force change may indicate delayed esophageal transit.
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Baiocco G, Bartzsch S, Conte V, Friedrich T, Jakob B, Tartas A, Villagrasa C, Prise KM. A matter of space: how the spatial heterogeneity in energy deposition determines the biological outcome of radiation exposure. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2022; 61:545-559. [PMID: 36220965 PMCID: PMC9630194 DOI: 10.1007/s00411-022-00989-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 08/03/2022] [Indexed: 05/10/2023]
Abstract
The outcome of the exposure of living organisms to ionizing radiation is determined by the distribution of the associated energy deposition at different spatial scales. Radiation proceeds through ionizations and excitations of hit molecules with an ~ nm spacing. Approaches such as nanodosimetry/microdosimetry and Monte Carlo track-structure simulations have been successfully adopted to investigate radiation quality effects: they allow to explore correlations between the spatial clustering of such energy depositions at the scales of DNA or chromosome domains and their biological consequences at the cellular level. Physical features alone, however, are not enough to assess the entity and complexity of radiation-induced DNA damage: this latter is the result of an interplay between radiation track structure and the spatial architecture of chromatin, and further depends on the chromatin dynamic response, affecting the activation and efficiency of the repair machinery. The heterogeneity of radiation energy depositions at the single-cell level affects the trade-off between cell inactivation and induction of viable mutations and hence influences radiation-induced carcinogenesis. In radiation therapy, where the goal is cancer cell inactivation, the delivery of a homogenous dose to the tumour has been the traditional approach in clinical practice. However, evidence is accumulating that introducing heterogeneity with spatially fractionated beams (mini- and microbeam therapy) can lead to significant advantages, particularly in sparing normal tissues. Such findings cannot be explained in merely physical terms, and their interpretation requires considering the scales at play in the underlying biological mechanisms, suggesting a systemic response to radiation.
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Affiliation(s)
- Giorgio Baiocco
- Radiation Biophysics and Radiobiology Group, Physics Department, University of Pavia, Pavia, Italy.
| | - Stefan Bartzsch
- Institute for Radiation Medicine, Helmholtz Centre Munich, Munich, Germany
- Department of Radiation Oncology, Technical University of Munich, Munich, Germany
| | - Valeria Conte
- Istituto Nazionale Di Fisica Nucleare INFN, Laboratori Nazionali Di Legnaro, Legnaro, Italy
| | - Thomas Friedrich
- Department of Biophysics, GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, Germany
| | - Burkhard Jakob
- Department of Biophysics, GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, Germany
| | - Adrianna Tartas
- Biomedical Physics Division, Institute of Experimental Physics, University of Warsaw, Warsaw, Poland
| | - Carmen Villagrasa
- IRSN, Institut de Radioprotection et de Sûreté Nucléaire, Fontenay aux Roses, France
| | - Kevin M Prise
- Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK
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5
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Microbeam Radiation Therapy controls local growth of radioresistant melanoma and treats out-of-field locoregional metastasis. Int J Radiat Oncol Biol Phys 2022; 114:478-493. [DOI: 10.1016/j.ijrobp.2022.06.090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 06/17/2022] [Accepted: 06/24/2022] [Indexed: 11/21/2022]
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6
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Fernandez-Palomo C, Chang S, Prezado Y. Should Peak Dose Be Used to Prescribe Spatially Fractionated Radiation Therapy?-A Review of Preclinical Studies. Cancers (Basel) 2022; 14:3625. [PMID: 35892895 PMCID: PMC9330631 DOI: 10.3390/cancers14153625] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 12/04/2022] Open
Abstract
Spatially fractionated radiotherapy (SFRT) is characterized by the coexistence of multiple hot and cold dose subregions throughout the treatment volume. In preclinical studies using single-fraction treatment, SFRT can achieve a significantly higher therapeutic index than conventional radiotherapy (RT). Published clinical studies of SFRT followed by RT have reported promising results for bulky tumors. Several clinical trials are currently underway to further explore the clinical benefits of SFRT. However, we lack the important understanding of the correlation between dosimetric parameters and treatment response that we have in RT. In this work, we reviewed and analyzed this important correlation from previous preclinical SFRT studies. We reviewed studies prior to 2022 that treated animal-bearing tumors with minibeam radiotherapy (MBRT) or microbeam radiotherapy (MRT). Eighteen studies met our selection criteria. Increased lifespan (ILS) relative to control was used as the treatment response. The preclinical SFRT dosimetric parameters analyzed were peak dose, valley dose, average dose, beam width, and beam spacing. We found that valley dose was the dosimetric parameter with the strongest correlation with ILS (p-value < 0.01). For studies using MRT, average dose and peak dose were also significantly correlated with ILS (p-value < 0.05). This first comprehensive review of preclinical SFRT studies shows that the valley dose (rather than the peak dose) correlates best with treatment outcome (ILS).
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Affiliation(s)
| | - Sha Chang
- Department of Radiation Oncology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7512, USA
| | - Yolanda Prezado
- Institut Curie, Université PSL, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France;
- Université Paris-Saclay, CNRS UMR3347, Inserm U1021, Signalisation Radiobiologie et Cancer, 91400 Orsay, France
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Fukunaga H, Yokoya A, Prise KM. A Brief Overview of Radiation-Induced Effects on Spermatogenesis and Oncofertility. Cancers (Basel) 2022; 14:cancers14030805. [PMID: 35159072 PMCID: PMC8834293 DOI: 10.3390/cancers14030805] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/03/2022] [Accepted: 02/03/2022] [Indexed: 02/06/2023] Open
Abstract
Simple Summary Spermatogenesis is one of the most important processes for the propagation of life; however, the testes’ ability to form sperm via this differentiation process is highly radiosensitive and easily impacted by exposure to environmental, occupational, or therapeutic radiation. Furthermore, the possibility that radiation effects on the gonads can be passed on from generation to generation should not be overlooked. This review focuses on the radiation-induced effects on spermatogenesis and the transgenerational effects. We also explore the potential of novel radiobiological approaches to improve male fertility preservation during radiotherapy. Abstract The genotoxicity of radiation on germ cells may be passed on to the next generation, thus its elucidation is not only a scientific issue but also an ethical, legal, and social issue in modern society. In this article, we briefly overview the effects of radiation on spermatogenesis and its associated genotoxicity, including the latest findings in the field of radiobiology. The potential role of transgenerational effects is still poorly understood, and further research in this area is desirable. Furthermore, from the perspective of oncofertility, we discuss the historical background and clinical importance of preserving male fertility during radiation treatment and the potential of microbeam radiotherapy. We hope that this review will contribute to stimulating further discussions and investigations for therapies for pediatric and adolescent/young adult patients.
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Affiliation(s)
- Hisanori Fukunaga
- Center for Environmental and Health Sciences, Hokkaido University, Sapporo 060-0812, Japan
- Correspondence:
| | - Akinari Yokoya
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, Ibaraki 319-1106, Japan;
- Graduate School of Science and Engineering, Ibaraki University, Ibaraki 310-8512, Japan
| | - Kevin M. Prise
- Patrick G Johnstone Centre for Cancer Research, Queen’s University Belfast, Belfast BT9 7AE, UK;
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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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Fukunaga H. Stem Cell Migration: A Possible Mechanism for the Tissue-Sparing Effect of Spatially Fractionated Radiation. Radiat Res 2021; 196:680-685. [PMID: 34496025 DOI: 10.1667/rade-21-00134.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/17/2021] [Indexed: 11/03/2022]
Abstract
Stem cell responses in tissues after exposure to radiation are of significance for maintaining tissue functions. From the point of view of stem cell characteristics, this article seeks to illustrate some contributions of microbeam research to spatially fractionated radiotherapy (SFRT), such as grid radiotherapy and microbeam radiotherapy. Although the tissue-sparing response after SFRT was first reported more than a century ago, current radiation dose-volume metrics are still unable to accurately predict such tissue-level changes in response to spatially fractionated radiation fields. However, microbeam approaches could contribute to uncovering the mechanisms of tissue response, significantly improving the outcomes of SFRT and reducing its adverse effects. Studies with microbeams have shown that the testicular tissue-sparing effect for maintaining spermatogenesis after exposure to spatially fractionated radiation depends on biological parameters, such as the radiation dose distribution at the microscale level for tissue-specific stem cells and the microenvironment, or niche. This indicates that stem cell survival, migration, and repopulation are involved in the tissue-level changes during or after SFRT. The illustration of microbeam applications in this article focuses on the stem cell migration as a possible mechanism of the tissue-sparing effect for preserving functionality.
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Affiliation(s)
- Hisanori Fukunaga
- Center for Environmental and Health Sciences, Hokkaido University, N12 W7 Kita-ku, Sapporo 060-0812, Japan
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10
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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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11
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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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12
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Steel H, Brüningk SC, Box C, Oelfke U, Bartzsch SH. Quantification of Differential Response of Tumour and Normal Cells to Microbeam Radiation in the Absence of FLASH Effects. Cancers (Basel) 2021; 13:3238. [PMID: 34209502 PMCID: PMC8268803 DOI: 10.3390/cancers13133238] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/11/2021] [Accepted: 06/24/2021] [Indexed: 12/12/2022] Open
Abstract
Microbeam radiotherapy (MRT) is a preclinical method of delivering spatially-fractionated radiotherapy aiming to improve the therapeutic window between normal tissue complication and tumour control. Previously, MRT was limited to ultra-high dose rate synchrotron facilities. The aim of this study was to investigate in vitro effects of MRT on tumour and normal cells at conventional dose rates produced by a bench-top X-ray source. Two normal and two tumour cell lines were exposed to homogeneous broad beam (BB) radiation, MRT, or were separately irradiated with peak or valley doses before being mixed. Clonogenic survival was assessed and compared to BB-estimated surviving fractions calculated by the linear-quadratic (LQ)-model. All cell lines showed similar BB sensitivity. BB LQ-model predictions exceeded the survival of cell lines following MRT or mixed beam irradiation. This effect was stronger in tumour compared to normal cell lines. Dose mixing experiments could reproduce MRT survival. We observed a differential response of tumour and normal cells to spatially fractionated irradiations in vitro, indicating increased tumour cell sensitivity. Importantly, this was observed at dose rates precluding the presence of FLASH effects. The LQ-model did not predict cell survival when the cell population received split irradiation doses, indicating that factors other than local dose influenced survival after irradiation.
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Affiliation(s)
- Harriet Steel
- Division of Radiotherapy and Imaging, The Institute of Cancer Research, 123 Old Brompton Road, London SW7 3RP, UK; (C.B.); (U.O.)
| | - Sarah C. Brüningk
- Machine Learning & Computational Biology, Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland;
- Swiss Institute for Bioinformatics (SIB), 1015 Lausanne, Switzerland
| | - Carol Box
- Division of Radiotherapy and Imaging, The Institute of Cancer Research, 123 Old Brompton Road, London SW7 3RP, UK; (C.B.); (U.O.)
| | - Uwe Oelfke
- Division of Radiotherapy and Imaging, The Institute of Cancer Research, 123 Old Brompton Road, London SW7 3RP, UK; (C.B.); (U.O.)
| | - Stefan H. Bartzsch
- Department of Radiation Oncology, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675 Munich, Germany;
- Helmholtz Centre Munich, Institute for Radiation Medicine, Ingolstädter Landstraße 1, 85764 Munich, Germany
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13
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Fukunaga H, Kaminaga K, Sato T, Butterworth KT, Watanabe R, Usami N, Ogawa T, Yokoya A, Prise KM. Spatially Fractionated Microbeam Analysis of Tissue-sparing Effect for Spermatogenesis. Radiat Res 2021; 194:698-706. [PMID: 33348374 DOI: 10.1667/rade-19-00018.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/18/2020] [Indexed: 11/03/2022]
Abstract
Spatially fractionated radiation therapy (SFRT) has been based on the delivery of a single high-dose fraction to a large treatment area that has been divided into several smaller fields, reducing the overall toxicity and adverse effects. Complementary microbeam studies have also shown an effective tissue-sparing effect (TSE) in various tissue types and species after spatially fractionated irradiation at the microscale level; however, the underlying biological mechanism remains elusive. In the current study, using the combination of an ex vivo mouse spermatogenesis model and high-precision X-ray microbeams, we revealed the significant TSE for maintaining spermatogenesis after spatially fractionated microbeam irradiation. We used the following ratios of the irradiated to nonirradiated areas: 50:50, 150:50 and 350:50 µm-slit, where approximately 50, 75 and 87.5% of the sample was irradiated (using center-to-center distances of 100, 200 and 400 µm, respectively). We found that the 50 and 75% micro-slit irradiated testicular tissues showed an almost unadulterated TSE for spermatogenesis, whereas the 87.5% micro-slit irradiated tissues showed an incomplete TSE. This suggests that the TSE efficiency for spermatogenesis is dependent on the size of the nonirradiated spermatogonial stem cell pool in the irradiated testicular tissues. In addition, there would be a spatiotemporal limitation of stem cell migration/competition, resulting in the insufficient TSE for 87.5% micro-slit irradiated tissues. These stem cell characteristics are essential for the accurate prediction of tissue-level responses during or after SFRT, indicating the clinical potential for achieving better outcomes while preventing adverse effects.
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Affiliation(s)
- Hisanori Fukunaga
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast BT9 7AE, United Kingdom.,Shonan Kamakura General Hospital, Kamakura 247-8533, Japan
| | - Kiichi Kaminaga
- Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology (QST), Tokai 319-1106, Japan
| | - Takuya Sato
- Institute of Molecular Medicine and Life Science, Yokohama City University Association of Medical Science, Yokohama 236-0004, Japan
| | - Karl T Butterworth
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast BT9 7AE, United Kingdom
| | - Ritsuko Watanabe
- Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology (QST), Tokai 319-1106, Japan
| | - Noriko Usami
- Photon Factory, High Energy Accelerator Research Organization, Tsukuba 305-0801, Japan
| | - Takehiko Ogawa
- Institute of Molecular Medicine and Life Science, Yokohama City University Association of Medical Science, Yokohama 236-0004, Japan
| | - Akinari Yokoya
- Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology (QST), Tokai 319-1106, Japan
| | - Kevin M Prise
- Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, Belfast BT9 7AE, United Kingdom
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14
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Pellicioli P, Donzelli M, Davis JA, Estève F, Hugtenburg R, Guatelli S, Petasecca M, Lerch MLF, Bräuer-Krisch E, Krisch M. Study of the X-ray radiation interaction with a multislit collimator for the creation of microbeams in radiation therapy. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:392-403. [PMID: 33650550 DOI: 10.1107/s1600577520016811] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 12/31/2020] [Indexed: 06/12/2023]
Abstract
Microbeam radiation therapy (MRT) is a developing radiotherapy, based on the use of beams only a few tens of micrometres wide, generated by synchrotron X-ray sources. The spatial fractionation of the homogeneous beam into an array of microbeams is possible using a multislit collimator (MSC), i.e. a machined metal block with regular apertures. Dosimetry in MRT is challenging and previous works still show differences between calculated and experimental dose profiles of 10-30%, which are not acceptable for a clinical implementation of treatment. The interaction of the X-rays with the MSC may contribute to the observed discrepancies; the present study therefore investigates the dose contribution due to radiation interaction with the MSC inner walls and radiation leakage of the MSC. Dose distributions inside a water-equivalent phantom were evaluated for different field sizes and three typical spectra used for MRT studies at the European Synchrotron Biomedical beamline ID17. Film dosimetry was utilized to determine the contribution of radiation interaction with the MSC inner walls; Monte Carlo simulations were implemented to calculate the radiation leakage contribution. Both factors turned out to be relevant for the dose deposition, especially for small fields. Photons interacting with the MSC walls may bring up to 16% more dose in the valley regions, between the microbeams. Depending on the chosen spectrum, the radiation leakage close to the phantom surface can contribute up to 50% of the valley dose for a 5 mm × 5 mm field. The current study underlines that a detailed characterization of the MSC must be performed systematically and accurate MRT dosimetry protocols must include the contribution of radiation leakage and radiation interaction with the MSC in order to avoid significant errors in the dose evaluation at the micrometric scale.
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Affiliation(s)
- P Pellicioli
- ID17 Biomedical Beamline, ESRF - The European Synchrotron, 71 avenue des Martyrs, Grenoble, France
| | - M Donzelli
- ID17 Biomedical Beamline, ESRF - The European Synchrotron, 71 avenue des Martyrs, Grenoble, France
| | - J A Davis
- School of Physics, University of Wollongong, Wollongong, Australia
| | - F Estève
- STROBE - Synchrotron Radiation for Biomedicine, Grenoble, France
| | - R Hugtenburg
- Swansea University Medical School, Singleton Park, Swansea, United Kingdom
| | - S Guatelli
- School of Physics, University of Wollongong, Wollongong, Australia
| | - M Petasecca
- School of Physics, University of Wollongong, Wollongong, Australia
| | - M L F Lerch
- School of Physics, University of Wollongong, Wollongong, Australia
| | - E Bräuer-Krisch
- ID17 Biomedical Beamline, ESRF - The European Synchrotron, 71 avenue des Martyrs, Grenoble, France
| | - M Krisch
- ID17 Biomedical Beamline, ESRF - The European Synchrotron, 71 avenue des Martyrs, Grenoble, France
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15
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The Effect of Low Temperatures on Environmental Radiation Damage in Living Systems: Does Hypothermia Show Promise for Space Travel? Int J Mol Sci 2020; 21:ijms21176349. [PMID: 32882991 PMCID: PMC7504535 DOI: 10.3390/ijms21176349] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/31/2020] [Accepted: 08/31/2020] [Indexed: 12/23/2022] Open
Abstract
Low-temperature treatments (i.e., hypothermia) may be one way of regulating environmental radiation damage in living systems. With this in mind, hibernation under hypothermic conditions has been proposed as a useful approach for long-term human space flight. However, the underlying mechanisms of hypothermia-induced radioresistance are as yet undetermined, and the conventional risk assessment of radiation exposure during hibernation remains insufficient for estimating the effects of chronic exposure to galactic cosmic rays (GCRs). To promote scientific discussions on the application of hibernation in space travel, this literature review provides an overview of the progress to date in the interdisciplinary research field of radiation biology and hypothermia and addresses possible issues related to hypothermic treatments as countermeasures against GCRs. At present, there are concerns about the potential effects of chronic radiation exposure on neurological disorders, carcinogenesis, ischemia heat failures, and infertility in astronauts; these require further study. These concerns may be resolved by comparing and integrating data gleaned from experimental and epidemiological studies.
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16
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The Tissue-Sparing Effect of Spatially Fractionated X-rays for Maintaining Spermatogenesis: A Radiobiological Approach for the Preservation of Male Fertility after Radiotherapy. J Clin Med 2020; 9:jcm9041089. [PMID: 32290436 PMCID: PMC7231089 DOI: 10.3390/jcm9041089] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/07/2020] [Accepted: 04/10/2020] [Indexed: 01/15/2023] Open
Abstract
Radiotherapy can result in temporary or permanent gonadal toxicity in male cancer patients despite the high precision and accuracy of modern radiation treatment techniques. Previous radiobiological studies have shown an effective tissue-sparing response in various tissue types and species following exposure to spatially fractionated radiation. In the present study, we used an ex vivo mouse testicular tissue culture model and a conventional X-ray irradiation device to evaluate the tissue-sparing effect (TSE) of spatially fractionated X-rays for the protection of male fertility from radiotherapy-related adverse effects. We revealed a significant TSE for maintaining spermatogenesis in the ex vivo testes model following spatially fractionated X-ray irradiation. Moreover, we experimentally propose a possible mechanism by which the migration of spermatogonial cells, from the non-irradiated areas to the irradiated ones, in irradiated testicular tissue, is essential for the TSE and maintaining spermatogenesis. Therefore, our findings demonstrate that the control of TSE following spatially fractionated X-rays in the testes has a considerable potential for clinical application. Interdisciplinary research will be essential for further expanding the applicability of this method as an approach for the preservation of male fertility during or after radiotherapy.
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17
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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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18
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Bartzsch S, Corde S, Crosbie JC, Day L, Donzelli M, Krisch M, Lerch M, Pellicioli P, Smyth LML, Tehei M. Technical advances in x-ray microbeam radiation therapy. Phys Med Biol 2020; 65:02TR01. [PMID: 31694009 DOI: 10.1088/1361-6560/ab5507] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In the last 25 years microbeam radiation therapy (MRT) has emerged as a promising alternative to conventional radiation therapy at large, third generation synchrotrons. In MRT, a multi-slit collimator modulates a kilovoltage x-ray beam on a micrometer scale, creating peak dose areas with unconventionally high doses of several hundred Grays separated by low dose valley regions, where the dose remains well below the tissue tolerance level. Pre-clinical evidence demonstrates that such beam geometries lead to substantially reduced damage to normal tissue at equal tumour control rates and hence drastically increase the therapeutic window. Although the mechanisms behind MRT are still to be elucidated, previous studies indicate that immune response, tumour microenvironment, and the microvasculature may play a crucial role. Beyond tumour therapy, MRT has also been suggested as a microsurgical tool in neurological disorders and as a primer for drug delivery. The physical properties of MRT demand innovative medical physics and engineering solutions for safe treatment delivery. This article reviews technical developments in MRT and discusses existing solutions for dosimetric validation, reliable treatment planning and safety. Instrumentation at synchrotron facilities, including beam production, collimators and patient positioning systems, is also discussed. Specific solutions reviewed in this article include: dosimetry techniques that can cope with high spatial resolution, low photon energies and extremely high dose rates of up to 15 000 Gy s-1, dose calculation algorithms-apart from pure Monte Carlo Simulations-to overcome the challenge of small voxel sizes and a wide dynamic dose-range, and the use of dose-enhancing nanoparticles to combat the limited penetrability of a kilovoltage energy spectrum. Finally, concepts for alternative compact microbeam sources are presented, such as inverse Compton scattering set-ups and carbon nanotube x-ray tubes, that may facilitate the transfer of MRT into a hospital-based clinical environment. Intensive research in recent years has resulted in practical solutions to most of the technical challenges in MRT. Treatment planning, dosimetry and patient safety systems at synchrotrons have matured to a point that first veterinary and clinical studies in MRT are within reach. Should these studies confirm the promising results of pre-clinical studies, the authors are confident that MRT will become an effective new radiotherapy option for certain patients.
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Affiliation(s)
- Stefan Bartzsch
- Department of Radiation Oncology, School of Medicine, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany. Helmholtz Centre Munich, Institute for Radiation Medicine, Munich, Germany
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19
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Fukunaga H, Kaminaga K, Sato T, Butterworth KT, Watanabe R, Usami N, Ogawa T, Yokoya A, Prise KM. High-precision microbeam radiotherapy reveals testicular tissue-sparing effects for male fertility preservation. Sci Rep 2019; 9:12618. [PMID: 31575926 PMCID: PMC6773706 DOI: 10.1038/s41598-019-48772-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 08/05/2019] [Indexed: 12/24/2022] Open
Abstract
Microbeam radiotherapy (MRT) is based on a spatial fractionation of synchrotron X-ray microbeams at the microscale level. Although the tissue-sparing effect (TSE) in response to non-uniform radiation fields was recognized more than one century ago, the TSE of MRT in the testes and its clinical importance for preventing male fertility remain to be determined. In this study, using the combination of MRT techniques and a unique ex vivo testes organ culture, we show, for the first time, the MRT-mediated TSE for the preservation of spermatogenesis. Furthermore, our high-precision microbeam analysis revealed that the survival and potential migration steps of the non-irradiated germ stem cells in the irradiated testes tissue would be needed for the effective TSE for spermatogenesis. Our findings indicated the distribution of dose irradiated in the testes at the microscale level is of clinical importance for delivering high doses of radiation to the tumor, while still preserving male fertility.
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Affiliation(s)
- Hisanori Fukunaga
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK.,Shonan Kamakura General Hospital, 1370-1 Okamoto, Kamakura, Kanagawa, 247-8533, Japan
| | - Kiichi Kaminaga
- Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology, 2-4 Shirakata-Shirane, Tokai, Ibaraki, 319-1195, Japan
| | - Takuya Sato
- Institute of Molecular Medicine and Life Science, Yokohama City University Association of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Karl T Butterworth
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK
| | - Ritsuko Watanabe
- Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology, 2-4 Shirakata-Shirane, Tokai, Ibaraki, 319-1195, Japan
| | - Noriko Usami
- Institute of Materials Structure Science, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Takehiko Ogawa
- Institute of Molecular Medicine and Life Science, Yokohama City University Association of Medical Science, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Akinari Yokoya
- Institute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology, 2-4 Shirakata-Shirane, Tokai, Ibaraki, 319-1195, Japan.
| | - Kevin M Prise
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK.
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20
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Fukunaga H, Prise KM. Non-uniform radiation-induced biological responses at the tissue level involved in the health risk of environmental radiation: a radiobiological hypothesis. Environ Health 2018; 17:93. [PMID: 30630478 PMCID: PMC6329136 DOI: 10.1186/s12940-018-0444-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND The conventional concept of radiation protection is based on epidemiological studies of radiation that support a positive correlation between dose and response. However, there is a remarkable difference in biological responses at the tissue level, depending on whether radiation is delivered as a uniform or non-uniform spatiotemporal distribution due to tissue sparing effects (TSE). From the point of view of radiation micro-dosimetry, environmental radiation is delivered as a non-uniform distribution, and radiation-induced biological responses at the tissue level, such as TSE, would be implicated in individual risk following exposure to environmental radiation. HYPOTHESIS We hypothesize that the health risks of non-uniform radiation exposure are lower than the same dose at a uniform exposure, due to TSE following irradiation. Testing the hypothesis requires both radiobiological studies using high-precision microbeams and the epidemiological data of environmental radiation-induced effects. The implications of the hypothesis will lead to more personalized approaches in the field of environmental radiation protection. CONCLUSION The detection of spatiotemporal dose distribution could be of scientific importance for more accurate individual risk assessment of exposure to environmental radiation. Further radiobiological studies on non-uniform radiation-induced biological responses at the tissue level are expected.
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Affiliation(s)
- Hisanori Fukunaga
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, 97 Lisburn Road, Belfast, BT9 7AE UK
| | - Kevin M. Prise
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, 97 Lisburn Road, Belfast, BT9 7AE UK
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21
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Ghita M, Fernandez-Palomo C, Fukunaga H, Fredericia PM, Schettino G, Bräuer-Krisch E, Butterworth KT, McMahon SJ, Prise KM. Microbeam evolution: from single cell irradiation to pre-clinical studies. Int J Radiat Biol 2018; 94:708-718. [PMID: 29309203 DOI: 10.1080/09553002.2018.1425807] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE This review follows the development of microbeam technology from the early days of single cell irradiations, to investigations of specific cellular mechanisms and to the development of new treatment modalities in vivo. A number of microbeam applications are discussed with a focus on pre-clinical modalities and translation towards clinical application. CONCLUSIONS The development of radiation microbeams has been a valuable tool for the exploration of fundamental radiobiological response mechanisms. The strength of micro-irradiation techniques lies in their ability to deliver precise doses of radiation to selected individual cells in vitro or even to target subcellular organelles. These abilities have led to the development of a range of microbeam facilities around the world allowing the delivery of precisely defined beams of charged particles, X-rays, or electrons. In addition, microbeams have acted as mechanistic probes to dissect the underlying molecular events of the DNA damage response following highly localized dose deposition. Further advances in very precise beam delivery have also enabled the transition towards new and exciting therapeutic modalities developed at synchrotrons to deliver radiotherapy using plane parallel microbeams, in Microbeam Radiotherapy (MRT).
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Affiliation(s)
- Mihaela Ghita
- a Centre for Cancer Research and Cell Biology , Queen's University Belfast , Belfast , UK
| | | | - Hisanori Fukunaga
- a Centre for Cancer Research and Cell Biology , Queen's University Belfast , Belfast , UK
| | - Pil M Fredericia
- c Centre for Nuclear Technologies , Technical University of Denmark , Roskilde , Denmark
| | | | | | - Karl T Butterworth
- a Centre for Cancer Research and Cell Biology , Queen's University Belfast , Belfast , UK
| | - Stephen J McMahon
- a Centre for Cancer Research and Cell Biology , Queen's University Belfast , Belfast , UK
| | - Kevin M Prise
- a Centre for Cancer Research and Cell Biology , Queen's University Belfast , Belfast , UK
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22
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Kamali-Zonouzi P, Shutt A, Nisbet A, Bradley D. Feasibility of employing thick microbeams from superficial and orthovoltage kVp x-ray tubes for radiotherapy of superficial cancers. Radiat Phys Chem Oxf Engl 1993 2017. [DOI: 10.1016/j.radphyschem.2017.02.047] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Schültke E, Balosso J, Breslin T, Cavaletti G, Djonov V, Esteve F, Grotzer M, Hildebrandt G, Valdman A, Laissue J. Microbeam radiation therapy - grid therapy and beyond: a clinical perspective. Br J Radiol 2017; 90:20170073. [PMID: 28749174 PMCID: PMC5853350 DOI: 10.1259/bjr.20170073] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Microbeam irradiation is spatially fractionated radiation on a micrometer scale. Microbeam irradiation with therapeutic intent has become known as microbeam radiation therapy (MRT). The basic concept of MRT was developed in the 1980s, but it has not yet been tested in any human clinical trial, even though there is now a large number of animal studies demonstrating its marked therapeutic potential with an exceptional normal tissue sparing effect. Furthermore, MRT is conceptually similar to macroscopic grid based radiation therapy which has been used in clinical practice for decades. In this review, the potential clinical applications of MRT are analysed for both malignant and non-malignant diseases.
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Affiliation(s)
- Elisabeth Schültke
- 1 Department of Radiooncology, Rostock University Medical Center, Rostock, Germany
| | - Jacques Balosso
- 2 Departement of Radiation Oncology and Medical Physics, University Grenoble Alpes (UGA) and Centre Hospitalier Universitaire Grenoble Alpes (CHUGA), Grenoble, France
| | - Thomas Breslin
- 3 Department of Oncology, Clinical Sciences, Lund University, Lund, Sweden.,4 Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Guido Cavaletti
- 5 Experimental Neurology Unit and Milan Center for Neuroscience, School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Valentin Djonov
- 6 Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Francois Esteve
- 2 Departement of Radiation Oncology and Medical Physics, University Grenoble Alpes (UGA) and Centre Hospitalier Universitaire Grenoble Alpes (CHUGA), Grenoble, France
| | - Michael Grotzer
- 7 Department of Oncology, University Children's Hospital of Zurich, Zurich, Switzerland
| | - Guido Hildebrandt
- 1 Department of Radiooncology, Rostock University Medical Center, Rostock, Germany
| | - Alexander Valdman
- 8 Department of Oncology and Pathology, Karolinska University Hospital, Stockholm, Sweden
| | - Jean Laissue
- 6 Institute of Anatomy, University of Bern, Bern, Switzerland
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24
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Abstract
The aim of this work is to review the uses of laser microirradiation and ion microbeam techniques within the scope of radiobiological research. Laser microirradiation techniques can be used for many different purposes. In a specific condition, through the use of pulsed lasers, cell lysis can be produced for subsequent separation of different analytes. Microsurgery allows for the identification and isolation of tissue sections, single cells and subcellular components, using different types of lasers. The generation of different types of DNA damage, via this type of microirradiation, allows for the investigation of DNA dynamics. Ion microbeams are important tools in radiobiological research. There are only a limited number of facilities worldwide where radiobiological experiments can be performed. In the beginning, research was mostly focused on the bystander effect. Nowadays, with more sophisticated molecular and cellular biological techniques, ion microirradiation is used to unravel molecular processes in the field of radiobiology. These include DNA repair protein kinetics or chromatin modifications at the site of DNA damage. With the increasing relevance of charged particles in tumour therapy and new concepts on how to generate them, ion microbeam facilities are able to address unresolved questions concerning particle tumour therapy.
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Affiliation(s)
- Guido A Drexler
- 1Department of Radiation Oncology, University of Munich, Schillerstr. 42, 80336, Munich, Germany,
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Smyth LML, Senthi S, Crosbie JC, Rogers PAW. The normal tissue effects of microbeam radiotherapy: What do we know, and what do we need to know to plan a human clinical trial? Int J Radiat Biol 2016; 92:302-11. [DOI: 10.3109/09553002.2016.1154217] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Lloyd M. L. Smyth
- University of Melbourne, Department of Obstetrics and Gynaecology, Royal Women's Hospital, Parkville, Victoria, Australia
- Epworth Radiation Oncology, Epworth HealthCare, Melbourne, Victoria, Australia
| | - Sashendra Senthi
- William Buckland Radiotherapy Centre, Alfred Hospital, Melbourne, Victoria, Australia
| | - Jeffrey C. Crosbie
- William Buckland Radiotherapy Centre, Alfred Hospital, Melbourne, Victoria, Australia
- School of Applied Sciences, RMIT University, Melbourne, Victoria, Australia
| | - Peter A. W. Rogers
- University of Melbourne, Department of Obstetrics and Gynaecology, Royal Women's Hospital, Parkville, Victoria, Australia
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Bouchet A, Serduc R, Laissue JA, Djonov V. Effects of microbeam radiation therapy on normal and tumoral blood vessels. Phys Med 2015; 31:634-41. [DOI: 10.1016/j.ejmp.2015.04.014] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 04/22/2015] [Accepted: 04/25/2015] [Indexed: 10/23/2022] Open
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Grotzer MA, Schültke E, Bräuer-Krisch E, Laissue JA. Microbeam radiation therapy: Clinical perspectives. Phys Med 2015; 31:564-7. [PMID: 25773883 DOI: 10.1016/j.ejmp.2015.02.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 02/12/2015] [Accepted: 02/16/2015] [Indexed: 11/19/2022] Open
Abstract
Microbeam radiation therapy (MRT), a novel form of spatially fractionated radiotherapy (RT), uses arrays of synchrotron-generated X-ray microbeams (MB). MRT has been identified as a promising treatment concept that might be applied to patients with malignant central nervous system (CNS) tumours for whom, at the current stage of development, no satisfactory therapy is available yet. Preclinical experimental studies have shown that the CNS of healthy rodents and piglets can tolerate much higher radiation doses delivered by spatially separated MBs than those delivered by a single, uninterrupted, macroscopically wide beam. High-dose, high-precision radiotherapies such as MRT with reduced probabilities of normal tissue complications offer prospects of improved therapeutic ratios, as extensively demonstrated by results of experiments published by many international groups in the last two decades. The significance of developing MRT as a new RT approach cannot be understated. Up to 50% of cancer patients receive conventional RT, and any new treatment that provides better tumour control whilst preserving healthy tissue is likely to significantly improve patient outcomes.
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Affiliation(s)
- M A Grotzer
- University Children's Hospital of Zurich, Steinwiesstrasse 75, CH-8032 Zurich, Switzerland.
| | - E Schültke
- Rostock University Medical Center, Department of Radiotherapy, Südring 75, 18059 Rostock, Germany
| | - E Bräuer-Krisch
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, F-38043 Grenoble Cedex 9, France
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Laissue JA, Bartzsch S, Blattmann H, Bräuer-Krisch E, Bravin A, Dalléry D, Djonov V, Hanson AL, Hopewell JW, Kaser-Hotz B, Keyriläinen J, Laissue PP, Miura M, Serduc R, Siegbahn AE, Slatkin DN. Response of the rat spinal cord to X-ray microbeams. Radiother Oncol 2013; 106:106-11. [DOI: 10.1016/j.radonc.2012.12.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 12/07/2012] [Accepted: 12/11/2012] [Indexed: 11/26/2022]
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Smith RW, Wang J, Schültke E, Seymour CB, Bräuer-Krisch E, Laissue JA, Blattmann H, Mothersill CE. Proteomic changes in the rat brain induced by homogenous irradiation and by the bystander effect resulting from high energy synchrotron X-ray microbeams. Int J Radiat Biol 2012; 89:118-27. [DOI: 10.3109/09553002.2013.732252] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Anderson D, Siegbahn EA, Fallone BG, Serduc R, Warkentin B. Evaluation of dose-volume metrics for microbeam radiation therapy dose distributions in head phantoms of various sizes using Monte Carlo simulations. Phys Med Biol 2012; 57:3223-48. [PMID: 22546732 DOI: 10.1088/0031-9155/57/10/3223] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This work evaluates four dose-volume metrics applied to microbeam radiation therapy (MRT) using simulated dosimetric data as input. We seek to improve upon the most frequently used MRT metric, the peak-to-valley dose ratio (PVDR), by analyzing MRT dose distributions from a more volumetric perspective. Monte Carlo simulations were used to calculate dose distributions in three cubic head phantoms: a 2 cm mouse head, an 8 cm cat head and a 16 cm dog head. The dose distribution was calculated for a 4 × 4 mm² microbeam array in each phantom, as well as a 16 × 16 mm² array in the 8 cm cat head, and a 32 × 32 mm² array in the 16 cm dog head. Microbeam widths of 25, 50 and 75 µm and center-to-center spacings of 100, 200 and 400 µm were considered. The metrics calculated for each simulation were the conventional PVDR, the peak-to-mean valley dose ratio (PMVDR), the mean dose and the percentage volume below a threshold dose. The PVDR ranged between 3 and 230 for the 2 cm mouse phantom, and between 2 and 186 for the 16 cm dog phantom depending on geometry. The corresponding ranges for the PMVDR were much smaller, being 2-49 (mouse) and 2-46 (dog), and showed a slightly weaker dependence on phantom size and array size. The ratio of the PMVDR to the PVDR varied from 0.21 to 0.79 for the different collimation configurations, indicating a difference between the geometric dependence on outcome that would be predicted by these two metrics. For unidirectional irradiation, the mean lesion dose was 102%, 79% and 42% of the mean skin dose for the 2 cm mouse, 8 cm cat and 16 cm dog head phantoms, respectively. However, the mean lesion dose recovered to 83% of the mean skin dose in the 16 cm dog phantom in intersecting cross-firing regions. The percentage volume below a 10% dose threshold was highly dependent on geometry, with ranges for the different collimation configurations of 2-87% and 33-96% for the 2 cm mouse and 16 cm dog heads, respectively. The results of this study illustrate that different dose-volume metrics exhibit different functional dependences on MRT geometry parameters, and suggest that reliance on the PVDR as a predictor of therapeutic outcome may be insufficient.
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Affiliation(s)
- Danielle Anderson
- Department of Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2, Canada.
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Laissue JA, Blattmann H, Siegbahn EA, Slatkin DN. A misprint in a description of microbeam irradiations of rats’ heads. Vet Ophthalmol 2012; 15:210-1. [DOI: 10.1111/j.1463-5224.2012.01023.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Prezado Y, Martínez-Rovira I, Sánchez M. Scatter factors assessment in microbeam radiation therapy. Med Phys 2012; 39:1234-8. [DOI: 10.1118/1.3681274] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Rothkamm K, Crosbie JC, Daley F, Bourne S, Barber PR, Vojnovic B, Cann L, Rogers PAW. In situ biological dose mapping estimates the radiation burden delivered to 'spared' tissue between synchrotron X-ray microbeam radiotherapy tracks. PLoS One 2012; 7:e29853. [PMID: 22238667 PMCID: PMC3253092 DOI: 10.1371/journal.pone.0029853] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/05/2011] [Indexed: 11/24/2022] Open
Abstract
Microbeam radiation therapy (MRT) using high doses of synchrotron X-rays can destroy tumours in animal models whilst causing little damage to normal tissues. Determining the spatial distribution of radiation doses delivered during MRT at a microscopic scale is a major challenge. Film and semiconductor dosimetry as well as Monte Carlo methods struggle to provide accurate estimates of dose profiles and peak-to-valley dose ratios at the position of the targeted and traversed tissues whose biological responses determine treatment outcome. The purpose of this study was to utilise γ-H2AX immunostaining as a biodosimetric tool that enables in situ biological dose mapping within an irradiated tissue to provide direct biological evidence for the scale of the radiation burden to 'spared' tissue regions between MRT tracks. Γ-H2AX analysis allowed microbeams to be traced and DNA damage foci to be quantified in valleys between beams following MRT treatment of fibroblast cultures and murine skin where foci yields per unit dose were approximately five-fold lower than in fibroblast cultures. Foci levels in cells located in valleys were compared with calibration curves using known broadbeam synchrotron X-ray doses to generate spatial dose profiles and calculate peak-to-valley dose ratios of 30-40 for cell cultures and approximately 60 for murine skin, consistent with the range obtained with conventional dosimetry methods. This biological dose mapping approach could find several applications both in optimising MRT or other radiotherapeutic treatments and in estimating localised doses following accidental radiation exposure using skin punch biopsies.
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Affiliation(s)
- Kai Rothkamm
- Health Protection Agency Centre for Radiation, Chemical and Environmental Hazards, Chilton, Oxon, United Kingdom.
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Martínez-Rovira I, Sempau J, Prezado Y. Development and commissioning of a Monte Carlo photon beam model for the forthcoming clinical trials in microbeam radiation therapy. Med Phys 2011; 39:119-31. [DOI: 10.1118/1.3665768] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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35
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Sabatasso S, Laissue JA, Hlushchuk R, Graber W, Bravin A, Bräuer-Krisch E, Corde S, Blattmann H, Gruber G, Djonov V. Microbeam radiation-induced tissue damage depends on the stage of vascular maturation. Int J Radiat Oncol Biol Phys 2011; 80:1522-32. [PMID: 21740994 DOI: 10.1016/j.ijrobp.2011.03.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 02/21/2011] [Accepted: 03/20/2011] [Indexed: 10/18/2022]
Abstract
PURPOSE To explore the effects of microbeam radiation (MR) on vascular biology, we used the chick chorioallantoic membrane (CAM) model of an almost pure vascular system with immature vessels (lacking periendothelial coverage) at Day 8 and mature vessels (with coverage) at Day 12 of development. METHODS AND MATERIALS CAMs were irradiated with microplanar beams (width, ∼25 μm; interbeam spacing, ∼200 μm) at entrance doses of 200 or 300 Gy and, for comparison, with a broad beam (seamless radiation [SLR]), with entrance doses of 5 to 40 Gy. RESULTS In vivo monitoring of Day-8 CAM vasculature 6 h after 200 Gy MR revealed a near total destruction of the immature capillary plexus. Conversely, 200 Gy MR barely affected Day-12 CAM mature microvasculature. Morphological evaluation of Day-12 CAMs after the dose was increased to 300 Gy revealed opened interendothelial junctions, which could explain the transient mesenchymal edema immediately after irradiation. Electron micrographs revealed cytoplasmic vacuolization of endothelial cells in the beam path, with disrupted luminal surfaces; often the lumen was engorged with erythrocytes and leukocytes. After 30 min, the capillary plexus adopted a striated metronomic pattern, with alternating destroyed and intact zones, corresponding to the beam and the interbeam paths within the array. SLR at a dose of 10 Gy caused growth retardation, resulting in a remarkable reduction in the vascular endpoint density 24 h postirradiation. A dose of 40 Gy damaged the entire CAM vasculature. CONCLUSIONS The effects of MR are mediated by capillary damage, with tissue injury caused by insufficient blood supply. Vascular toxicity and physiological effects of MR depend on the stage of capillary maturation and appear in the first 15 to 60 min after irradiation. Conversely, the effects of SLR, due to the arrest of cell proliferation, persist for a longer time.
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Affiliation(s)
- Sara Sabatasso
- Institute of Anatomy, University of Fribourg, Fribourg, Switzerland
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Prezado Y, Martínez-Rovira I, Thengumpallil S, Deman P. Dosimetry protocol for the preclinical trials in white-beam minibeam radiation therapy. Med Phys 2011; 38:5012-5020. [DOI: 10.1118/1.3608908] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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Preferential Effect of Synchrotron Microbeam Radiation Therapy on Intracerebral 9L Gliosarcoma Vascular Networks. Int J Radiat Oncol Biol Phys 2010; 78:1503-12. [DOI: 10.1016/j.ijrobp.2010.06.021] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2009] [Revised: 06/10/2010] [Accepted: 06/15/2010] [Indexed: 11/22/2022]
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