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Optimisation de la reconstruction en tomographie d'émission monophotonique avec collimateur sténopé

Abstract : In SPECT small animal imaging, it is highly recommended to accurately model the response of the detector in order to improve the low spatial resolution. The volume to reconstruct is thus obtained both by backprojecting and deconvolving the projections. We chose iterative methods, which permit one to solve the inverse problem independently from the model's complexity.
We describe in this work a gaussian model of point spread function (PSF) whose position, width and maximum are computed according to physical and geometrical parameters. Then we use the rotation symmetry to replace the computation of P projection operators, each one corresponding to one position of the detector around the object, by the computation of only one of them. This is achieved by choosing an appropriate polar discretization, for which we control the angular density of voxels to avoid oversampling the center of the field of view.
Finally, we propose a new family of algorithms, the so-called frequency adapted algorithms, which enable to optimize the reconstruction of a given band in the frequency domain on both the speed of convergence and the quality of the image.
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https://tel.archives-ouvertes.fr/tel-00112526
Contributor : Vincent Israel-Jost <>
Submitted on : Monday, November 27, 2006 - 3:04:27 PM
Last modification on : Monday, October 19, 2020 - 11:08:09 AM
Long-term archiving on: : Friday, November 25, 2016 - 1:13:29 PM

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  • HAL Id : tel-00112526, version 2

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Vincent Israel-Jost. Optimisation de la reconstruction en tomographie d'émission monophotonique avec collimateur sténopé. Mathématiques [math]. Université Louis Pasteur - Strasbourg I, 2006. Français. ⟨NNT : 2006STR13198⟩. ⟨tel-00112526v2⟩

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