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Détecteurs spectrométriques pour la mammographie et traitements associés

Abstract : Detectors based on CdTe and CdZnTe have been developed for applications in X-ray and gamma ray high resolution spectrometry at room temperature. Recent advances in this type of detector and the development of fast readout electronics, allow to consider the use of this type of detectors for imaging applications or X-ray tomography. Several research teams have developed X-ray imaging systems with resolutions ranging from 50 to 1000 microns and a number of energy channels between 2 and 8. These detectors make discriminate the energy of the photons received, thus bringing additional information to traditional attenuation images. We used a material base decomposition algorithm to process the spectral information from the detector in order to provide quantitative information on the imaged tissues. This method was used in particular to determine the breast glandular density, which corresponds to the fraction of glandular tissues, and which is a risk factor for the development of cancer. It was also applied to contrast enhanced mammography to map the concentration of Iodine after injection of a contrast agent in order to highlight over-vascularized areas that may correspond to cancerous lesions. We therefore proposed to estimate the glandular density of breast and the concentration of iodine simultaneously, with one of a single acquisition, at a dose of 0.93 mGy. We used a spectral data processing algorithm to decompose the images on a 3 material base. First, polynomial methods have been adapted to be compatible with spectral information from 3 energy channels. Then, we showed that a second approach based on the maximization of the likelihood between a measured spectrum and spectra from a calibration database, was able to achieve better results. Finally, we have developed a method that takes into account breast compression in mammography to improve the results obtained by the maximum likelihood method. This method uses a priori flexible to take into account the density variation in the biological tissues as well as a minor error on the measurement of the total thickness by the compression system. Finally, an experimental validation of the proposed methods completes this work.
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https://hal-cea.archives-ouvertes.fr/tel-01758614
Contributor : Andrea Brambilla <>
Submitted on : Wednesday, April 4, 2018 - 4:02:11 PM
Last modification on : Monday, October 19, 2020 - 11:07:12 AM

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Yoann Pavia. Détecteurs spectrométriques pour la mammographie et traitements associés. Imagerie. Université de Lyon, 2017. Français. ⟨tel-01758614⟩

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