Le Carcinome Hépatocellulaire a une incidence mondiale élevée et est associé à un mauvais pronostic. Les traitements curatifs existants ne sont applicables qu’à une minorité de patients. La radiothérapie sélective interne (SIRT) est un traitement palliatif de plus en plus utilisé. Elle consiste à l’injection sélective intra-tumorale de microsphères d’yttrium-90 par infusion intra-artérielle, et repose sur deux étapes : une étape pré-thérapeutique de simulation du traitement avec l’injection de macroagrégats d’albumines marqués au 99mTc et le traitement en lui-même. Cependant les caractéristiques de ces deux vecteurs diffèrent et peuvent conduire à des variations de biodistribution et à une dosimétrie approximative. Ce travail a pour but de développer un vecteur radiothéranostique unique pour la SIRT : les microparticules à base d’amidon (SBMP), afin de pallier aux différents problèmes rencontrés en clinique. L’optimisation du radiomarquage par le 68Ga et le 188Re sous forme de kits lyophilisés prêts-à-l’emploi, a permis d’obtenir une pureté radiochimique > 98 % et > 95 % respectivement. Une étude préliminaire par imagerie TEP/TDM in vivo chez le rat, suite à l’injection intraartérielle des 68Ga-SBMP a montré une biodistribution spécifique des microparticules avec plus de 95 % de l’activité retrouvée dans le foie et plus particulièrement dans les tumeurs. Les SBMP offrent plusieurs avantages répondant à différents problèmes actuels et constituent un agent théranostique prometteur pour la SIRT. Une présentation de la SIRT, des différentes microparticules en développement pour la SIRT et des modèles animaux de tumeur hépatique existants seront également développées dans ce travail. / The Hepatocellular Carcinoma has a high incidence worldwide and is associated with a bad prognostic. The existing curative treatments can only be apply in a minority of cases. The selective internal radiation therapy (SIRT) is a palliative treatment that is increasingly used. This technique is define by the selective intratumoral injection of yttrium-90microspheres via intra-arterial infusion. It involves two steps : a pre-therapeutic one for treatment simulation purpose with the injection of serum albumin macroaggregates radiolabeled with 99mTc and the treatment itself. However the characteristics of these two vectors are different and can lead to variations in biodistribution and approximate dosimetry. This works aims to develop a unique radiotheranostic vector for the SIRT: the starch-basedmicroparticles (SBMP), in order to overcome the different currents clinical problems. The optimization of the radiolabeling by the 68Ga and the 188Re in the form of ready-to-use radiolabeling kits allowed to obtain a radiochemical purity > 98 % and > 95 % respectively. A preliminary in vivo study by PET/CT imaging in rat, following the intra-arterial injection of 68Ga-SBMP displayed a specific biodistribution of the microparticles with more than 95 % of the activity found in the liver and mostly in the tumors. The SBMP offer several advantages that answer different current issues and area promising theranostic agent for the SIRT. A presentation of the SIRT, the different microparticles in development and the existing animal models of hepatic tumor will also be developed in this work.

Magister Chirurgiae Dentium (MChD) / Purpose: To evaluate and compare the in-vitro shear bond strength and micro leakage of two compomers with their adhesive systems and to examine the dentine-restorative interface under confocal scanning laser microscopy (CSLM). Matoiats and Methods: For shear bond strength (SBS) testing thirty non-carious human molars were used of which fifteen molars were restored with Dyract AP using Non-Rinse Conditioner (NRC) and Prime&Bond NT (PBNT) and fifteen were restored with F2000 and Scotchbond Multi-Purpose Plus (SBMP). For the microleakage evaluation cavity preparations were made on the facial surfaces of thirty non-carious premolars. These were then restored with the respective compomer system. The specimens were thermocycled, sectioned and examined for dye penetration. The dentine-restorative interface was examined through a confocal scanning laser microscope. The primers of the bonding agents were labelled with rhodamine B and the adhesive resins were labelled with fluorescein and examined under CSLM in fluorescent mode. Results: The mean SBS for PBNT and SBMP were 12.8 and 18.1 MPa, respectively. The microleakage scores showed Dyract with PBNT leaked on the dentine side in 13 of the 15 specimens examined. On the enamel side 2 of the 15 specimens showed microleakage. With F2000 and SBMP no micro leakage was observed on either enamel or dentine sides. The CSLM images show clear resin tag and hybrid layer formation for both the materials examined, although SBMP showed deeper penetration into the dentine with longer resin tags. The length of the resin tags and thickness of the hybrid layer for PBNT was found to be approximately 10 um and 2 um respectively. SBMP showed resin tags measuring about 100 um while the hybrid layer measured about 5 um. Conclusion: This study demonstrates that the acid-etch technique ofSBMP with F2000 produces higher bond strength and no micro leakage when compared to the self-etching/self-priming "non-rinse technique" of NRC with PBNT and Dyract.