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  • 1
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    X-ray grating interferometry at photon energies over 180 keV (2015)
    American Institute of Physics (AIP)
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    Publication Date: 2015-04-16
    Description: We report on the implementation and characterization of grating interferometry operating at an x-ray energy of 183 keV. With the possibility to use this technique at high x-ray energies, bigger specimens could be studied in a quantitative way. Also, imaging strongly absorbing specimens will benefit from the advantages of the phase and dark-field signals provided by grating interferometry. However, especially at these high photon energies the performance of the absorption grating becomes a key point on the quality of the system, because the grating lines need to keep their small width of a couple of micrometers and exhibit a greater height of hundreds of micrometers. The performance of high aspect ratio absorption gratings fabricated with different techniques is discussed. Further, a dark-field image of an alkaline multicell battery highlights the potential of high energy x-ray grating based imaging.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Published by American Institute of Physics (AIP)
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  • 2
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    Efficient Deep Network Architectures for Fast Chest X-Ray Tuberculosis Screening and Visualization (2019)
    Springer Nature
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    Publication Date: 2019
    Electronic ISSN: 2045-2322
    Topics: Natural Sciences in General
    Published by Springer Nature
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  • 3
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    Experimental comparison of grating- and propagation-based hard X-ray phase tomography of soft tissue (2014)
    American Institute of Physics (AIP)
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    Publication Date: 2014-10-22
    Description: When imaging soft tissues with hard X-rays, phase contrast is often preferred over conventional attenuation contrast due its superior sensitivity. However, it is unclear which of the numerous phase tomography methods yields the optimized results at given experimental conditions. Therefore, we quantitatively compared the three phase tomography methods implemented at the beamline ID19 of the European Synchrotron Radiation Facility: X-ray grating interferometry (XGI), and propagation-based phase tomography, i.e., single-distance phase retrieval (SDPR) and holotomography (HT), using cancerous tissue from a mouse model and an entire heart of a rat. We show that for both specimens, the spatial resolution derived from the characteristic morphological features is about a factor of two better for HT and SDPR compared to XGI, whereas the XGI data generally exhibit much better contrast-to-noise ratios for the anatomical features. Moreover, XGI excels in fidelity of the density measurements, and is also more robust against low-frequency artifacts than HT, but it might suffer from phase-wrapping artifacts. Thus, we can regard the three phase tomography methods discussed as complementary. The application will decide which spatial and density resolutions are desired, for the imaging task and dose requirements, and, in addition, the applicant must choose between the complexity of the experimental setup and the one of data processing.
    Print ISSN: 0021-8979
    Electronic ISSN: 1089-7550
    Topics: Physics
    Published by American Institute of Physics (AIP)
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  • 4
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    Ptychographic X-ray nanotomography quantifies mineral distributions in human dentine (2015)
    Springer Nature
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    Publication Date: 2015-03-21
    Description: Bones are bio-composites with biologically tunable mechanical properties, where a polymer matrix of nanofibrillar collagen is reinforced by apatite mineral crystals. Some bones, such as antler, form and change rapidly, while other bone tissues, such as human tooth dentine, develop slowly and maintain constant composition and architecture for entire lifetimes. When studying apatite mineral microarchitecture, mineral distributions or mineralization activity of bone-forming cells, representative samples of tissue are best studied at submicrometre resolution while minimizing sample-preparation damage. Here, we demonstrate the power of ptychographic X-ray tomography to map variations in the mineral content distribution in three dimensions and at the nanometre scale. Using this non-destructive method, we observe nanostructures surrounding hollow tracts that exist in human dentine forming dentinal tubules. We reveal unprecedented quantitative details of the ultrastructure clearly revealing the spatially varying mineralization density. Such information is essential for understanding a variety of natural and therapeutic effects for example in bone tissue healing and ageing. Scientific Reports 5 doi: 10.1038/srep09210
    Electronic ISSN: 2045-2322
    Topics: Natural Sciences in General
    Published by Springer Nature
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  • 5
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    Dark-field X-ray imaging of unsaturated water transport in porous materials (2014)
    American Institute of Physics (AIP)
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    Publication Date: 2014-10-18
    Description: We introduce in this Letter an approach to X-ray imaging of unsaturated water transport in porous materials based upon the intrinsic X-ray scattering produced by the material microstructural heterogeneity at a length scale below the imaging system spatial resolution. The basic principle for image contrast creation consists in a reduction of such scattering by permeation of the porosity by water. The implementation of the approach is based upon X-ray dark-field imaging via Talbot-Lau interferometry. The proof-of-concept is provided by performing laboratory-scale dark-field X-ray radiography of mortar samples during a water capillary uptake experiment. The results suggest that the proposed approach to visualizing unsaturated water transport in porous materials is complementary to neutron and magnetic resonance imaging and alternative to standard X-ray imaging, the latter requiring the use of contrast agents because based upon X-ray attenuation only.
    Print ISSN: 0003-6951
    Electronic ISSN: 1077-3118
    Topics: Physics
    Published by American Institute of Physics (AIP)
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  • 6
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    Quantitative electron density characterization of soft tissue substitute plastic materials using grating-based x-ray phase-contrast imaging (2014)
    American Institute of Physics (AIP)
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    Publication Date: 2014-10-17
    Description: Many scientific research areas rely on accurate electron density characterization of various materials. For instance in X-ray optics and radiation therapy, there is a need for a fast and reliable technique to quantitatively characterize samples for electron density. We present how a precise measurement of electron density can be performed using an X-ray phase-contrast grating interferometer in a radiographic mode of a homogenous sample in a controlled geometry. A batch of various plastic materials was characterized quantitatively and compared with calculated results. We found that the measured electron densities closely match theoretical values. The technique yields comparable results between a monochromatic and a polychromatic X-ray source. Measured electron densities can be further used to design dedicated X-ray phase contrast phantoms and the additional information on small angle scattering should be taken into account in order to exclude unsuitable materials.
    Print ISSN: 0034-6748
    Electronic ISSN: 1089-7623
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Published by American Institute of Physics (AIP)
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  • 7
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    D-Glucosamine supplementation extends life span of nematodes and of ageing mice (2014)
    Springer Nature
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    Publication Date: 2014-04-10
    Description: Article D -Glucosamine is a dietary supplement widely used for the treatment of osteoarthritis. Here Weimer et al. show that D -glucosamine extends the life span of Caenorhabditis elegan s and of mice by mimicking the molecular effects of a diet low in carbohydrates. Nature Communications doi: 10.1038/ncomms4563 Authors: Sandra Weimer, Josephine Priebs, Doreen Kuhlow, Marco Groth, Steffen Priebe, Johannes Mansfeld, Troy L. Merry, Sébastien Dubuis, Beate Laube, Andreas F. Pfeiffer, Tim J. Schulz, Reinhard Guthke, Matthias Platzer, Nicola Zamboni, Kim Zarse, Michael Ristow
    Electronic ISSN: 2041-1723
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General , Physics
    Published by Springer Nature
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  • 8
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    Two-dimensional x-ray waveguides and point sources (2002)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2002-07-13
    Description: We show that resonant coupling of synchrotron beams into suitable nanostructures can be used for the generation of coherent x-ray point sources. A two-dimensionally confining x-ray waveguide structure has been fabricated by e-beam lithography. By shining a parallel undulator beam onto the structure, a discrete set of resonant modes can be excited in the dielectric cavity, depending on the two orthogonal coupling angles between the beam and the waveguide interfaces. The resonant excitation of the modes is evidenced from the characteristic set of coupling angles as well as the observed far-field pattern. The x-ray nanostructure may be used as coherent x-ray point sources with a beam cross section in the nanometer range.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Pfeiffer, F -- David, C -- Burghammer, M -- Riekel, C -- Salditt, T -- New York, N.Y. -- Science. 2002 Jul 12;297(5579):230-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Universitat des Saarlandes, Im Stadtwald 38, Postfach 15 11 50, 66041 Saarbrucken, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/12114620" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 9
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    Six-dimensional real and reciprocal space small-angle X-ray scattering tomography (2015)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2015-11-20
    Description: When used in combination with raster scanning, small-angle X-ray scattering (SAXS) has proven to be a valuable imaging technique of the nanoscale, for example of bone, teeth and brain matter. Although two-dimensional projection imaging has been used to characterize various materials successfully, its three-dimensional extension, SAXS computed tomography, poses substantial challenges, which have yet to be overcome. Previous work using SAXS computed tomography was unable to preserve oriented SAXS signals during reconstruction. Here we present a solution to this problem and obtain a complete SAXS computed tomography, which preserves oriented scattering information. By introducing virtual tomography axes, we take advantage of the two-dimensional SAXS information recorded on an area detector and use it to reconstruct the full three-dimensional scattering distribution in reciprocal space for each voxel of the three-dimensional object in real space. The presented method could be of interest for a combined six-dimensional real and reciprocal space characterization of mesoscopic materials with hierarchically structured features with length scales ranging from a few nanometres to a few millimetres--for example, biomaterials such as bone or teeth, or functional materials such as fuel-cell or battery components.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Schaff, Florian -- Bech, Martin -- Zaslansky, Paul -- Jud, Christoph -- Liebi, Marianne -- Guizar-Sicairos, Manuel -- Pfeiffer, Franz -- England -- Nature. 2015 Nov 19;527(7578):353-6. doi: 10.1038/nature16060.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Lehrstuhl fur Biomedizinische Physik, Physik-Department &Institut fur Medizintechnik, Technische Universitat Munchen, 85748 Garching, Germany. ; Department of Medical Radiation Physics, Clinical Sciences, Lund, Lund University, 22185 Lund, Sweden. ; Julius Wolff Institute, Charite - Universitatsmedizin Berlin, 13353 Berlin, Germany. ; Paul Scherrer Institut, 5232 Villigen PSI, Switzerland. ; Institut fur diagnostische und interventionelle Radiologie, Klinikum rechts der Isar, Technische Universitat Munchen, 81675 Munchen, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26581292" target="_blank"〉PubMed〈/a〉
    Keywords: Collagen/ultrastructure ; Humans ; Imaging, Three-Dimensional/methods ; Nanostructures/ultrastructure ; *Scattering, Small Angle ; Tomography/*methods ; Tooth/ultrastructure ; *X-Ray Diffraction
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 10
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    Ptychographic X-ray computed tomography at the nanoscale (2010)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2010-09-25
    Description: X-ray tomography is an invaluable tool in biomedical imaging. It can deliver the three-dimensional internal structure of entire organisms as well as that of single cells, and even gives access to quantitative information, crucially important both for medical applications and for basic research. Most frequently such information is based on X-ray attenuation. Phase contrast is sometimes used for improved visibility but remains significantly harder to quantify. Here we describe an X-ray computed tomography technique that generates quantitative high-contrast three-dimensional electron density maps from phase contrast information without reverting to assumptions of a weak phase object or negligible absorption. This method uses a ptychographic coherent imaging approach to record tomographic data sets, exploiting both the high penetration power of hard X-rays and the high sensitivity of lensless imaging. As an example, we present images of a bone sample in which structures on the 100 nm length scale such as the osteocyte lacunae and the interconnective canalicular network are clearly resolved. The recovered electron density map provides a contrast high enough to estimate nanoscale bone density variations of less than one per cent. We expect this high-resolution tomography technique to provide invaluable information for both the life and materials sciences.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dierolf, Martin -- Menzel, Andreas -- Thibault, Pierre -- Schneider, Philipp -- Kewish, Cameron M -- Wepf, Roger -- Bunk, Oliver -- Pfeiffer, Franz -- England -- Nature. 2010 Sep 23;467(7314):436-9. doi: 10.1038/nature09419.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics (E17), Technische Universitat Munchen, 85748 Garching, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20864997" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Bone Density ; Bone and Bones/*cytology/*radiography ; Femur/cytology/radiography ; Imaging, Three-Dimensional/methods ; Mice ; Mice, Inbred C57BL ; Microscopy/*methods ; Nanotechnology/*methods ; Tomography, X-Ray Computed/*methods
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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