title: Medical physics aspects of the synchrotron radiation therapies: Microbeam radiation therapy (MRT) and synchrotron stereotactic radiotherapy (SSRT).
abstract: Stereotactic Synchrotron Radiotherapy (SSRT) and Microbeam Radiation Therapy (MRT) are both novel approaches to treat brain tumor and potentially other tumors using synchrotron radiation. Although the techniques differ by their principles, SSRT and MRT share certain common aspects with the possibility of combining their advantages in the future. For MRT, the technique uses highly collimated, quasi-parallel arrays of X-ray microbeams between 50 and 600 keV. Important features of highly brilliant Synchrotron sources are a very small beam divergence and an extremely high dose rate. The minimal beam divergence allows the insertion of so called Multi Slit Collimators (MSC) to produce spatially fractionated beams of typically ∼25-75 micron-wide microplanar beams separated by wider (100-400 microns center-to-center(ctc)) spaces with a very sharp penumbra. Peak entrance doses of several hundreds of Gy are extremely well tolerated by normal tissues and at the same time provide a higher therapeutic index for various tumor models in rodents. The hypothesis of a selective radio-vulnerability of the tumor vasculature versus normal blood vessels by MRT was recently more solidified. SSRT (Synchrotron Stereotactic Radiotherapy) is based on a local drug uptake of high-Z elements in tumors followed by stereotactic irradiation with 80 keV photons to enhance the dose deposition only within the tumor. With SSRT already in its clinical trial stage at the ESRF, most medical physics problems are already solved and the implemented solutions are briefly described, while the medical physics aspects in MRT will be discussed in more detail in this paper.
authors.affiliation: ESRF-The European Synchrotron, 71, Avenue des Martyrs, Grenoble, France. Electronic address: brauer@esrf.fr.
authors.forename: Elke
authors.initials: E
authors.lastname: Bräuer-Krisch
authors.affiliation: INSERM, Grenoble, France.
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Adam
authors.affiliation: University of Bergen Department of Physics and Technology, PB 7803 5020, Norway.
authors.forename: Enver
authors.initials: E
authors.lastname: Alagoz
authors.affiliation: The Institute of Cancer Research, 15 Cotswold Rd, Sutton SM2 5NG, United Kingdom.
authors.forename: Stefan
authors.initials: S
authors.lastname: Bartzsch
authors.affiliation: RMIT University, Melbourne, VIC, 3001, Australia.
authors.forename: Jeff
authors.initials: J
authors.lastname: Crosbie
authors.affiliation: Ghent University Hospital, 9000 Gent, Belgium.
authors.forename: Carlos
authors.initials: C
authors.lastname: DeWagter
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Northfields Ave, NSW, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Dipuglia
authors.affiliation: ESRF-The European Synchrotron, 71, Avenue des Martyrs, Grenoble, France.
authors.forename: Mattia
authors.initials: M
authors.lastname: Donzelli
authors.affiliation: CRUK Cancer Imaging Centre, Institute of Cancer Research, 15 Cotswold Rd, Sutton Surrey, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Doran
authors.affiliation: ESRF-The European Synchrotron, 71, Avenue des Martyrs, Grenoble, France; Centre for Medical Radiation Physics, University of Wollongong, Northfields Ave, NSW, Australia.
authors.forename: Pauline
authors.initials: P
authors.lastname: Fournier
authors.affiliation: Medical Physics Laboratory, University of Ioannina, 451.10, Ioannina, Greece.
authors.forename: John
authors.initials: J
authors.lastname: Kalef-Ezra
authors.affiliation: Sintef Minalab, Gaustadalléen 23C, 0373, Oslo, Norway.
authors.forename: Angela
authors.initials: A
authors.lastname: Kock
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Northfields Ave, NSW, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Lerch
authors.affiliation: CRUK Cancer Imaging Centre, Institute of Cancer Research, 15 Cotswold Rd, Sutton Surrey, UK.
authors.forename: Ciara
authors.initials: C
authors.lastname: McErlean
authors.affiliation: The Institute of Cancer Research, 15 Cotswold Rd, Sutton SM2 5NG, United Kingdom.
authors.forename: Uwe
authors.initials: U
authors.lastname: Oelfke
authors.affiliation: Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342, Krawkow, Poland.
authors.forename: Pawel
authors.initials: P
authors.lastname: Olko
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Northfields Ave, NSW, Australia.
authors.forename: Marco
authors.initials: M
authors.lastname: Petasecca
authors.affiliation: University of Oslo, Department of Physics, 0316, Oslo, Norway.
authors.forename: Marco
authors.initials: M
authors.lastname: Povoli
authors.affiliation: Centre for Medical Radiation Physics, University of Wollongong, Northfields Ave, NSW, Australia.
authors.forename: Anatoly
authors.initials: A
authors.lastname: Rosenfeld
authors.affiliation: Department of Oncolgy-Pathology, Karolinska Institutet, S-177176, Stockholm, Sweden.
authors.forename: Erik A
authors.initials: EA
authors.lastname: Siegbahn
authors.affiliation: National Institute for Laser, Plasma and Radiation Physics, Magurele, RO-077125, Romania.
authors.forename: Dan
authors.initials: D
authors.lastname: Sporea
authors.affiliation: University of Bergen, Department of Physics and Technology, PB 7803, 5020, Bergen, Norway.
authors.forename: Bjarne
authors.initials: B
authors.lastname: Stugu
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D004867:Equipment Design; D019317:Evidence-Based Medicine; D006801:Humans; D009369:Neoplasms / Q000601:surgery*; D011874:Radiometry / Q000295:instrumentation / Q000379:methods; D016634:Radiosurgery / Q000295:instrumentation* / Q000379:methods; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D011882:Radiotherapy, High-Energy / Q000295:instrumentation* / Q000379:methods; D013552:Swine; D017356:Synchrotrons / Q000295:instrumentation*; D013673:Technology Assessment, Biomedical; D016896:Treatment Outcome
keywords: Dosimetry; MRT; Microbeam radiation therapy; Monte Carlo calculations; Radiation oncology; SSRT; Synchrotron X-rays