995 resultados para Pet Society (Joc)
Resumo:
The failure of current strategies to provide an explanation for controversial findings on the pattern of pathophysiological changes in Alzheimer's Disease (AD) motivates the necessity to develop new integrative approaches based on multi-modal neuroimaging data that captures various aspects of disease pathology. Previous studies using [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) and structural magnetic resonance imaging (sMRI) report controversial results about time-line, spatial extent and magnitude of glucose hypometabolism and atrophy in AD that depend on clinical and demographic characteristics of the studied populations. Here, we provide and validate at a group level a generative anatomical model of glucose hypo-metabolism and atrophy progression in AD based on FDG-PET and sMRI data of 80 patients and 79 healthy controls to describe expected age and symptom severity related changes in AD relative to a baseline provided by healthy aging. We demonstrate a high level of anatomical accuracy for both modalities yielding strongly age- and symptom-severity- dependant glucose hypometabolism in temporal, parietal and precuneal regions and a more extensive network of atrophy in hippocampal, temporal, parietal, occipital and posterior caudate regions. The model suggests greater and more consistent changes in FDG-PET compared to sMRI at earlier and the inversion of this pattern at more advanced AD stages. Our model describes, integrates and predicts characteristic patterns of AD related pathology, uncontaminated by normal age effects, derived from multi-modal data. It further provides an integrative explanation for findings suggesting a dissociation between early- and late-onset AD. The generative model offers a basis for further development of individualized biomarkers allowing accurate early diagnosis and treatment evaluation.
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In oncology, positron emission computed tomography (PET/CT) has become an essential tool for initial staging, response evaluation and follow-up of cancer patients. Most of the frequent tumors (lung, breast, esophagus, and lymphomas) are highly avid for (18)F-fluorodeoxyglucose ((18)FDG), but prostate cancer has not demonstrated significant uptake of FDG. The development of new tracers labeled with (18)F such as choline analogs allowed already to obtain interesting results particularly in patients with biological relapse and inconclusive conventional imaging workup. The impact of (18)F-flurocholine PET/CT on patient management needs to be validated in large studies, but many centers use already this examination in order to guide further management, including radiotherapy planning. (C) 2011 Elsevier Masson SAS. All rights reserved.
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OBJECTIVES: The purpose of this study was to compare myocardial blood flow (MBF) and myocardial flow reserve (MFR) estimates from rubidium-82 positron emission tomography ((82)Rb PET) data using 10 software packages (SPs) based on 8 tracer kinetic models. BACKGROUND: It is unknown how MBF and MFR values from existing SPs agree for (82)Rb PET. METHODS: Rest and stress (82)Rb PET scans of 48 patients with suspected or known coronary artery disease were analyzed in 10 centers. Each center used 1 of 10 SPs to analyze global and regional MBF using the different kinetic models implemented. Values were considered to agree if they simultaneously had an intraclass correlation coefficient >0.75 and a difference <20% of the median across all programs. RESULTS: The most common model evaluated was the Ottawa Heart Institute 1-tissue compartment model (OHI-1-TCM). MBF values from 7 of 8 SPs implementing this model agreed best. Values from 2 other models (alternative 1-TCM and Axially distributed) also agreed well, with occasional differences. The MBF results from other models (e.g., 2-TCM and retention) were less in agreement with values from OHI-1-TCM. CONCLUSIONS: SPs using the most common kinetic model-OHI-1-TCM-provided consistent results in measuring global and regional MBF values, suggesting that they may be used interchangeably to process data acquired with a common imaging protocol.
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Abordamos el Informe del Grupo de Alto Nivel sobre la Coherencia en todo el Sistema de las Naciones Unidas («Informe del Grupo») y el proceso de reforma de las Naciones Unidas del que forma parte como grupos de la sociedad civil que tienen una larga experiencia por lo que se refiere a propugnar reformas del sistema de las Naciones Unidas.
Resumo:
For the past decade, PET and PET/CT have been widely studied for myocardial perfusion imaging. Several studies demonstrated the incremental value of PET for the diagnostic and prognostic assessment of patients with coronary artery disease. Moreover, PET allows for non-invasively quantifying myocardial blood flow and myocardial flow reserve, that both are recognized as surrogate marker of cardiac event free survival. By enabling the exploration of epicardial disease and the microvasculature, PET constitutes a unique tool to study pathophysiogical mechanisms leading to atherosclerosis genesis. The recent emergence of high-tech hybrid machines may even provide further incremental information about coronary function and morphology. By taking the best of each modality, a better assessment of patients with coronary artery disease is expected. (C) 2011 Elsevier Masson SAS. All rights reserved.
Resumo:
O objetivo deste trabalho foi avaliar a eficácia de armadilha de garrafa Pet vermelha contendo compostos voláteis alcoólicos atrativos, no controle massal da broca-do-café (Hypothenemus hampei). As avaliações foram realizadas em quatro lavouras de café, durante dois anos. Foram distribuídas 900 armadilhas de garrafa Pet, pintadas de vermelho, em três das quatro lavouras; uma lavoura sem armadilhas foi usada como controle. O broqueamento dos frutos (%) foi determinado nessas lavouras. Houve redução do broqueamento de frutos nas lavouras com armadilhas, da safra 2007/2008 para a safra 2008/2009. As maiores densidades da broca-do-café nas armadilhas foram observadas nos estádios de floração e de frutos chumbinho. A armadilha de garrafa Pet vermelha é eficaz no controle massal da população da broca-do-café, por reduzir a percentagem de frutos broqueados em 57%; entretanto, essa redução não é suficiente para manter as densidades da broca abaixo do nível de controle.
Resumo:
Tämän tutkielman tavoitteena on selvittää informaatio- ja kommunikaatioyhteiskunnan vaikutusta paperin kulutukseen maailmanlaajuisesti. Tarkoituksena on löytää informaatio- ja kommunikaatioyhteiskuntaa kuvaavia mittareita, joiden avulla voidaan vertailla kehittyneitä ja kehittyviä markkina-alueita keskenään. Tutkimusongelmaan haetaan ratkaisua tutkimalla sekä kirjallisuutta että tilastoja, ja vertaamalla niitä esitettyihin teorioihin informaatio- ja kommunikaatioyhteiskunnan kehityksestä. Tutkielman avulla pyritään arvioimaan ja kuvaamaantoimintaympäristön muutoksia paperin kulutuksen suhteen pitkällä aikavälillä informaatio- ja kommunikaatioyhteiskunnan näkökulmasta.
Resumo:
Des del Grup de Recerca i Investigació sobre Esport i Societat (GRIES) ha semblat escaient iniciar un projecte de recerca que permeti aprofundir en l’estudi de la “Cultura lúdica com a patrimoni”. Aquest projecte de recerca i la dedicada a “Esport i modernització a Catalunya en el segle XX” són els dos projectes que sostenen una de les quatre línies d’investigació desplegades per aquest grup de recerca, en concret aquella que fa referència a “Cultura, esport i patrimoni”. Doncs bé, el present article dóna a conèixer els resultats obtinguts en tres estudis en relació a la utilització d’una de les fonts iconogràfi ques que al nostre entendre no ha merescut la sufi cient atenció per part dels investigadors malgrat disposar d’informacions força valuoses, si més no, en l’àmbit de l’estudi dels jocs populars i tradicionals. Ens estem referim a la iconografi a fi latèlica. El primer dels estudis mostra els resultats obtinguts en la investigació d’una emissió fi latèlica que aplegava força manifestacions lúdiques, la “Serie Europa -Juegos infantiles - 1989”. El segon ha consistit en l’elaboració d’un catàleg fi latèlic de jocs tradicionals d’Europa i el seu corresponent anàlisi. Per últim, el tercer, pretén consolidar aquest projecte, amb la realització d’una tesi doctoral que pretén estudiar els jocs i esports tradicionals d’arreu del món a través de la fi latèlia.
Resumo:
Self-measurement of blood pressure at home is increasingly used in the diagnostic and therapeutic approach of hypertension. This technique allows multiple measurements of blood pressure away from the clinical setting, making it possible to improve the evaluation of cardiovascular risk. Recently new guidelines on the use of self-measured blood pressure have been made available by the European Society of Hypertension, as summarized in the present paper.
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Comprend : Histoire du prince Pet-en-l'Air et de la reine des Amazones ; La Société des francs-péteurs
Resumo:
Le présent travail a eu comme but la comparaison de la performance de deux méthodes d'imagerie diagnostique pour la détection de métastases hépatiques du mélanome uvéal : la tomographie d'émission par positons au F-18-fluorodésoxyglucose (TEP FDG) couplée à la tomodensitométrie (TDM) et l'imagerie par résonance magnétique (IRM). Dans cette étude rétrospective, nous avons analysé les données radiologiques de patients inclus dans une étude multicentrique randomisée de phase III de l'Uveal Melanoma Group of the European Organization for Research and Treatment of Cancer (EORTC). L'IRM s'est révélée nettement plus sensible que le FDG-PET/CT pour mettre en évidence les métastases hépatiques notamment de taille infra-centimétrique. Néanmoins, l'analyse des changements de l'accumulation du traceur métabolique par les métastases hépatiques au cours du traitement suggère la possibilité d'évaluer, de manière précoce, la réponse des métastases hépatiques à la chimiothérapie. Le nombre de cas étudiés est trop faible pour déterminer la précision et la valeur clinique d'une telle évaluation mais les résultats obtenus dans cette étude pilote justifient une étude plus étendue.
Resumo:
The implementation of new techniques of imaging in the daily practice of the radiation oncologist is a major advance in these last 10 years. This allows optimizing the therapeutic intervals and locoregional control of the disease while limiting side effects. Among them, positron emission tomography (PET) offers an opportunity to the clinician to obtain data relative to the tumoral biological mechanisms, while benefiting from the morphological images of the computed tomography (CT) scan. Recently hybrid PET/CT has been developed and numerous studies aimed at optimizing its use in the planning, the evaluation of the treatment response and the prognostic value. The choice of the radiotracer (according to the type of cancer and to the studied biological mechanism) and the various methods of tumoral delineation, require a regular update to optimize the practices. We propose throughout this article, an exhaustive review of the published researches (and in process of publication) until December 2011, as user guide of PET/CT in all the aspects of the modern radiotherapy (from the diagnosis to the follow-up): biopsy guiding, optimization of treatment planning and dosimetry, evaluation of tumor response and prognostic value, follow-up and early detection of recurrence versus tumoral necrosis. In a didactic purpose, each of these aspects is approached by primary tumoral location, and illustrated with representative iconographic examples. The current contribution of PET/CT and its perspectives of development are described to offer to the radiation oncologist a clear and up to date reading in this expanding domain.