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Prise en compte du mouvement respiratoire pour la reconstruction d'images tomodensitométriques : Obtention d’images TDM 4D en salle de traitement pour la radiothérapie du cancer du poumon

Simon Rit 1
1 imagine - Extraction de Caractéristiques et Identification
LIRIS - Laboratoire d'InfoRmatique en Image et Systèmes d'information
Abstract : A computed tomography (CT) represents the 3D map of the linear attenuation coefficients of a X-ray beam. If the patient breath and the motion is not taken into account, the CT images of the thorax are disturbed by strong artifacts such as blur, streaks and bands. The objective of this thesis is to propose methods to correct these artifacts and to apply them in the context of the radiotherapy of the lung cancer to sequences of cone-beam projections acquired with a CT scanner mounted on the gantry of a linear accelerator. The first method uses a respiratory signal to select for the reconstruction the projections corresponding to a same phase. To apply it, we proposed a method to extract automatically the respiratory signal from the cone-beam projections. A quantitative analysis was then performed on simulated data to evaluate the impact of the reconstruction algorithm and of the different selection parameters of the cone-beam projections. We obtain thus CT images without blur but with a quality limited due to the small number of projections used. Other approaches modify the reconstruction algorithm to compensate for the respiratory motion using a realistic model, which allows to use all the acquired projections. We proposed two motion compensated reconstruction methods. The first one is analytic and based on a heuristic. The second one solves the problem algebraically from a discrete formulation of the transformations at stake via two new approaches, one forward and the other backward.
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https://hal.archives-ouvertes.fr/hal-01456881
Contributor : Équipe Gestionnaire Des Publications Si Liris <>
Submitted on : Monday, February 6, 2017 - 9:45:14 AM
Last modification on : Thursday, October 1, 2020 - 2:26:03 PM

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  • HAL Id : hal-01456881, version 1

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Simon Rit. Prise en compte du mouvement respiratoire pour la reconstruction d'images tomodensitométriques : Obtention d’images TDM 4D en salle de traitement pour la radiothérapie du cancer du poumon. Informatique [cs]. Université Lumière Lyon 2, France, 2007. Français. ⟨hal-01456881⟩

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