Review This Product. Welcome to Loot. Checkout Your Cart Price. Special order. This item is a special order that could take a long time to obtain. Description Details Customer Reviews With the development of potent x-ray sources at many synchrotron laboratories worldwide, Compton scattering has become a standard tool for studying electron densities in materials. This book provides condensed matter and materials physicists with an authoritative, up-to-date, and very accessible account of the Compton scattering method, leading to a fundamental understanding of the electrical and magnetic properties of solid materials.
The spectrum of Compton scattered x-rays is particularly sensitive to this behavior and thus can be used as a direct probe and to test the predictions of theory. The current generation of synchrotron facilities allows this method to be readily exploited to study the ground state electron density in both elements and in complex compounds. This is due to the volume being rotated with respect to the CT acquisition plane in which the artefacts are created; hence the artefacts are minimised. In panel 8a, the frontal lobe, frontal cortex, and striatum can be seen.
The strongest streak artefacts can be seen in the axial images. This is because the axial orientation corresponds to only slightly acute angles with respect to the acquisition plane, while the angles of the other orientations are much larger. In general, streak artefacts pose a particular problem for brain PCXI-CT due to the very low contrast between structures within the brain.
Streaks that are not distinguishable above the noise in absorption contrast CT can dominate brain structures once that noise has been suppressed on phase retrieval, since they often display similar or even higher contrast. The many possible causes of these artefacts can also be very difficult to decouple. Nevertheless, we find that by paying particular care to the orientation of the sample in the CT acquisition plane, we can minimise these effects. Some residual streak artefacts still persist, and further investigation is required to determine the most appropriate method by which to correct for these effects.
For preclinical studies e. Ring artefacts can also be seen in the lower part of the coronal images of Fig. As with the streak artefacts, these are minimised by sectioning slices at an angle with respect to the CT acquisition plane. This means that fewer consecutive image pixels contain ring artefacts originating from the same detector elements, reducing structure in the artefacts. The artefacts, however, persist to some degree along the readout direction of the detector.
This results in a diffuse band that can be seen across panel 8b from the lower centre of the image, running diagonally upward and to the right, through the cerebellum. This effect is most prominent at the centre of rotation of the sample and becomes less so at larger radii. It should also be noted that it is of particular importance for phase contrast brain imaging to accurately account for all of the phenomena that cause each of the different types of artefact.
There are many correction methods that work effectively for absorption contrast CT imaging that are insufficient for the low-contrast edges that are enhanced using phase contrast imaging, as the latter exposes effects of these artefacts that, while present in absorption contrast imaging, are not generally problematic as they are below the noise threshold. With further development of artefact correction methods e. PSF deconvolution, improved detector characterisation, modelling source variations, etc.
Propagation-based PCXI-CT is shown here to be an effective tool for visualising the brain in situ for preclinical animal studies. While the surrounding skull, temporal fluctuations in the intensity of the source, and detector imperfections provide distinct challenges with respect to reconstruction artefacts, we find that there are ways to work around these limitations to see brain structures that might otherwise be obscured. We present a two-material phase retrieval algorithm for tomography, which was shown to be highly effective at delineating soft tissue from bone.
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We have identified the most problematic causes of these artefacts, and while further work will be required to address these phenomena, it is clear that it is already possible to identify structures that have previously been unresolved with conventional X-ray CT. All experiments were performed in accordance with relevant guidelines and regulations. The kittens were humanely killed in line with approved guidelines and the carcasses scavenged for this experiment.
To examine CT streak artefacts from strongly-absorbing samples, simulations were performed of a CT of an aluminium rod with a length and thickness designed to mimic those of the rabbit kitten skulls in the CTs discussed below. The phantom consisted of a 0.ofprobol.sdb.bo/wp-content/muskogee/3461-mujeres-solteras.php
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Further CTs were acquired at a higher resolution in order to test the effects of detector resolution on streak artefacts. Both were captured at an exposure time of The datasets supporting the findings of this study are available from the corresponding author on reasonable request. Rankin, S. CT and MRI. Oxford 26 , — Temple, N. Neuroimaging in adult penetrating brain injury: a guide for radiographers.
Brody, D. Current and future diagnostic tools for traumatic brain injury: CT, conventional MRI, and diffusion tensor imaging. Handbook of Clinical Neurology , — Cormack, A. Representation of a function by its line integrals, with some radiological applications.
Hounsfield, G. Computerized transverse axial scanning tomography : Part 1.
Ambrose, J. New techniques for diagnostic radiology. Cloetens, P. Holotomography: Quantitative phase tomography with micrometer resolution using hard synchrotron radiation x rays. Fitzgerald, R. Phase sensitive x-ray imaging. Today 53 , 23—26 Kitchen, M. CT dose reduction factors in the thousands using x-ray phase contrast.
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Foxley, S. Stucht, D. Highest resolution in vivo human brain MRI using prospective motion correction. PLoS One 10 , 1—17 Wu, D. In vivo mapping of macroscopic neuronal projections in the mouse hippocampus using high-resolution diffusion MRI. Neuroimage , 84—93 Astolfo, A.
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Synchrotron Rad. Hoshino, M. Phase-contrast x-ray microtomography of mouse fetus.
Open 1 , — Pfeiffer, F. High-resolution brain tumor visualization using three-dimensional x-ray phase contrast tomography. Schulz, G. High-resolution tomographic imaging of a human cerebellum: comparison of absorption and grating-based phase contrast. Interface rsif Beltran, M. Interface-specific x-ray phase retrieval tomography of complex biological organs. Pinzer, B. Imaging brain amyloid deposition using grating-based differential phase contrast tomography.