297 results on '"Hans Deyhle"'
Search Results
2. Flexible positioning of a large area detector using an industrial robot
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Christina Reinhard, Michael Drakopoulos, Christopher M. Charlesworth, Andrew James, Hiten Patel, Paul Tutthill, Davide Crivelli, Hans Deyhle, and Sharif I. Ahmed
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synchrotron power diffraction ,robot ,stability ,repeatability ,sr-xrd ,automation ,detector positioning ,Nuclear and particle physics. Atomic energy. Radioactivity ,QC770-798 ,Crystallography ,QD901-999 - Abstract
The DIAD beamline for Dual Imaging and Diffraction at Diamond Light Source has opted to use an industrial robot to position its Dectris Pilatus 2M CdTe diffraction detector. This setup was chosen to enable flexible positioning of the detector in a quarter-sphere around the sample position whilst reliably holding the large weight of 139 kg of detector, detector mount and cabling in a stable position. Metrology measurements showed that the detector can be positioned with a linear repeatability of
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- 2022
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3. Imaging the orientation of myelin sheaths in a non-stained histology slide of human brain
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Georg Schulz, Hans Deyhle, Christos Bikis, Oliver Bunk, and Bert Müller
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Medicine ,Medical technology ,R855-855.5 - Abstract
The human brain is one of the most fascinating and important structures in nature. So far, his-tology has been the gold standard for imaging anatomical features on the sub-cellular level. Us-ing standard optical microscopy spatial resolution is restricted to a fraction of a micron. Recip-rocal-space techniques, including small-angle X-ray scattering (SAXS), with an inverse relation-ship between a nanostructure's size and scattering angle, have been used to study animal and human tissues. The myelin sheaths responsible for insulating axons, for example, exhibit a pe-riodicity between 15 and 18 nm. To localize their abundance and orientation, we have performed SAXS measurements with a micrometer-sized beam along a slice of the human brain and related them to the histology of myelin-stained tissue. The experimental results elucidate that, compared to histology, micrometer resolved SAXS provides information about the orientation of myelin, and consequently, axons, in addition to myelin abundance. The acquired data show color-coded orientation maps of the nanostructures, thereby providing a detailed insight into a relevant part of the human brain's nano-anatomy.
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- 2020
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4. Spatially resolved small-angle X-ray scattering for characterizing mechanoresponsive liposomes using microfluidics
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Marzia Buscema, Hans Deyhle, Thomas Pfohl, Andreas Zumbuehl, and Bert Müller
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Medicine (General) ,R5-920 ,Biology (General) ,QH301-705.5 - Abstract
Atherosclerosis gives rise to blood vessel occlusion associated with blood flow alteration and substantial increase of average wall shear stress. This modification was proved acting as a purely physical trigger for targeted vasodilator release from a particular type of liposomes composed of 1,3-diaminophospholipids (Pad-PC-Pad). The flow-induced structural changes of these faceted liposomes, however, are completely unknown. Therefore, spatially resolved small-angle X-ray scattering was combined with microfluidics to uniquely study the purely physical mechanisms, which give rise to the highly efficient drug release from mechanoresponsive liposomes of nanometer size. The microfluidic device, designed to mimic a stenotic blood vessel, consisted of a 1-mm-wide channel with a constriction, 125 μm in diameter. Here, the changes of the average bilayer thickness and the mean size of the mechanoresponsive liposomes have been locally detected under flow conditions. Overall shape and bilayer thickness do change already near the constriction inlet, but the alteration is dominant near the outlet. At a flow rate of 0.2 μL/s, the liposome's bilayer thickness increased by 30% compared to the situation well before the constriction and under static condition. The detected bilayer thickness increase of the faceted liposomes is in line with the mechanically induced loss of interdigitation between the phospholipid amide chains. These results imply that rather the gradient force than the wall shear stress provokes structural changes of Pad-PC-Pad liposomes and the related drug release at stenoses. The approach, i.e. the combination of microfluidics and spatially resolved small-angle X-ray scattering, paves the way to design highly efficient and specific systems for the targeted drug delivery at constrictions with predefined morphology.
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- 2019
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5. Mineralization of Early Stage Carious Lesions In Vitro—A Quantitative Approach
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Hans Deyhle, Iwona Dziadowiec, Lucy Kind, Peter Thalmann, Georg Schulz, and Bert Müller
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enamel caries ,mineralization ,demineralization ,self-assembling peptide ,image registration ,micro computed tomography ,joint histogram ,Dentistry ,RK1-715 - Abstract
Micro computed tomography has been combined with dedicated data analysis for the in vitro quantification of sub-surface enamel lesion mineralization. Two artificial white spot lesions, generated on a human molar crown in vitro, were examined. One lesion was treated with a self-assembling peptide intended to trigger nucleation of hydroxyapatite crystals. We non-destructively determined the local X-ray attenuation within the specimens before and after treatment. The three-dimensional data was rigidly registered. Three interpolation methods, i.e., nearest neighbor, tri-linear, and tri-cubic interpolation were evaluated. The mineralization of the affected regions was quantified via joint histogram analysis, i.e., a voxel-by-voxel comparison of the tomography data before and after mineralization. After ten days incubation, the mean mineralization coefficient reached 35.5% for the peptide-treated specimen compared to 11.5% for the control. This pilot study does not give any evidence for the efficacy of peptide treatment nor allows estimating the necessary number of specimens to achieve significance, but shows a sound methodological approach on the basis of the joint histogram analysis.
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- 2015
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6. Hard X‐Ray Nanoholotomography: Large‐Scale, Label‐Free, 3D Neuroimaging beyond Optical Limit
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Anna Khimchenko, Christos Bikis, Alexandra Pacureanu, Simone E. Hieber, Peter Thalmann, Hans Deyhle, Gabriel Schweighauser, Jürgen Hench, Stephan Frank, Magdalena Müller‐Gerbl, Georg Schulz, Peter Cloetens, and Bert Müller
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cerebellum ,hierarchical imaging ,human brain ,neocortexes ,neuroimaging ,segmentation ,Science - Abstract
Abstract There have been great efforts on the nanoscale 3D probing of brain tissues to image subcellular morphologies. However, limitations in terms of tissue coverage, anisotropic resolution, stain dependence, and complex sample preparation all hinder achieving a better understanding of the human brain functioning in the subcellular context. Herein, X‐ray nanoholotomography is introduced as an emerging synchrotron radiation‐based technology for large‐scale, label‐free, direct imaging with isotropic voxel sizes down to 25 nm, exhibiting a spatial resolution down to 88 nm. The procedure is nondestructive as it does not require physical slicing. Hence, it allows subsequent imaging by complementary techniques, including histology. The feasibility of this 3D imaging approach is demonstrated on human cerebellum and neocortex specimens derived from paraffin‐embedded tissue blocks. The obtained results are compared to hematoxylin and eosin stained histological sections and showcase the ability for rapid hierarchical neuroimaging and automatic rebuilding of the neuronal architecture at the level of a single cell nucleolus. The findings indicate that nanoholotomography can complement microscopy not only by large isotropic volumetric data but also by morphological details on the sub‐100 nm level, addressing many of the present challenges in brain tissue characterization and probably becoming an important tool in nanoanatomy.
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- 2018
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7. Automated Analysis of Spatially Resolved X-ray Scattering and Micro Computed Tomography of Artificial and Natural Enamel Carious Lesions
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Hans Deyhle, Shane N. White, Lea Botta, Marianne Liebi, Manuel Guizar-Sicairos, Oliver Bunk, and Bert Müller
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enamel caries ,small-angle X-ray scattering ,image registration ,bivariate histogram plot ,segmentation ,multi-modal imaging ,Photography ,TR1-1050 ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
Radiography has long been the standard approach to characterize carious lesions. Spatially resolved X-ray diffraction, specifically small-angle X-ray scattering (SAXS), has recently been applied to caries research. The aims of this combined SAXS and micro computed tomography (µCT) study were to locally characterize and compare the micro- and nanostructures of one natural carious lesion and of one artificially induced enamel lesion; and demonstrate the feasibility of an automated approach to combined SAXS and µCT data in segmenting affected and unaffected enamel. Enamel, demineralized by natural or artificial caries, exhibits a significantly reduced X-ray attenuation compared to sound enamel and gives rise to a drastically increased small-angle scattering signal associated with the presence of nanometer-size pores. In addition, X-ray scattering allows the assessment of the overall orientation and the degree of anisotropy of the nanostructures present. Subsequent to the characterization with µCT, specimens were analyzed using synchrotron radiation-based SAXS in transmission raster mode. The bivariate histogram plot of the projected data combined the local scattering signal intensity with the related X-ray attenuation from µCT measurements. These histograms permitted the segmentation of anatomical features, including the lesions, with micrometer precision. The natural and artificial lesions showed comparable features, but they also exhibited size and shape differences. The clear identification of the affected regions and the characterization of their nanostructure allow the artificially induced lesions to be verified against selected natural carious lesions, offering the potential to optimize artificial demineralization protocols. Analysis of joint SAXS and µCT histograms objectively segmented sound and affected enamel.
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- 2018
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8. Comparative Analysis of Bone Structural Parameters Reveals Subchondral Cortical Plate Resorption and Increased Trabecular Bone Remodeling in Human Facet Joint Osteoarthritis
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Cordula Netzer, Pascal Distel, Uwe Wolfram, Hans Deyhle, Gregory F. Jost, Stefan Schären, and Jeroen Geurts
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osteoarthritis ,lumbar spine ,facet joint ,subchondral bone ,computed tomography ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Facet joint osteoarthritis is a prominent feature of degenerative spine disorders, highly prevalent in ageing populations, and considered a major cause for chronic lower back pain. Since there is no targeted pharmacological therapy, clinical management of disease includes analgesic or surgical treatment. The specific cellular, molecular, and structural changes underpinning facet joint osteoarthritis remain largely elusive. The aim of this study was to determine osteoarthritis-related structural alterations in cortical and trabecular subchondral bone compartments. To this end, we conducted comparative micro computed tomography analysis in healthy (n = 15) and osteoarthritic (n = 22) lumbar facet joints. In osteoarthritic joints, subchondral cortical plate thickness and porosity were significantly reduced. The trabecular compartment displayed a 42 percent increase in bone volume fraction due to an increase in trabecular number, but not trabecular thickness. Bone structural alterations were associated with radiological osteoarthritis severity, mildly age-dependent but not gender-dependent. There was a lack of association between structural parameters of cortical and trabecular compartments in healthy and osteoarthritic specimens. The specific structural alterations suggest elevated subchondral bone resorption and turnover as a potential treatment target in facet joint osteoarthritis.
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- 2018
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9. Arbitrarily large tomography with iterative algorithms on multiple GPUs using the TIGRE toolbox.
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Ander Biguri, Reuben Lindroos, Robert Bryll, Hossein Towsyfyan, Hans Deyhle, Ibrahim El Khalil Harrane, Richard P. Boardman, Mark Mavrogordato, Manjit Dosanjh, Steven Hancock, and Thomas Blumensath
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- 2020
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10. Arbitrarily large iterative tomographic reconstruction on multiple GPUs using the TIGRE toolbox.
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Ander Biguri, Reuben Lindroos, Robert Bryll, Hossein Towsyfyan, Hans Deyhle, Richard P. Boardman, Mark Mavrogordato, Manjit Dosanjh, Steven Hancock, and Thomas Blumensath
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- 2019
11. Extending two-dimensional histology into the third dimension through conventional micro computed tomography.
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Anna Khimchenko, Hans Deyhle, Georg Schulz, Gabriel Schweighauser, Jürgen Hench, Natalia Chicherova, Christos Bikis, Simone E. Hieber, and Bert Müller
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- 2016
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12. Three-dimensional imaging of human teeth: an in vitro study of caries detection using micro computed tomography
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Andres Izquierdo, Christine Tanner, Georg Schulz, Jeannette von Jackowski, Griffin Rodgers, Hans Deyhle, and Bert Müller
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- 2022
13. Practical implementations of speckle-based phase-retrieval methods in Python and GPU for tomography
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Nghia T. Vo, Hongchang Wang, Lingfei Hu, Tunhe Zhou, Marie-Christine A. Zdora, Hans Deyhle, Robert C. Atwood, and Michael Drakopoulos
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- 2022
14. DIAD: A new instrument for Dual Imaging and Diffraction at Diamond Light Source (Conference Presentation)
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Sharif Ahmed, Hans Deyhle, Andrew James, James . Le Houx, Peter Garland, Michael Drakopoulos, Christina Reinhard, and Navid Aslani
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- 2022
15. Effects of fast x-ray cone-beam tomographic measurement on dimensional metrology
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Charalambos Rossides, Hossein Towsyfyan, Ander Biguri, Hans Deyhle, Reuben Lindroos, Mark Mavrogordato, Richard Boardman, Wenjuan Sun, Thomas Blumensath, Rossides, C [0000-0002-7547-0256], Biguri, A [0000-0002-2636-3032], Deyhle, H [0000-0002-9095-2069], Mavrogordato, M [0000-0002-3956-2866], Boardman, R [0000-0002-4008-0098], Sun, W [0000-0001-5888-111X], Blumensath, T [0000-0002-7489-265X], and Apollo - University of Cambridge Repository
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General Engineering ,Bioengineering ,51 Physical Sciences ,5108 Quantum Physics - Abstract
X-ray computed tomography (XCT) is increasingly used for dimensional metrology, where it can offer accurate measurements of internal features that are not accessible with other techniques. However, XCT scanning can be relatively slow, which often prevents routine uptake for many applications. This paper explores the feasibility of improving the speed of XCT measurements while maintaining the quality of the dimensional measurements derived from reconstructed volumes. In particular, we compare two approaches to fast XCT acquisition, the use of fewer XCT projections as well as the use of shortened x-ray exposure times for each projection. The study shows that the additional Poisson noise produced by reducing the exposure for each projection has significantly less impact on dimensional measurements compared to the artefacts associated with strategies that take fewer projection images, leading to about half the measurement error variability. Advanced reconstruction algorithms such as the conjugate gradient least squares method or total variation constrained approaches, are shown to allow further improvements in measurement speed, though this can come at the cost of increased measurement bias (e.g. 2.8% increase in relative error in one example) and variance (e.g. 25% in the same example).
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- 2022
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16. Dental composites for wide color matching
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Mattia Humbel, Corinne Mattle, Mario Scheel, Ana Diaz, Iwan Jerjen, Robert Lominski, Robert Sterchi, Georg Schulz, Andres Izquierdo, Guido Sigron, Hans Deyhle, and Bert Müller
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- 2022
17. Arbitrarily large tomography with iterative algorithms on multiple GPUs using the TIGRE toolbox
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S. Hancock, Richard P. Boardman, Thomas Blumensath, Hossein Towsyfyan, Ibrahim El Khalil Harrane, Hans Deyhle, Robert Bryll, Manjit Dosanjh, Ander Biguri, Reuben Lindroos, and Mark Mavrogordato
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Tomographic reconstruction ,Computer Networks and Communications ,Iterative method ,Computer science ,Computation ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,020206 networking & telecommunications ,02 engineering and technology ,Iterative reconstruction ,Inverse problem ,Regularization (mathematics) ,Theoretical Computer Science ,Arbitrarily large ,Artificial Intelligence ,Hardware and Architecture ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Tomography ,Projection (set theory) ,Algorithm ,Software - Abstract
3D tomographic imaging requires the computation of solutions to very large inverse problems. In many applications, iterative algorithms provide superior results, however, memory limits in available computing hardware restrict the size of problems that can be solved. For this reason, iterative methods are not normally used to reconstruct typical data sets acquired with lab based CT systems. We thus use state of the art techniques such as dual buffering to develop an efficient strategy to compute the required operations for iterative reconstruction. This allows the iterative reconstruction of volumetric images of arbitrary size using any number of GPUs, each with arbitrarily small memory. Strategies for both the forward and backprojection operators are presented, along with two regularization approaches that are easily generalized to other projection types or regularizers. The proposed improvement also accelerates reconstruction of smaller images on single or multiple GPU systems, providing faster code for time-critical applications. The resulting algorithm has been added to the TIGRE toolbox, a repository for iterative reconstruction algorithms for general CT, but this memory-saving and problem-splitting strategy can be easily adapted for use with other GPU-based tomographic reconstruction code.
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- 2020
18. X-ray phase tomography with near-field speckles for three-dimensional virtual histology
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Pierre Thibault, Vincent Fernandez, Vartan Kurtcuoglu, Marie-Christine Zdora, Matthew J. Lawson, Peter M. Lackie, Alexander Rack, Christoph Rau, Willy Kuo, Hans Deyhle, Orestis L. Katsamenis, Margie P. Olbinado, Joan Vila-Comamala, Franz Pfeiffer, Irene Zanette, University of Zurich, Zdora, Marie-Christine, Thibault, Pierre, Kuo, Willy, Fernandez, Vincent, Deyhle, Han, Vila-Comamala, Joan, Olbinado, Margie P., Rack, Alexander, Lackie, Peter M., Katsamenis, Orestis L., Lawson, Matthew J., Kurtcuoglu, Vartan, Rau, Christoph, Pfeiffer, Franz, and Zanette, Irene
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PHASE CONTRAST ,Materials science ,Image quality ,Phase (waves) ,610 Medicine & health ,Phase tomography ,02 engineering and technology ,BIOMEDICAL IMAGING AND THERAPY BEAMLINES ,3107 Atomic and Molecular Physics, and Optics ,01 natural sciences ,X-ray absorption ,10052 Institute of Physiology ,Imaging ,010309 optics ,Speckle pattern ,3D imaging ,Atomic and Molecular Physics ,0103 physical sciences ,Biomedical specimens ,Medical imaging ,Electronic ,Speckle-based imaging ,Optical and Magnetic Materials ,Image resolution ,SOFT TISSUES ,PHASE CONTRAST MICROTOMOGRAPHY ,Resolution (electron density) ,2504 Electronic, Optical and Magnetic Materials ,021001 nanoscience & nanotechnology ,Biomedical specimen ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Visualization ,COHERENT IMAGING ,570 Life sciences ,biology ,Tomography ,and Optics ,0210 nano-technology ,Biomedical engineering - Abstract
High-contrast, high-resolution imaging of biomedical specimens is indispensable for studying organ function and pathologies. Conventional histology, the gold standard for soft-tissue visualization, is limited by its anisotropic spatial resolution, elaborate sample preparation, and lack of quantitative image information. X-ray absorption or phase tomography have been identified as promising alternatives enabling non-destructive, distortion-free three-dimensional (3D) imaging. However, reaching sufficient contrast and resolution with a simple experimental procedure remains a major challenge. Here, we present a solution based on x-ray phase tomography through speckle-based imaging (SBI). We demonstrate on a mouse kidney that SBI delivers comprehensive 3D maps of hydrated, unstained soft tissue, revealing its microstructure and delivering quantitative tissue-density values at a density resolution of better than 2 m g / c m 3 and spatial resolution of better than 8 µm. We expect that SBI virtual histology will find widespread application in biomedicine and will open up new possibilities for research and histopathology.
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- 2020
19. Accuracy of commercial intraoral scanners
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Mattia Sacher, Bert Müller, Georg Schulz, Kurt Jäger, and Hans Deyhle
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Scanner ,business.industry ,Triangulation (computer vision) ,3D modeling ,030218 nuclear medicine & medical imaging ,law.invention ,Metrology ,03 medical and health sciences ,0302 clinical medicine ,Data acquisition ,Software ,law ,030220 oncology & carcinogenesis ,Medicine ,Radiology, Nuclear Medicine and imaging ,Computer vision ,Artificial intelligence ,Tomography ,business ,Stereolithography - Abstract
Purpose: In dental offices, there is a trend replacing conventional silicone impressions and plaster cast models by imaging data of intraoral scanners to map the denture and surrounding tissues. The aim of the study is the analysis of the accuracy of selected commercially available scanners. The accuracy is considered as the main drawback in comparison to the conventional approach. Approach: We evaluated the reproduction performance of five optical scanners by a direct comparison with high-resolution hard x-ray computed tomography data, all obtained from a polyetheretherketone model with similarity to a full-arch upper jaw. Results: Using the software GOM Inspect (GOM GmbH, Braunschweig, Germany), we could classify the intraoral scanners into two groups. The more accurate instruments gave rise to the following precision values: 35 μm (TRIOS® 3, 3shape, Copenhagen, Denmark), 43 μm (CS 3600, Carestream, Atlanta, Georgia), and 46 μm (3M™ True Definition Scanner, 3M ESPE, St. Paul, Minnesota). The less precise systems yielded 93 μm (Medit i500, Medit corp., Seongbuk-gu, South Korea) and 97 μm (Emerald™, Planmeca Oy, Helsinki, Finland). Conclusions: The selected scanners are suitable for single crowns, small bridges, and separate quadrants prostheses. Scanners based on triangulation are hardly appropriate for full-arch prostheses. Besides precision, however, the choice of the scanner depends on scanning time, intraoral-camera size, and the user’s learning curve. The developed protocol, which includes three-dimensional (3D) imaging and advanced computational tools for the registration with the design data, will be increasingly used in geometrical metrology by nondestructive procedures to perform dimensional measurements with micrometer precision and is capable for detailed 3D geometrical models reconstruction.
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- 2021
20. X-ray phase imaging with the unified modulated pattern analysis of near-field speckles at a laboratory source
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Marie-Christine Zdora, Pierre Thibault, Hans Deyhle, Nicholas W. Phillips, Toby Walker, Ronan Smith, Irene Zanette, Sharif Ahmed, Zdora, M. -C., Zanette, I., Walker, T., Phillips, N. W., Smith, R., Deyhle, H., Ahmed, S., and Thibault, P.
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Physics ,business.industry ,Image quality ,Near and far field ,Translation (geometry) ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Synchrotron ,Phase Contrast ,law.invention ,010309 optics ,Radiography ,Speckle pattern ,Optics ,Transmission (telecommunications) ,law ,0103 physical sciences ,Medical imaging ,Grating ,Sensitivity (control systems) ,Electrical and Electronic Engineering ,business ,Engineering (miscellaneous) ,Gratings - Abstract
X-ray phase-contrast techniques are powerful methods for discerning features with similar densities, which are normally indistinguishable with conventional absorption contrast. While these techniques are well-established tools at large-scale synchrotron facilities, efforts have increasingly focused on implementations at laboratory sources for widespread use. X-ray speckle-based imaging is one of the phase-contrast techniques with high potential for translation to conventional x-ray systems. It yields phase-contrast, transmission, and dark-field images with high sensitivity using a relatively simple and cost-effective setup tolerant to divergent and polychromatic beams. Recently, we have introduced the unified modulated pattern analysis (UMPA) [Phys. Rev. Lett. 118, 203903 (2017)PRLTAO0031-900710.1103/PhysRevLett.118.203903], which further simplifies the translation of x-ray speckle-based imaging to low-brilliance sources. Here, we present the proof-of-principle implementation of UMPA speckle-based imaging at a microfocus liquid-metal-jet x-ray laboratory source.
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- 2020
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21. Osteoarthritis alters the patellar bones subchondral trabecular architecture
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Sebastian Hoechel, Magdalena Müller-Gerbl, Mireille Toranelli, and Hans Deyhle
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030203 arthritis & rheumatology ,0301 basic medicine ,business.industry ,Biomechanics ,Osteoarthritis ,Anatomy ,Trabecular architecture ,medicine.disease ,03 medical and health sciences ,Trabecular bone ,030104 developmental biology ,0302 clinical medicine ,Subchondral bone ,Medicine ,Orthopedics and Sports Medicine ,business ,Bone volume - Abstract
Following the principles of "morphology reveals biomechanics," the cartilage-osseous interface and the trabecular network show defined adaptation in response to physiological loading. In the case of a compromised relationship, the ability to support the load diminishes and the onset of osteoarthritis (OA) may arise. To describe and quantify the changes within the subchondral bone plate (SBP) and trabecular architecture, 10 human OA patellae were investigated by CT and micro-CT. The results are presented in comparison to a previously published dataset of 10 non-OA patellae which were evaluated in the same manner. The analyzed OA samples showed no distinctive mineralization pattern in regards to the physiological biomechanics, but a highly irregular disseminated distribution. In addition, no regularity in bone distribution and architecture across the trabecular network was found. We observed a decrease of material as the bone volume and trabecular thickness/number were significantly reduced. In comparison to non-OA samples, greatest differences for all parameters were found within the first mm of trabecular bone. The differences decreased toward the fifth mm in a logarithmic manner. The interpretation of the logarithmic relation leads to the conclusion that the main impact of OA on bony structures is located beneath the SBP and lessens with depth. In addition to the clear difference in material with approximately 12% less bone volume in the first mm in OA patellae, the architectural arrangement is more rod-like and isotropic, accounting for an architectural decrease in stability and support. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1982-1989, 2017.
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- 2016
22. Correction of phase wrapping artifacts in grating-based hard x-ray tomography
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Griffin Rodgers, Hans Deyhle, Timm Weitkamp, Georg Schulz, Christos Bikis, Bert Müller, and Shashidhara Marathe
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Wavefront ,Optics ,Materials science ,business.industry ,X-Ray Phase-Contrast Imaging ,Phase (waves) ,Tomography ,Grating ,business ,Refractive index ,Rotation (mathematics) ,Differential phase - Abstract
X-ray grating interferometry (XGI) is a phase-contrast imaging technique that allows for a quantitative measurement of the refractive index with high density resolution in a model-independent manner—i.e. without a priori knowledge of the specimen composition. However, the retrieval of the X-ray wavefront phase shift relies on the accurate measurement of the interference pattern phase shift, making XGI vulnerable to phase wrapping when the interference pattern phase shift, related to the derivative of the wavefront phase shift, is large. Standard procedure for avoiding phase wrapping involves submerging the specimen in a water bath to reduce the mismatch of the index of refraction at the boundaries, but this requires a top-down rotation stage and is susceptible to gas bubble formation inside the water bath. Our team has presented an algorithm to remove phase wrapping artifacts for cylindrically shaped specimens that is applied to the phase-retrieved sinogram. This algorithm models and replaces phase-wrapped data to prevent the spread of “cupping” artifacts due to the integration of the differential phase during reconstruction. We give a criterion for selecting the modeling parameters so that the resulting measurement of the index of refraction matches the results of measurements without phase wrapping. We also apply this technique to cases where phase wrapping occurs at multiple interfaces. This algorithm allows for XGI measurements without a water bath and top-down rotation stage at synchrotron and laboratory facilities, especially as sensitivity increases.
- Published
- 2019
23. Comparing the accuracy of intraoral scanners, using advanced micro computed tomography
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Hans Deyhle, Mattia Sacher, Kurt Jäger, Georg Schulz, and Bert Müller
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Intraoral scanner ,Scanner ,Pixel ,Computer science ,Micro computed tomography ,Dental Models ,Imaging data ,law.invention ,Dental arch ,medicine.anatomical_structure ,law ,medicine ,Stereolithography ,Biomedical engineering - Abstract
Intraoral scanners have been gaining importance in dental offices. The technology has become a valuable and economically reasonable alternative to conventional silicone impressions and the conventional plaster casts because of the reduced treatment time and the sufficient precision achieved. The required precision of the dental prostheses depends on the clinical needs. For the production of working models, the tolerable inaccuracy is relatively large. Especially for crowns, bridges and larger dental prostheses, which include several teeth over the dental arch, however, extra work is often performed, that presumably caused by the limited accuracy of intraoral scanners. Therefore, the paper deals with the detailed evaluation of selected, commercially available intraoral scanner systems. For this purpose, we have designed and realized a model of a full arch upper jaw on the basis of clinically relevant imaging data. As well-defined references, we have incorporated cylinders with a diameter of 4 mm. This standard to be used as reference, was quantitatively characterized by four independent measurements using the advanced CT-system phoenix nanotom® m (GE Sensing & Inspection Technologies GmbH, Wunstorf, Germany) with a pixel size of 35 μm. The standard was also scanned using five commercially available intraoral scanners. In order to compare the accuracy of the ten measurements per scanner, the data were matched to the standard. Their displacements were made visible with GOM Inspect (GOM GmbH Braunschweig, Germany). Applying the same approach, we have analyzed the accuracy of two three-dimensionally printed dental models by the stereolithography printers Form 2, Formlabs Inc., Somerville MA, USA). The results demonstrate the currently possible level of precision by the selected intraoral scanners. They differ, however, not only in scanning time necessary and the ease of handling, but also in reachable accuracy. The precision ranged from (35 ± 5) μm (TRIOS® 3) to (97 ± 22) μm (EmeraldTM). The largest deviations to the standard were found in the transversal plane (412 ± 247) μm (Medit i500). The combination of advanced conventional microCT and adequate software for quantitative analysis permits a detailed evaluation of the performance of the currently available intraoral scanners.
- Published
- 2019
24. Small-Angle Neutron Scattering Study of Temperature-Induced Structural Changes in Liposomes
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Sofiya Matviykiv, Joachim Kohlbrecher, Frederik Neuhaus, Andreas Zumbuehl, Bert Müller, and Hans Deyhle
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Materials science ,Hot Temperature ,02 engineering and technology ,Neutron scattering ,010402 general chemistry ,01 natural sciences ,Dynamic light scattering ,Scattering, Small Angle ,Electrochemistry ,General Materials Science ,Lipid bilayer ,Spectroscopy ,Phospholipids ,Liposome ,Bilayer ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Small-angle neutron scattering ,0104 chemical sciences ,body regions ,Neutron Diffraction ,Transmission electron microscopy ,Drug delivery ,Liposomes ,Biophysics ,0210 nano-technology - Abstract
Liposomes of specific artificial phospholipids, such as Pad-PC-Pad and Rad-PC-Rad, are mechanically responsive. They can release encapsulated therapeutics via physical stimuli, as naturally present in blood flow of constricted vessel segments. The question is how these synthetic liposomes change their structure in the medically relevant temperature range from 22 to 42 °C. In the present study, small-angle neutron scattering (SANS) was employed to evaluate the temperature-induced structural changes of selected artificial liposomes. For Rad-PC-Rad, Pad-Pad-PC, Sur-PC-Sur, and Sad-PC-Sad liposomes, the SANS data have remained constant because the phase transition temperatures are above 42 °C. For Pad-PC-Pad and Pes-PC-Pes liposomes, whose phase transitions are below 42 °C, the q-plots have revealed temperature-dependent structural changes. The average diameter of Pad-PC-Pad liposomes remained almost constant, whereas the eccentricity decreased by an order of magnitude. Related measurements using transmission electron microscopy at cryogenic temperatures, as well as dynamic light scattering before and after the heating cycles, underpin the fact that the non-spherical liposomes flatten out. The SANS data further indicated that, as a consequence of the thermal loop, the mean bilayer thickness increased by 20%, associated with the loss of lipid membrane interdigitation. Therefore, Pad-PC-Pad liposomes are unsuitable for local drug delivery in the atherosclerotic human blood vessel system. In contrast, Rad-PC-Rad liposomes are thermally stable for applications within the human body.
- Published
- 2019
25. High-resolution synchrotron radiation-based phase tomography of the healthy and epileptic brain
- Author
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Natalia Chicherova, Luigi Mariani, Hans Deyhle, Bert Müller, Philipp Janz, Carola A. Haas, Anna Khimchenko, Alexander Rack, Christos Bikis, Simone E. Hieber, Peter Thalmann, Georg Schulz, Jürgen Hench, and Gabriel Schweighauser
- Subjects
0301 basic medicine ,Physics ,Focus (geometry) ,business.industry ,Dentate gyrus ,Thalamus ,Hippocampus ,Ventricular system ,medicine.disease ,03 medical and health sciences ,Epilepsy ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,Optics ,Cortex (anatomy) ,medicine ,Tomography ,business ,030217 neurology & neurosurgery ,Biomedical engineering - Abstract
Phase-contrast micro-tomography using synchrotron radiation has yielded superior soft tissue visualization down to the sub-cellular level. The isotropic spatial resolution down to about one micron is comparable to the one of histology. The methods, however, provide different physical quantities and are thus complementary, also allowing for the extension of histology into the third dimension. To prepare for cross-sectional animal studies on epilepsy, we have standardized the specimen’s preparation and scanning procedure for mouse brains, so that subsequent histology remains entirely unaffected and scanning of all samples (n = 28) is possible in a realistic time frame. For that, we have scanned five healthy and epileptic mouse brains at the ID19 beamline, ESRF, Grenoble, France, using grating- and propagation-based phase contrast micro-tomography. The resulting datasets clearly show the cortex, ventricular system, thalamus, hypothalamus, and hippocampus. Our focus is on the latter, having planned kainate-induced epilepsy experiments. The cell density and organization in the dentate gyrus and Ammon’s horn region were clearly visualized in control animals. This proof of principle was required to initiate experiment. The resulting three-dimensional data have been correlated to histology. The goal is a brain-wide quantification of cell death or structural reorganization associated with epilepsy as opposed to histology alone that represents small volumes of the total brain only. Thus, the proposed technique bears the potential to correlate the gold standard in analysis with independently obtained data sets. Such an achievement also fuels interest for other groups in neuroscience research to closely collaborate with experts in phase micro-tomography.
- Published
- 2016
- Full Text
- View/download PDF
26. Mineralization of Early Stage Carious Lesions In Vitro—A Quantitative Approach
- Author
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Georg Schulz, Lucy Kind, Hans Deyhle, Bert Müller, Peter Thalmann, and Iwona Dziadowiec
- Subjects
Molar ,Pathology ,medicine.medical_specialty ,enamel caries ,Mineralization (biology) ,Article ,joint histogram ,Lesion ,medicine ,mineralization ,General Dentistry ,self-assembling peptide ,Enamel paint ,Chemistry ,Micro computed tomography ,micro computed tomography ,demineralization ,In vitro ,Demineralization ,lcsh:RK1-715 ,image registration ,visual_art ,lcsh:Dentistry ,visual_art.visual_art_medium ,Tomography ,medicine.symptom ,Biomedical engineering - Abstract
Micro computed tomography has been combined with dedicated data analysis for the in vitro quantification of sub-surface enamel lesion mineralization. Two artificial white spot lesions, generated on a human molar crown in vitro, were examined. One lesion was treated with a self-assembling peptide intended to trigger nucleation of hydroxyapatite crystals. We non-destructively determined the local X-ray attenuation within the specimens before and after treatment. The three-dimensional data was rigidly registered. Three interpolation methods, i.e., nearest neighbor, tri-linear, and tri-cubic interpolation were evaluated. The mineralization of the affected regions was quantified via joint histogram analysis, i.e., a voxel-by-voxel comparison of the tomography data before and after mineralization. After ten days incubation, the mean mineralization coefficient reached 35.5% for the peptide-treated specimen compared to 11.5% for the control. This pilot study does not give any evidence for the efficacy of peptide treatment nor allows estimating the necessary number of specimens to achieve significance, but shows a sound methodological approach on the basis of the joint histogram analysis.
- Published
- 2015
27. Spatial resolution of a laboratory based X-Ray cone-beam laminography scanning system for various trajectories
- Author
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Thomas Blumensath, Hans Deyhle, Ander Biguri, Richard P. Boardman, Hossein Towsyfyan, and Mark Mavrogordato
- Subjects
010302 applied physics ,Scanner ,Materials science ,business.industry ,Orientation (computer vision) ,Mechanical Engineering ,computer.file_format ,Condensed Matter Physics ,01 natural sciences ,Metrology ,Characterization (materials science) ,Optics ,Nondestructive testing ,0103 physical sciences ,General Materials Science ,Raster graphics ,business ,010301 acoustics ,Image resolution ,computer ,Beam (structure) - Abstract
Computed laminography (CL), a long established NDT method, is ideal for the non-destructive evaluation of plate-like structures, for which conventional computed tomography (CT) is less well suited. This paper demonstrates the feasibility of implementing raster CL on a Nikon Metrology custom build X-ray CT scanner without the need for specialised equipment. To provide a more principled way to demonstrate the widespread adoption of CL for defect characterization in plate-like structures, a test specimen was designed and manufactured from Polyoxymethylene (Delrin) that allows well defined features of different size and orientation to be characterized. The study highlights the relation between direction-dependent spatial resolution, feature geometry and scan trajectory. It demonstrates that high-resolution and high-speed in situ volume-imaging of plate-like structures with large aspect ratios is viable at levels that would be challenging via CT or alternative three-dimensional NDT methods.
- Published
- 2020
28. Optimizing contrast and spatial resolution in hard x-ray tomography of medically relevant tissues
- Author
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Griffin Rodgers, Georg Schulz, Willy Kuo, Bert Müller, Christoph Rau, Hans Deyhle, and Timm Weitkamp
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Image quality ,Gaussian ,media_common.quotation_subject ,FOS: Physical sciences ,Applied Physics (physics.app-ph) ,02 engineering and technology ,01 natural sciences ,symbols.namesake ,Optics ,0103 physical sciences ,Contrast (vision) ,Image resolution ,media_common ,010302 applied physics ,business.industry ,Physics - Applied Physics ,Filter (signal processing) ,021001 nanoscience & nanotechnology ,Physics - Medical Physics ,3. Good health ,Gaussian filter ,symbols ,Medical Physics (physics.med-ph) ,Tomography ,0210 nano-technology ,Phase retrieval ,business - Abstract
Hard X-ray tomography with Paganin's widespread single-distance phase retrieval filter improves contrast-to-noise ratio (CNR) while reducing spatial resolution (SR). We demonstrate that a Gaussian filter provided larger CNR at high SR with interpretable density measurements for two medically relevant soft tissue samples. Paganin's filter produced larger CNR at low SR, though \emph{a priori} assumptions were generally false and image quality gains diminish for CNR $>1$. Therefore, simple absorption measurements of low-$Z$ specimens combined with Gaussian filtering can provide improved image quality and model-independent density measurements compared to single-distance phase retrieval., This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Applied Physics Letters 116, 023702 (2020), and may be found at https://aip.scitation.org/doi/10.1063/1.5133742
- Published
- 2020
29. Advanced X-ray phase-contrast and dark-field imaging with the unified modulated pattern analysis (UMPA)
- Author
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Irene Zanette, Joan Vila-Comamala, Marie-Christine Zdora, Willy Kuo, Pierre Thibault, Hans Deyhle, and Christoph Rau
- Subjects
Physics ,business.industry ,Phase contrast microscopy ,X-ray ,Pattern analysis ,01 natural sciences ,Dark field microscopy ,law.invention ,010309 optics ,Optics ,law ,0103 physical sciences ,010306 general physics ,business ,Instrumentation - Published
- 2018
30. Tunable X-ray speckle-based phase-contrast and dark-field imaging using the unified modulated pattern analysis approach
- Author
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Irene Zanette, Christoph Rau, Pierre Thibault, Marie-Christine Zdora, Joan Vila-Comamala, Hans Deyhle, Zdora, M. -C., Thibault, P., Deyhle, H., Vila-Comamala, J., Raua, C., and Zanette, I.
- Subjects
Multi-modality systems ,Computer science ,Phase contrast microscopy ,Signal Sensitivity ,Pattern analysis ,02 engineering and technology ,Grating ,Inspection with x-rays ,01 natural sciences ,law.invention ,Speckle pattern ,Optics ,law ,0103 physical sciences ,Inspection with x-ray ,010306 general physics ,Instrumentation ,Image resolution ,Mathematical Physics ,Multi-modality system ,Multimodal imaging ,Computerized Tomography (CT) and Computed Radiography (CR) ,X-ray radiography and digital radiography (DR) ,business.industry ,021001 nanoscience & nanotechnology ,Dark field microscopy ,0210 nano-technology ,business - Abstract
X-ray phase-contrast and dark-field imaging provides valuable, complementary information about the specimen under study. Among the multimodal X-ray imaging methods, X-ray grating interferometry and speckle-based imaging have drawn particular attention, which, however, in their common implementations incur certain limitations that can restrict their range of applications. Recently, the unified modulated pattern analysis (UMPA) approach was proposed to overcome these limitations and combine grating- and speckle-based imaging in a single approach. Here, we demonstrate the multimodal imaging capabilities of UMPA and highlight its tunable character regarding spatial resolution, signal sensitivity and scan time by using different reconstruction parameters., Journal of Instrumentation, 13, ISSN:1748-0221
- Published
- 2018
31. Hard X-Ray Nanoholotomography: Large-Scale, Label-Free, 3D Neuroimaging beyond Optical Limit
- Author
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Peter Cloetens, Magdalena Müller-Gerbl, Christos Bikis, Jürgen Hench, Alexandra Pacureanu, Georg Schulz, Simone E. Hieber, Anna Khimchenko, Peter Thalmann, Hans Deyhle, Gabriel Schweighauser, Bert Müller, and Stephan Frank
- Subjects
0301 basic medicine ,Materials science ,General Chemical Engineering ,Resolution (electron density) ,General Engineering ,General Physics and Astronomy ,Medicine (miscellaneous) ,Context (language use) ,Human brain ,computer.software_genre ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Characterization (materials science) ,03 medical and health sciences ,030104 developmental biology ,medicine.anatomical_structure ,Neuroimaging ,Voxel ,Microscopy ,medicine ,General Materials Science ,computer ,Image resolution ,Biomedical engineering - Abstract
There have been great efforts on the nanoscale 3D probing of brain tissues to image subcellular morphologies. However, limitations in terms of tissue coverage, anisotropic resolution, stain dependence, and complex sample preparation all hinder achieving a better understanding of the human brain functioning in the subcellular context. Herein, X-ray nanoholotomography is introduced as an emerging synchrotron radiation-based technology for large-scale, label-free, direct imaging with isotropic voxel sizes down to 25 nm, exhibiting a spatial resolution down to 88 nm. The procedure is nondestructive as it does not require physical slicing. Hence, it allows subsequent imaging by complementary techniques, including histology. The feasibility of this 3D imaging approach is demonstrated on human cerebellum and neocortex specimens derived from paraffin-embedded tissue blocks. The obtained results are compared to hematoxylin and eosin stained histological sections and showcase the ability for rapid hierarchical neuroimaging and automatic rebuilding of the neuronal architecture at the level of a single cell nucleolus. The findings indicate that nanoholotomography can complement microscopy not only by large isotropic volumetric data but also by morphological details on the sub-100 nm level, addressing many of the present challenges in brain tissue characterization and probably becoming an important tool in nanoanatomy.
- Published
- 2017
32. Imaging of the human tooth cementum ultrastructure of archeological teeth, using hard x-ray microtomography to determine age-at-death and stress periods
- Author
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Werner Vach, Georg Schulz, Ursula Wittwer-Backofen, Gabriela Mani-Caplazi, Hans Deyhle, Gerhard Hotz, and Bert Müller
- Subjects
010302 applied physics ,X-ray microtomography ,Micro computed tomography ,Age at death ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Archaeology ,Birth history ,City hospital ,stomatognathic diseases ,medicine.anatomical_structure ,stomatognathic system ,Human tooth ,0103 physical sciences ,medicine ,Cementum ,Life history ,0210 nano-technology ,Geology - Abstract
Tooth cementum annulation (TCA) is used by anthropologists to decipher age-at-death and stress periods based on yearly deposited incremental lines (ILs). The destructive aspect of the TCA method, which requires cutting the tooth root in sections to display the ILs, using transmission light microscopy, can be problematic for archeological teeth, and so a non-invasive imaging technique is preferred. The purpose of this study is to evaluate conventional micro computed tomography (μCT) and synchrotron radiation-based X-ray micro computed tomography (SRμCT) as a non-destructive technique to explore the tooth cementum ultrastructure and to display ILs. Seven archeological teeth from the Basel- Spitalfriedhof collection (patients died between 1845 and 1868 in the city hospital) were selected for the μCT experiments. This collection is considered a unique worldwide reference series in the anthropological science community, due to the high level of documented life history data in the medical files and the additionally collected and verified birth history by genealogists. The results demonstrate that the conventional μCT is complementary to the SRμCT allowing to prescreen the teeth using conventional μCT to identify the appropriate specimens and areas for the SRμCT measurements. SRμCT displayed cementum ring structure corresponding to the ILs in the microscope view in archeological teeth in a non-invasive fashion with the potential for more accurate assessments of ILs compared to conventional techniques. The ILs were mainly clearly visible, and it was possible to count them for age-at-death assessment and identify qualitatively irregular ILs which could constitute stress markers.
- Published
- 2017
33. Imaging cellular and subcellular structure of human brain tissue using micro computed tomography
- Author
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Georg Schulz, Bekim Osmani, Gabriel Schweighauser, Magdalena Müller-Gerbl, Jürgen Hench, Peter Cloetens, Bert Müller, Alexandra-Teodora Joita-Pacureanu, Simone E. Hieber, Peter Thalmann, Hans Deyhle, Anna Khimchenko, Christos Bikis, and Natalia Chicherova
- Subjects
Wavefront ,Materials science ,Image quality ,Synchrotron radiation ,Human brain ,law.invention ,medicine.anatomical_structure ,Beamline ,Optical microscope ,law ,medicine ,Tomography ,Image resolution ,Biomedical engineering - Abstract
Brain tissues have been an attractive subject for investigations in neuropathology, neuroscience, and neurobiol- ogy. Nevertheless, existing imaging methodologies have intrinsic limitations in three-dimensional (3D) label-free visualisation of extended tissue samples down to (sub)cellular level. For a long time, these morphological features were visualised by electron or light microscopies. In addition to being time-consuming, microscopic investigation includes specimen fixation, embedding, sectioning, staining, and imaging with the associated artefacts. More- over, optical microscopy remains hampered by a fundamental limit in the spatial resolution that is imposed by the diffraction of visible light wavefront. In contrast, various tomography approaches do not require a complex specimen preparation and can now reach a true (sub)cellular resolution. Even laboratory-based micro computed tomography in the absorption-contrast mode of formalin-fixed paraffin-embedded (FFPE) human cerebellum yields an image contrast comparable to conventional histological sections. Data of a superior image quality was obtained by means of synchrotron radiation-based single-distance X-ray phase-contrast tomography enabling the visualisation of non-stained Purkinje cells down to the subcellular level and automated cell counting. The question arises, whether the data quality of the hard X-ray tomography can be superior to optical microscopy. Herein, we discuss the label-free investigation of the human brain ultramorphology be means of synchrotron radiation-based hard X-ray magnified phase-contrast in-line tomography at the nano-imaging beamline ID16A (ESRF, Grenoble, France). As an example, we present images of FFPE human cerebellum block. Hard X-ray tomography can provide detailed information on human tissues in health and disease with a spatial resolution below the optical limit, improving understanding of the neuro-degenerative diseases.
- Published
- 2017
34. Nanostructure Formation: Time-Resolved Plasmonics used to On-Line Monitor Metal/Elastomer Deposition for Low-Voltage Dielectric Elastomer Transducers (Adv. Electron. Mater. 8/2017)
- Author
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Samuel Lörcher, Tino Töpper, Bekim Osmani, Hans Deyhle, Thomas Pfohl, Vanessa Leung, and Bert Müller
- Subjects
Nanostructure ,Materials science ,business.industry ,Nanotechnology ,Dielectric ,Electron ,Elastomer ,Electronic, Optical and Magnetic Materials ,Transducer ,Optoelectronics ,Deposition (phase transition) ,business ,Low voltage ,Plasmon - Published
- 2017
35. Three-dimensional imaging of human brain tissues using absorption-contrast high-resolution X-ray tomography
- Author
-
Anna Khimchenko, Georg Schulz, Natalia Chicherova, Hans Deyhle, Jürgen Hench, Bert Müller, Simone E. Hieber, Christos Bikis, and Gabriel Schweighauser
- Subjects
0301 basic medicine ,Physics ,business.industry ,media_common.quotation_subject ,Purkinje cell ,X-ray ,Synchrotron radiation ,Human brain ,Absorption contrast ,03 medical and health sciences ,030104 developmental biology ,medicine.anatomical_structure ,Optics ,medicine ,Contrast (vision) ,Tomography ,business ,Image resolution ,media_common - Abstract
Our body is hierarchically organized down to individual cells. Cutting-edge clinical imaging facilities reach a spatial resolution of a fraction of a millimeter, living cells invisible. A decade ago, post-mortem X-ray imaging by means of synchrotron radiation enabled the identification of Os-stained ganglion and unstained Purkinje cells. Very recently, even sub-cellular structures, such as nucleolus and the dendritic tree of Purkinje cells, were extracted by means of phase-contrast single-distance synchrotron radiation-based hard X-ray tomography. At the same time, conventional absorption-contrast, laboratory-based micro computed tomography was successfully applied to visualize brain components including individual Purkinje cells within a cerebellum specimen. Thus, the goal of isotropic-cellular-resolution visualization of soft tissues within a laboratory environment without application of any dedicated contrast agent was achieved. In this communication, we are discussing (1) to which extend the quality gain of the laboratory-based absorption-contrast tomography can be driven with respect to optical microscopy of stained tissue sections and (2) what value such a technique would add. As a proof of principle, four histological sections were affine-registered to corresponding three-dimensional (3D) tomography dataset. We are discussing a semi-automatic landmark-based 2D-3D registration framework and compare registration results based on mean square difference (MSD) metrics.
- Published
- 2017
36. Combined use of micro computed tomography and histology to evaluate the regenerative capacity of bone grafting materials
- Author
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Felix Beckmann, Simone E. Hieber, Anja K. Stalder, Natalia Chicherova, Bert Müller, Bernd Ilgenstein, and Hans Deyhle
- Subjects
Materials science ,Micro computed tomography ,medicine.medical_treatment ,Combined use ,Metals and Alloys ,Histology ,030206 dentistry ,02 engineering and technology ,Bone grafting ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Bone augmentation ,03 medical and health sciences ,0302 clinical medicine ,Materials Chemistry ,medicine ,Physical and Theoretical Chemistry ,0210 nano-technology ,Biomedical engineering - Abstract
Pre-clinical animal models are commonly used to evaluate the osteogenic potential of bone grafting materials in-vivo. Based on the histology analysis, the currently commercially available bone grafting materials show comparable results with respect to biocompatibility, incorporation and remodeling. In the present pilot study we introduce a methodology to compare calcium phosphate-based bone grafting materials from world-leading companies in clinical trials and analyze them by means of established histology and synchrotron radiation-based micro computed tomography (SRμCT). The results indicate that the morphology of the bony structures depends on the selected bone grafting material and that an arbitrarily selected histological slice can lead to misleading conclusions. Complementary μCT data can become the basis for the identification of a representative slice. The registration of the selected histological slice with its counterpart in the three-dimensional μCT dataset was performed both visually and automatically with well comparable results. This registration allows for the compilation of a joint histogram to identify anatomical features, which can neither be extracted from histology nor from μCT data on their own. Accordingly, μCT will become an integral part of studies on the efficacy of bone augmentation materials and beyond.
- Published
- 2014
37. Assessing the grain structure of highly X-ray absorbing metallic alloys
- Author
-
Bert Müller, Hans Deyhle, Felix Beckmann, Therese Bormann, Michael de Wild, and Michael Schinhammer
- Subjects
Diffraction ,Fabrication ,Materials science ,Metals and Alloys ,X-ray ,Synchrotron radiation ,Condensed Matter Physics ,Microstructure ,Laser ,law.invention ,Crystallography ,law ,Materials Chemistry ,Physical and Theoretical Chemistry ,Selective laser melting ,Composite material ,Electron backscatter diffraction - Abstract
Selective laser melting allows the fabrication of NiTi implants with pre-defined, complex shapes. The control of the process parameters regulates the arrangement of the granular microstructure of the NiTi alloy. We prepared specimens with elongated grains, which build a sound basis for diffraction contrast tomography experiments using synchrotron radiation and for electron backscatter diffraction measurements. Both approaches reveal the orientation and size of the individual grains within the specimen. Still, electron backscatter diffraction is confined to two-dimensional cross-sections while diffraction contrast tomography reveals these microstructural features in three dimensions. We demonstrate that the grains in the selective laser melted specimen, which are oriented along the building direction, do not exhibit a well-defined planar grain orientation but are twisted. These twisted grains give rise to diffraction spots observable for several degrees of specimen rotation simultaneously to the acquisition of tomography data.
- Published
- 2014
38. Nanostructure of carious tooth enamel lesion
- Author
-
Felix Beckmann, Oliver Bunk, Shane N. White, Bert Müller, and Hans Deyhle
- Subjects
Nanostructure ,Materials science ,Surface Properties ,Biomedical Engineering ,Dentistry ,Dental Caries ,Biochemistry ,Biomaterials ,Lesion ,Human tooth ,medicine ,Dentin ,Humans ,Scattering, Radiation ,Dental Enamel ,Molecular Biology ,Small-angle X-ray scattering ,business.industry ,X-Rays ,X-Ray Microtomography ,General Medicine ,Tooth enamel ,Nanostructures ,Surface loss ,medicine.anatomical_structure ,Crystallite ,medicine.symptom ,business ,Biotechnology ,Biomedical engineering - Abstract
Carious lesions exhibit a complex structural organization composed of zones of higher and lower mineralization, formed by successive periods of cyclic de- and re-mineralization. A thorough understanding of the lesion morphology is necessary for the development of suitable treatments aiming to repair rather than replace the damaged tissue. This detailed understanding includes the entire lesion down to individual crystallites and nanopores within the natural organization of the crown. A moderate lesion, with surface loss and reaching dentin, and a very early lesion were studied. Scanning small-angle X-ray scattering (SAXS) with a pixel size of 20 × 20 μm(2) was used to characterize these lesions, allowing for the identification of distinct zones with varied absorption and scattering behavior, indicative of varied porosity and pore morphology. Despite these differences, the overall orientation and anisotropy of the SAXS signal was unaltered throughout both lesions, indicating that an anisotropic scaffold is still present in the lesion. The finding that crystallite orientation is preserved throughout the lesions facilitates the identification of preventive re-mineralizing strategies with the potential to recreate the original nanostructure.
- Published
- 2014
39. Revealing the Nano-Architecture of Human Hard and Soft Tissues by Spatially Resolved Hard X-Ray Scattering
- Author
-
Hans Deyhle and Bert Müller
- Subjects
Nano architecture ,Optics ,Materials science ,business.industry ,Scattering ,Spatially resolved ,X-ray ,Soft tissue ,business - Published
- 2016
40. Trabecular network arrangement within the human patella: how osteoarthritis remodels the 3D trabecular structure
- Author
-
Hans Deyhle, Sebastian Hoechel, Mireille Toranelli, and Magdalena Müller-Gerbl
- Subjects
0301 basic medicine ,030222 orthopedics ,education.field_of_study ,Micro computed tomography ,Population ,Biomechanics ,Parameter distribution ,Osteoarthritis ,Trabecular architecture ,medicine.disease ,03 medical and health sciences ,0302 clinical medicine ,Subchondral bone ,medicine ,Patella ,030101 anatomy & morphology ,education ,Mathematics ,Biomedical engineering - Abstract
Following the principles of “morphology reveals biomechanics”, the anatomical structure of the cartilage-osseous interface and the supporting trabecular network show defined adaptation in their architectural properties to physiological loading. In case of a faulty relationship, the ability to support the load diminishes and the onset of osteoarthritis (OA) may arise and disturb the balanced formation and resorption processes. To describe and quantify the changes occurring, 10 human OA patellae were analysed concerning the architectural parameters of the trabecular network within the first five mms by the evaluation of 3Dmicro-CT datasets. The analysed OA-samples showed a strong irregularity for all trabecular parameters across the trabecular network, no regularity in parameter distribution was found. In general, we saw a decrease of material in the OA population as BV/TV, BS/TV, Tb.N and Tb.Th were decreased and the spacing increased. The development into depth showed a logarithmic dependency, which revealed the greatest difference for all parameters within the first mm in comparison to the physiologic samples. The differences decreased towards the 5th mm. The interpretation of the mathematic dependency leads to the conclusion that the main impact of OA is beneath the subchondral bone plate (SBP) and lessens with depth. Next to the clear difference in material, the architectural arrangement is more rod-like and isotropic just beneath the SBP in comparison to the plate-like and more anisotropic physiological arrangement.
- Published
- 2016
41. X-ray micro-tomography for investigations of brain tissues on cellular level
- Author
-
Simone E. Hieber, Peter Thalmann, Georg Schulz, Gabriel Schweighauser, Christos Bikis, Jürgen Hench, Marie-Christine Zdora, Alexander Hipp, Hans Deyhle, Bert Müller, Irene Zanette, and Anna Khimchenko
- Subjects
0301 basic medicine ,Materials science ,business.industry ,media_common.quotation_subject ,Resolution (electron density) ,X-ray ,Synchrotron radiation ,law.invention ,03 medical and health sciences ,Interferometry ,030104 developmental biology ,Optics ,Beamline ,Optical microscope ,law ,Contrast (vision) ,Tomography ,business ,media_common - Abstract
X-ray imaging in absorption contrast mode is well established for hard tissue visualization. However, performance for lower density materials is limited due to a reduced contrast. Our aim is three-dimensional (3D) characterization of micro-morphology of human brain tissues down to (sub-)cellular resolution within a laboratory environment. Using the laboratory-based microtomography (μCT) system nanotom m (GE Sensing and Inspection Technologies GmbH, Wunstorf, Germany) and synchrotron radiation at the Diamond-Manchester Imaging Branchline I13-2 (Diamond Light Source, Didcot, UK), we have acquired 3D data with a resolution down to 0.45 μm for visualization of a human cerebellum specimen down to cellular level. We have shown that all selected modalities, namely laboratory-based absorption contrast micro-tomography (LBμCT), synchrotron radiation based in-line single distance phase contrast tomography (SDPR) and synchrotron radiation based single-grating interferometry (GI), can reach cellular resolution for tissue samples with a size in the mm-range. The results are discussed qualitatively in comparison to optical microscopy of haematoxylin and eosin (HE) stained sections. As phase contrast yields to a better data quality for soft tissues and in order to overcome restrictions of limited beamline access for phase contrast measurements, we have equipped the μCT system nanotom m with a double-grating phase contrast set-up. Preliminary experimental results of a knee sample consisting of a bony part and a cartilage demonstrate that phase contrast data exhibits better quality compared to absorption contrast. Currently, the set-up is under adjustment. It is expected that cellular resolution would also be achieved. The questions arise (1) what would be the quality gain of laboratory-based phase contrast in comparison to laboratory-based absorption contrast tomography and (2) could laboratory-based phase contrast data provide comparable results to synchrotron radiation based phase contrast data.
- Published
- 2016
42. Histology-validated x-ray tomography for imaging human coronary arteries
- Author
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Marzia Buscema, Katarzyna Michaud, Anna Khimchenko, Alexander Hipp, Felix Beckmann, Bert Müller, Georg Schulz, Sofiya Matviykiv, Till Saxer, Hans Deyhle, and Margaret N. Holme
- Subjects
0301 basic medicine ,Bone decalcification ,Heart disease ,business.industry ,Lumen (anatomy) ,Soft tissue ,Histology ,medicine.disease ,Coronary arteries ,03 medical and health sciences ,030104 developmental biology ,medicine.anatomical_structure ,Optics ,medicine ,Tomography ,ddc:620 ,business ,Biomedical engineering ,Blood vessel - Abstract
[Proceedings] - , 2016. - ISBN - doi:10.1117/12.2238702 Developments in X-Ray Tomography X, San Diego, California, 28 Aug 2016 - 1 Sep 2016; Proceedings of SPIE 9967, 99670O (2016). doi:10.1117/12.2238702, Heart disease is the number one cause of death worldwide. To improve therapy and patient outcome, the knowledge of anatomical changes in terms of lumen morphology and tissue composition of constricted arteries is crucial for designing a localized drug delivery to treat atherosclerosis disease. Traditional tissue characterization by histology is a pivotal tool, although it brings disadvantages such as vessel morphology modification during decalcification and slicing. X-ray tomography in absorption and phase contrast modes yields a deep understanding in blood vessel anatomy in healthy and diseased stages: measurements in absorption mode make visible highly absorbing tissue components including cholesterol plaques, whereas phase contrast tomography gains better contrast of the soft tissue components such as vessel walls. Established synchrotron radiation-based micro-CT techniques ensure high performance in terms of 3D visualization of highly absorbing and soft tissues., Published by SPIE, Bellingham, Wash.
- Published
- 2016
43. Computational cell quantification in the human brain tissues based on hard x-ray phase-contrast tomograms
- Author
-
Jürgen Hench, Alexander Rack, Irene Zanette, Georg Schulz, Gabriel Schweighauser, Christos Bikis, Simone E. Hieber, Peter Thalmann, Hans Deyhle, Marie-Christine Zdora, Bert Müller, Anna Khimchenko, and Natalia Chicherova
- Subjects
0301 basic medicine ,Materials science ,business.industry ,media_common.quotation_subject ,Context (language use) ,Image segmentation ,Edge detection ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Optics ,Region of interest ,Microscopy ,Contrast (vision) ,Segmentation ,Tomography ,business ,030217 neurology & neurosurgery ,Biomedical engineering ,media_common - Abstract
Cell visualization and counting plays a crucial role in biological and medical research including the study of neurodegenerative diseases. The neuronal cell loss is typically determined to measure the extent of the disease. Its characterization is challenging because the cell density and size already differs by more than three orders of magnitude in a healthy cerebellum. Cell visualization is commonly performed by histology and fluorescence microscopy. These techniques are limited to resolve complex microstructures in the third dimension. Phase- contrast tomography has been proven to provide sufficient contrast in the three-dimensional imaging of soft tissue down to the cell level and, therefore, offers the basis for the three-dimensional segmentation. Within this context, a human cerebellum sample was embedded in paraffin and measured in local phase-contrast mode at the beamline ID19 (ESRF, Grenoble, France) and the Diamond Manchester Imaging Branchline I13-2 (Diamond Light Source, Didcot, UK). After the application of Frangi-based filtering the data showed sufficient contrast to automatically identify the Purkinje cells and to quantify their density to 177 cells per mm3 within the volume of interest. Moreover, brain layers were segmented in a region of interest based on edge detection. Subsequently performed histological analysis validated the presence of the cells, which required a mapping from the two- dimensional histological slices to the three-dimensional tomogram. The methodology can also be applied to further tissue types and shows potential for the computational tissue analysis in health and disease.
- Published
- 2016
44. Imaging tissues for biomedical research using the high-resolution micro-tomography system nanotom® m
- Author
-
Anna Khimchenko, Margaret N. Holme, Till Saxer, Nadja Rohr, Christos Bikis, Anja K. Stalder, Felix Beckmann, Sebastian Höchel, Bert Müller, Marzia Buscema, Georg Schulz, Magdalena Müller-Gerbl, Claude Jaquiery, Bernd Ilgenstein, Simone E. Hieber, Peter Thalmann, Christoph Kunz, and Hans Deyhle
- Subjects
Materials science ,Pixel ,business.industry ,Resolution (electron density) ,Detector ,Synchrotron radiation ,Ranging ,02 engineering and technology ,Radiation ,021001 nanoscience & nanotechnology ,01 natural sciences ,010309 optics ,chemistry.chemical_compound ,Optics ,chemistry ,0103 physical sciences ,Millimeter ,Mercury cadmium telluride ,0210 nano-technology ,business - Abstract
Micro computed tomography (mCT) is well established in virtually all fields of biomedical research, allowing for the non-destructive volumetric visualization of tissue morphology. A variety of specimens can be investigated, ranging from soft to hard tissue to engineered structures like scaffolds. Similarly, the size of the objects of interest ranges from a fraction of a millimeter to several tens of centimeters. While synchrotron radiation-based μCT still offers unrivaled data quality, the ever-improving technology of cathodic tube-based machines offers a valuable and more accessible alternative. The Biomaterials Science Center of the University of Basel operates a nanotomOR m (phoenix|x-ray, GE Sensing and Inspection Technologies GmbH, Wunstorf, Germany), with a 180 kV source and a minimal spot size of about 0.9 μm. Through the adjustable focus-specimen and focus-detector distances, the effective pixel size can be adjusted from below 500 nm to about 80 μm. On the high-resolution side, it is for example possible to visualize the tubular network in sub-millimeter thin dentin specimens. It is then possible to locally extract parameters such as tubule diameter, density, or alignment, giving information on cell movements during tooth formation. On the other side, with a horizontal shift of the 3,072 pixels x 2,400 pixels detector, specimens up to 35 cm in diameter can be scanned. It is possible, for example, to scan an entire human knee, albeit with inferior resolution. Lab source μCT machines are thus a powerful and flexible tool for the advancement of biomedical research, and a valuable and more accessible alternative to synchrotron radiation facilities.
- Published
- 2016
45. Propagation-based X-ray Phase Contrast Microtomography of Zebrafish Embryos to Understand Drug Delivery
- Author
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Hans Deyhle, Jörg Huwyler, Georg Schulz, Alexander Rack, Emre Cörek, Bert Müller, Peter Thalmann, and Stefan Siegrist
- Subjects
0301 basic medicine ,030103 biophysics ,03 medical and health sciences ,Materials science ,law ,Phase contrast microscopy ,Drug delivery ,X-ray ,Biophysics ,Zebrafish embryo ,Instrumentation ,law.invention - Published
- 2018
46. Double Grating Interferometry in a Commercial Micro Computed Tomography System for Biomedical Imaging
- Author
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Hans Deyhle, Georg Schulz, Griffin Rodgers, Anna Khimchenko, Joachim Schulz, and Bert Müller
- Subjects
0301 basic medicine ,03 medical and health sciences ,030104 developmental biology ,Optics ,Materials science ,business.industry ,Micro computed tomography ,Medical imaging ,business ,Grating interferometry ,Instrumentation - Published
- 2018
47. Visualization and Segmentation of Cells in Unstained Paraffin-Embedded Cerebral Tissue
- Author
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Hans Deyhle, Jiirgen Hench, Georg Schulz, Christos Bikis, Bert Müller, Anna Khimchenko, Simone E. Hieber, and Gabriel Schweighauser
- Subjects
0301 basic medicine ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,Materials science ,Segmentation ,Cerebral tissue ,Instrumentation ,030217 neurology & neurosurgery ,Paraffin embedded ,Visualization ,Biomedical engineering - Published
- 2018
48. Sensitivity comparison of absorption and grating-based phase tomography of paraffin-embedded human brain tissue
- Author
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Felix Beckmann, Hans Deyhle, Peter Thalmann, Georg Schulz, Alexander Hipp, Bert Müller, Christoph Rau, Christos Bikis, Timm Weitkamp, Griffin Rodgers, and Stamatios Theocharis
- Subjects
010302 applied physics ,Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Resolution (electron density) ,Phase (waves) ,Synchrotron radiation ,Context (language use) ,02 engineering and technology ,Grating ,021001 nanoscience & nanotechnology ,01 natural sciences ,Optics ,0103 physical sciences ,ddc:530 ,Tomography ,0210 nano-technology ,Absorption (electromagnetic radiation) ,business ,Image resolution - Abstract
Applied physics letters 114(8), 083702 (2019). doi:10.1063/1.5085302, Advances in high-resolution hard X-ray computed tomography have led to the field of virtual histology to complement histopathological analyses. Phase-contrast modalities have been favored because, for soft tissues, the real part of the refractive index is orders of magnitude greater than the imaginary part. Nevertheless, absorption-contrast measurements of paraffin-embedded tissues have provided exceptionally high contrast combined with a submicron resolution. In this work, we present a quantitative comparison of phase tomography using synchrotron radiation-based X-ray double grating interferometry and conventional synchrotron radiation-based computed tomography in the context of histopathologically relevant paraffin-embedded human brain tissue. We determine the complex refractive index and compare the contrast-to-noise ratio (CNR) of each modality, accounting for the spatial resolution and optimizing the photon energy for absorption tomography. We demonstrate that the CNR in the phase modality is 1.6 times higher than the photon-energy optimized and spatial resolution-matched absorption measurements. We predict, however, that a further optimized phase tomography will provide a CNR gain of 4. This study seeks to boost the discussion of the relative merits of phase and absorption modalities in the context of paraffin-embedded tissues for virtual histology, highlighting the importance of optimization procedures for the two complementary modes and the trade-off between spatial and density resolution, not to mention the disparity in data acquisition and processing., Published by American Inst. of Physics, Melville, NY
- Published
- 2019
49. Micro CT analysis of the subarticular bone structure in the area of the talar trochlea
- Author
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Andrej M. Nowakowski, Hans Deyhle, André Leumann, Magdalena Müller-Gerbl, and Silvan Zander
- Subjects
Male ,X-ray microtomography ,medicine.disease_cause ,Mineralization (biology) ,Talus ,Pathology and Forensic Medicine ,Weight-bearing ,Weight-Bearing ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Trabecular meshwork ,Micro ct ,Numerical parameter ,Aged ,Aged, 80 and over ,Structure model index ,business.industry ,X-Ray Microtomography ,Anatomy ,Structural parameter ,Adaptation, Physiological ,medicine.anatomical_structure ,Radiology Nuclear Medicine and imaging ,Loading history ,Micro CT ,Anisotropy ,Original Article ,Female ,Surgery ,business ,Bone volume ,Cancellous bone ,Bone structure - Abstract
Purpose: Certain regions of the talar trochlea are recognized as exhibiting varying cartilage thickness and degrees of subchondral bone mineralization. These changes have been attributed to the long-term loading history. For the current study, we accepted the hypothesis that stress-induced alterations of the joint surface include not only varying degrees of subchondral lamellar mineralization, but also structural changes of the subarticular cancellous bone. Methods: In order to examine the structure of the subarticular cancellous bone, ten formalin-fixed talar trochleae were analyzed using micro CT. Sixteen measurement zones were defined and then evaluated in five layers each of 1-mm thickness, enabling assessment of the cancellous architecture extending 5mm below the trochlear surface using numerical and structural parameters. Results: As with mineralization patterns in the subchondral lamella, large variation was observed regarding bone volume, trabecular quantity, thickness, and spacing, as well as for structure model index and degree of anisotropy, depending on localization. In addition, like previous reports examining mineralization of the subchondral lamella, two distinct groups could be identified as "bicentric” or "monocentric”. Conclusions: These results show that structural tissue adaptation probably due to loading history is also evident within the subarticular cancellous bone
- Published
- 2013
50. Non-destructive phase contrast hard x-ray imaging to reveal the three-dimensional microstructure of soft and hard tissues
- Author
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Georg Schulz, Simone E. Hieber, Christos Bikis, Hans Deyhle, Samiul Hasan, Loïc Costeur, Bert Müller, Joachim Schulz, and Anna Khimchenko
- Subjects
Materials science ,X-ray microtomography ,medicine.diagnostic_test ,business.industry ,Soft tissue ,Magnetic resonance imaging ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,010309 optics ,Interferometry ,Optics ,0103 physical sciences ,Astronomical interferometer ,medicine ,Tomography ,Biomimetics ,0210 nano-technology ,business ,Image resolution - Abstract
X-ray imaging in the absorption contrast mode is an established method of visualising calcified tissues such as bone and teeth. Physically soft tissues such as brain or muscle are often imaged using magnetic resonance imaging (MRI). However, the spatial resolution of MRI is insufficient for identifying individual biological cells within three-dimensional tissue. X-ray grating interferometry (XGI) has advantages for the investigation of soft tissues or the simultaneous three-dimensional visualisation of soft and hard tissues. Since laboratory microtomography (μCT) systems have better accessibility than tomography set-ups at synchrotron radiation facilities, a great deal of effort has been invested in optimising XGI set-ups for conventional μCT systems. In this conference proceeding, we present how a two-grating interferometer is incorporated into a commercially available nanotom m (GE Sensing and Inspection Technologies GmbH) μCT system to extend its capabilities toward phase contrast. We intend to demonstrate superior contrast in spiders (Hogna radiata (Fam. Lycosidae) and Xysticus erraticus (Fam. Thomisidae)), as well as the simultaneous visualisation of hard and soft tissues. XGI is an imaging modality that provides quantitative data, and visualisation is an important part of biomimetics; consequently, hard X-ray imaging provides a sound basis for bioinspiration, bioreplication and biomimetics and allows for the quantitative comparison of biofabricated products with their natural counterparts.
- Published
- 2016
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