L’objectif de cette thèse est de réaliser un agent de contraste vasculaire pour tomodensitométrie utilisable en préclinique. En collaboration avec le laboratoire de biogalénique de Strasbourg, ce travail a permis d’obtenir des nano-émulsions iodées produites par diffusion spontanée de surfactif et des nanoparticules iodées produites par ”émulsion - diffusion de solvant”, comme agent de contraste vasculaire. Ces émulsions et particules polymériques présentent en effet, un temps de rémanence vasculaire de plusieurs heures, un pouvoir contrastant suffisant pour un usage en tomodensitométrie (compris entre 170 et 400 HU), la possibilité de les administrer par intraveineuse et une stabilité de plusieurs mois. Les nano-émulsions, notamment celles produites à partir de Lipiodol®, sont les plus prometteuses comme agents de contraste vasculaire de par leur forte radiopacité (475 ± 30 HU) et leur rémanence vasculaire (T1/2 of 4.1 ± 1.10 h). Les nanoparticules iodées à base de PCL présentent un pouvoir contrastant inférieur (168 ± 13 HU) mais elles sont connus pour leur capacité à modifier la libération du principe actif encapsulé. De ce fait même si les agents de contraste de nature lipidique ou ceux inorganiques sont plus performant, elles restent intéressantes pour une visualisation rapide de la distribution du principe actif dans l’organisme. Cette thèse par ailleurs, apporte plusieurs éléments pour la compréhension de la formulation des nano-émulsions obtenues par diffusion spontanée de surfactif et celle des nanoparticules produites par ”émulsion - diffusion de solvant”. Concernant les nano-émulsions, l’influence de l’iodation des huiles et du surfactif a été étudiée autant sur le plan pharmacotechnique que ceux toxicologique et pharmacocinétique. Concernant les nanoparticules à base de PCL, nous avons montré que l’impact du type d’huile et de l’iodation, des polymères PCL et PCL-mPEG et de diverses méthodes de concentration sur la formulation / The aim of this thesis is to formulate a blood pool contrast agent for preclinical X-ray imaging application. In collaboration with the galenic laboratory of Strasbourg, this work has allowed to obtain iodinated nano-emulsions produced by spontaneous diffusion of surfactant and nano-particles produced by iodine ”emulsion - solvent diffusion” as blood pool contrast agent. These emulsions and polymer particles present indeed a vascular persistence of several hours, a sufficient contrast to be use in computed tomography (between 170 and 400 HU), the ability to be administered intravenous and stability of several months. Nano-emulsions, including those produced from Lipiodol®, are the most promising as blood pool contrast media by their high radiopacity (475 ± 30 HU) and vascular persistence (T1/2 of 4.1 ± 1.10 h). Iodinated nano-particles of PCL have a lower X-ray attenuation (168 ± 13 HU), but they are known for their control release of the encapsulated substances. Therefore even if inorganic or lipidic contrast agents show a better contrast, they remain attractive for rapid visualization of the co-encapsulated substance distribution in the body. This thesis also introduced several features for understanding the formulation of nano-emulsions obtained by spontaneous diffusion of surfactant and the nano-particles produced by ”emulsion - solvent diffusion.”

Orientador: Osvair Vidal Trevisan / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T00:58:52Z (GMT). No. of bitstreams: 1 VidalVargas_JanethAlina_D.pdf: 6980631 bytes, checksum: 2e858ba97bc5f6f4bb3b1a075776555f (MD5) Previous issue date: 2015 / Resumo: O conhecimento dos fenômenos físicos envolvidos no transporte de fluidos no meio poroso é muito importante para o projeto e o sucesso dos processos de recuperação melhorada de petróleo. O deslocamento miscível é um dos métodos mais eficientes de recuperação melhorada de petróleo. O parâmetro mais relevante na eficiência do deslocamento miscível é a dispersão, que controla a evolução da zona de mistura dos dois fluidos e a propagação do fluido injetado. Neste trabalho é desenvolvido e avaliado um modelo matemático para o deslocamento miscível 1-D em meios heterogêneos. O modelo, referido como modelo de concentração total (MCT) é desenvolvido com base na equação de convecção-dispersão (ECD) considerando a interação entre a rocha e os fluidos. Os parâmetros fenomenológicos envolvidos no MCT são o coeficiente de dispersão, o coeficiente de transferência de massa, a porosidade efetiva do meio poroso no momento de deslocamento e a fração de soluto que é depositada ou retirada do meio poroso. Estes parâmetros podem ser determinados por meio de ajustes multiparâmétricos do modelo aos dados obtidos em laboratório. Para avaliar a aplicação do modelo MCT foram realizados dois experimentos A e B, cada um formado por 4 e 5 testes de deslocamento respectivamente. Os testes de deslocamento utilizaram duas salmouras e foram realizados empregando-se uma rocha carbonática. A evolução das concentrações ao longo do meio poroso foi medida por Tomografia Computadorizada de Raios-X (TC). A grande quantidade de dados dos perfis de concentração determinados a partir das imagens da TC do Experimento A foi analisada e ajustada utilizando-se o modelo MCT por meio do método metaheurístico de recozimento simulado (Simulated Annealing, SA). O procedimento de ajuste global, considerando todas as curvas do histórico de concentração, foi utilizado para a determinação dos parâmetros governantes dos fenômenos envolvidos. A quantidade de dados utilizados e a robustez do método permitiu um ajuste muito bom do modelo aos dados experimentais. Determinou-se um coeficiente de dispersão de aproximadamente 0,01cm2/s para vazão de 1 cm3/min e 0,05 cm2/s para vazão de 5 cm3/min. Foram avaliados também os parâmetros de transferência de massa e interação do fluido com o meio poroso. O Experimento B foi realizado com a finalidade de comprovar a deposição de soluto enquanto o fluido se deslocava através da amostra de rocha. No modelo MCT, este fenômeno foi quantificado por meio do parâmetro fr. Os perfis de concentração do Experimento B foram medidos na entrada, ao longo da amostra (rocha) e na saída. A partir desses perfis, foi realizado um balanço de massa para avaliar a fração de deposição de soluto (fr) formulada e determinada a partir do MCT. Os valores de fr obtidos foram de 0,2 a 0,4, que são valores coerentes com os resultados obtidos com o modelo MCT / Abstract: The knowledge of the physical phenomena involved in fluid transport in porous medium is very important for the design and successful execution of oil enhanced recovery processes. Miscible displacement is one of the most efficient recovery methods. Dispersion is a key phenomenon in miscible displacement. It controls the evolution of the mixing zone of both fluids and the propagation of injected fluid. The present study focuses on the development and evaluation of a mathematical model for the 1-D miscible and active displacement in an intrinsically heterogeneous porous media. The model, referred to as total concentration model (TCM), is developed based on the convection-dispersion equation (CDE) considering the interaction between rock and fluids. The phenomenological parameters involved in TCM are the dispersion coefficient, the mass transfer coefficient, the effective porosity of the porous medium at the time of the displacement and the amount of solute that is deposited or removed from the porous medium. These parameters may be better determined through multiparametric matching of the model to the data obtained in the laboratory. In order to evaluate the application of the TCM model, two sets of experiments (A and B), totaling 9 tests, were carried out. The tests were conducted with two brines displaced in carbonate rock samples. The concentration evolution along the porous medium was measured by X-Ray Computed Tomography (CT). The vast amount of data from the concentration profiles determined from the CT images from set A was analyzed and matched to the TCM model through the simulated annealing metaheuristic method (Simulated Annealing, SA). The global matching procedure, considering all curves in the concentration history, was used to determine the governing parameters for the involved phenomena. The amount of data used and the robustness of the method allowed a very good matching of the model to the experimental data. A dispersion coefficient of 0.01cm2/s for a 1 cm3/min flow rate; and 0.05 cm2/s for a 5 cm3/min flow rate was determined. The parameters of mass transfer and of the fluid interaction with the rock porous structure were also evaluated. Experiment B was carried out in order to double check solute deposition while flowing through the rock sample. In the TCM model, the phenomenon was quantified by the fr parameter. The concentration profiles of Experiment B were measured at the input, along the rock sample and at the output. From these profiles a mass balance was carried out to evaluate the fraction of solute deposited (fr) during the experiment. The determined values for fr were 0.2 to 0.4, figures that are consistent with the results obtained with the TCM matching procedure / Doutorado / Reservatórios e Gestão / Doutora em Ciências e Engenharia de Petróleo

A expansão rápida de maxila assistida cirurgicamente (ERMAC) é uma das formas de tratamento para a deficiência transversal de maxila. Essa técnica depende do uso de dispositivos expansores, os quais podem ter relação com a movimentação dos dentes superiores, não existindo estudos que apontem alterações dos dentes inferiores. O presente trabalho teve como objetivo mensurar a movimentação dos dentes superiores e inferiores, produzidas pela ERMAC, por meio de técnicas cirúrgicas com diferentes tipos de corticotomias da parede anterior da maxila. O estudo foi composto 87 exames de tomografia computadorizada por feixe cônico (TCFC), sendo esses divididos de acordo com o osteotomia realizada: Grupo I (n= 42) osteotomia do tipo Le Fort I subtotal com degrau no pilar zigomático-maxilar e Grupo 2 (n = 45) osteotomia do tipo Le Fort I subtotal com osteotomia linear descendente. Os períodos avaliados foram divididos em: pré-operatório (T0), após o término da ativação do dispositivo expansor (T1) e período de contenção ortodôntica (T2). Os dados foram tabulados, comparados entre os períodos estudados e analisados estatisticamente por meio da análise de variância para medidas repetidas (ANOVA) e Teste de Tukey para comparação entre os três tempos, nos quais foram avaliados o total de pacientes (GI+GII) e cada grupo isoladamente (GI) (GII). Os resultados demonstraram aumento estatisticamente significativo das dimensões maxilares, além a inclinação vestibular dos dentes 13, 23, 16 e 26, em ambos os grupos; observaram-se efeitos dentoesqueléticos mandibulares na largura da cortical lingual, aumento da distância entre os ápices dos dentes 46 e 36 e inclinação vestibular do dente 36. Porém, somente esse último foi estatisticamente significante (p < 0,05). Isso nos permitiu concluir que, em procedimentos de expansão rápida de maxila assistida cirurgicamente são verificados efeitos dento-esqueléticos predominantemente maxilares, mas podem ocorrer efeitos mandibulares, sendo esses sem significância estatística. / Surgically assisted rapid maxillary expansion (SARME) is the main treatment option for transverse maxillary deficiency in adults. This technique depends on the use of expanders, which are commonly related to the movement of teeth in the maxilla, however, there are no studies analyzing the occurrence of alterations in the lower teeth to this date. The aim of this study was to assess the movement of upper and lower teeth produced by SARME executed by means of two surgical techniques with different types of corticotomies on the anterior wall of the maxilla. The sample consisted of 87 cone beam computed tomography (CBCT) scans, which were divided in two groups according to the osteotomy performed: Group I (n = 42) Le Fort I subtotal osteotomy with a step on the zygomatic-buttress and Group 2 (n = 45) Le Fort I type subtotal osteotomy with a linear descending osteotomy of the maxilla. The time periods evaluated were divided into: preoperative (T0), immediately after activation of the expander device was ceased (T1) and ending of orthodontic containment period (T2). The data were tabulated and compared between the periods studied and statistically analyzed by means of analysis of variance for repeated measurements (ANOVA) and Tukey\'s test for comparison between the three time periods. The total number of individuals (GI + GII) and each isolated group (GI) (GII) were analyzed. The results showed a statistically significant increase of all the maxillary dimensions associated with buccal inclination of the teeth 13, 23, 16 and 26 in both groups; mandibular dentoskeletal effects on the width of the lingual cortex were observed, there was also an increased distance between the apexes of teeth 46 and 36, and buccal inclination of the tooth 36 were noted, however, only the latter was statistically significant (p <0.05). This has allowed us to conclude that, in procedures of surgically assisted rapid maxillary expansion, dento-skeletal effects are predominantly maxillary, but mandibular effects may also occur, mainly without statistical significance.

A gordura pericárdica (GP), um componente do tecido adiposo visceral, tem sido consistentemente relacionada com aterosclerose coronária na população geral. Este estudo avaliou a associação entre GP e a calcificação arterial coronária (CAC) em pacientes com doença renal crônica (DRC) não dialítica. Este é um estudo transversal post-hoc da linha de base de coorte prospectiva de 117 pacientes com DRC em seguimento ambulatorial sem doença coronária manifesta (idade, 56,8 ± 11 anos; 64% do sexo masculino; 95,1% hipertensos; 25,2% diabéticos; 15,5% com história prévia de tabagismo; e estágios 2 a 5 da DRC e ritmo de filtração glomerular estimado de 36,8 ± 18,1 ml/min). O escore de CAC, volume de GP e gordura visceral abdominal (GVA) foram medidos por tomografia computadorizada. A associação da GP, como variável contínua, com a presença de CAC foi analisada por regressão logística multivariada. CAC (escore de cálcio>0) esteve presente em 59,2% dos pacientes. Na comparação com os pacientes sem CAC, aqueles com CAC eram 10 anos mais velhos, apresentaram maior proporção de homens (78,7% versus 42,9%, p < 0.001), tiveram maior circunferência de abdominal (95,9 ± 10,7 versus 90,2 ± 13,2 centímetros, p=0,02), maior volume de GP (224,8 ± 107,6 versus 139,1 ± 85,0 cm³, p < 0,01), e maior área de GVA (109,2 ± 81,5 versus 70,2 ± 62,9 cm², p=0,01). Em análise multivariada ajustada para idade, sexo, diabetes, história de tabagismo, história de tabagismo, e hipertrofia ventricular concêntrica; GP esteve significantemente associada com a presença de CAC (OR: 1,88 95% IC: 1,03-3,43 por desvio padrão, p=0,04). GP permaneceu associada com CAC mesmo após ajuste adicional para ritmo de filtração glomerular e fósforo sérico (OR: 1,85 95% IC: 1,00 - 3,42, p=0,05). A GP está independentemente associada com CAC em pacientes com DRC não dialítica. / Pericardial fat (PF), a component of visceral adipose tissue has been consistently related to coronary atherosclerosis in the general population. This study evaluated the association between PF and coronary artery calcification (CAC) in non-dialysis dependent chronic kidney disease (CKD) patients. This is a post-hoc cross sectional analysis of the baseline of a prospective cohort of 117 outward CKD patients without manifest coronary artery disease (age, 56.9 ± 11.0 years, 64,1% males, 95.1% hypertensive, 25.2% diabetics, 15.5% ever smokers, CKD stage 2 to 5 with estimated glomerular filtration rate 36.8 ± 18.1 ml/min). CAC scores, PF volume and abdominal visceral fat (AVF) areas were measured by computed tomography. The association of PF as a continuous variable with the presence of CAC was analyzed by multivariate logistic regression. CAC (calcium score >0) was present in 59.2% patients. On the comparison with patients with no CAC, those with CAC were 10 years older on average, had a higher proportion of male gender (78.7% vs. 42.9%, p < 0.001), and had higher values of waist circumference (95.9 ± 10.7 versus 90.2 ± 13.2 cm, p=0.02), PF volumes (224.8±107.6 versus 139.1±85.0 cm³, p < 0.01) and AVF areas (109.2 ± 81.5 versus 70.2 ± 62.9 cm², p=0.01). In the multivariate analysis, adjusting for age, gender, diabetes, smoking and, left ventricular concentric hypertrophy, PF was significantly associated with the presence of CAC (OR: 1.88 95% CI: 1.03-3.43 per standard deviation, p=0.04). PF remained associated with CAC even after additional adjustments for estimated glomerular filtration rate or serum phosphorus (OR: 1.85 95% CI: 1.00-3.42, p=0.05). PF is independently associated with CAC in non-dialysis dependent CKD patients

<p>Uprkos postojanju dijagnostičkih procedura za ranu dijagnostiku, sprovođenju preventivnog skrining programa, te dugom preinvazivnom periodu u kojem je moguće izvr&scaron;iti detekciju, karcinom grlića materice i dalje predstavlja jedan od vodećih zdravstvenih problema, imajući u vidu činjenicu da je uzrok obolevanja i umiranja velikog broja žena &scaron;irom sveta. Oko 85% karcinoma grlića materice dijagnostikuje se u zemljama u razvoju, čineći čak 15% svih malignih tumora kod žena, dok u razvijenim zemljama ovaj procenat iznosi 3,6% novootkrivenih karcinoma. Prema podacima Registra za rak Vojvodine, u AP Vojvodini u 2011. godini, od ukupnog broja novoregistrovanih malignih bolesti kod žena, karcinom grlića materice se nalazio na četvrtom mestu, sa procentualnim uče&scaron;ćem od 6,66%, dok je najveći broj novoobolelih slučajeva u starosnoj grupi 45&ndash;49 godina, pokazujući trend pomeranja prema mladjim starosnim grupama. Primena novih, savremenih dijagnostičkih metoda u inicijalnom zbrinjavanju obolelih od karcinoma grlića materice može doprineti pravilnijem tretmanu bolesti, utičući na tok bolesti, ishod i preživljavanje. PET/CT je hibridna imidžing metoda koja poslednjih godina zauzima značajno<br />mesto u određivanju stadijuma malignih bolesti i dijagnostikovanju recidiva, a kojom se stiče uvid u metaboličko/funkcionalni status ispitivanih tkiva i organa, superponiran na morfoanatomsku CT sliku. Kako je za cilj istraživanja postavljeno utvrđivanje značaja PET/CT pregleda u preoperativnoj evaluaciji karcinoma grlića materice, ispitanice koje su ispunjavale kriterijume za uključivanje u istraživanje su operisane nakon načinjenog PET/CT pregleda, a zatim su poređeni parametri dobijeni kliničkim pregledom, PET/CT pregledom, intraoperativnim pregledom i patohistolo&scaron;kim pregledom. Rezultati načinjenog istraživanja ukazuju da hibridni PET/CT imidžing ne demonstrira prednost u odnosu na dosada&scaron;nje preporuke vezane za preoperativnu dijagnostičku evaluciju ispitanica sa ranim stadijumom karcinoma grlića materice, naročito u detekciji postojanja primarnog tumora dimenzija manjih od 7mm i u detekciji prisustva mikrometastaza u lokoregionalnim limfnim čvorovima zbog jo&scaron; uvek ograničene prostorne rezolucije. PET/CT je pokazao izuzetno visoku specifičnost u utvrđivanju nepostojanja primarnog tumora i visoku komplementarnost sa patohistolo&scaron;kim nalazom. Uočeno je da PET/CT demonstrira statistički značajniju tačnost u proceni stepena pro&scaron;irenosti osnovne bolesti u odnosu na kliničko i intraoperativno utvrđivanje stepena pro&scaron;irenosti osnovne bolesti. Standardizovana vrednost preuzimanja radiofarmaka (SUV) zavisna od histolo&scaron;kog tipa karcinoma grlića materice, demonstrirajući najvi&scaron;e vrednosti u planocelularnom karcinomu i u lo&scaron;e diferentovanom tip G3 karcinomu grlića materice, pozitivno korelirajući sa promerom tumora. Pokazujući značajan potencijal u detekciji primarnog karcinoma grlića materice, kao i u detekciji metastaza u lokoregionalnim limfnim čvorovima, PET/CT nalazi svoje mesto u dijagnostičkoj obradi bolesnica sa karcinomom grlića materice.</p> / <p>Despite the existence of the diagnostic procedures for early diagnosis, implementing preventive screening programs and long preinvasive period in which it is possible to perform detection, cervical cancer remains one of the leading health problems, bearing in mind the fact that it is the cause of morbidity and mortality of a large number of women throughout the world. About 85% cases of cervical cancer are diagnosed in underdeveloped and developing countries. In economically underdeveloped countries, cervical cancer accounts for 15% of all malignant tumors in women, whereas in developed countries it is 3.6% of new cancers. According to data from the Cancer Registry of Vojvodina, in AP Vojvodina, in 2011, of the total number of newly registered malignant diseases in women, cervical cancer was in fourth place, with a percentage share of 6.66% , the largest number of new cases is in the 45-49 years age group, with the shifting the peak in the incidence of cervical cancer towards younger age groups. Applying of new diagnostic methods in the initial management of patients with cervical cancer, indirectly affect the course of the disease, its treatment, and survival. PET-CT hybrid imaging method in recent years occupies an important place in the staging of malignant disease and the diagnosis of recurrence, showing the functional state of certain tissues and organs (PET) with anatomical details (CT). As the aim of this study was to assess the importance of PET / CT scans in the preoperative evaluation of cervical cancer, the women who met the criteria were included in the study, and were operated after having PET / CT scans done, after which the parameters of the results of clinical examination, PET / CT examination, intraoperative examination and histopathological examination, were compared. It was observed that the hybrid PET / CT imaging does not demonstrate the advantage compared to the previous recommendations related to the preoperative diagnostic evaluation of patients with early-stage cervical cancer, especially in the detection of primary tumor measuring less than 7mm and the detection of the presence of micrometastases in the locoregional lymph nodes, due to the still limited spatial resolution. PET / CT showed extremely high specificity in determining the absence of primary tumor and high complementarity with histopathological findings. The study showed that PET / CT demonstrates statistically more significant accuracy in the assessment of the extent of the underlying disease, compared with the clinical and intraoperative determination of the extent of the underlying disease. It has been shown that the standardized uptake value of radiopharmaceuticals (SUV) depends on the histological type of cervical cancer, demonstrating the highest values in squamous-cell carcinoma and then in poorly differentiated G3 carcinoma of the cervix, positively correlating with the diameter of the tumor. Demonstrating significant potential in the detection of primary cervical cancer, as well as in the detection of metastases in locoregional lymph nodes, PET / CT has its place in diagnostic treatment of patients with cervical cancer.</p>

Rentgenová počítačová tomografie je metoda sloužící ke 3D zobrazování vnitřní struktury objektů. Mikrostruktura objektů ukrývá důležité informace, které mohou být použity k jejich charakterizaci. Tato práce podává spojení mezi datasety získanými pomocí rentgenové počítačové mikrotomografie a oblastí statistického zpracování dat. Výstupem metody, pak bude klasifikace vzorků na základě informací o jejich mikrostruktuře. Z výsledků klasifikace vzorků, pak můžeme vyvodit různé hypotézy týkající se původu vzorků. Tato práce by mimo jiné mohla sloužit jako takový nový vhled do problematiky kombinace dat různého původu, pomocí metod statistické analýzy.

At present, the medical industry rapidly develops new imaging techniques and improves the imaging methods. Simultaneously also are developed new methods for processing data acquired by these methods. Especially in the past few years has become very used method of registration data, which leads to image transformations of the same scene so that the condition as possible. The work deals with the method of processing data that provides detailed information to individual structures, developments of individual structures over time, allows to simultaneously displayanatomical and physiological information or preprocessing data for further processing.

The aim of the thesis is to design and implement a simulator of image reconstruction during x-ray computed tomography fluoroscopy. Apart from quantitative evaluation of particular imaging process parameters influence, the intended program application will lie in optimization of these parameter values. Introductory part is focused on brief theoretical description of x-ray computed tomography imaging process. Emphasis is placed on fluoroscopy-specific approaches, particularly the division of scanned projections into chosen amount of sectors as well as fluoroscopic imaging process evaluation methods. The subsequent part deals with program implementation and its limitations and sketches the possible working framework. Moreover, one of the chapters is devoted to optimization of imaging process parameters measurement. The final part aims at impact analysis of particular process parameters as well as fluoroscopic imaging process optimization approaches. The thesis consists also of a didactic simulator enabling real-time intervention simulation with manual instrument manipulation. Since both simulators are intended for teaching purposes, the thesis is supplemented with a laboratory exercise draft.

Dans un contexte industriel, la tomographie 3D par rayons X vise à imager virtuellement une pièce afin d'en contrôler l'intérieur. Le volume virtuel de la pièce est obtenu par un algorithme de reconstruction, prenant en entrées les projections de rayons X qui ont été envoyés à travers la pièce. Beaucoup d'incertitudes résident dans ces projections à cause de phénomènes non contrôlés tels que la diffusion et le durcissement de faisceau, causes d'artefacts dans les reconstructions conventionnelles par rétroprojection filtrée. Afin de compenser ces incertitudes, les méthodes de reconstruction dites itératives tentent de faire correspondre la reconstruction à un modèle a priori, ce qui, combiné à l'information apportée par les projections, permet d'améliorer la qualité de reconstruction. Dans ce contexte, cette thèse propose de nouvelles méthodes de reconstruction itératives pour le contrôle de pièces produites par le groupe SAFRAN. Compte tenu de nombreuses opérations de projection et de rétroprojection modélisant le processus d'acquisition, les méthodes de reconstruction itératives peuvent être accélérées grâce au calcul parallèle haute performance sur processeur graphique (GPU). Dans cette thèse, les implémentations sur GPU de plusieurs paires de projecteur-rétroprojecteur sont décrites. En particulier, une nouvelle implémentation pour la paire duale dite à empreinte séparable est proposée. Beaucoup de pièces produites par SAFRAN pouvant être vues comme des volumes constants par morceaux, un modèle a priori de Gauss-Markov-Potts est introduit, à partir duquel est déduit un algorithme de reconstruction et de segmentation conjointes. Cet algorithme repose sur une approche bayésienne permettant d'expliquer le rôle de chacun des paramètres. Le caractère polychromatique des rayons X par lequel s'expliquent la diffusion et le durcissement de faisceau est pris en compte par l'introduction d'un modèle direct séparant les incertitudes sur les projections. Allié à un modèle de Gauss-Markov-Potts sur le volume, il est montré expérimentalement que ce nouveau modèle direct apporte un gain en précision et en robustesse. Enfin, l'estimation des incertitudes sur la reconstruction est traitée via l'approche bayésienne variationnelle. Pour obtenir cette estimation en un temps de calcul raisonnable, il est montré qu'il est nécessaire d'utiliser une paire duale de projecteur-rétroprojecteur. / In industry, 3D X-ray Computed Tomography aims at virtually imaging a volume in order to inspect its interior. The virtual volume is obtained thanks to a reconstruction algorithm based on projections of X-rays sent through the industrial part to inspect. In order to compensate uncertainties in the projections such as scattering or beam-hardening, which are cause of many artifacts in conventional filtered backprojection methods, iterative reconstruction methods bring further information by enforcing a prior model on the volume to reconstruct, and actually enhance the reconstruction quality. In this context, this thesis proposes new iterative reconstruction methods for the inspection of aeronautical parts made by SAFRAN group. In order to alleviate the computational cost due to repeated projection and backprojection operations which model the acquisition process, iterative reconstruction methods can take benefit from the use of high-parallel computing on Graphical Processor Unit (GPU). In this thesis, the implementation on GPU of several pairs of projector and backprojector is detailed. In particular, a new GPU implementation of the matched Separable Footprint pair is proposed. Since many of SAFRAN's industrial parts are piecewise-constant volumes, a Gauss-Markov-Potts prior model is introduced, from which a joint reconstruction and segmentation algorithm is derived. This algorithm is based on a Bayesian approach which enables to explain the role of each parameter. The actual polychromacy of X-rays, which is responsible for scattering and beam-hardening, is taken into account by proposing an error-splitting forward model. Combined with Gauss-Markov-Potts prior on the volume, this new forward model is experimentally shown to bring more accuracy and robustness. At last, the estimation of the uncertainties on the reconstruction is investigated by variational Bayesian approach. In order to have a reasonable computation time, it is highlighted that the use of a matched pair of projector and backprojector is necessary.

The importance of aggregate structure and air voids distribution for asphalt mixture rutting and cracking performance has been well established on the basis of experience and is well documented in the literature. Past and current investigations are limited to assessment of performance based on macroscopic behavior due to the difficulty associated with the quantitative measurement and analysis of the internal structure of asphalt mixtures. Lately, technical advances in X-ray Computed Tomography (CT) and image processing and analysis has made possible to bring the attention also to the internal structure of asphalt mixtures. SPT results from asphalt field cores, including dynamic modulus (before and after loading) and microstrain accumulation (flow number), exhibited significant variability; most likely, induced by irregularities in the core shape. The analysis of aggregate structure and air voids distribution performed trough X-ray CT, clearly identified segregation in the asphalt mixture as a key factor that induced variability in SPT results. / QC 20120320