Röntgen‐Mikrotomographie

Bonse, U.

doi:10.1002/phbl.19970530305

Cited by 6 publications

(3 citation statements)

References 6 publications

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“…Micro-CT is a powerful technique that allows visualization of the internal structure of opaque objects without destroying the sample. As with synchrotron illumination (Bonse 1997), micro-CT with laboratory polychromatic x-ray sources already has several applications in bone research (Elliott et al 1997, Stenstrom et al 2000, Ruegsegger et al 1976. The overall bone quality is determined by its structural and material properties, such as bone mass, geometry, architecture and composition of the bone (Einhorn 1992).…”

Section: Introductionmentioning

confidence: 99%

Quantitative analysis of bone mineral content by x-ray microtomography

et al. 2003

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A new non-destructive method based on x-ray microtomography (micro-CT) was developed to measure calcium density in bone. X-ray micro-CT was used as a quantitative approach to acquire and reconstruct virtual cross-sections through the sample. Accurate beam-hardening correction was implemented. Grey values in the virtual cross-sections were calibrated as calcium mineral density in bone. From these cross-sections, three-dimensional models were created. Calcium content was calculated directly from images and expressed as percentage per volume and per weight. Calcium mineral density was studied by this method in a unique set of bones isolated from newts (Pleurodeles waltlii Michah) that had travelled into space. A demineralization of 10% was shown as a consequence of sustained micro-gravity.

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Section: Introductionmentioning

confidence: 99%

Quantitative analysis of bone mineral content by x-ray microtomography

et al. 2003

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“…The contrast advantage for phase, i.e. the relation between the real and the imaginary parts of the refractive index, is several orders of magnitude, as pointed by the pioneer in the field, U. Bonse, decades ago [17].…”

Section: Phase-contrast Imaging Using Hard X Raysmentioning

confidence: 99%

X-ray imaging of human brain tissue down to the molecule level

Müller¹,

Khimchenko

Rodgers³

et al. 2021

International Conference on X-Ray Lasers 2020

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X rays have been used for medical imaging since RÖNTGEN's fascinating discovery 125 years ago. The first radiographs of human hands were made public less than a month after his famous paper. The conventional X-ray sources integrated into the CT-machines of today's hospitals still rely on the same physical principles. X-ray imaging has traditionally offered high spatial resolution and low contrast for soft tissues such as the brain. Magnetic resonance imaging is therefore the method of choice for brain imaging in a clinical setting, although for cellular resolution studies it suffers from limited spatial resolution. The gold standard in post mortem brain imaging is histology, which involves fixation, embedding, physical sectioning, staining, and optical microscopy. Currently, section thickness limits isotropic voxel sizes to 20 µm. Advanced X-ray sources including synchrotron radiation facilities offer complementary modalities such as phase-contrast imaging and spatially resolved small-angle X-ray scattering. We showed that X-ray phase contrast of the human cerebellum with micrometer resolution yields complementary three-dimensional images to magnetic resonance microscopy with even better contrast and spatial resolution. Grating interferometry enabled us to visualize individual Purkinje cells in the nonstained cerebellum. Taking advantage of well-established paraffin embedding, Purkinje cells were visualized within the human cerebellum even with conventional instrumentation. Hard X-ray nano-holotomography allowed for label-free, three-dimensional neuroimaging beyond the optical limit with a spatial resolution below 100 nm. Spatially resolved smallangle X-ray scattering permitted the localization of periodic nanostructures such as myelin sheaths on square-inch brain slices and included the orientational information on the axons. These developments have contributed to the establishment of virtual histology and extended the conventional histology to the third dimension. Further advances are required to image the entire human brain with an isotropic micrometer resolution and to suitably handle the petabyte datasets.

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“…2 Therefore, researchers estimated that phase-contrast tomography could reach a hundred to thousand times greater sensitivity than absorption-contrast tomography. 3,4 Pioneering tomography studies with hard X-rays revealed that not only the widely used absorption-contrast and the newer phase-contrast imaging techniques provide complementary information but also phase imaging yields a substantially better contrast-to-noise ratio (CNR) than absorption. During the last two decades, high-resolution tomography in the phase-contrast mode has enabled the visualization of individual cells 5 and even sub-cellular details 6,7 in the post mortem human brain.…”

mentioning

confidence: 99%

Sensitivity comparison of absorption and grating-based phase tomography of paraffin-embedded human brain tissue

Bikis

Rodgers

Deyhle

et al. 2019

Applied Physics Letters

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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.

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Röntgen‐Mikrotomographie

Cited by 6 publications

References 6 publications

Quantitative analysis of bone mineral content by x-ray microtomography

Quantitative analysis of bone mineral content by x-ray microtomography

X-ray imaging of human brain tissue down to the molecule level

Sensitivity comparison of absorption and grating-based phase tomography of paraffin-embedded human brain tissue

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