Дисертації з теми "Tomographie par émission – Innovation"
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Maronnier, Quentin. "Développement de tests et de procédures innovants pour la conception et l'évaluation d'une nouvelle technologie de TEP/TDM : du fantôme à l'humain." Electronic Thesis or Diss., Toulouse 3, 2023. http://www.theses.fr/2023TOU30292.
Positron Emission Tomography (PET) coupled with Computed Tomography (CT) is commonly used in oncology at various stages of the management of many cancers, either for diagnosis, treatment follow-up or monitoring. However, the technical performances of PET have so far been limited in detecting lesions smaller than 10 mm in diameter, preventing the quantification of metabolic activity in small volumes. Various hardware and software improvements, such as detection geometry, embedded electronics and reconstruction algorithms, have improved the overall performances of PET. To assess these performances, scientific experts from national and international authorities provide users and manufacturers with standardized procedures. These are useful for evaluating and comparing systems using test objects, but are unrealistic in terms of clinical practice. Regarding clinical data, the gold standard method for determining diagnostic accuracy is based on lesion detection. It is assessed by the rates of true positives and true negatives from patient examinations. Diagnostic accuracy can only be obtained by anatomocytopathological analysis of biopsies. Simulation provides an alternative method to the use of physical data through computational modeling. The most realistic is particle-tracking-based simulation, which is generically referred to as Monte Carlo method. A major limitation in particle-tracking simulation is the significant computation time which limits the generation of large datasets. Analytical simulation is another method that models the average probability of photon interactions instead of individual photon tracking. By combining physical data with fast analytical simulation, we are able to quickly generate significant sets of imaging configurations from a PET-CT system. As part of a research collaboration, we have a dedicated workstation and software solution for modelling, simulation and reconstruction of PET data. The simulation method used is based on the Insertion of Synthetic Lesion (ISL). The ISL consists in embedding synthetic information with known characteristics such as location, volume, shape and activity into pre-acquired data using system modeling. The aim is to use the method on physical data to create a scalable ground truth that meets clinical needs. In a first experimental study, we evaluate the accuracy of the ISL method in multiple scenarios in comparison to equivalent physical experiments. It is a first validation step performed on standardized objects. In a second study, we apply the ISL method to clinical examinations from two PET-CT systems. From this study, we highlight differences in clinical performances between the devices and establish a clinical trial model to quantify these differences. Finally, the clinical trial study the relevance of the ISL method applied to examinations of the same patients acquired consecutively on different PET-CT systems. The methodology used provides a cross-comparison of the performances under clinical conditions. ISL makes it possible to evaluate the differences in performances between two PET-CT scanners with a limited number of experiments or examinations. By using synthetically modified clinical images, it is possible to produce a ground truth in a realistic anatomical model and thus supports the clinical optimization of PET-CT scanners
Lapointe, David. "Tomographie par émission de positrons chez l'animal." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0020/MQ56924.pdf.
Juillard, Laurent. "Mesure du débit sanguin rénal par tomographie par émission de positons." Lyon 1, 2000. http://www.theses.fr/2000LYO1T195.
Maze, Anne. "Correction non uniforme de l'atténuation en tomographie d'émission simple." Rennes 1, 1992. http://www.theses.fr/1992REN1A006.
Le, Meunier Ludovic. "Développement d'un simulateur de tomographes à émission de positions." Université Joseph Fourier (Grenoble), 2004. http://www.theses.fr/2004GRE19003.
The positron emission tomography (PET) is a functional imaging modality. Due to the development of the FDG and due to its good sensitivity and its good resolution compared with gamma-cameras, PET is widely used in oncology in France and over the world. In this context, LETI has restarted its activity in whole body PET and it has launched a research study concerning new detection materials efficient at PET energy. Because of the cost of prototypes, a simulation step has been decided to provide a tool to compare performances of different devices. This thesis book shows the works around the simulation software, SimSET. The main part of this work is the validation step from data obtained with others simulation softwares and from two physical tomographs
Crivello, Fabrice. "Détection et localisation des activations cérébrales en tomographie par émission de positons." Paris 12, 1997. http://www.theses.fr/1997PA120019.
Prunier-Levilion, Caroline. "Etude du système dopaminergique par tomographie par émission monophotonique : des modèles animaux à l'homme." Tours, 2002. http://www.theses.fr/2002TOUR3309.
Grotus, Nicolas. "La synchronisation respiratoire pour l’exploration des tumeurs pulmonaires par tomographie par émission de positons." Paris 11, 2009. http://www.theses.fr/2009PA112085.
Positron Emission Tomography (PET) is a medical imaging technique that requires several minutes of acquisition to get an image. PET images are thus severely affected by the respiratory motion of the patient, which introduces a blur in the images. Techniques consisting in gating the PET acquisition as a function of the patient respiration exist and reduce the respiratory blur in the PET images. However, these techniques increase the noise in the reconstructed images. The aim of this work was to propose a method for respiratory motion compensation that would not enhance the noise in the PET images, without increasing the acquisition duration nor estimating the deformation field associated with the respiratory motion. We proposed 2 original spatiotemporal (4D) reconstruction algorithms of gated PET images. These 2 methods take advantage of the temporal correlation between the images corresponding to the different breathing phases. The performances of these techniques were evaluated and compared to classic approaches using phantom data and simulated data. The results showed that the 4D reconstructions increase the signal-to-noise ratio compared to the classic reconstructions while maintaining the reduction of the respiratory blur. For a fixed acquisition duration, the 4D reconstructions can thus yield gated images that are almost free of respiratory blur and of the same quality in terms of noise level as the ones obtained without respiratory gating. The clinical feasibility of the proposed techniques was also demonstrated
Stéphan, Cécile. "Mise au point d'une voie de synthèse des hexahydropyrrolo[2,1-a]isoquinoléines, destinées à l'imagerie médicale." Metz, 2002. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2002/Stephan_Coindet.Cécile.SMZ0208.pdf.
Zanotti, Fregonara Paolo. "Extraction de la fonction d'entrée artérielle des traceurs pour les études cérébrales en tomographie par émission de positrons." Paris 13, 2009. http://www.theses.fr/2009PA132003.
For the in vivo modelisation of radioactive tracer kinetics, it is necessary to know the input function, i. E the variation of arterial plasma tracer concentration over time. The input function is usually obtained by arterial blood sampling. Some studies have shown the possibility to calculate the input function directly from dynamic TEP images, using the time-activity curves obtained from large vascular structures. However, for brain studies, the largest blood vessels in the camera field of view are the internal carotids, the diameter of which is about 5mm. This aim of this work is to evaluate comparatively the existing methods for the segmentation of the internal carotids and for the PVE correction. We are proposed an original method for PVE corection as well, which be evaluated comparatively to the methods proposed in the literature
Sureau, Florent. "Exploitation de corrélations spatiales et temporelles en tomographie par émission de positrons." Phd thesis, Université Paris Sud - Paris XI, 2008. http://tel.archives-ouvertes.fr/tel-00348272.
Goldman, Serge. "Contribution a l'utilisation de la tomographie par émission de positons en neurologie." Doctoral thesis, Universite Libre de Bruxelles, 1997. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212110.
Carmona, Vincent. "Étude de l'endommagement de matériaux composites par tomographie X et émission acoustique." Lyon, INSA, 2009. http://theses.insa-lyon.fr/publication/2009ISAL0056/these.pdf.
Acoustic emission and X-ray tomography are used to study damage evolution of composite materials. This work is characterized by the coupling of these two particular techniques and by a new and fast tomography acquisition procedure. The metal matrix composites studied are made of aluminium alloys reinforced by ceramic particles. Depending on the matrix composition and the particle size damage occurs by decohesion or by particle fracture. The interpretation of the acoustic activity during a mechanical test is easier when damage is observed. And, actually tomography can provide a 3D imaging of damage during a mechanical test. This study confronts in a quantitative way results obtained by tomography and acoustic emission. Therefore, we have been able to ascertain several correlations between parameters from both techniques. For example, acoustic activity is linked to particles fracture whereas the acoustic emission energy is related to the fracture area. The fast tomography technique allows us to perform a continuous tensile test. The fast setup allows to increase of number of scans by test and thus improves the description of damage
Ballester, Michel. "Exploration des projections corticales sacculaires humaines en tomographie par émission de positons." Bordeaux 2, 2000. http://www.theses.fr/2000BOR23102.
Bay, Xavier. "Estimation non paramétrique de projections en tomographie par émission de photons simples." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10096.
Dreuille, Olivier de. "Quantification en tomographie d'émission monophotonique myocardique : mise au point, validation et comparaison par rapport à la tomographie d'émission de positons." Toulouse 3, 1996. http://www.theses.fr/1996TOU30280.
Cacheux, Fanny. "Synthèse de nouveaux ligands pour l'imagerie de la neuroinflammation par tomographie par émission de positons." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS342/document.
Neuroinflammation plays an important role in many neurodegenerative diseases (Alzheimer, Parkinson, Multiple sclerosis …) and recent developments in molecular imaging provide today new insights into the diagnostic and the treatement managment of these diseases. Among the existing imaging techniques, the highly sensitive and quantitative nuclear modalities SPECT (single photon emission computed tomography) but especially PET (positron emission tomography) play key roles. My PhD program is devoted to the design and synthesis of novel radioligands, all dedicated to the imaging of specific targets and processes linked to neuroinflammation. For this, PET and the short-lived positron-emitter fluorine-18 (T1/2: 109.8 min) remain the main focuses. The project has been divided into two sections, the first one concentrates on the development of novel ligands targeting the Translocator Protein 18 kDa (TSPO). Indeed, this target is today recognized as an early biomarker of neuroinflammatory processes and PK11195, an isoquinoline carboxamide labelled with carbon-11, was, in the late 80’s, the first reported PET-radioligand. More recently, new compounds, all belonging to different chemical classes, have emerged and notably the pyrazolopyrimidine acetamide [11C]DPA-713 and the pyridazinoindole acetamide [11C]SSR180575. Within the first section of my PhD, novel derivatives of both DPA-713 and SSR180575 have been synthesized and in vitro characterized. Dedicated precursors for labelling were also developed for the most promising candidates, and radiolabelling has been performed. Some results have been presented at the 21st International Symposium on Radiopharmaceutical Sciences (Columbia, MO, USA – May 26-31, 2015).The second part of my PhD, deals with the development of ligands for alternative targets to the TSPO, like the type-2 cannabinoid receptor (CB2R) and the purinergic P2Y14 / P2Y12 receptors, the latter emerging today as a hot topic for imaging opportunities. Up to now, a series of seven compounds targeting the CB2R has been successfully synthetized and in vitro characterized. Dedicated precursors of the most promising compounds have also been prepared and labelling will be shortly performed. The synthesis of ligands targeting the purinergic receptors has also been initiated and a first couple of reference / precursor has been obtained for the P2Y12R
Huet, Pauline. "Modélisation, simulation et quantification de lésions athéromateuses en tomographie par émission de positons." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112132/document.
Cardiovascular disease is the leading cause of death in western countries. New strategies and tools for diagnosis and therapeutic monitoring need to be developed to manage patients with atherosclerosis, which is one major cause of cardiovascular disease. Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) is a powerful imaging technique that can detect at early stages plaques prone to rupture. Yet, Partial Volume Effect (PVE), due to the small lesion dimensions (around 1 mm) with respect to the scanner spatial resolution (around 6 mm full width at half maximum), and statistical variations considerably challenge the precise characterization of plaques from PET images. An original model of atheromatous lesion parameterized by its dimensions and activity concentration, was developed. Thirty six Monte Carlo simulations of FDG-PET acquisitions were produced. Based on the simulations, we showed that the number of iterations in iterative reconstructions, the post filtering of reconstructed images and the quantification method in the Volume Of Interests (VOI) varied sharply in an analysis of the dedicated literature. Changes in one of these parameters only could induce variations by a factor of 1.5 to 4 in the quantitative index. Overall, inflammation remained largely underestimated (> 50% of the real uptake). We demonstrated that modeling the detector response could reduce the bias by 10% of its value in comparison to a standard OSEM recontruction and for an identical level of noise. In reconstructed images, we showed that the measured values depended not only on the real uptake but also on the lesion dimensions because of PVE. A minimum contrast of 4 with respect to blood activity was required for the lesion to be observable. Without PVE correction, the measured values exhibited a correlation with activity concentration but were much more correlated with the total uptake in the lesion. Applying a PVE correction leads to an activity estimate that was less sensitive to the geometry of the lesion. The corrected values were more correlated to the activity concentration and less correlated to the total activity. In conclusion, we showed that the total activity in inflammatory lesions could be assessed in FDG-PET images. This estimate did not require PVE correction. Tracer concentration estimates are largely biased due to PVE, and the bias can be reduced by measuring the maximum voxel in the lesion in images reconstructed with at least 80 iterations and by modeling the detector response. Explicit PVE correction is recommended to detect metabolic changes independent of geometric changes. An accurate estimation of plaque uptake will however require the intrinsic spatial resolution of PET scanners to be improved
Giffard-Quillon, Gaëlle. "Neuroanatomie fonctionnelle de la mémoire autobiographique : étude en tomographie par émission de positons." Caen, 2003. http://www.theses.fr/2003CAEN1387.
Depas, Gisèle. "La tomographie par émission de positions au FDG chez l'enfant : une approche historique et critique." Paris 6, 2012. http://www.theses.fr/2012PA066177.
Farman, Ara Bardia. "Méthode de quantification relative de la perfusion cérébrale suivant une systématisation vasculaire en tomographie d'émission monophotonique." Paris 12, 1996. http://www.theses.fr/1996PA120018.
Safai, Hossein. "Aspects quantitatifs de la gammatomoscintigraphie cérébrale." Paris 12, 1986. http://www.theses.fr/1986PA120013.
Priem, Thomas. "Développement et automatisation de la synthèse de nouveaux groupements prosthétiques pour le radiomarquage au fluor-18 de macromolécules." Rouen, 2012. http://www.theses.fr/2012ROUES050.
Positron Emission Tomography has emerged as a major technique of molecular imaging for the visualization and understanding of biological targets or phenomena. Indeed, thanks to its excellent sensitivity and the minor structural modifications of the radio-labeled compounds following introduction of the selected radio-isotope, there is almost no limitation in terms of targeted substrates. For example, in the case of sensitive substrates such as peptides or proteins, which are increasingly proposed as biological targets, the introduction of the radio-isotope under mild conditions is ensured by means of a prosthetic group. As a proof of its interest, PET has now been combined with other imaging techniques, such as fluorescent optical imaging or MRI, to build bimodal sensors. This growing area represents a breakthrough in the field of molecular imaging. During this PhD work, new prosthetic groups based on sultones units were synthesized. The advantageous properties of sultones have been used for the automated radio-syntheses of these prosthetic groups, which could be applied to the radio-labeling of a bio-relevant peptide. Our research interests then focused on the synthesis of fluorinated organic fluorophores, as preliminary work for the preparation of bimodal sensors. We especially designed a general way to radio-label and water-solubilize amino-based fluorophores through an efficient acylation reaction involving a previously-designed prosthetic group. This new strategy was applied for the preparation of a radio-fluorinated cyanine whose spectral properties are suitable for in vivo application
Genin, Rémi. "Intérêt de la tomographie par émission monophotonique dans la maladie d'Alzheimer et le vieillissement cérébral." Montpellier 1, 1997. http://www.theses.fr/1997MON11117.
Duthil, Pierre. "La tomographie d'émission monophotonique : premiers éléments vers la modernisation des volumes scintigraphiques." Toulouse 3, 1996. http://www.theses.fr/1996TOU30297.
Caderas, de Kerleau Charles. "Analyse tridimensionnelle des modes de contractions ventriculaires sur des tomoscintigraphies synchronisées à l'électrocardiogramme." Montpellier 2, 2003. http://www.theses.fr/2003MON20159.
Rousset, Olivier. "Correction in vivo des effets de volume partiel en tomographie par émission de positons." Lyon 1, 1998. http://www.theses.fr/1998LYO1T003.
Coez, Arnaud. "Evaluation des dispositifs médicaux correcteurs de la surdité par tomographie à émission de positons." Paris 11, 2009. http://www.theses.fr/2009PA112046.
Deafness is a dysfunction of auditory pathways that modifies the abilities of sound perception and the oral communication skills. The objective of this thesis was to adapt functional neuro-imaging technics like water labelled oxygen 15 (H₂¹⁵0) positron emission tomography to improve our knowledges about the cortical networks engaged in sound perception in deafness rehabilitation. A serie of activation studies in controls group allowed to explore by PET (H₂¹⁵0) the cortical networks engaged in intensity, frequency, duration, time attack, timbre and voice perception. These technics allowed to study a pathology like autism, and to find subtil cortical dysfunction networks in human voice perception compared to environmental non-human sounds. This paradigm has been used to evaluate medical devices in deafness rehabilitation like cochlear implants. There was a link between the temporal voice area (TVA) activation and the intelligibility score. TVA activation PET (H₂¹⁵0) study allowed to evaluate also auditory brainstem implants and bilateral cochlear implants. It could become a good neuro¬imaging tool to evalulate the effectiveness of technological innovations in deafness rehabilitation
Belin, Pascal. "Etude en tomographie par émission de positions des mécanismes de la latéralisation du langage." Paris, EHESS, 1997. http://www.theses.fr/1997EHESA024.
Anizan, Nadège. "Imagerie quantitative à l'iode-124 en tomographie par émission de positons du petit animal." Nantes, 2010. https://archive.bu.univ-nantes.fr/pollux/show/show?id=c64acd83-1c60-46d1-8815-0c6a3002c879.
Iodine-124 PET quantitative imaging requires the optimisation of acquisition parameters and of corrections adapted to the complex nature of the emission spectrum of that isotope. A first experimental approach establishes the performance of the Inveon, Siemens PET system dedicated to small animal and highlights the consequences of iodine-124 physical properties on images. To adapt or develop correction methods for various biases demonstrated experimentally, the PET camera Inveon was modelled with the Monte-Carlo simulation platform, GATE. Model validation was conducted by comparing simulated and experimental performances obtained for fluorine-18 and iodine-124. The simulation of test object placed in the Inveon system model determined the correction method most suitable for singles photons emitted by iodine-124. All optimisations performed on test objects of simple geometric shapes were tested in the case of small animal. The results show that some parameters optimised on the test objects did not influence the quantification of activity in the realistic case of a mouse injected with iodine-124. This thesis demonstrates the possibility of quantification by PET imaging of the distribution of monoclonal antibodies labelled with iodine-124 injected into a mouse
Ricq, Stéphane. "Etude de détecteurs en CdTe-Cl et CdZnTe pour la tomographie X médicale multicoupes." Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10137.
Marette, Caroline. "Approche de synthèses énantiosélectives automatisables de la 6-[18F] fluoro-L-Dopa et de la 3-O-méthyl-6-[18 Fluoro-L-Dopa." Toulouse 3, 2006. http://www.theses.fr/2006TOU30299.
Itti, Emmanuel. "Apport de la normalisation spatiale des tomoscintigraphies à un modèle de référence pour la mesure quantitative de la contraction et de la perfusion myocardiques." Paris 12, 2006. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990003939480204611&vid=upec.
The ability for gated SPECT to measure simultaneously myocardial contraction and perfusion constitutes a major step forward in the management of coronary artery disease, such diagnostically than prognostically. Numerous image processing approaches have been proposed since the 1990's to quantify as best as possible these variables. In the present work, we first have analyzed the performances and limitations of the main approaches proposed in the literature. Then, we have proposed an alternative approach, based on the spatial normalization of images to a reference heart template, which has been developed during a collaboration between our institution and the Quantificare company. The interest of spatial normalization is twofold : 1) to improve myocardial segmentation with help of an a priori anatomical reference provided by an averaged normal population (for the assessment of left ventricular ejection fraction), and 2) to better characterize perfusion distribution by performing a voxel-by-voxel comparison with the averaged normal population (for the assessment of extent and severity of hypoperfusions). Finally, we have validated this approach on appropriate patient populations, in terms of precision, accuracy and clinical pertinence. We provide the text of four original articles published in international journals in the scope of the present work. We conclude that spatial normalization not only allows to obtain reproducible and accurate measurements of left ventricular ejection fraction but also is adapted to monitor serial changes of ischemic pathologies
Tylski, Perrine. "Caractérisation des tumeurs et de leur évolution en TEP/TDM au ₁₈F-FDG." Paris 11, 2009. http://www.theses.fr/2009PA112235.
18F-FDG plays a major role in oncology. Accurate estimation of the tumor metabolic activity and metabolically-active volume from the images would considerably enhance the usefulness of the PET data. However, there is still no consensus on the most accurate methods for estimating these parameters. An original method estimating simultaneously the tumor volume and metabolic activity (measured by the SUV) has been developed. The method fits a model to the data. We compared its performances to 4 volume estimation methods and to 9 SUV estimation methods using phantom and simulated data. Using several optimization and validation procedures, we showed that two methods (including the proposed method) yielded more accurate and less variable estimates of volume and activity than the others. The results concerning the activity estimates were confirmed using patient data. Two tests assessing the significance of SUV change between two scans were also proposed. The first test uses several SUV indices from a standard PET scan. The second test takes advantage of 8 estimates of a single SUV index calculated from 8 images obtained using a respiratory-gated acquisition. Using simulated data, both tests properly detected real SUV changes. The second test was more efficient than the first but unlike the second test, the first test could be readily applied to any PET scan. These tests will now be assessed clinically to determine whether they can indeed facilitate PET-based therapy monitoring
Le, Digarcher Sandrine. "Détection automatique de fixations radioactives dans les images TEP oncologiques." Lyon, INSA, 2009. http://theses.insa-lyon.fr/publication/2009ISAL0119/these.pdf.
Therapeutic follow-up of patients with cancer is nowadays of main interest in research. Positron Emission Tomography (PET) appears to become a reference exam for monitoring treatment of cancers, particular in lymphoma. This PhD thus lieas on the development of a computer aided detection (CAD) tool focused on hardly visible tumors for whole-body 3D PET images. To achieve such a goal, we proposed an approach based on the combinaison of two classifiers, the Linear Discriminant Analysis (LDA) and the Support Vector Machines, associated with wavelet image features. Each classifier gives a 3D score map quantifying the probability of its voxels to correspond to a tumor. We proposed a 3D evaluation strategy based on the use of simulated images giving the targeted tumor characteristic gold standard. Such database was developed in this PhD from hundred Monte Carlo simulations of the Zuba phantom. It includes hundred images presenting 375 sperical tumors of calibrated contrasts. Results of the CAD obtained from the binary detection maps are promising. They open the perspective of enriching the binary information generally given to the clinician with parametric indices quantifying the pertinence of each detected tumor
Tang, Sandrine. "Synthèse, marquage et validation pharmacologique de ligands des récepteurs sérotoninergiques 5-HT6 et 5-HT7 de type indole et pyrrolidine." Lyon 1, 2007. http://www.theses.fr/2007LYO10233.
Thobois, Stéphane Christophe. "Étude par tomographie par émission de positons de la physiopathologie de la maladie de Parkinson et de l'effet de la stimulation sous-thalamique." Lyon 1, 2003. http://www.theses.fr/2003LYO1T029.
Jeanjean, Fabien. "Synthèse énantiosélective d'α-aminoacides par carboxylation d'α-aminolithiens : synthèse de la L-1-[11C]-méthionine utilisable en tomographie par émission de positons". Lyon 1, 1999. http://www.theses.fr/1999LYO10085.
Ploux, Lydie. "Développement et applications de Thor, un système original de tomographie d'émission, adapté au petit animal." Compiègne, 1997. http://www.theses.fr/1997COMP1064.
For many neurobiological studies, it is necessary to link microscopic aspects of the brain's organisation with integrated brain functions. Details of the former are obtained by in vitro and in situ molecular biology techniques, whereas the latter are acquired through behavioural studies. In vivo radio-imaging methods, like emission tomography, are the ideal tools to investigate the links between these two levels of brain organisation. The work which is presented here focuses on a new approach of emission tomography adapted to small animal studies: TOHR (french acronym for TOmographe Haute Résolution). The principle is based on the use of a large solid angle, high resolution and high efficiency focusing collimator. High resolution and high signal to noise ratio are improved by using nuclides having a two-photon decay with small angular correlation (125I, 123I, 111In,. . . ). The image is built step-by-step, by moving the animal relative to the collimator focal point. First, numerical simulations showed the possibility of reaching sub-rnillimetric resolutions; these results led to the collimator geometry (at present 10 over the 20 faces of an icosahedron, 15 faces in the future). Then, a prototype of TOHR has been built and characterised. Its performance is very close to the numerical predictions : spatial resolution of 1,4 mm and detection efficiency of 0,64 %. Finally, experiments on a rat thyroid allowed the preparation and realisation of the first experiments on a rat striatum. The good quality of these images shows that it is now possible to evaluate TOHR capabilities on a dopaminergic neuron degeneration model in rats, in the field of neurodegenerative disease studies
Monclus, Michel. "Développement de nouveaux traceurs radiopharmaceutiques pour les études oncologiques en tomographie par émission de positions." Doctoral thesis, Universite Libre de Bruxelles, 1999. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211874.
Jouvie, Camille. "Estimation de la fonction d'entrée en tomographie par émission de positons dynamique : application au fluorodesoxyglucose." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00966453.
Jouvie, Camille. "Estimation de la fonction d’entrée en tomographie par émission de positons dynamique : application au fluorodesoxyglucose." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112303/document.
Positron Emission Tomography (PET) is a method of functional imaging, used in particular for drug development and tumor imaging. In PET, the estimation of the arterial plasmatic activity concentration of the non-metabolized compound (the "input function") is necessary for the extraction of the pharmacokinetic parameters. These parameters enable the quantification of the compound dynamics in the tissues. This PhD thesis contributes to the study of the input function by the development of a minimally invasive method to estimate the input function. This method uses the PET image and a few blood samples. In this work, the example of the FDG tracer is chosen. The proposed method relies on compartmental modeling: it deconvoluates the three-compartment-model. The originality of the method consists in using a large number of regions of interest (ROIs), a large number of sets of three ROIs, and an iterative process. To validate the method, simulations of PET images of increasing complexity have been performed, from a simple image simulated with an analytic simulator to a complex image simulated with a Monte-Carlo simulator. After simulation of the acquisition, reconstruction and corrections, the images were segmented (through segmentation of an IRM image and registration between PET and IRM images) and corrected for partial volume effect by a variant of Rousset’s method, to obtain the kinetics in the ROIs, which are the input data of the estimation method. The evaluation of the method on simulated and real data is presented, as well as a study of the method robustness to different error sources, for example in the segmentation, in the registration or in the activity of the used blood samples
Richard, Jean-Christophe. "Imagerie fonctionnelle pulmonaire par tomographie en émission de positons et physiopathologie de l'agression pulmonaire aigue͏̈." Lyon 1, 2003. http://www.theses.fr/2003LYO10049.
David, Simon. "Analyse d'images pour les études de la réponse thérapeutique en Tomographie par Émission de Positon." Brest, 2011. http://www.theses.fr/2011BRES2059.
Positron Emission Tomography (PET) is a tool for therapy response assessment. It is also used for the definition of a biological tumour volume with one or more PET scans measuring different tumour. Three fusion methods have been developed to combine follow-up or multi-tracer PET scans. Based on the Bayesian classification principle, the first approach noted ASEM can be used for the fusion of either follow-up or multi-tracer scans. The second method consists in merging multi-tracer scans through the Dempster-Shafer theory (DS) in order to define a global tumour volume. The third approach is based on the change detection principle using the Dezert-Smarandache theory (DSm), applied to follow-up scans. The methods were applied to simulated and clinical datasets in follow-up and multi-tracer context. Their performances were compared to the use of fixed and adaptive thresholding and the Fuzzy-Cmean algorithm. On simulated datasets, the fixed and adaptive thresholds and the FCM algorithm led to higher errors than the ASEM approach. The change detection method was associated with satisfactory performance on simulated follow-up data. For the clinical follow-up data, the fixed threshold and the FCM segmentation failed to provide coherent measurements. The adaptive threshold demonstrated low robustness, leading to very high variability in the measurements. The ASEM method wais the one for which the variations of the measurement are the most coherent with the therapeutic response. These results were further confirmed by the results obtained on multi-tracer clinical cases. The threshold methods and the FCM segmentation were less robust versus noise arid tumour contrast. On the other hand, the analysis associated with the ASEM fusion emphasized the robustness of this approach
Pouletaut, Philippe. "Reconstruction d'images en tomographie par émission de photons uniques pour le contrôle de déchets radioactifs." Clermont-Ferrand 2, 1992. http://www.theses.fr/1992CLF21490.
Mallon, Agnès. "Reconstruction 3D pour la tomographie par émission de positons avec mesure du temps de vol." Grenoble 1, 1993. http://www.theses.fr/1993GRE10159.
Nguyen, Pham Truong. "Imagerie corrélative : autoradiographie - tomographie par émission de positons : application à l’imagerie cérébrale dans le lupus." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAE027.
Nuclear imaging is essential in the clinical and pre-clinical field for studying the biodistribution of the drug and observing the evolution of the pathology. Positron Emission Tomography (PET) scan is today a gold standard functional imaging with picomolar sensitivity. It offers a resolution of the order of a millimetre. As part of this thesis, autoradiography, with Mimosa-28 semiconductor sensors, provides a sub-millimetre resolution while keeping a good sensitivity in order to visualize the cerebral distribution of the radiotracer in the mouse. Before the autoradiography acquisition, this sensor is characterized with isotopes usually used in preclinical systems in the PET system : 18F, 64Cu and 89Zr. Measurements of efficiency and spatial resolution are made to compare with other current systems such as emulsion films, phosphorescence, scintillation and gaseous detectors. PET scans enable both to explore biodistribution at the animal scale before to visualize the distribution with autoradiography at the tissue scale. We then explore the possibility of improving the quality of images through GEANT4 Application for Tomography Emission (GATE) Monte-Carlo simulation and reconstruction using a Maximum Likelihood Estimation Method (MLEM) algorithm. The autoradiographic images gain in contrast and the scattering effect of the charged particles into the medium is attenuated
Truchot, Lydie. "Apports diagnostiques du 18F-MPPF en Tomographie par émission de Positons dans la maladie d’Alzheimer." Lyon 1, 2007. http://www.theses.fr/2007LYO10102.
A probable diagnosis of Alzheimer’s disease (AD) is possible during the life of the patient. Recent studies have shown modifications of the serotonergic metabolism in AD. In the early and differential diagnostic approach of AD, we have studied in vivo serotonergic system of AD patients at different stages of the disease and patients with other dementia with 18F-MPPF PET, which allows studying the 5-HT1A serotonergic receptors which mainly located the limbic structures, affected early in AD. Our results show that serotonergic system is early affected in AD, allowing the discrimination of AD at the different stages and with other dementia, suggesting the presence of a compensatory mechanism at the early stage of AD. This study shows that the 18F-MPPF PET is an interesting tool for the physiopathological study of AD and that it is a tool for early diagnosis of AD
Collet, Solène. "L'IRM multiparamétrique et la TEP pour les gliomes : deux outils complémentaires pour la détermination du grade, l'évaluation de la survie et l'analyse spatiale." Caen, 2013. http://www.theses.fr/2013CAEN3165.
Imaging is used at different stages of management of glioma patients including conventional MRI. To better characterize this disease, more specific physiological and / or metabolical markers of tumor cells, vascularization or hypoxia mesured from multiparametric MRI (IRMmp) as perfusion (CBV), diffusion (ADC) and magnetic resonance spectroscopy (MRS) or PET with tracer [18F]-FLT and [18F]-FMISO. In this work, except FMISO, these imaging markers have been studied to determine the grade of gliomas and in relationship with the survival of patients with glioblastoma (GBM) to evaluate their diagnostic and prognostic value. Modalities for a better classification of tumor grade are the ADC and uptake [18F]-FLT. In addition, multivariate analysis also highlights the FLT PET and ADC as the best imaging biomarkers to predict survival. The analysis of the spatial relationships of various biomarkers in GBM shows that potentially aggressive areas, uptake of [18F]-FLT and vascularity are present outside areas of contrast enhancement usually treated. These could be incorporated to optimize the treatment of surgery and radiotherapy. These multimodal images also allow us to study the links between the different pathophysiological mechanisms and suggest that tumor proliferation is the cause of hypoxia and vasculature and that these two phenomena are spatially dissociated
Israel-Jost, Vincent. "Optimisation de la reconstruction en tomographie d'émission monophotonique avec colimateur sténopé." Université Louis Pasteur (Strasbourg) (1971-2008), 2006. https://publication-theses.unistra.fr/public/theses_doctorat/2006/ISRAEL-JOST_Vincent_2006.pdf.
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