236 research outputs found
Accelerating time to scientific discovery with a grid-enhanced microsoft project
The composition, execution, and monitoring of challenging scientific applications is often a complex affair. To cope with the issue of workflow management, several tools and frameworks have been designed and put into use. However, the entry barrier to using these tools productively is high, and may hinder the progress of many scientists, or nonexperts, that develop workflows infrequently. As part of our Cyberaide framework we enable workflow definition, execution and monitoring through the Microsoft Project software package. The motivation for this choice is that many scientists are already familiar with Microsoft Project, a project management software package that is perceived to be user friendly. Through our tool we have the ability to seamlessly access Grids, such as the NSF sponsored TeraGrid. Cyberaide abstractions have also the potential to allow integration with other resources, including Microsoft HPC clusters. We test our hypothesis of usability while evaluating the tool as part of several graduate level courses taught in the field of Grid and Cloud computing
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Radiation therapy with orthovoltage X-ray minibeams
A method for delivering therapeutic radiation to a target includes positioning a multi-aperture collimator on the skin within a trajectory of orthovoltage x-rays directed at the target, thus generating an array of minibeams, each of width between 0.1 mm to 0.6 mm. The skin is irradiated with the array. An effective beam of therapeutic radiation, which may be a solid beam, is delivered to the target at a predetermined tissue depth by merging adjacent orthovoltage x-ray minibeams sufficiently to form the effective beam. The effective beam may be formed proximal to the target. The depth at which the effective, preferably, solid, beam is formed is controlled by varying one or more of the spacing of the minibeams in the array, the minibeam width, the distance from the x-ray source to the collimator, and the x-ray source spot size. Planar minibeams can be arc-scanned while continuously modulating beam shape and intensity.Board of Regents, University of Texas Syste
Survival Analysis of F98 Glioma Rat Cells Following Minibeam or Broad-Beam Synchrotron Radiation Therapy
Background: In the quest of a curative radiotherapy treatment for gliomas new delivery modes are being explored. At the Biomedical Beamline of the European Synchrotron Radiation Facility (ESRF), a new spatially-fractionated technique, called Minibeam Radiation Therapy (MBRT) is under development. The aim of this work is to compare the effectiveness of MBRT and broad-beam (BB) synchrotron radiation to treat F98 glioma rat cells. A dose escalation study was performed in order to delimit the range of doses where a therapeutic effect could be expected. These results will help in the design and optimization of the forthcoming in vivo studies at the ESRF. Methods: Two hundred thousand F98 cells were seeded per well in 24-well plates, and incubated for 48 hours before being irradiated with spatially fractionated and seamless synchrotron x-rays at several doses. The percentage of each cell population (alive, early apoptotic and dead cells, where either late apoptotic as necrotic cells are included) was assessed by flow cytometry 48 hours after irradiation, whereas the metabolic activity of surviving cells was analyzed on days 3, 4, and 9 post-irradiation by using QBlue test. Results
DNA damage and repair kinetics after microbeam radiation therapy emulation in living cells using monoenergetic synchrotron X-ray microbeams
The molecular response of mammalian cells to a monoenergetic synchrotron X-ray microbeam which emulated microbeam radiation configurations has been investigated. Very few γH2AX foci were found outside the irradiated zone within 1 h of irradiation, even within a single nucleus. Furthermore, 12 h after radiation there was a large decrease in foci number but many cells still contained γH2AX foci, of which many were outside the directly irradiated regions
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The tomography beamline at the National Synchrotron Light Source
We compared the image contrast of a monochromatic CT, Multiple Energy Computed Tomography (MECT), and conventional CT scanner using phantoms. The experimental results indicate that monochromatic CT, with beam energy tuned just above the iodine K-edge, has about a 3 fold advantage in iodine contrast over conventional CT with a 120 kVp beam. Modeling using the same beams at a 3 rad dose and 3 mm slice height on an 18 cm diameter acrylic phantom, the simulations show a noise of 1.2 HU for MECT and 1.9 HU for CCT. Furthermore, despite the Cupping-effect corrections the bone contrast is lower in CCT and varies by 24 HU moving from the phantom`s center to the edge; this indicates an advantage for MECT in detecting and quantifying lesions differing from surrounding tissue by their mean atomic number
Merging Orthovoltage X-Ray Minibeams spare the proximal tissues while producing a solid beam at the target
© 2019, The Author(s). 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
Development of High-Speed Fluorescent X-Ray Micro-Computed Tomography
A high-speed fluorescent x-ray CT (FXCT) system using monochromatic synchrotron x rays was developed to detect very low concentration of medium-Z elements for biomedical use. The system is equipped two types of high purity germanium detectors, and fast electronics and software. Preliminary images of a 10mm diameter plastic phantom containing channels field with iodine solutions of different concentrations showed a minimum detection level of 0.002 mg I/ml at an in-plane spatial resolution of 100µm. Furthermore, the acquisition time was reduced about 1/2 comparing to previous system. The results indicate that FXCT is a highly sensitive imaging modality capable of detecting very low concentration of iodine, and that the method has potential in biomedical applications
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Measurement of rocking curve wings at high x-ray energies
Measurements done recently at the NSLS have indicated that the level of intensity found in the wings of diffraction peaks from silicon at higher x-ray energies (>20keV) far exceeds the value which would be predicted based on the dynamical theory. We have measured Si(220) double crystal rocking curves at the 40keV fundamental and harmonics with various crystal scattering geometries: Bragg-Bragg, Laue-Bragg, Laue-Lauel. The comparison of the Bragg and Laue case diffraction geometries was done to determine scattering volume effects. Comparisons with dynamical theory calculations will be discussed. These measurements have been carried out in order to assess the level of harmonic contamination which will be present from a double crystal monochromator being designed for the X17 Superconducting Wiggler Beamline
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