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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

General Geometry Computed Tomography Reconstruction

Ramotar, Alexei January 2006 (has links)
The discovery of Carbon Nanotubes and their ability to produce X-rays can usher in a new era in Computed Tomography (CT) technology. These devices will be lightweight, flexible and portable. The proposed device, currently under development, is envisioned as a flexible band of tiny X-ray emitters and detectors. The device is wrapped around an appendage and a CT image is obtained. However, current CT reconstruction algorithms can only be used if the geometry of the CT device is regular (usually circular). We present an efficient and accurate reconstruction technique that is unconstrained by the geometry of the CT device. Indeed the geometry can be both regular and highly irregular. To evaluate the feasibility of reconstructing a CT image from such a device, a simulated test bed was built to generate simulated CT ray sums of an image. This data was then used in our reconstruction method. We take this output data and grid it according to what we would expect from a parallel-beam CT scanner. The Filtered Back Projection can then be used to perform reconstruction. We have also included data inaccuracies as is expected in "real world" situations. Observations of reconstructions, as well as quantitative results, suggest that this simple method is efficient and accurate.
2

General Geometry Computed Tomography Reconstruction

Ramotar, Alexei January 2006 (has links)
The discovery of Carbon Nanotubes and their ability to produce X-rays can usher in a new era in Computed Tomography (CT) technology. These devices will be lightweight, flexible and portable. The proposed device, currently under development, is envisioned as a flexible band of tiny X-ray emitters and detectors. The device is wrapped around an appendage and a CT image is obtained. However, current CT reconstruction algorithms can only be used if the geometry of the CT device is regular (usually circular). We present an efficient and accurate reconstruction technique that is unconstrained by the geometry of the CT device. Indeed the geometry can be both regular and highly irregular. To evaluate the feasibility of reconstructing a CT image from such a device, a simulated test bed was built to generate simulated CT ray sums of an image. This data was then used in our reconstruction method. We take this output data and grid it according to what we would expect from a parallel-beam CT scanner. The Filtered Back Projection can then be used to perform reconstruction. We have also included data inaccuracies as is expected in "real world" situations. Observations of reconstructions, as well as quantitative results, suggest that this simple method is efficient and accurate.
3

Imagerie multimodale (radiographie numérique, tomodensitométrie, résonance magnétique à 1,5 Tesla) pour l'évaluation des lésions d'ostéoarthrose

Bouchgua, Maria January 2007 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
4

Imagerie multimodale (radiographie numérique, tomodensitométrie, résonance magnétique à 1,5 Tesla) pour l'évaluation des lésions d'ostéoarthrose

Bouchgua, Maria January 2007 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

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