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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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2
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Technical aspects of proton minibeam radiation therapy: Minibeam generation and delivery. Phys Med 2022; 100:64-71. [PMID: 35750002 DOI: 10.1016/j.ejmp.2022.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 06/02/2022] [Accepted: 06/13/2022] [Indexed: 11/23/2022] Open
Abstract
Proton minibeam radiation therapy (pMBRT) is a novel therapeutic strategy that combines the normal tissue sparing of sub-millimetric, spatially fractionated beams with the improved ballistics of protons. This may allow a safe dose escalation in the tumour and has already proven to provide a remarkable increase of the therapeutic index for high-grade gliomas in animal experiments. One of the main challenges in pMBRT concerns the generation of minibeams and the implementation in a clinical environment. This article reviews the different approaches for generating minibeams, using mechanical collimators and focussing magnets, and discusses the technical aspects of the implementation and delivery of pMBRT.
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Burger K, Urban T, Dombrowsky AC, Dierolf M, Günther B, Bartzsch S, Achterhold K, Combs SE, Schmid TE, Wilkens JJ, Pfeiffer F. Technical and dosimetric realization of in vivo x-ray microbeam irradiations at the Munich Compact Light Source. Med Phys 2020; 47:5183-5193. [PMID: 32757280 DOI: 10.1002/mp.14433] [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] [Received: 12/11/2019] [Revised: 04/15/2020] [Accepted: 07/20/2020] [Indexed: 12/20/2022] Open
Abstract
PURPOSE X-ray microbeam radiation therapy is a preclinical concept for tumor treatment promising tissue sparing and enhanced tumor control. With its spatially separated, periodic micrometer-sized pattern, this method requires a high dose rate and a collimated beam typically available at large synchrotron radiation facilities. To treat small animals with microbeams in a laboratory-sized environment, we developed a dedicated irradiation system at the Munich Compact Light Source (MuCLS). METHODS A specially made beam collimation optic allows to increase x-ray fluence rate at the position of the target. Monte Carlo simulations and measurements were conducted for accurate microbeam dosimetry. The dose during irradiation is determined by a calibrated flux monitoring system. Moreover, a positioning system including mouse monitoring was built. RESULTS We successfully commissioned the in vivo microbeam irradiation system for an exemplary xenograft tumor model in the mouse ear. By beam collimation, a dose rate of up to 5.3 Gy/min at 25 keV was achieved. Microbeam irradiations using a tungsten collimator with 50 μm slit size and 350 μm center-to-center spacing were performed at a mean dose rate of 0.6 Gy/min showing a high peak-to-valley dose ratio of about 200 in the mouse ear. The maximum circular field size of 3.5 mm in diameter can be enlarged using field patching. CONCLUSIONS This study shows that we can perform in vivo microbeam experiments at the MuCLS with a dedicated dosimetry and positioning system to advance this promising radiation therapy method at commercially available compact microbeam sources. Peak doses of up to 100 Gy per treatment seem feasible considering a recent upgrade for higher photon flux. The system can be adapted for tumor treatment in different animal models, for example, in the hind leg.
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Affiliation(s)
- Karin Burger
- Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.,Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany
| | - Theresa Urban
- Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.,Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany
| | - Annique C Dombrowsky
- Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.,Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, 85764, Germany
| | - Martin Dierolf
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany
| | - Benedikt Günther
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany
| | - Stefan Bartzsch
- Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.,Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, 85764, Germany
| | - Klaus Achterhold
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany
| | - Stephanie E Combs
- Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.,Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, 85764, Germany
| | - Thomas E Schmid
- Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.,Institute of Radiation Medicine (IRM), Department of Radiation Sciences (DRS), Helmholtz Zentrum München, Neuherberg, 85764, Germany
| | - Jan J Wilkens
- Department of Radiation Oncology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, 81675, Germany.,Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, 85748, Germany.,Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, München, 81675, Germany
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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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5
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Sammer M, Teiluf K, Girst S, Greubel C, Reindl J, Ilicic K, Walsh DWM, Aichler M, Walch A, Combs SE, Wilkens JJ, Dollinger G, Schmid TE. Beam size limit for pencil minibeam radiotherapy determined from side effects in an in-vivo mouse ear model. PLoS One 2019; 14:e0221454. [PMID: 31483811 PMCID: PMC6726230 DOI: 10.1371/journal.pone.0221454] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 08/06/2019] [Indexed: 11/29/2022] Open
Abstract
Side effects caused by radiation are a limiting factor to the amount of dose that can be applied to a tumor volume. A novel method to reduce side effects in radiotherapy is the use of spatial fractionation, in which a pattern of sub-millimeter beams (minibeams) is applied to spare healthy tissue. In order to determine the skin reactions in dependence of single beam sizes, which are relevant for spatially fractionated radiotherapy approaches, single pencil beams of submillimeter to 6 millimeter size were applied in BALB/c mice ears at a Small Animal Radiation Research Platform (SARRP) with a plateau dose of 60 Gy. Radiation toxicities in the ears were observed for 25 days after irradiation. Severe radiation responses were found for beams ≥ 3 mm diameter. The larger the beam diameter the stronger the observed reactions. No ear swelling and barely reddening or desquamation were found for the smallest beam sizes (0.5 and 1 mm). The findings were confirmed by histological sections. Submillimeter beams are preferred in minibeam therapy to obtain optimized tissue sparing. The gradual increase of radiation toxicity with beam size shows that also larger beams are capable of healthy tissue sparing in spatial fractionation.
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Affiliation(s)
- Matthias Sammer
- Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg, Germany
- * E-mail:
| | - Katharina Teiluf
- Department of Radiation Oncology, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
- Institut für innovative Radiotherapy (iRT), Department of Radiation Sciences (DRS), Helmholtz Zentrum München (HMGU), Oberschleißheim, Germany
- Deutches Konsortium für Translationale Krebsforschung (DKTK), Partner Site Munich, Munich, Germany
| | - Stefanie Girst
- Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg, Germany
| | - Christoph Greubel
- Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg, Germany
| | - Judith Reindl
- Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg, Germany
| | - Katarina Ilicic
- Department of Radiation Oncology, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
- Institut für innovative Radiotherapy (iRT), Department of Radiation Sciences (DRS), Helmholtz Zentrum München (HMGU), Oberschleißheim, Germany
- Deutches Konsortium für Translationale Krebsforschung (DKTK), Partner Site Munich, Munich, Germany
| | - Dietrich W. M. Walsh
- Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg, Germany
- Department of Radiation Oncology, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
| | - Michaela Aichler
- Research Unit Analytical Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, Oberschleißheim, Germany
| | - Axel Walch
- Research Unit Analytical Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, Oberschleißheim, Germany
| | - Stephanie E. Combs
- Department of Radiation Oncology, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
- Institut für innovative Radiotherapy (iRT), Department of Radiation Sciences (DRS), Helmholtz Zentrum München (HMGU), Oberschleißheim, Germany
- Deutches Konsortium für Translationale Krebsforschung (DKTK), Partner Site Munich, Munich, Germany
| | - Jan J. Wilkens
- Department of Radiation Oncology, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
- Institut für innovative Radiotherapy (iRT), Department of Radiation Sciences (DRS), Helmholtz Zentrum München (HMGU), Oberschleißheim, Germany
| | - Günther Dollinger
- Institut für Angewandte Physik und Messtechnik (LRT2), Universität der Bundeswehr München, Neubiberg, Germany
| | - Thomas E. Schmid
- Department of Radiation Oncology, Technical University of Munich, Klinikum rechts der Isar, Munich, Germany
- Institut für innovative Radiotherapy (iRT), Department of Radiation Sciences (DRS), Helmholtz Zentrum München (HMGU), Oberschleißheim, Germany
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Dilmanian FA, Krishnan S, McLaughlin WE, Lukaniec B, Baker JT, Ailawadi S, Hirsch KN, Cattell RF, Roy R, Helfer J, Kruger K, Spuhler K, He Y, Tailor R, Vassantachart A, Heaney DC, Zanzonico P, Gobbert MK, Graf JS, Nassimi JR, Fatemi NN, Schweitzer ME, Bangiyev L, Eley JG. Merging Orthovoltage X-Ray Minibeams spare the proximal tissues while producing a solid beam at the target. Sci Rep 2019; 9:1198. [PMID: 30718607 PMCID: PMC6362296 DOI: 10.1038/s41598-018-37733-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 12/07/2018] [Indexed: 02/07/2023] Open
Abstract
Conventional radiation therapy of brain tumors often produces cognitive deficits, particularly in children. We investigated the potential efficacy of merging Orthovoltage X-ray Minibeams (OXM). It segments the beam into an array of parallel, thin (~0.3 mm), planar beams, called minibeams, which are known from synchrotron x-ray experiments to spare tissues. Furthermore, the slight divergence of the OXM array make the individual minibeams gradually broaden, thus merging with their neighbors at a given tissue depth to produce a solid beam. In this way the proximal tissues, including the cerebral cortex, can be spared. Here we present experimental results with radiochromic films to characterize the method's dosimetry. Furthermore, we present our Monte Carlo simulation results for physical absorbed dose, and a first-order biologic model to predict tissue tolerance. In particular, a 220-kVp orthovoltage beam provides a 5-fold sharper lateral penumbra than a 6-MV x-ray beam. The method can be implemented in arc-scan, which may include volumetric-modulated arc therapy (VMAT). Finally, OXM's low beam energy makes it ideal for tumor-dose enhancement with contrast agents such as iodine or gold nanoparticles, and its low cost, portability, and small room-shielding requirements make it ideal for use in the low-and-middle-income countries.
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Affiliation(s)
- F Avraham Dilmanian
- Department of Radiology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA.
- Department of Radiation Oncology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA.
- Department of Neurology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA.
- Department of Psychiatry, Stony Brook University Hospital, Stony Brook, NY, 11794, USA.
- Department of Biomedical Engineering, Stony Brook University Hospital, Stony Brook, NY, 11794, USA.
- Stony Brook Cancer Center, Stony Brook University Hospital, Stony Brook, NY, 11794, USA.
| | - Sunil Krishnan
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA.
| | | | | | - Jameson T Baker
- Department of Radiation Oncology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
- Department of Radiation Medicine, Northwell Health Medical Center, Northwell, NY, USA
| | - Sandeep Ailawadi
- Department of Radiation Oncology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
| | - Kara N Hirsch
- Department of Radiology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
| | - Renee F Cattell
- Department of Radiology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
- Department of Biomedical Engineering, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
| | - Rahul Roy
- Department of Radiation Oncology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
| | - Joel Helfer
- Precision X-ray Inc., North Branford, CT, 06471, USA
| | - Kurt Kruger
- Precision X-ray Inc., North Branford, CT, 06471, USA
| | - Karl Spuhler
- Department of Radiology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
| | - Yulun He
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Ramesh Tailor
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | | | - Dakota C Heaney
- Department of Radiology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
- Department of Radiation Oncology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
| | - Pat Zanzonico
- Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Matthias K Gobbert
- Department of Mathematics and Statistics, University of Maryland, Baltimore County, Baltimore, MD, 21250, USA
| | - Jonathan S Graf
- Department of Mathematics and Statistics, University of Maryland, Baltimore County, Baltimore, MD, 21250, USA
| | - Jessica R Nassimi
- Department of Radiology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
| | - Nasrin N Fatemi
- Department of Radiology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
- Department of Radiology, City of Hope, Duarte, CA, 91010, USA
| | - Mark E Schweitzer
- Department of Radiology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
| | - Lev Bangiyev
- Department of Radiology, Stony Brook University Hospital, Stony Brook, NY, 11794, USA
| | - John G Eley
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
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7
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Lobachevsky PN, Ventura J, Giannakandropoulou L, Forrester H, Palazzolo JS, Haynes NM, Stevenson AW, Hall CJ, Mason J, Pollakis G, Pateras IS, Gorgoulis V, Terzoudi GI, Hamilton JA, Sprung CN, Georgakilas AG, Martin OA. A Functional Immune System Is Required for the Systemic Genotoxic Effects of Localized Irradiation. Int J Radiat Oncol Biol Phys 2018; 103:1184-1193. [PMID: 30529375 DOI: 10.1016/j.ijrobp.2018.11.066] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 11/19/2018] [Accepted: 11/29/2018] [Indexed: 02/06/2023]
Abstract
PURPOSE Nontargeted effects of ionizing radiation, by which unirradiated cells and tissues are also damaged, are a relatively new paradigm in radiobiology. We recently reported radiation-induced abscopal effects (RIAEs) in normal tissues; namely, DNA damage, apoptosis, and activation of the local and systemic immune responses in C57BL6/J mice after irradiation of a small region of the body. High-dose-rate, synchrotron-generated broad beam or multiplanar x-ray microbeam radiation therapy was used with various field sizes and doses. This study explores components of the immune system involved in the generation of these abscopal effects. METHODS AND MATERIALS The following mice with various immune deficiencies were irradiated with the microbeam radiation therapy beam: (1) SCID/IL2γR-/- (NOD SCID gamma, NSG) mice, (2) wild-type C57BL6/J mice treated with an antibody-blocking macrophage colony-stimulating factor 1 receptor, which depletes and alters the function of macrophages, and (3) chemokine ligand 2/monocyte chemotactic protein 1 null mice. Complex DNA damage (ie, DNA double-strand breaks), oxidatively induced clustered DNA lesions, and apoptotic cells in tissues distant from the irradiation site were measured as RIAE endpoints and compared with those in wild-type C57BL6/J mice. RESULTS Wild-type mice accumulated double-strand breaks, oxidatively induced clustered DNA lesions, and apoptosis, enforcing our RIAE model. However, these effects were completely or partially abrogated in mice with immune disruption, highlighting the pivotal role of the immune system in propagation of systemic genotoxic effects after localized irradiation. CONCLUSIONS These results underline the importance of not only delineating the best strategies for tumor control but also mitigating systemic radiation toxicity.
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Affiliation(s)
- Pavel N Lobachevsky
- Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
| | - Jessica Ventura
- University of Melbourne Department of Obstetrics & Gynaecology and Royal Women's Hospital
| | - Lina Giannakandropoulou
- School of Applied Mathematical & Physical Sciences, National Technical University of Athens, Athens, Greece
| | - Helen Forrester
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research and Monash University, Clayton, Victoria, Australia
| | - Jason S Palazzolo
- Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Nicole M Haynes
- Cancer Therapeutics Program, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Andrew W Stevenson
- Commonwealth Scientific and Industrial Research Organisation, Clayton, Victoria, Australia; Australian Synchrotron, Clayton, Victoria, Australia
| | | | - Joel Mason
- Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
| | - Gerasimos Pollakis
- School of Applied Mathematical & Physical Sciences, National Technical University of Athens, Athens, Greece
| | - Ioannis S Pateras
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, University of Athens, Athens, Greece
| | - Vassilis Gorgoulis
- Molecular Carcinogenesis Group, Department of Histology and Embryology, School of Medicine, University of Athens, Athens, Greece; Biomedical Research Foundation, Academy of Athens, Athens, Greece; Institute for Cancer Sciences and Manchester Centre for Cellular Metabolism, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Georgia I Terzoudi
- Laboratory of Health Physics, Radiobiology & Cytogenetics, Institute of Nuclear & Radiological Sciences & Technology, Energy & Safety, National Center for Scientific Research 'Demokritos', Athens, Greece
| | - John A Hamilton
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia; Australian Institute for Musculoskeletal Science (AIMSS), University of Melbourne and Western Health, St. Albans, Victoria, Australia
| | - Carl N Sprung
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research and Monash University, Clayton, Victoria, Australia
| | - Alexandros G Georgakilas
- School of Applied Mathematical & Physical Sciences, National Technical University of Athens, Athens, Greece
| | - Olga A Martin
- Research Division, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia; Division of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
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8
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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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Sammer M, Greubel C, Girst S, Dollinger G. Optimization of beam arrangements in proton minibeam radiotherapy by cell survival simulations. Med Phys 2017; 44:6096-6104. [PMID: 28880369 DOI: 10.1002/mp.12566] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 08/30/2017] [Accepted: 08/30/2017] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Proton minibeam radiotherapy using submillimeter beam dimensions allows to enhance tissue sparing in the entrance channel by spatial fractionation additionally to advantageous proton depth dose distribution. In the entrance channel, spatial fractionation leads to reduced side effects compared to conventional proton therapy. The submillimeter sized beams widen with depth due to small angle scattering and enable therefore, in contrary to x-ray microbeam radiation therapy (MRT), the homogeneous irradiation of a tumor. Proton minibeams can either be applied as planar minibeams or pencil shaped with an additional possibility to vary between a quadratic and a hexagonal arrangement for pencil minibeams. The purpose of this work is to deduce interbeam distances to achieve a homogeneous dose distribution for different tumor depths and tumor thicknesses. Furthermore, we aim for a better understanding of the sparing effect on the basis of surviving cells calculated by the linear-quadratic model. METHODS Two-dimensional dose distributions are calculated for proton minibeams of different shapes and arrangements. For a tumor in 10-15 cm depth, treatment plans are calculated with initial beam size of σ0 = 0.2 mm in a water phantom. Proton minibeam depth dose distributions are finally converted into cell survival using a linear-quadratic model. RESULTS Inter proton beam distances are maximized under the constraint of dose homogeneity in the tumor for tumor depths ranging from 4 to 15 cm and thickness ranging from 0.5 to 10 cm. Cell survival calculations for a 5 cm thick tumor covered by 10 cm healthy tissue show less cell death by up to 85%, especially in the superficial layers, while keeping the cell death in the tumor as in conventional therapy. In the entrance channel, the pencil minibeams result in higher cell survival in comparison to the planar minibeams while all proton minibeam irradiations show higher cell survival than conventional broadbeam irradiation. CONCLUSION The deduced constraints for interbeam distances simplify treatment planning for proton minibeam radiotherapy applications in future studies. The cell survival results indicate that proton minibeam radiotherapy reduces side effects but keeps tumor control as in conventional proton therapy. It makes proton minibeam, especially pencil minibeam radiotherapy a potentially attractive new approach for radiation therapy.
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Lee MH, Lee KM, Kim EH. Neighbor effect: penumbra-dose exposed neighbor cells contribute to the enhanced survival of high-dose targeted cells. Int J Radiat Biol 2017; 93:1227-1238. [PMID: 28738724 DOI: 10.1080/09553002.2017.1359430] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE In the last decade, new types of 'bystander effect' have been suggested by multiple research groups and have been challenged by others. In this study, we explored a new type of bystander effect, which has been defined in previous studies as the enhancement of the survival of high-dose targeted cells due to the penumbra-dose exposed neighbor cells. Intensity-modulated radiation therapy, which is the most widely used treatment modality, generates local regions of gradient doses between targeted and shielded cells throughout the treatment volume; therefore, we were urged to ascertain whether the new type of effect is real and to suggest a revised treatment planning. MATERIALS AND METHODS Cellular responses under non-uniform beam fields were observed in rat gliosarcoma cells, rat diencephalon cells, and mouse endothelial cells. The cells were irradiated with 200 kVp X-rays in two types: (1) all the cells in the flask were exposed to the X-ray beam (whole-beam exposure) and (2) half of the cells in the flask were exposed to the beam while the other half, or neighbor cells, were shielded from the beam (half-beam exposure). Target cells were exposed to 1, 2, 4, 6, 8, and 10 Gy, and the penumbra dose was approximately 10%-20% of the target dose. RESULTS Target cells survived high-dose (> 6 Gy) radiation exposures better under half-beam exposure with the low penumbra-dose exposed neighbor cells around than under whole-beam exposure. The survival of the targeted cells from half-beam exposure was reduced when the radiation self-conditioned medium was replaced with a fresh one immediately after irradiation. Survival was further reduced when the targeted cells were harvested immediately after irradiation and incubated in new dishes with fresh culture media until the colony was counted. CONCLUSION We have collected data of good statistics by several post-irradiation treatments of targeted cells to ascertain that the new type of bystander effect is real. The low penumbra-dose exposed neighbor cells benefited the survival of the high-dose targeted cells.
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Affiliation(s)
- Min-Ho Lee
- a Department of Nuclear Engineering, Radiation Bioengineering Laboratory , Seoul National University , Seoul , Republic of Korea
| | - Ki-Man Lee
- a Department of Nuclear Engineering, Radiation Bioengineering Laboratory , Seoul National University , Seoul , Republic of Korea
| | - Eun-Hee Kim
- a Department of Nuclear Engineering, Radiation Bioengineering Laboratory , Seoul National University , Seoul , Republic of Korea
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Mukumoto N, Nakayama M, Akasaka H, Shimizu Y, Osuga S, Miyawaki D, Yoshida K, Ejima Y, Miura Y, Umetani K, Kondoh T, Sasaki R. Sparing of tissue by using micro-slit-beam radiation therapy reduces neurotoxicity compared with broad-beam radiation therapy. JOURNAL OF RADIATION RESEARCH 2017; 58:17-23. [PMID: 27422939 PMCID: PMC5321181 DOI: 10.1093/jrr/rrw065] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 04/29/2016] [Accepted: 05/09/2016] [Indexed: 06/06/2023]
Abstract
Micro-slit-beam radiation therapy (MRT) using synchrotron-generated X-ray beams allows for extremely high-dose irradiation. However, the toxicity of MRT in central nervous system (CNS) use is still unknown. To gather baseline toxicological data, we evaluated mortality in normal mice following CNS-targeted MRT. Male C57BL/6 J mice were head-fixed in a stereotaxic frame. Synchrotron X-ray-beam radiation was provided by the SPring-8 BL28B2 beam-line. For MRT, radiation was delivered to groups of mice in a 10 × 12 mm unidirectional array consisting of 25-μm-wide beams spaced 100, 200 or 300 μm apart; another group of mice received the equivalent broad-beam radiation therapy (BRT) for comparison. Peak and valley dose rates of the MRT were 120 and 0.7 Gy/s, respectively. Delivered doses were 96-960 Gy for MRT, and 24-120 Gy for BRT. Mortality was monitored for 90 days post-irradiation. Brain tissue was stained using hematoxylin and eosin to evaluate neural structure. Demyelination was evaluated by Klüver-Barrera staining. The LD50 and LD100 when using MRT were 600 Gy and 720 Gy, respectively, and when using BRT they were 80 Gy and 96 Gy, respectively. In MRT, mortality decreased as the center-to-center beam spacing increased from 100 μm to 300 μm. Cortical architecture was well preserved in MRT, whereas BRT induced various degrees of cerebral hemorrhage and demyelination. MRT was able to deliver extremely high doses of radiation, while still minimizing neuronal death. The valley doses, influenced by beam spacing and irradiated dose, could represent important survival factors for MRT.
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Affiliation(s)
- Naritoshi Mukumoto
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Masao Nakayama
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Hiroaki Akasaka
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Yasuyuki Shimizu
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Saki Osuga
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Daisuke Miyawaki
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Kenji Yoshida
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Yasuo Ejima
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
| | - Yasushi Miura
- Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, Kobe, Hyogo, Japan
| | - Keiji Umetani
- Japan Synchrotron Radiation Research Institute, Sayo, Hyogo, Japan
| | - Takeshi Kondoh
- Department of Neurosurgery, Shinsuma Hospital, Kobe, Hyogo, Japan
| | - Ryohei Sasaki
- Division of Radiation Oncology, Kobe University Graduate School of Medicine, 7-5-2 Kusunokicho, Chuouku, Kobe, Hyogo, 650-0017, Japan
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Chen H, Wang B, Wang C, Cao W, Zhang J, Ma Y, Hong Y, Fu S, Wu F, Ying W. Dose-rate plays a significant role in synchrotron radiation X-ray-induced damage of rodent testes. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2016; 8:140-145. [PMID: 28078052 PMCID: PMC5209442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 11/08/2016] [Indexed: 06/06/2023]
Abstract
Synchrotron radiation (SR) X-ray has significant potential for applications in medical imaging and cancer treatment. However, the mechanisms underlying SR X-ray-induced tissue damage remain unclear. Previous studies on regular X-ray-induced tissue damage have suggested that dose-rate could affect radiation damage. Because SR X-ray has exceedingly high dose-rate compared to regular X-ray, it remains to be determined if dose-rate may affect SR X-ray-induced tissue damage. We used rodent testes as a model to investigate the role of dose-rate in SR X-ray-induced tissue damage. One day after SR X-ray irradiation, we determined the effects of the irradiation of the same dosage at two different dose-rates, 0.11 Gy/s and 1.1 Gy/s, on TUNEL signals, caspase-3 activation and DNA double-strand breaks (DSBs) of the testes. Compared to those produced by the irradiation at 0.11 Gy/s, irradiation at 1.1 Gy/s produced higher levels of DSBs, TUNEL signals, and caspase-3 activation in the testes. Our study has provided the first evidence suggesting that dose-rate could be a significant factor in SR X-ray-induced tissue damage, which may establish a valuable base for utilizing this factor to manipulate the tissue damage in SR X-ray-based medical applications.
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Affiliation(s)
- Heyu Chen
- School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong UniversityShanghai, P. R. China
| | - Ban Wang
- School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong UniversityShanghai, P. R. China
| | - Caixia Wang
- School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong UniversityShanghai, P. R. China
| | - Wei Cao
- School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong UniversityShanghai, P. R. China
| | - Jie Zhang
- School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong UniversityShanghai, P. R. China
| | - Yingxin Ma
- School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong UniversityShanghai, P. R. China
| | - Yunyi Hong
- School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong UniversityShanghai, P. R. China
| | - Shen Fu
- Department of Radiation Oncology, Shanghai Proton and Heavy Ion Center, Fudan University Cancer HospitalShanghai, P. R. China
| | - Fan Wu
- Department of Civil Engineering, School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong UniversityShanghai, P. R. China
| | - Weihai Ying
- School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong UniversityShanghai, P. R. China
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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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Dilmanian FA, Eley JG, Rusek A, Krishnan S. Charged Particle Therapy with Mini-Segmented Beams. Front Oncol 2015; 5:269. [PMID: 26649281 PMCID: PMC4664668 DOI: 10.3389/fonc.2015.00269] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 11/16/2015] [Indexed: 02/06/2023] Open
Abstract
One of the fundamental attributes of proton therapy and carbon ion therapy is the ability of these charged particles to spare tissue distal to the targeted tumor. This significantly reduces normal tissue toxicity and has the potential to translate to a wider therapeutic index. Although, in general, particle therapy also reduces dose to the proximal tissues, particularly in the vicinity of the target, dose to the skin and to other very superficial tissues tends to be higher than that of megavoltage x-rays. The methods presented here, namely, “interleaved carbon minibeams” and “radiosurgery with arrays of proton and light ion minibeams,” both utilize beams segmented into arrays of parallel “minibeams” of about 0.3 mm incident-beam size. These minibeam arrays spare tissues, as demonstrated by synchrotron x-ray experiments. An additional feature of particle minibeams is their gradual broadening due to multiple Coulomb scattering as they penetrate tissues. In the case of interleaved carbon minibeams, which do not broaden much, two arrays of planar carbon minibeams that remain parallel at target depth, are aimed at the target from 90° angles and made to “interleave” at the target to produce a solid radiation field within the target. As a result, the surrounding tissues are exposed only to individual carbon minibeam arrays and are therefore spared. The method was used in four-directional geometry at the NASA Space Radiation Laboratory to ablate a 6.5-mm target in a rabbit brain at a single exposure with 40 Gy physical absorbed dose. Contrast-enhanced magnetic resonance imaging and histology 6-month later showed very focal target necrosis with nearly no damage to the surrounding brain. As for minibeams of protons and light ions, for which the minibeam broadening is substantial, measurements at MD Anderson Cancer Center in Houston, TX, USA; and Monte Carlo simulations showed that the broadening minibeams will merge with their neighbors at a certain tissue depth to produce a solid beam to treat the target. The resulting sparing of proximal normal tissue allows radiosurgical ablative treatments with smaller impact on the skin and shallow tissues. This report describes these two methods and discusses their potential clinical applications.
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Affiliation(s)
- F Avraham Dilmanian
- Department of Radiation Oncology, Health Sciences Center, Stony Brook University , Stony Brook, NY , USA ; Department of Neurology, Health Sciences Center, Stony Brook University , Stony Brook, NY , USA ; Department of Radiology, Health Sciences Center, Stony Brook University , Stony Brook, NY , USA
| | - John G Eley
- Department of Radiation Oncology, School of Medicine, University of Maryland , Baltimore, MD , USA
| | - Adam Rusek
- Brookhaven National Laboratory , Upton, NY , USA ; NASA Space Radiation Laboratory , Upton, NY , USA
| | - Sunil Krishnan
- Department of Radiation Oncology, MD Anderson Cancer Center , Houston, TX , USA
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Gagliardi FM, Cornelius I, Blencowe A, Franich RD, Geso M. High resolution 3D imaging of synchrotron generated microbeams. Med Phys 2015; 42:6973-86. [DOI: 10.1118/1.4935410] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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16
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Chtcheprov P, Burk L, Yuan H, Inscoe C, Ger R, Hadsell M, Lu J, Zhang L, Chang S, Zhou O. Physiologically gated microbeam radiation using a field emission x-ray source array. Med Phys 2015; 41:081705. [PMID: 25086515 DOI: 10.1118/1.4886015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Microbeam radiation therapy (MRT) uses narrow planes of high dose radiation beams to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000 Gy of peak entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during treatment can lead to significant movement of microbeam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), which reduces the effectiveness of MRT. Recently, the authors have demonstrated the feasibility of generating microbeam radiation for small animal treatment using a carbon nanotube (CNT) x-ray source array. The purpose of this study is to incorporate physiological gating to the CNT microbeam irradiator to minimize motion-induced microbeam blurring. METHODS The CNT field emission x-ray source array with a narrow line focal track was operated at 160 kVp. The x-ray radiation was collimated to a single 280 μm wide microbeam at entrance. The microbeam beam pattern was recorded using EBT2 Gafchromic(©) films. For the feasibility study, a strip of EBT2 film was attached to an oscillating mechanical phantom mimicking mouse chest respiratory motion. The servo arm was put against a pressure sensor to monitor the motion. The film was irradiated with three microbeams under gated and nongated conditions and the full width at half maximums and PVDRs were compared. An in vivo study was also performed with adult male athymic mice. The liver was chosen as the target organ for proof of concept due to its large motion during respiration compared to other organs. The mouse was immobilized in a specialized mouse bed and anesthetized using isoflurane. A pressure sensor was attached to a mouse's chest to monitor its respiration. The output signal triggered the electron extraction voltage of the field emission source such that x-ray was generated only during a portion of the mouse respiratory cycle when there was minimum motion. Parallel planes of microbeams with 12.4 Gy/plane dose and 900 μm pitch were delivered. The microbeam profiles with and without gating were analyzed using γ-H2Ax immunofluorescence staining. RESULTS The phantom study showed that the respiratory motion caused a 50% drop in PVDR from 11.5 when there is no motion to 5.4, whereas there was only a 5.5% decrease in PVDR for gated irradiation compared to the no motion case. In the in vivo study, the histology result showed gating increased PVDR by a factor of 2.4 compared to the nongated case, similar to the result from the phantom study. The full width at tenth maximum of the microbeam decreased by 40% in gating in vivo and close to 38% with phantom studies. CONCLUSIONS The CNT field emission x-ray source array can be synchronized to physiological signals for gated delivery of x-ray radiation to minimize motion-induced beam blurring. Gated MRT reduces valley dose between lines during long-time radiation of a moving object. The technique allows for more precise MRT treatments and makes the CNT MRT device practical for extended treatment.
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Affiliation(s)
- Pavel Chtcheprov
- Department of Biomedical Engineering, University of North Carolina, 152 MacNider Hall, Campus Box 7575, Chapel Hill, North Carolina 27599
| | - Laurel Burk
- Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599
| | - Hong Yuan
- Department of Radiology, University of North Carolina, 2006 Old Clinic, CB #7510, Chapel Hill, North Carolina 27599
| | - Christina Inscoe
- Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599
| | - Rachel Ger
- Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599
| | - Michael Hadsell
- Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599
| | - Jianping Lu
- Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599
| | - Lei Zhang
- Department of Applied Physical Sciences, University of North Carolina, Chapman Hall, CB#3216, Chapel Hill, North Carolina 27599
| | - Sha Chang
- Department of Radiation Oncology, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 and UNC Lineberger Comprehensive Cancer Center, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514
| | - Otto Zhou
- Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599 and UNC Lineberger Comprehensive Cancer Center, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514
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17
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Proton microbeam radiotherapy with scanned pencil-beams – Monte Carlo simulations. Phys Med 2015; 31:621-6. [DOI: 10.1016/j.ejmp.2015.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 04/09/2015] [Accepted: 04/11/2015] [Indexed: 11/22/2022] Open
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18
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Wright MD. Microbeam radiosurgery: An industrial perspective. Phys Med 2015; 31:601-6. [DOI: 10.1016/j.ejmp.2015.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 04/01/2015] [Accepted: 04/07/2015] [Indexed: 11/15/2022] Open
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Zhang L, Yuan H, Inscoe C, Chtcheprov P, Hadsell M, Lee Y, Lu J, Chang S, Zhou O. Nanotube x-ray for cancer therapy: a compact microbeam radiation therapy system for brain tumor treatment. Expert Rev Anticancer Ther 2015; 14:1411-8. [PMID: 25417729 DOI: 10.1586/14737140.2014.978293] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Microbeam radiation therapy (MRT) is a promising preclinical modality for cancer treatment, with remarkable preferential tumoricidal effects, that is, tumor eradication without damaging normal tissue functions. Significant lifespan extension has been demonstrated in brain tumor-bearing small animals treated with MRT. So far, MRT experiments can only be performed in a few synchrotron facilities around the world. Limited access to MRT facilities prevents this enormously promising radiotherapy technology from reaching the broader biomedical research community and hinders its potential clinical translation. We recently demonstrated, for the first time, the feasibility of generating microbeam radiation in a laboratory environment using a carbon nanotube x-ray source array and performed initial small animal studies with various brain tumor models. This new nanotechnology-enabled microbeam delivery method, although still in its infancy, has shown promise for achieving comparable therapeutic effects to synchrotron MRT and has offered a potential pathway for clinical translation.
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Affiliation(s)
- Lei Zhang
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Fernandez-Palomo C, Bräuer-Krisch E, Laissue J, Vukmirovic D, Blattmann H, Seymour C, Schültke E, Mothersill C. Use of synchrotron medical microbeam irradiation to investigate radiation-induced bystander and abscopal effects in vivo. Phys Med 2015; 31:584-95. [PMID: 25817634 DOI: 10.1016/j.ejmp.2015.03.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 01/01/2023] Open
Abstract
The question of whether bystander and abscopal effects are the same is unclear. Our experimental system enables us to address this question by allowing irradiated organisms to partner with unexposed individuals. Organs from both animals and appropriate sham and scatter dose controls are tested for expression of several endpoints such as calcium flux, role of 5HT, reporter assay cell death and proteomic profile. The results show that membrane related functions of calcium and 5HT are critical for true bystander effect expression. Our original inter-animal experiments used fish species whole body irradiated with low doses of X-rays, which prevented us from addressing the abscopal effect question. Data which are much more relevant in radiotherapy are now available for rats which received high dose local irradiation to the implanted right brain glioma. The data were generated using quasi-parallel microbeams at the biomedical beamline at the European Synchrotron Radiation Facility in Grenoble France. This means we can directly compare abscopal and "true" bystander effects in a rodent tumour model. Analysis of right brain hemisphere, left brain and urinary bladder in the directly irradiated animals and their unirradiated partners strongly suggests that bystander effects (in partner animals) are not the same as abscopal effects (in the irradiated animal). Furthermore, the presence of a tumour in the right brain alters the magnitude of both abscopal and bystander effects in the tissues from the directly irradiated animal and in the unirradiated partners which did not contain tumours, meaning the type of signal was different.
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Affiliation(s)
- Cristian Fernandez-Palomo
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
| | - Elke Bräuer-Krisch
- European Synchrotron Radiation Facility, BP 220 6, rue Jules Horowitz, 38043 Grenoble, France
| | - Jean Laissue
- University of Bern, Hochschulstrasse 4, CH-3012 Bern, Switzerland
| | - Dusan Vukmirovic
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | | | - Colin Seymour
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Elisabeth Schültke
- Department of Radiotherapy, Rostock University Medical Center, Südring 75, 18059 Rostock, Germany
| | - Carmel Mothersill
- Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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Fernandez-Palomo C, Mothersill C, Bräuer-Krisch E, Laissue J, Seymour C, Schültke E. γ-H2AX as a marker for dose deposition in the brain of wistar rats after synchrotron microbeam radiation. PLoS One 2015; 10:e0119924. [PMID: 25799425 PMCID: PMC4370487 DOI: 10.1371/journal.pone.0119924] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 01/17/2015] [Indexed: 01/01/2023] Open
Abstract
Objective Synchrotron radiation has shown high therapeutic potential in small animal models of malignant brain tumours. However, more studies are needed to understand the radiobiological effects caused by the delivery of high doses of spatially fractionated x-rays in tissue. The purpose of this study was to explore the use of the γ-H2AX antibody as a marker for dose deposition in the brain of rats after synchrotron microbeam radiation therapy (MRT). Methods Normal and tumour-bearing Wistar rats were exposed to 35, 70 or 350 Gy of MRT to their right cerebral hemisphere. The brains were extracted either at 4 or 8 hours after irradiation and immediately placed in formalin. Sections of paraffin-embedded tissue were incubated with anti γ-H2AX primary antibody. Results While the presence of the C6 glioma does not seem to modulate the formation of γ-H2AX in normal tissue, the irradiation dose and the recovery versus time are the most important factors affecting the development of γ-H2AX foci. Our results also suggest that doses of 350 Gy can trigger the release of bystander signals that significantly amplify the DNA damage caused by radiation and that the γ-H2AX biomarker does not only represent DNA damage produced by radiation, but also damage caused by bystander effects. Conclusion In conclusion, we suggest that the γ-H2AX foci should be used as biomarker for targeted and non-targeted DNA damage after synchrotron radiation rather than a tool to measure the actual physical doses.
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Affiliation(s)
- Cristian Fernandez-Palomo
- Stereotactic Neurosurgery and Laboratory for Molecular Neurosurgery, Freiburg University Medical Center, Freiburg, Germany
- Medical Physics and Applied Radiation Sciences Department, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
| | - Carmel Mothersill
- Medical Physics and Applied Radiation Sciences Department, McMaster University, Hamilton, Ontario, Canada
| | | | - Jean Laissue
- Institute of Pathology, University of Bern, Bern, Switzerland
| | - Colin Seymour
- Medical Physics and Applied Radiation Sciences Department, McMaster University, Hamilton, Ontario, Canada
| | - Elisabeth Schültke
- Stereotactic Neurosurgery and Laboratory for Molecular Neurosurgery, Freiburg University Medical Center, Freiburg, Germany
- Department of Radiotherapy/Laboratory of Radiobiology, Rostock University Medical Center, Rostock, Germany
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Ibahim MJ, Crosbie JC, Yang Y, Zaitseva M, Stevenson AW, Rogers PAW, Paiva P. An evaluation of dose equivalence between synchrotron microbeam radiation therapy and conventional broad beam radiation using clonogenic and cell impedance assays. PLoS One 2014; 9:e100547. [PMID: 24945301 PMCID: PMC4063937 DOI: 10.1371/journal.pone.0100547] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 05/29/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND High-dose synchrotron microbeam radiation therapy (MRT) has shown the potential to deliver improved outcomes over conventional broadbeam (BB) radiation therapy. To implement synchrotron MRT clinically for cancer treatment, it is necessary to undertake dose equivalence studies to identify MRT doses that give similar outcomes to BB treatments. AIM To develop an in vitro approach to determine biological dose equivalence between MRT and BB using two different cell-based assays. METHODS The acute response of tumour and normal cell lines (EMT6.5, 4T1.2, NMuMG, EMT6.5ch, 4T1ch5, SaOS-2) to MRT (50-560 Gy) and BB (1.5-10 Gy) irradiation was investigated using clonogenic and real time cell impedance sensing (RT-CIS)/xCELLigence assays. MRT was performed using a lattice of 25 or 50 µm-wide planar, polychromatic kilovoltage X-ray microbeams with 200 µm peak separation. BB irradiations were performed using a Co60 teletherapy unit or a synchrotron radiation source. BB doses that would generate biological responses similar to MRT were calculated by data interpolation and verified by clonogenic and RT-CIS assays. RESULTS For a given cell line, MRT equivalent BB doses identified by RT-CIS/xCELLigence were similar to those identified by clonogenic assays. Dose equivalence between MRT and BB were verified in vitro in two cell lines; EMT6.5ch and SaOS-2 by clonogenic assays and RT-CIS/xCELLigence. We found for example, that BB doses of 3.4±0.1 Gy and 4.40±0.04 Gy were radiobiologically equivalent to a peak, microbeam dose of 112 Gy using clonogenic and RT-CIS assays respectively on EMT6.5ch cells. CONCLUSION Our data provides the first determination of biological dose equivalence between BB and MRT modalities for different cell lines and identifies RT-CIS/xCELLigence assays as a suitable substitute for clonogenic assays. These results will be useful for the safe selection of MRT doses for future veterinary and clinical trials.
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Affiliation(s)
- Mohammad Johari Ibahim
- Department of Obstetrics and Gynaecology, Royal Women’s Hospital, University of Melbourne, Parkville, Victoria, Australia
- Faculty of Medicine, Universiti Teknologi MARA, Sungai Buloh Campus, Jalan Hospital, Sungai Buloh, Selangor, Malaysia
| | - Jeffrey C. Crosbie
- Department of Obstetrics and Gynaecology, Royal Women’s Hospital, University of Melbourne, Parkville, Victoria, Australia
- William Buckland Radiotherapy Centre, Alfred Hospital, Melbourne, Australia
| | - Yuqing Yang
- Department of Obstetrics and Gynaecology, Royal Women’s Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Marina Zaitseva
- Department of Obstetrics and Gynaecology, Royal Women’s Hospital, University of Melbourne, Parkville, Victoria, Australia
| | - Andrew W. Stevenson
- Australian Synchrotron Imaging and Medical Beamline, Clayton, Australia
- CSIRO Materials Science & Engineering, Clayton, Australia
| | - Peter A. W. Rogers
- Department of Obstetrics and Gynaecology, Royal Women’s Hospital, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
| | - Premila Paiva
- Department of Obstetrics and Gynaecology, Royal Women’s Hospital, University of Melbourne, Parkville, Victoria, Australia
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Kim SR, Kim EH. Effect of acidic environment on the response of endothelial cells to irradiation: implications for microbeam radiation therapy. Int J Radiat Biol 2014; 90:325-33. [PMID: 24467329 DOI: 10.3109/09553002.2014.887867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE Microbeam radiation therapy (MRT) is a novel experimental radiotherapy regimen, which delivers high doses of synchrotron-generated X-rays in the form of quasi-parallel arrays of microbeam separated by microplanar spaces. The repair or healing of irradiated regions (Peak) via migration of endothelial cells (EC) from unirradiated regions (Valley) plays an important role in the response of tumors and normal tissues to MRT. It is known that intratumor microenvironment is acidic. We investigated the influence of environmental acidity on the response of EC to ionizing radiation. MATERIALS AND METHODS Effects of irradiation on the viability, clonogenicity and migration rate of endothelial cells were studied using human umbilical vascular endothelial cells and mouse endothelial cells in pH 7.3 and 6.4 environments. RESULTS An exposure to acidic environment (pH 6.4) for 2-4 days exerted little effect on the viability of EC. On the other hand, acidic environment significantly retarded the migration of control and irradiated EC. The migration of EC into 2000 μm-wide wound was slower than that into 1000 μm-side wounds. CONCLUSION The microenvironmental acidity and the size of beam opening in MRT may greatly affect the repair of irradiated peak regions via migration of EC from unirradiated valley regions.
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Affiliation(s)
- So-Ra Kim
- Radiation Bioengineering Laboratory, Department of Nuclear Engineering, Seoul National University , Seoul , Republic of Korea
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Zhang L, Yuan H, Burk LM, Inscoe CR, Hadsell MJ, Chtcheprov P, Lee YZ, Lu J, Chang S, Zhou O. Image-guided microbeam irradiation to brain tumour bearing mice using a carbon nanotube x-ray source array. Phys Med Biol 2014; 59:1283-303. [PMID: 24556798 DOI: 10.1088/0031-9155/59/5/1283] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Microbeam radiation therapy (MRT) is a promising experimental and preclinical radiotherapy method for cancer treatment. Synchrotron based MRT experiments have shown that spatially fractionated microbeam radiation has the unique capability of preferentially eradicating tumour cells while sparing normal tissue in brain tumour bearing animal models. We recently demonstrated the feasibility of generating orthovoltage microbeam radiation with an adjustable microbeam width using a carbon nanotube based x-ray source array. Here we report the preliminary results from our efforts in developing an image guidance procedure for the targeted delivery of the narrow microbeams to the small tumour region in the mouse brain. Magnetic resonance imaging was used for tumour identification, and on-board x-ray radiography was used for imaging of landmarks without contrast agents. The two images were aligned using 2D rigid body image registration to determine the relative position of the tumour with respect to a landmark. The targeting accuracy and consistency were evaluated by first irradiating a group of mice inoculated with U87 human glioma brain tumours using the present protocol and then determining the locations of the microbeam radiation tracks using γ-H2AX immunofluorescence staining. The histology results showed that among 14 mice irradiated, 11 received the prescribed number of microbeams on the targeted tumour, with an average localization accuracy of 454 µm measured directly from the histology (537 µm if measured from the registered histological images). Two mice received one of the three prescribed microbeams on the tumour site. One mouse was excluded from the analysis due to tissue staining errors.
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Affiliation(s)
- Lei Zhang
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Romanelli P, Bravin A. Synchrotron-generated microbeam radiosurgery: a novel experimental approach to modulate brain function. Neurol Res 2013; 33:825-31. [DOI: 10.1179/016164111x13123658647445] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Gokeri G, Kocar C, Tombakoglu M, Cecen Y. Monte Carlo simulation of stereotactic microbeam radiation therapy: evaluation of the usage of a linear accelerator as the x-ray source. Phys Med Biol 2013; 58:4621-42. [PMID: 23771153 DOI: 10.1088/0031-9155/58/13/4621] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The usage of linear accelerator-generated x-rays for the stereotactic microbeam radiation therapy technique was evaluated in this study. Dose distributions were calculated with the Monte Carlo code MCNPX. Unidirectional single beams and beam arrays were simulated in a cylindrical water phantom to observe the effects of x-ray energies and irradiation geometry on dose distributions. Beam arrays were formed with square pencil beams. Two orthogonally interlaced beam arrays were simulated in a detailed head phantom and dose distributions were compared with ones which had been calculated for a bidirectional interlaced microbeam therapy (BIMRT) technique that uses synchrotron-generated x-rays. A parallel pattern of the beams was preserved through the phantom; however an unsegmented dose region could not be formed at the target. Five orthogonally interlaced beam array pairs (ten beam arrays) were simulated in a mathematical head phantom and the unsegmented dose region was formed. However, the dose fall-off distance is longer than the one that had been calculated for the BIMRT technique. Besides, the peak-to-dose ratios between the phantom's outer surface and the target region are lower. Therefore, the advantages of the MRT technique may not be preserved with the usage of a linac as the x-ray source.
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Affiliation(s)
- Gurdal Gokeri
- Department of Nuclear Engineering, Hacettepe University, Ankara, Turkey.
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Synchrotron-generated microbeam sensorimotor cortex transections induce seizure control without disruption of neurological functions. PLoS One 2013; 8:e53549. [PMID: 23341950 PMCID: PMC3544911 DOI: 10.1371/journal.pone.0053549] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 12/03/2012] [Indexed: 11/19/2022] Open
Abstract
Synchrotron-generated X-ray microplanar beams (microbeams) are characterized by the ability to deliver extremely high doses of radiation to spatially restricted volumes of tissue. Minimal dose spreading outside the beam path provides an exceptional degree of protection from radio-induced damage to the neurons and glia adjacent to the microscopic slices of tissue irradiated. The preservation of cortical architecture following high-dose microbeam irradiation and the ability to induce non-invasively the equivalent of a surgical cut over the cortex is of great interest for the development of novel experimental models in neurobiology and new treatment avenues for a variety of brain disorders. Microbeams (size 100 µm/600 µm, center-to-center distance of 400 µm/1200 µm, peak entrance doses of 360-240 Gy/150-100 Gy) delivered to the sensorimotor cortex of six 2-month-old naïve rats generated histologically evident cortical transections, without modifying motor behavior and weight gain up to 7 months. Microbeam transections of the sensorimotor cortex dramatically reduced convulsive seizure duration in a further group of 12 rats receiving local infusion of kainic acid. No subsequent neurological deficit was associated with the treatment. These data provide a novel tool to study the functions of the cortex and pave the way for the development of new therapeutic strategies for epilepsy and other neurological diseases.
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Dilmanian FA, Jenkins AL, Olschowka JA, Zhong Z, Park JY, Desnoyers NR, Sobotka S, Fois GR, Messina CR, Morales M, Hurley SD, Trojanczyk L, Ahmad S, Shahrabi N, Coyle PK, Meek AG, O'Banion MK. X-ray microbeam irradiation of the contusion-injured rat spinal cord temporarily improves hind-limb function. Radiat Res 2012; 179:76-88. [PMID: 23216524 DOI: 10.1667/rr2921.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Spinal cord injury is a devastating condition with no effective treatment. The physiological processes that impede recovery include potentially detrimental immune responses and the production of reactive astrocytes. Previous work suggested that radiation treatment might be beneficial in spinal cord injury, although the method carries risk of radiation-induced damage. To overcome this obstacle we used arrays of parallel, synchrotron-generated X-ray microbeams (230 μm with 150 μm gaps between them) to irradiate an established model of rat spinal cord contusion injury. This technique is known to have a remarkable sparing effect in tissue, including the central nervous system. Injury was induced in adult female Long-Evans rats at the level of the thoracic vertebrae T9-T10 using 25 mm rod drop on an NYU Impactor. Microbeam irradiation was given to groups of 6-8 rats each, at either Day 10 (50 or 60 Gy in-beam entrance doses) or Day 14 (50, 60 or 70 Gy). The control group was comprised of two subgroups: one studied three months before the irradiation experiment (n = 9) and one at the time of the irradiations (n = 7). Hind-limb function was blindly scored with the Basso, Beattie and Bresnahan (BBB) rating scale on a nearly weekly basis. The scores for the rats irradiated at Day 14 post-injury, when using t test with 7-day data-averaging time bins, showed statistically significant improvement at 28-42 days post-injury (P < 0.038). H&E staining, tissue volume measurements and immunohistochemistry at day ≈ 110 post-injury did not reveal obvious differences between the irradiated and nonirradiated injured rats. The same microbeam irradiation of normal rats at 70 Gy in-beam entrance dose caused no behavioral deficits and no histological effects other than minor microglia activation at 110 days. Functional improvement in the 14-day irradiated group might be due to a reduction in populations of immune cells and/or reactive astrocytes, while the Day 10/Day 14 differences may indicate time-sensitive changes in these cells and their populations. With optimizations, including those of the irradiation time(s), microbeam pattern, dose, and perhaps concomitant treatments such as immunological intervention this method may ultimately reach clinical use.
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Griffin RJ, Koonce NA, Dings RPM, Siegel E, Moros EG, Bräuer-Krisch E, Corry PM. Microbeam radiation therapy alters vascular architecture and tumor oxygenation and is enhanced by a galectin-1 targeted anti-angiogenic peptide. Radiat Res 2012; 177:804-812. [PMID: 22607585 PMCID: PMC3391740 DOI: 10.1667/rr2784.1] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
In this study, we sought to determine the therapeutic potential of variably sized (50 μm or 500 μm wide, 14 mm tall) parallel microbeam radiation therapy (MRT) alone and in combination with a novel anti-angiogenic peptide, anginex, in mouse mammary carcinomas (4T1)--a moderately hypoxic and radioresistant tumor with propensity to metastasize. The fraction of total tumor volume that was directly irradiated was approximately 25% in each case, but the distance between segments irradiated by the planar microbeams (width of valley dose region) varied by an order of magnitude from 150-1500 μm corresponding to 200 μm and 2000 μm center-to-center inter-microbeam distances, respectively. We found that MRT administered in 50 μm beams at 150 Gy was most effective in delaying tumor growth. Furthermore, tumor growth delay induced by 50 μm beams at 150 Gy was virtually indistinguishable from the 500 μm beams at 150 Gy. Fifty-micrometer beams at the lower peak dose of 75 Gy induced growth delay intermediate between 150 Gy and untreated tumors, while 500 μm beams at 75 Gy were unable to alter tumor growth compared to untreated tumors. However, the addition of anginex treatment increased the relative tumor growth delay after 500 μm beams at 75 Gy most substantially out of the conditions tested. Anginex treatment of animals whose tumors received the 50 μm beams at 150 Gy also led to an improvement in growth delay from that induced by the comparable MRT alone. Immunohistochemical staining for CD31 (endothelial cells) and αSMA (smooth muscle pericyte-associated blood vessels as a measure of vessel normalization) indicated that vessel density was significantly decreased in all irradiated groups and pericyte staining was significantly increased in the irradiated groups on day 14 after irradiation. The addition of anginex treatment further decreased the mean vascular density in all combination treatment groups and further increased the amount of pericyte staining in these tumors. Finally, evidence of tumor hypoxia was found to decrease in tumors analyzed at 1-14 days after MRT in the groups receiving 150 Gy peak dose, but not 75 Gy peak dose. Our results suggest that tumor vascular damage induced by MRT at these potentially clinically acceptable peak entrance doses may provoke vascular normalization and may be exploited to improve tumor control using agents targeting angiogenesis.
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Affiliation(s)
- Robert J Griffin
- Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
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Sprung CN, Cholewa M, Usami N, Kobayashi K, Crosbie JC. DNA damage and repair kinetics after microbeam radiation therapy emulation in living cells using monoenergetic synchrotron X-ray microbeams. JOURNAL OF SYNCHROTRON RADIATION 2011; 18:630-636. [PMID: 21685681 PMCID: PMC3267636 DOI: 10.1107/s0909049511011836] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 03/30/2011] [Indexed: 05/30/2023]
Abstract
A novel synchrotron-based approach, known as microbeam radiation therapy (MRT), currently shows considerable promise in increased tumour control and reduced normal tissue damage compared with conventional radiotherapy. Different microbeam widths and separations were investigated using a controlled cell culture system and monoenergetic (5.35 keV) synchrotron X-rays in order to gain further insight into the underlying cellular response to MRT. DNA damage and repair was measured using fluorescent antibodies against phosphorylated histone H2AX, which also allowed us to verify the exact location of the microbeam path. Beam dimensions that reproduced promising MRT strategies were used to identify useful methods to study the underpinnings of MRT. These studies include the investigation of different spatial configurations on bystander effects. γH2AX foci number were robustly induced in directly hit cells and considerable DNA double-strand break repair occurred by 12 h post-10 Gy irradiation; however, many cells had some γH2AX foci at the 12 h time point. γH2AX foci at later time points did not directly correspond with the targeted regions suggesting cell movement or bystander effects as a potential mechanism for MRT effectiveness. Partial irradiation of single nuclei was also investigated and in most cases γH2AX foci were not observed outside the field of irradiation within 1 h after irradiation indicating very little chromatin movement in this time frame. These studies contribute to the understanding of the fundamental radiation biology relating to the MRT response, a potential new therapy for cancer patients.
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Affiliation(s)
- Carl N Sprung
- Centre for Women's Health Research and Centre for Innate Immunology and Infectious Disease, Monash Institute for Medical Research, Monash University, Clayton, Victoria, Australia.
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Influence of Gold Nanoparticles on Radiation Dose Enhancement and Cellular Migration in Microbeam-Irradiated Cells. BIONANOSCIENCE 2011. [DOI: 10.1007/s12668-011-0001-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ghasemi M, Kakuee O, Fathollahi V, Shahvar A, Mohati M, Ghafoori M. Physical dose distribution due to multi-sliced kV X-ray beam in labeled tissue-like media: An experimental approach. Appl Radiat Isot 2011; 69:482-91. [DOI: 10.1016/j.apradiso.2010.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 10/06/2010] [Accepted: 10/11/2010] [Indexed: 10/18/2022]
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Gokeri G, Kocar C, Tombakoglu M. Monte Carlo simulation of microbeam radiation therapy with an interlaced irradiation geometry and an Au contrast agent in a realistic head phantom. Phys Med Biol 2010; 55:7469-87. [DOI: 10.1088/0031-9155/55/24/006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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van der Sanden B, Bräuer-Krisch E, Siegbahn EA, Ricard C, Vial JC, Laissue J. Tolerance of Arteries to Microplanar X-Ray Beams. Int J Radiat Oncol Biol Phys 2010; 77:1545-52. [DOI: 10.1016/j.ijrobp.2010.02.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 02/15/2010] [Accepted: 02/17/2010] [Indexed: 11/30/2022]
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Abstract
Radiosurgery involves the precise delivery of sharply collimated high-energy beams of radiation to a distinct target volume along selected trajectories. Historically, accurate targeting required the application of a stereotactic frame, thus limiting the use of this procedure to single treatments of selected intracranial lesions. However, the scope of radiosurgery has undergone a remarkable broadening since the introduction of image-guided robotic radiosurgery. Recent developments in real-time image guidance provide an effective frameless alternative to conventional radiosurgery and allow both the treatment of lesions outside the skull and the possibility of performing hypofractionation. As a consequence, targets in the spine, chest and abdomen can now also be radiosurgically ablated with submillimetric precision. Meanwhile, the combination of image guidance, robotic beam delivery, and non-isocentric inverse planning can greatly enhance the conformality and homogeneity of radiosurgery. The aim of this article is to describe the technological basis of image-guided radiosurgery and provide a perspective on future developments. The current clinical usage of robotic radiosurgery will be reviewed with an emphasis on those applications that may represent a major shift in the therapeutic paradigm.
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Induction of DNA Double-Strand Breaks and Cellular Migration Through Bystander Effects in Cells Irradiated With the Slit-Type Microplanar Beam of the Spring-8 Synchrotron. Int J Radiat Oncol Biol Phys 2009; 74:229-36. [DOI: 10.1016/j.ijrobp.2008.09.060] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 09/11/2008] [Accepted: 09/30/2008] [Indexed: 11/17/2022]
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Nettelbeck H, Takacs GJ, Lerch MLF, Rosenfeld AB. Microbeam radiation therapy: A Monte Carlo study of the influence of the source, multislit collimator, and beam divergence on microbeams. Med Phys 2009; 36:447-56. [DOI: 10.1118/1.3049786] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Ghasemi M, Shamsaei M, Ghannadi M, Raisali G. Dosimetric studies of micropencil X-ray beam interacting with labelled tissues by Au and Gd agents using Geant4. RADIATION PROTECTION DOSIMETRY 2009; 133:97-104. [PMID: 19223291 DOI: 10.1093/rpd/ncp017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The aim of microbeam radiation therapy is to deliver a high dose to tumours while sparing adjacent healthy tissues. Recovery of normal tissues injured by the beam irradiation and ablation of tumour are dependent on the dose distribution generated by the incident microbeams. Using microbeams has the advantage that the areas outside the beams' trajectories (valley region) are poorly irradiated by the radiation scattered inside the tissues. Thus, the normal tissues not directly irradiated are adequately preserved, resulting in a rapid regeneration of blood vessels in the directly irradiated areas (peak region). The goal of this work was to study the effects of using gold (Au) and gadolinium (Gd) as dose enhancement factors on the radial dose distribution when target tissue is irradiated by a micropencil X-ray beam. The Monte Carlo Geant4 simulation program was used to evaluate dose distribution in the phantom in two phases. In phase 1, validity of this model based on Geant4 was evaluated by comparing the obtained results with those of the published reports. In phase 2 of this simulation, Au and Gd were introduced to the assumed cancerous cylindrical shell-shaped region both on the surface (i.e. in the 0-1 cm depth of phantom) and in the depth (i.e. in the 4-5 cm depth of phantom). Then the phantom was exposed to a micropencil beam mimicking the typical conditions used at the European synchrotron radiation facility in the simulated model. The simulated dose profiles indicate that introducing high Z elements considerably enhances the absorbed dose both in the beam path and in the surrounding region. However, this enhancement is more effective for Au in the beam path and for Gd in the surrounding region. This approach of introducing high Z elements leading to their accumulation in cancerous tissue could hopefully prepare new treatment planning of preclinical trials.
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Affiliation(s)
- M Ghasemi
- Nuclear Engineering and Physics Department, Amirkabir University of Technology, PO Box 15875-4413, Tehran, Iran.
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Kim EH. BETTER UNDERSTANDING OF THE BIOLOGICAL EFFECTS OF RADIATION BY MICROSCOPIC APPROACHES. NUCLEAR ENGINEERING AND TECHNOLOGY 2008. [DOI: 10.5516/net.2008.40.7.551] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Microbeam radiation therapy: Tissue dose penetration and BANG-gel dosimetry of thick-beams’ array interlacing. Eur J Radiol 2008; 68:S129-36. [DOI: 10.1016/j.ejrad.2008.04.055] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Accepted: 04/28/2008] [Indexed: 11/18/2022]
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Hoh DJ, Liu CY, Chen JC, Pagnini PG, Yu C, Wang MY, Apuzzo ML. CHAINED LIGHTNING. Neurosurgery 2007; 61:1111-29; discussion 1129-30. [DOI: 10.1227/01.neu.0000306089.22894.4e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Abstract
RADIOSURGERY IS FUNDAMENTALLY the harnessing of energy and delivering it to a focal target for a therapeutic effect. The evolution of radiosurgical technology and practice has served toward refining methodologies for better conformal energy delivery. In the past, this has resulted in developing strategies for improved beam generation and delivery. Ultimately, however, our current instrumentation and treatment modalities may be approaching a practical limit with regard to further optimizing energy containment.
In looking forward, several strategies are emerging to circumvent these limitations and improve conformal radiosurgery. Refinement of imaging techniques through functional imaging and nanoprobes for cancer detection may benefit lesion localization and targeting. Methods for enhancing the biological effect while reducing radiation-induced changes are being examined through dose fractionation schedules. Radiosensitizers and photosensitizers are being investigated as agents for modulating the biological response of tissues to radiation and alternative energy forms. Discovery of new energy modalities is being pursued through development of microplanar beams, free electron lasers, and high-intensity focused ultrasound. The exploration of these future possibilities will provide the tools for radiosurgical treatment of a broader spectrum of diseases for the next generation.
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Affiliation(s)
- Daniel J. Hoh
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Charles Y. Liu
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Joseph C.T. Chen
- Departments of Radiation Oncology and Neurological Surgery, Southern California Permanente Medical Group, Los Angeles, California
| | - Paul G. Pagnini
- Department of Radiation Oncology, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Cheng Yu
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Michael Y. Wang
- Miller School of Medicine, University of Miami, Miami, Florida
| | - Michael L.J. Apuzzo
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
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Spiga J, Siegbahn EA, Bräuer-Krisch E, Randaccio P, Bravin A. The GEANT4
toolkit for microdosimetry calculations: Application to microbeam radiation therapy (MRT). Med Phys 2007; 34:4322-30. [DOI: 10.1118/1.2794170] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Laissue JA, Blattmann H, Wagner HP, Grotzer MA, Slatkin DN. Prospects for microbeam radiation therapy of brain tumours in children to reduce neurological sequelae. Dev Med Child Neurol 2007; 49:577-81. [PMID: 17635201 DOI: 10.1111/j.1469-8749.2007.00577.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Microbeam radiation therapy (MRT), a form of experimental radiosurgery of tumours using multiple parallel, planar, micrometres-wide, synchrotron-generated X-ray beams ('microbeams'), can safely deliver radiation doses to contiguous normal animal tissues that are much higher than the maximum doses tolerated by the same normal tissues of animals or patients from any standard millimetres-wide radiosurgical beam. An array of parallel microbeams, even in doses that cause little damage to radiosensitive developing tissues, for example, the chick chorioallantoic membrane, can inhibit growth or ablate some transplanted malignant tumours in rodents. The cerebella of 100 normal 20 to 38g suckling Sprague-Dawley rat pups and of 13 normal 5 to 12kg weanling Yorkshire piglets were irradiated with an array of parallel, synchrotron-wiggler-generated X-ray microbeams in doses overlapping the MRT-relevant range (about 50-600Gy) using the ID17 wiggler beamline tangential to the 6GeV electron synchrotron ring at the European Synchrotron Radiation Facility in Grenoble, France. Subsequent favourable development of most animals over at least 1 year suggests that MRT might be used to treat children's brain tumours with less risk to the development of the central nervous system than is presently the case when using wider beams.
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Affiliation(s)
- J A Laissue
- Institut für Pathologie der Universität Bern, Bern, Switzerland.
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Dilmanian FA, Qu Y, Feinendegen LE, Peña LA, Bacarian T, Henn FA, Kalef-Ezra J, Liu S, Zhong Z, McDonald JW. Tissue-sparing effect of x-ray microplanar beams particularly in the CNS: is a bystander effect involved? Exp Hematol 2007; 35:69-77. [PMID: 17379090 DOI: 10.1016/j.exphem.2007.01.014] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Normal tissues, including the central nervous system, tolerate single exposures to narrow planes of synchrotron-generated x-rays (microplanar beams; microbeams) up to several hundred Gy. The repairs apparently involve the microvasculature and the glial system. We evaluate a hypothesis on the involvement of bystander effects in these repairs. METHODS Confluent cultures of bovine aortic endothelial cells were irradiated with three parallel 27-microm microbeams at 24 Gy. Rats' spinal cords were transaxially irradiated with a single microplanar beam, 270 microm thick, at 750 Gy; the dose distribution in tissue was calculated. RESULTS Within 6 hours following irradiation of the cell culture the hit cells died, apparently by apoptosis, were lost, and the confluency was maintained. The spinal cord study revealed a loss of oligodendrocytes, astrocytes, and myelin in 2 weeks, but by 3 months repopulation and remyelination was nearly complete. Monte Carlo simulations showed that the microbeam dose fell from the peak's 80% to 20% in 9 microm. CONCLUSIONS In both studies the repair processes could have involved "beneficial" bystander effects leading to tissue restoration, most likely through the release of growth factors, such as cytokines, and the initiation of cell-signaling cascades. In cell culture these events could have promoted fast disappearance of the hit cells and fast structural response of the surviving neighboring cells, while in the spinal cord study similar events could have been promoting angiogenesis to replace damaged capillary blood vessels, and proliferation, migration, and differentiation of the progenitor glial cells to produce new, mature, and functional glial cells.
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Affiliation(s)
- F Avraham Dilmanian
- Medical Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
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Dilmanian FA, Zhong Z, Bacarian T, Benveniste H, Romanelli P, Wang R, Welwart J, Yuasa T, Rosen EM, Anschel DJ. Interlaced x-ray microplanar beams: a radiosurgery approach with clinical potential. Proc Natl Acad Sci U S A 2006; 103:9709-14. [PMID: 16760251 PMCID: PMC1480471 DOI: 10.1073/pnas.0603567103] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Studies have shown that x-rays delivered as arrays of parallel microplanar beams (microbeams), 25- to 90-microm thick and spaced 100-300 microm on-center, respectively, spare normal tissues including the central nervous system (CNS) and preferentially damage tumors. However, such thin microbeams can only be produced by synchrotron sources and have other practical limitations to clinical implementation. To approach this problem, we first studied CNS tolerance to much thicker beams. Three of four rats whose spinal cords were exposed transaxially to four 400-Gy, 0.68-mm microbeams, spaced 4 mm, and all four rats irradiated to their brains with large, 170-Gy arrays of such beams spaced 1.36 mm, all observed for 7 months, showed no paralysis or behavioral changes. We then used an interlacing geometry in which two such arrays at a 90-degree angle produced the equivalent of a contiguous beam in the target volume only. By using this approach, we produced 90-, 120-, and 150-Gy 3.4 x 3.4 x 3.4 mm(3) exposures in the rat brain. MRIs performed 6 months later revealed focal damage within the target volume at the 120- and 150-Gy doses but no apparent damage elsewhere at 120 Gy. Monte Carlo calculations indicated a 30-microm dose falloff (80-20%) at the edge of the target, which is much less than the 2- to 5-mm value for conventional radiotherapy and radiosurgery. These findings strongly suggest potential application of interlaced microbeams to treat tumors or to ablate nontumorous abnormalities with minimal damage to surrounding normal tissue.
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Affiliation(s)
- F Avraham Dilmanian
- Medical Department, National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973, USA.
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