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Reconstruction 3D complète par modélisation Monte Carlo de la matrice système. Apport aux approches quantitatives à l'iode 131

Abstract : The accuracy of quantitative imaging in SPECT is degraded by physical effects, namely photon attenuation, Compton scatter and spatially varying collimator response. This problem is particularly difficult to tackle when using iodine-131-based acquisition because of the complexity of the associated spectrum. The objective of this thesis was to implement a fully 3D reconstruction using precise Monte Carlo simulations for estimating the projector (F3DMC) and to optimize the latter in order to be used in a clinical context. The first results were obtained using the EGEE grid infrastructure and suggest that a more robust projector is needed to improve the accuracy of the quantitative information. To deal with this conclusion, we used a novel method to speed up simulations based on the angular response function of the collimator/detector (ARF). Therefore, we assessed the ARF methodology in the context of iodine-131 simulations. We found that a global acceleration factor of 100 could be reached compared to a standard Monte Carlo simulations when a realistic heterogeneous medium was involved. The ARF method was implemented in our F3DMC algorithm and was assessed with an analytical phantom and real data extracted from a patient acquisition. The association of the F3DMC and ARF methodologies came with a clear improvement of the quantitative results.
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https://tel.archives-ouvertes.fr/tel-00441675
Contributor : Thomas Carlier Connect in order to contact the contributor
Submitted on : Friday, December 18, 2009 - 4:02:33 PM
Last modification on : Wednesday, November 10, 2021 - 3:32:02 PM
Long-term archiving on: : Thursday, September 23, 2010 - 11:08:23 AM

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  • HAL Id : tel-00441675, version 2

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Thomas Carlier. Reconstruction 3D complète par modélisation Monte Carlo de la matrice système. Apport aux approches quantitatives à l'iode 131. Biophysique [physics.bio-ph]. Université de Nantes, 2009. Français. ⟨tel-00441675v2⟩

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