High-Precision Radiosurgical Dose Delivery by Interlaced Microbeam Arrays of High-Flux Low-Energy Synchrotron X-Rays

Microbeam Radiation Therapy (MRT) is a preclinical form of radiosurgery dedicated to brain tumor treatment. It uses micrometer-wide synchrotron-generated X-ray beams on the basis of spatial beam fractionation. Due to the radioresistance of normal brain vasculature to MRT, a continuous blood supply can be maintained which would in part explain the surprising tolerance of normal tissues to very high radiation doses (hundreds of Gy). Based on this well described normal tissue sparing effect of microplanar beams, we developed a new irradiation geometry which allows the delivery of a high uniform dose deposition at a given brain target whereas surrounding normal tissues are irradiated by well tolerated parallel microbeams only. Normal rat brains were exposed to 4 focally interlaced arrays of 10 microplanar beams (52 µm wide, spaced 200 µm on-center, 50 to 350 keV in energy range), targeted from 4 different ports, with a peak entrance dose of 200Gy each, to deliver an homogenous dose to a target volume of 7 mm3 in the caudate nucleus. Magnetic resonance imaging follow-up of rats showed a highly localized increase in blood vessel permeability, starting 1 week after irradiation. Contrast agent diffusion was confined to the target volume and was still observed 1 month after irradiation, along with histopathological changes, including damaged blood vessels. No changes in vessel permeability were detected in the normal brain tissue surrounding the target. The interlacing radiation-induced reduction of spontaneous seizures of epileptic rats illustrated the potential pre-clinical applications of this new irradiation geometry. Finally, Monte Carlo simulations performed on a human-sized head phantom suggested that synchrotron photons can be used for human radiosurgical applications. Our data show that interlaced microbeam irradiation allows a high homogeneous dose deposition in a brain target and leads to a confined tissue necrosis while sparing surrounding tissues. The use of synchrotron-generated X-rays enables delivery of high doses for destruction of small focal regions in human brains, with sharper dose fall-offs than those described in any other conventional radiation therapy

An Interactive Workflow to Manage Tomography Experiments at ESRF

International audienceAt the ESRF the activity of several beamlines is based upon tomography X-ray imaging in various fields such as Paleontology, Medical Imaging and Materials Science. The instrument control and data processing systems are cloned on all the relevant beamlines, however the steps of the processing pipeline from the data acquisition to their full exploitation in premier quality publications are based upon a heterogeneous software scenario comprised of e.g. SPEC, Python, Octave, PyHST2 and MATLAB modules. The need has thus clearly appeared to logically sequence the operations performed by these different actors into user-friendly workflows. At the ESRF we selected a generic workflow tool, Orange, which was originally developed at the University of Ljubljana and designed for data mining in collaboration with the open source community. The graphical interface enables the easy inclusion/exclusion of functionalities represented by individual boxes. Each box can be managed by simple pieces of Python code generating graphical interfaces via the PyQT5 library and is defined by a set of inputs and outputs which can be linked together to produce consistent data processing workflows

Les enjeux de la transdisciplinarité autour de l’accompagnement d’un projet de revitalisation de Bourg-Centre

National audiencePartant du constat d’une diffusion du paradigme originel de la géographie sociale, ces journées jeunes chercheurs visent à questionner les approches interdisciplinaires de l’espace. Si ce questionnement nous interroge tout particulièrement au sein de l’UMR Espaces et sociétés (ESO), fondée autour de ce paradigme, il interroge aussi tou·te·s les jeunes chercheur·e·s qui se reconnaissent dans les approches spécifiques de la compréhension des rapports entre espaces et sociétés, et ce quelle que soit leur thématique de recherche (environnement, genre, santé, politiques publiques, mobilités, logement, etc.) et leur discipline (géographie, sociologie, psychologie, etc.)

Les enjeux de la transdisciplinarité autour de l’accompagnement d’un projet de revitalisation de Bourg-Centre

National audiencePartant du constat d’une diffusion du paradigme originel de la géographie sociale, ces journées jeunes chercheurs visent à questionner les approches interdisciplinaires de l’espace. Si ce questionnement nous interroge tout particulièrement au sein de l’UMR Espaces et sociétés (ESO), fondée autour de ce paradigme, il interroge aussi tou·te·s les jeunes chercheur·e·s qui se reconnaissent dans les approches spécifiques de la compréhension des rapports entre espaces et sociétés, et ce quelle que soit leur thématique de recherche (environnement, genre, santé, politiques publiques, mobilités, logement, etc.) et leur discipline (géographie, sociologie, psychologie, etc.)

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