Profissionais da área aeronáutica, como pilotos e comissários de bordo, são submetidos a doses de radiação de origem cósmica, que podem ser maiores do que as doses médias dos trabalhadores da indústria nuclear. A diversidade de partículas de altas energias presentes no campo de radiação a bordo das aeronaves torna complexa a mensuração da dose e requer cuidados especiais em relação aos sistemas de dosimetria a serem empregados nesta área. A Força Aérea Brasileira, por meio de seu Instituto de Estudos Avançados (IEAv /DCTA), em conjunto com o Instituto de Pesquisas Energéticas e Nucleares (IPEN / CNEN -SP) vem estudando o assunto desde 2008. Um protótipo de detector de radiação passivo para medições em aeronaves foi previamente construído e testado em condições de voo e de laboratório. O detector é capaz de medir a grandeza dosimétrica conhecida como dose absorvida (usando dosímetros passivos), que serão posteriormente correlacionados ao equivalente de dose ambiente e à dose efetiva recebidos por profissionais da área aeronáutica. Neste contexto, uma abordagem teórica por meio de simulações Monte Carlo com os códigos computacionais MCNP5 e MCNPX, foi usada para modelar e caracterizar a resposta do detector em determinadas condições experimentais. Este trabalho apresenta os resultados preliminares da modelagem computacional, com ênfase especial na comparação entre a grandeza fundamental dose absorvida (mensurada e simulada) e sua relação com o equivalente de dose ambiente e dose efetiva para este detector. / Aircrews, as pilots and flight attendants, are subjected to cosmic ray doses which can be higher than the average doses on workers from the nuclear industry. The diversity of particles of high energies present in the radiation field on board of aircrafts, turns the determination of the incident dose and requires special care regarding dosimetric systems to be used in this kind of field. The Brazilian Air Force, through the Institute for Advanced Studies (Instituto de Estudos Avançados, IEAv/DCTA) in conjunction with the Institute of Energetic and Nuclear Research (Instituto de Pesquisas Energéticas e Nucleares IPEN/CNEN-SP) are working on this subject since 2008. A prototype of a radiation detector for aircraft measurements was previously built and tested in flight and laboratory conditions. The detector is able of measuring a quantity known as absorbed dose (using passive dosimeters), which will subsequently be correlated to the ambient dose equivalent and the effective dose received by aircrews. In this context, a theoretical approach through Monte Carlo simulations with the computational codes MCNP5 and MCNPX was used to model and characterize the detector response at such experimental conditions. This work presents the preliminary results of the computational modeling, with special emphasis on the comparison between the absorbed dose quantity (measured and simulated) and its relationship with the ambient dose equivalent and the effective Dose for this detector.

O fosfogesso é um resíduo da indústria de fertilizantes fosfatados que concentra radionuclídeos naturais. Neste trabalho foi estudada a taxa de exalação de 222Rn em placas e tijolos de fosfogesso, visando sua utilização na construção de residências. Para tanto, foram determinadas a taxa de exalação de 222Rn por meio da técnica da câmara de acumulação com detectores sólidos de traços nucleares (SSNTD) inseridos em uma câmara de difusão e a dose efetiva para um indivíduo habitando uma residência construída com esses materiais. A título de comparação foi também determinada a taxa de exalação teórica, por meio do modelo proposto pela UNSCEAR, a partir da concentração de 226Ra nas placas e tijolos de fosfogesso. A contribuição do revestimento na superfície dos materiais para a diminuição da taxa de exalação de radônio foi também avaliada. Foram estudados placas e tijolos fabricados com fosfogesso das empresas Bunge Fertilizantes, Ultrafertil e Fosfertil e tijolos fabricados com gesso comum. Os valores médios obtidos foram 0,19 0,06 Bq m-2 h-1, 1,3 0,3 Bq m-2 h-1 e 0,41 0,07 Bq m-2 h-1 para as placas fabricadas com fosfogesso proveniente das empresas Bunge, Ultrafertil e Fosfertil, respectivamente. Já para os tijolos de fosfogesso, os valores foram 0,11 0,01 Bq m-2 h-1, 1,2 0,6 Bq m-2 h-1, 0,47 0,15 Bq m-2 h-1, para o fosfogesso da Bunge, Ultrafertil e Fosfertil. O tijolo fabricado com gesso comum apresentou valor médio de 0,18 0,08 Bq m-2 h-1. As doses efetivas anuais para um indivíduo habitando uma residência construída como os tijolos ou placas de fosfogesso de qualquer uma das procedências ficaram abaixo do limite de dose efetiva para indivíduos do público de 1 mSva-1 estabelecido pela Comissão Internacional de Proteção Radiológica. / Phosphogypsum is a waste of the fertilizer industry that concentrates radionuclides. In this work, the 222Rn exhalation rate from phosphogypsum paltes and blocks from different origins used at dwellings construction was studied. The 222Rn exhalation rate was determined through the accumulation chamber technique with solid state nuclear track detectors (SSNTD). The effective dose for an individual living in a residence built with phosphogypsum based materials was evaluated. It also was calculated the 222Rn exhalation rate through the UNSCEAR model, from the 226Ra concentration in the materials, in order to compare the experimental results. It was evaluated the contribution of building component (paint) to the reduction of 222Rn exhalation rate. The plates and blocks were manufactured with phosphogypsum from Bunge Fertilizantes, Ultrafertil and Fosfertil. Blocks manufactured with ordinary gypsum was also evaluated. The average results obtained were 0.19 ± 0.06 Bq m-2 h-1, 1.3 ± 0.3 Bq m-2 h-1 and 0.41 ± 0.07 Bq m-2 h-1for plates manufactured with phosphogypsum from Bunge Fertilizer, Ultrafertil and Fosfertil, respectively. For the phosphogypsum blocks the values were 0.11 ± 0.01 Bq m-2 h-1, 1.2 ± 0.6 Bq m-2 h-1, 0.47 ± 0.15 Bq m-2 h-1, for Bunge, Ultrafertil and Fosfertil. The blocks manufactured with ordinary gypsum presented average value of 0.18 ± 0.08 Bq m-2 h-1. All phosphogypsum plates and blocks evaluated in this study presented effective dose for radon inhalation lower than the recommended value of 1mSv y1, the annual effective dose limit for public exposure by International Commission on Radiological Protection.

De acordo com a Comissão Nacional de Energia Nuclear (CNEN), a avaliação de impacto radiológico ambiental resultante da liberação de radionuclídeos para o meio ambiente, devido à operação normal de instalações nucleares, para propósito de proteção do público, é feita considerando o conceito de grupo crítico. Contudo, em 2006, a International Commission on Radiological Protection (ICRP), para o mesmo propósito, propôs a adoção do conceito de indivíduo representativo. Uma vez que, em algum momento, o Brasil possa adotar esse novo conceito, no presente trabalho são avaliadas as alterações, em termos de procedimentos de cálculo e dos consequentes resultados, decorrentes da aplicação da metodologia de indivíduo representativo em comparação com a metodologia de grupo crítico atualmente utilizada para o controle regulatório das instalações nucleares brasileiras. Como referência, utilizou-se as potenciais liberações de radionuclídeos previstas para a operação normal da Unidade de Produção de Hexafluoreto de Urânio (USEXA), localizada no Centro Experimental Aramar (CEA). De forma específica, os objetivos são: efetuar a avaliação de impacto radiológico ambiental para o CEA, utilizando as duas metodologias recomendadas (determinística e probabilística) para o indivíduo representativo, conforme descritas pela ICRP (2006); efetuar a comparação dos resultados obtidos com essas metodologias com os obtidos com a metodologia utilizada para o grupo crítico; e efetuar uma análise crítica da necessidade e da disponibilidade de dados para a aplicação dessas metodologias, bem como das suas consequências para o controle operacional do CEA. Com base nos resultados obtidos, destaca-se que a utilização da metodologia de cálculo de grupo crítico continua sendo uma maneira simples e eficiente para a avaliação de impacto radiológico ambiental, quando comparada à utilização da metodologia de indivíduo representativo, o que torna o estabelecimento de programas de monitoramento e, consequentemente, o controle radiológico ambiental, mais simples e objetivos. / According to the National Commission for Nuclear Energy (CNEN), the assessment of environmental radiological impact from the release of radionuclides to the environment due to normal operation of nuclear facilities, for protecting the public, considers the concept of critical group. In 2006, the International Commission on Radiological Protection (ICRP), for the same purpose, proposed the adoption of the concept of representative person. Once, at some point, this new concept probably will be adopted in Brazil, in this study the changes in terms of procedures for calculating and consequent results arising from the application of the representative person methodology are evaluated and compared to the critical group methodology currently used for regulatory control of Brazilian nuclear facilities. As a reference, it was used the predicted potential releases of radionuclides resulting from the normal operation of the Uranium Hexafluoride Production Plant (USEXA), located at Centro Experimental Aramar (CEA). Specifically, the objectives are: to carry out the environmental radiological impact for CEA, using the two recommended methods (deterministic and probabilistic) for the representative person, as described by the ICRP (2006); to make the comparison of results obtained with these methods with those obtained with the methodology used for the critical group; and, make a critical analysis of the need and the availability of data for the application of these methodologies, as well as its consequences for the operational control of CEA. Based on the results obtained, it is emphasized that the use of the methodology for calculating critical group remains a simple and efficient way to evaluate radiological environmental impact when compared to the use of the representative person methodology, which makes the establishment of monitoring programs, and therefore the environmental radiological control, simpler and objectives.

O objetivo principal deste estudo foi analisar, na Gerência de Aceleradores Cíclotron do IPEN, o controle das doses de radiação ionizante e sua distribuição, comparando seus valores com as exigências regulamentares. A análise do controle das taxas de dose por meio do monitoramento de área foi realizada a partir de dados obtidos durante as produções de Flúor-18 no período de janeiro de 2010 a dezembro de 2011, totalizando 1011 medidas em cada ponto monitorado. A análise das doses provenientes de exposições ocupacionais foi realizada por meio de consulta aos históricos de dose individual. Durante os anos de 2007 a 2011 foram analisados os registros individuais das doses efetivas, totalizando 91 registros e de 2009 a 2011 foram analisados os registros de dose equivalente (nas mãos), totalizando 49 registros. Os indivíduos ocupacionalmente expostos envolvidos no estudo foram classificados, de acordo com a tarefa, em três grupos: alvos, radioproteção e operação e manutenção. Os resultados obtidos dos níveis de exposição ocupacional da radiação foram analisados e comparados com os limites estabelecidos pela autoridade regulatória nacional e com as recomendações internacionais. Com base nos resultados registrados do monitoramento de área e das doses recebidas, os procedimentos de radioproteção aplicados na instalação durante o período estudado foram averiguados e sugestões de melhorias foram dadas sob o ponto de vista da proteção radiológica. / The main purpose of this study was to analyze, at the Gerência de Aceleradores Cíclotron (Management of Cyclotron Accelerators) at IPEN, the control of ionizing radiation doses and their distribution by comparing their values with regulatory requirements. The analysis of the dose rate for the area monitoring was carried out from the data obtained during the production of Fluorine-18 from January 2010 to December 2011, totalizing 1011 measurements at each monitored spot. The doses analysis was performed through consultation of the individual dose records. During the years 2007 to 2011 the records of individual effective doses were analyzed, adding up to 91 records; from 2009 to 2011 the records of equivalent dose (hands) were analyzed, totalizing 49 records. The occupationally exposed individuals involved in the study were classified in three groups according to their task: targets, radioprotection and operation and maintenance. The results of occupational exposure levels of radiation were analyzed and compared with values established in national standards and international recommendations. Based on the results of the area monitoring and the doses received and recorded, radiation protection procedures implemented at the facility during the study period were checked and suggestions for improvements were given from the point of view of radiological protection.

Nos últimos anos, em áreas de produção de culturas transgênicas resistentes ao glyphosate, falhas no controle do capim-pé-de-galinha (Eleusine indica) são cada vez mais frequentes, estando provavelmente relacionadas ao uso indiscriminado do glyphosate e ao consequente aumento da pressão de seleção de biótipos de plantas daninhas resistentes a esse herbicida. Este trabalho teve como objetivo comparar a suscetibilidade de quatro populações de capim-pé-de-galinha ao herbicida glyphosate em diferentes estádios de desenvolvimento, bem como estudar a eficácia de herbicidas alternativos ao glyphosate no controle de plantas desta espécie na pré e pós-emergência das mesmas. Também foi objetivo deste trabalho estudar aspectos da biologia, tais como: crescimento, número de sementes produzidas por uma planta e influência da escarificação mecânica sobre a germinação do capim-pé-de- galinha. Foi verificado que existem diferenças na suscetibilidade das populações ao glyphosate, no qual a população denominada EIR2 proveniente de Primavera do Leste - MT foi a que necessitou de maiores doses para ser controlada, sendo caracterizada como um caso de resistência de nível baixo, pois a dose máxima de bula recomendada para a espécie é capaz de controlar todas as populações do estudo. Os herbicidas mais indicados para o controle de capim-pé-de-galinha na pré-emergência foram o flumioxazin, sulfentrazone, clomazone e trifluralina, apresentando maiores níveis de controle e efeito residual mais prolongado. O controle do capim-pé-de-galinha na pós-emergência inicial (2 a 3 perfilhos) e no estádio intermediário (6 a 8 perfilhos) foi eficiente com todos os herbicidas testados. No estádio mais avançado (10 a 12 perfilhos) o herbicida sethoxydim não controlou nenhuma das populações, não sendo indicado para plantas com mais de 6 perfilhos. Foram identificadas diferenças significativas entre o controle das populações com os inibidores da ACCase, sendo necessários outros estudos para confirmação da resistência a esses herbicidas. O capim-pé-de-galinha apresentou de maneira geral elevado acúmulo de matéria seca total, sendo considerado altamente competitivo. Foram encontradas diferenças entre o crescimento das populações, não havendo relação com a suscetibilidade diferencial ao glyphosate existente entre as mesmas. O perfilhamento iniciou-se aos 28 dias após a emergência (DAE), com um pico de crescimento dos 42 aos 63 DAE quando as plantas atingiram o ápice do acúmulo foliar e matéria seca, entrando posteriormente na senescência. O florescimento iniciou-se entre 42 e 49 DAE e perdurou até os 63 DAE. Uma planta da espécie Eleusine indica produziu em média 45000 sementes e não foram encontradas diferenças significativas na produção de sementes entre as populações. A escarificação mecânica das sementes acelerou o processo de germinação e aumentou a germinação final das populações de capim-pé-de-galinha. O mecanismo que confere a dormência física das sementes de capim-pé-de-galinha está relacionado com a impermeabilidade do tegumento. / Lately, in the areas of production of transgenic crops resistant to glyphosate failures in control of goosegrass has been reported frequently, probably by an intense using of glyphosate and consequent increasing in selection pressure of weeds resistant to glyphosate. For this reason this work was carried out in order to compare the susceptibility of four goosegrass populations to glyphosate in different stages of development, as well as studying the effectiveness of alternative herbicides to glyphosate in the control of such species in pre and post-emergence. It was also a goal of this work study biological aspects, such as growth, weed number produced by a plant and influence of mechanical scarification on the germination of the goosegrass. It was found that there are differences in the susceptibility of populations to glyphosate, in which EIR2 population from Primavera do Leste - MT was the one that required higher doses to be controlled, being characterized as a case of low-level resistance because of the maximum recommended dose is able to control all the populations studied. Herbicides the most suitable to control pre-emergence were flumioxazin, sulfentrazone, clomazone and trifluralin, with high levels of control were used a longer residual effect. The control of goosegrass in the early post-emergence (2-3 tillers) and the intermediate stage (6-8 tillers) was efficient with all the tested herbicides. In the most advanced stage (10 to 12 tillers) the herbicide sethoxydim did not control any of populations, was not were used suitable for plants with more than 6 tillers. Remarkable differences were identified between the control of populations with ACCase inhibitors. Other studies are necessary to confirm the resistance to these herbicides. The goosegrass showed high accumulation of total dry matter, being considered highly competitive. Some differences were found among the growth of the populations, with no relation to the differential susceptibility to glyphosate existing between them. The tillering began at 28 days after emergence (DAE), with a growth between of 42 to 63 DAE when the plants reached the apex of the leaf and dry matter accumulation, later entering senescence. The flowering started between 42 and 49 DAE and lasted until 63 DAE. A plant of Eleusine indica produced on average 45 000 seeds and there were no important differences between seed production among populations. Mechanical scarification of seeds accelerated the germination and increased the final germination populations of goosegrass. The mechanism that confers the physical dormancy of goosegrass seeds is related to the impermeability of the integument.

On considère généralement les biofilms comme des indicateurs biologiques d’alerte, les organismes les composant ayant des temps de génération relativement courts et présentant une grande diversité de preferenda environnementaux et de sensibilité aux altérations anthropiques. Dans ces travaux, les effets de pesticides sur les biofilms de rivière ont été étudiés à différentes échelles de représentativité, allant de mélanges complexes à faible dose en utilisant des extraits d’échantillonneur passif POCIS (Polar Organic Chemical Integrative Sampler) à des molécules testées seules, en passant par des mélanges simples.L’exposition chronique et à faible dose aux extraits de POCIS a révélé des impacts au niveau de la croissance, de la structure (assemblages de diatomées) et du fonctionnement du biofilm en lien avec son exposition passée. De plus les expériences utilisant des molécules testées seules (pesticides et métabolites) et les mélanges simples ont permis de caractériser la toxicité relative des composés présents dans les extraits de POCIS en lien avec leur mode d’action et d’explorer la réponse de descripteurs encore peu utilisés en écotoxicologie comme la construction de Rapid Light Curves (RLCs).Ce travail confirme la pertinence de l’utilisation des extraits d’échantillonneurs passifs comme le POCIS pour mieux appréhender les effets des pesticides en mélanges sur le biofilm de rivière ainsi que l’intérêt des RLCs en tant que descripteur précoces d’exposition aux pesticides. / Biofilms can be regarded as biological warming systems, because they are generally composed of short generation time organisms presenting a large range of environmental preferenda and various sensibilities to anthropogenic disturbance. In the present study, effects of pesticides on river biofilms have been studied at different levels of representativeness, from complex mixtures at low dose represented by POCIS passive sampler extracts (Polar Organic Chemical Integrative Sampler) to molecules tested alone via simple mixtures.Chronic exposure to low dose of POCIS extracts revealed impacts on growth related, structural (diatom assemblages) and functional parameters related to biofilm exposure history. Moreover experiment using single molecules and simple mixtures allowed to characterised the relative toxicity of compounds present in the POCIS extracts in link with their specific mode of action and explore the response of descriptor not very used in ecotoxicology field like the construction of Rapid Light Curves (RLCs).This work confirms the relevance of the use of passive sampler extracts as POCIS in order to better understand the effects of pesticides in mixture on river biofilms as well as the interest of RLCs as early exposure descriptors of pesticides exposure.

A olanzapina é um fármaco antipsicótico atípico utilizado no tratamento da esquizofrenia. Como efeitos adversos relacionados ao seu uso, encontram-se obesidade, hiperlipidemia, Diabetes Mellitus tipo II, entre outros. O presente trabalho avaliou os efeitos adversos passíveis de desenvolvimento em pacientes esquizofrênicos que fazem uso deste medicamento, avaliando o indivíduo antes de começar o tratamento, 30 e 60 dias após o início (T0, T1 e T2) através de dosagens antropométricas (peso, IMC, circunferência abdominal e porcentagens de tecido adiposo no organismo), hemodinâmicas (pressão arterial, frequência cardíaca), perfil lipídico (colesterol total, LDL-col, HDL-col e triglicérides), glicêmico (resistência à insulina HOMA-R, QUICKI e razão G/I; glicemia de jejum) e bioquímico (avaliação da função renal, hepática e dosagem de homocisteína, um marcador de risco cardiovascular). A olanzapina plasmática foi dosada nos mesmos tempos com intenção de se buscar uma correlação de dose-resposta (efeito adverso). A análise estatística foi realizada com auxílio dos \"softwares\" Graphpad Instat e Statgraphics, para o estudo e análise das médias (ANOVA), e análise de comparação múltipla entre os grupos (Tukey-Kramer). O nível de significância foi fixado em p<0,05. Para os grupos sem diferença estatística relevante, foram utilizadas técnicas de estatística descritiva para se observar diferenças mais sutis ou com relevância clínica. As altas concentrações plasmáticas encontradas não foram concordantes com os estudos prévios de outros autores, já que não foram mais propensos a desenvolver ganho de peso. Este efeito adverso foi encontrado no nosso grupo, porém sem apresentar uma correlação direta com a concentração plasmática. / The olanzapine is an atypical antipsychotic drug used to treat schizophrenia. The adverse effects related to its use are obesity, hyperlipidemia, diabetes mellitus type II and others. This study evaluated the adverse effects likely to develop in schizophrenia patients who use this drug, assessing the individual before starting treatment, 30 and 60 days after the start (T0, T1 and T2) by anthropometric measurements (weight, BMI , waist circumference and percentage of fat in the body), hemodynamic (blood pressure, heart rate), lipid profile (total cholesterol, LDL-col, col-HDL and triglycerides), glucose (insulin resistance - HOMA-R, QUICKI, G/I ratio and fasting plasma glucose) and biochemical (measurement of renal function, liver and determination of homocysteine, a marker of cardiovascular risk). The olanzapine plasma was measured at the same time looking for a dose-response (effect) correlation. Statistical analysis was performed using the \"software\" Statgraphics and GraphPad Instat for the study and analysis of means (ANOVA) and analysis of variance between groups (Tukey-Kramer). The significance level was set at p <0.05. For groups without statistical significant difference were used descriptive statistical techniques to observe more subtle differences or clinical relevance. The high plasma concentrations found were not consistent with previous studies of other authors, since there were more likely to develop weight gain. This adverse effect was found in our group, but without a direct correlation with plasma concentration.

Orientador: Antonio Celso Pezzato / Banca: Dirlei Antonio Berto / Banca: Manoel Garcia Neto / Resumo: O presente estudo objetivou avaliar os efeitos da suplementação de diferentes níveis de metionina digestível nas dietas de frangos de corte de 1 a 21 dias de idade, sobre o desempenho animal e o rendimento de carcaça, pelo do método tradicional de dose-resposta, e utilizar a técnica de isótopos estáveis através do turnover tecidual para certificar este procedimento de exigência nutricional. Foram realizados dois ensaios em delineamento inteiramente casualizado, com sete tratamentos que consistiram de níveis de metionina digestível para as fases pré-inicial e inicial, respectivamente: 70% (0,320 e 0,307), 80% (0,360 e 0,331), 90% (0,410 e 0,380), 100% (0,450 e 0,417), 110% (0,500 e 0,460), 120% (0,540 e 0,510) e 130% (0,591 e 0,540) de metionina digestível correspondentes às exigências preconizadas por Rostagno et al. (2011). No ensaio I foram utilizados 875 pintos de corte de um dia de idade alojados em 35 unidades experimentais e avaliou-se o desempenho e o rendimento de carcaça. No ensaio II foram alojados 567 pintos de corte de um dia de idade e avaliou-se o turnover do 13C no músculo peitoral e fígado. Todos os animais foram submetidos à dieta a base de arroz e farelo de soja do primeiro aos 21 dias de idade. No ensaio I foi verificado melhora no desempenho de 1 a 7 dias de idade nos tratamentos 100% e 120% para peso corporal e ganho de peso e de 1 a 21 dias de idade nos tratamentos 100%, 110%, 120% para ganho de peso e peso corporal. Observou-se melhora na conversão alimentar com os tratamentos 100%, 110%, 120% e 130%. Os tratamentos 100% e 120% apresentaram melhora no rendimento de peito, o 110% para gordura abdominal e o 120% para o peso do fígado aos 21 dias de idade. No ensaio II foi verificado diminuição da meia-vida e aumento da taxa metabólica para o músculo peitoral no tratamento 130% e para o fígado no tratamento 80%. Pode-se observar que os tratamentos 100%, 11 ... / Abstract: The present study aimed to evaluate the effects of different levels of digestible methionine in broiler diets on performance, carcass yield through the traditional method of dose-response, and use the stable isotopic of tissue turnover to certificate this procedure of nutritional requirement. Two trials were conducted in a completely randomized design with seven treatments that consisted in levels of digestible methionine to pre-starter and initial phase, respectively: 70% (0,320 e 0,307), 80% (0,360 e 0,331), 90% (0,410 e 0,380), 100% (0,450 e 0,417), 110% (0,500 e 0,460), 120% (0,540 e 0,510) e 130% (0,591 e 0,540) of digestible methionine corresponding to the requirements recommended by Rostagno et al. (2011). In the first trial, 875 one day old chicks were housed in 35 pens to evaluate the performance and carcass yield. In the second trial, 567 one day old chicks were housed to determinate the turnover of carbon-13 in the pectoral muscle and liver. All birds were fed a diet based on rice and soybean meal (predominantly C3) for the first 21 days of life. In the first trial was verified improved performance at 7 days old on treatments 100% and 120% for body weight and weight gain and at 21 days old on treatments 100%, 110% and 120% for body weight and weight gain. It was noted improving on feed conversion with treatments 100%, 110%, 120% and 130%. The treatments 100% and 120% showed improvement on breast yield, the 110% to fat abdominal and the 120% for liver weight at 21 days old. In the second trial was verified reduction of half-life and increase of metabolic rate to the breast muscle on treatment 130% and for liver on treatment 80%. It could be noted that treatments 100%, 110% and 120% improvement the animal performance / Mestre

Avec l’augmentation du nombre de scanner et de la dose collective, le risque potentiel d’apparition d’effets stochastiques est accentué. Pour limiter au maximum ce risque, les principes de justification et d’optimisation doivent être appliqués avec rigueur. L’optimisation des pratiques a pour but de délivrer la dose la plus faible possible tout en conservant une qualité diagnostique des images. C’est une tâche complexe qui implique de trouver en permanence un compromis entre la dose délivrée et la qualité image résultante. Pour faciliter cette démarche, des évolutions technologiques ont été développées. Les deux évolutions majeures sont la modulation du courant du tube en fonction de l’atténuation du patient et l’apparition des reconstructions itératives (IR). L’introduction des IR a modifié les habitudes puisqu’elles permettent de conserver des indices de qualité image équivalents en réduisant les doses. Cependant, leurs utilisations s’accompagnent d’une modification de la composition et de la texture de l’image nécessitant d’utiliser des métriques adaptées pour les évaluer. Le but de cette thèse est d’évaluer l’impact d’une utilisation des IR sur la réduction de la dose et sur la qualité des images afin de proposer en routine pour tous les patients, des protocoles avec la dose la plus faible possible et une qualité image adaptée au diagnostic. La première partie de cette thèse est consacrée à une mise au point sur la problématique du compromis dose/qualité image en scanographie. Les métriques de qualité image et les indicateurs dosimétriques à utiliser, ainsi que le principe et l’apport des reconstructions itératives y sont exposés. La deuxième partie est consacrée à la description des trois étapes réalisées dans cette thèse pour atteindre les objectifs. La troisième partie est constituée d’une production scientifique de 7 articles. Le 1er article présente la méthodologie d’optimisation globale permettant la mise en place de protocoles Basses Doses en routine avec utilisation de niveaux modérés des IR. Le 2ème article évalue l’impact et l’apport sur la qualité des images obtenues pour des niveaux de doses très bas. Le 3ème et le 4ème article montrent l’intérêt d’adapter ou de proposer des protocoles optimisés selon la morphologie du patient. Enfin les 3 derniers articles, illustrent la mise en place de protocoles Très Basses Doses pour des structures ayant un fort contraste spontané. Pour ces protocoles les doses sont proches des examens radiographiques avec des niveaux élevés des IR. La démarche d’optimisation mise en place a permis de réduire considérablement les doses. Malgré une modification de la texture et de la composition des images, la qualité des images obtenues pour tous les protocoles était jugée satisfaisante pour le diagnostic par les radiologues. L’utilisation des IR en routine nécessite une évaluation particulière et un temps d’apprentissage pour les radiologues. / The increasing number of scanner and the cumulative dose delivered lead to potential risk of stochastic effects. To minimize this risk, optimization on CT usage should be rigorously employed. Optimization aims to deliver the lowest dose but maintaining image quality for an accurate diagnosis. This is a complex task, which requires setting up the compromise between the dose delivered and the resulting image quality. To achieve such goal, several CT technological evolutions have been developed. Two predominant developments are the Tube Current Modulation and the Iterative Reconstruction (IR). The former lays one patient's attenuation, the latter depend on advanced mathematical approaches. Using IR allows one to maintain equivalent image quality values by reducing the dose. However, it changes the composition and texture of the image and requires the use of appropriate metric to evaluate them. The aim of this thesis was to evaluate the impact of using IR on dose reduction and image quality in routine for all patients, protocols with the lowest dose delivered with an image quality suitable for diagnosis. The first part of the thesis addressed the compromise between dose delivered and image quality. Metrics of the image quality and the dosimetric indicators were applied as well the principle and the contribution of IRs were explored. The second part targets the description of the three steps performed in this thesis to achieve the objectives. The third part of the thesis consists of a scientific production of seven papers. The first paper presents the global optimization methodology for the establishment of low dose protocols in routine using moderate levels of IR. The second paper assesses the impact and contribution of IR to the image quality obtained to levels very low doses. The third and the fourth papers show the interest to adapt or propose protocols optimized according to patient's morphology. Finally the last three papers illustrate the development of Very Low Dose protocols for structures with high spontaneous contrast. For these protocols, doses are close to radiographic examinations with high levels of IR. The optimization process implementation has significantly doses reduction. Despite the change on the texture and on composition of the images, the quality of images obtained for all protocols was satisfactory for the diagnosis by radiologists. However, the use of routine IR requires special assessment and a learning time for radiologists.

Le scanner a révolutionné la médecine permettant une accélération et une meilleure prise en charge du patient. La tomodensitométrie (TDM) s’accompagne d’un désavantage qui est l’augmentation du risque de cancer radio-induit des patients qui en bénéficient. La question se pose notamment aux urgences où l’emploi du scanner est de plus en plus prédominant, souvent après la réalisation d’une radiographie. Cette attitude, malgré tout justifiée dans la plupart des cas, peut s'avérer délétère. De ce fait les principes de radioprotection obligent à l’optimisation de la dose délivrée aux patients. L’inquiétude principale réside dans l’irradiation du thorax qui est la région la plus radiosensible du corps humain. Cela se traduit par une recherche continue d’un compromis entre l’obtention de la dose la plus basse possible tout en gardant une qualité d’image satisfaisante pour le diagnostic. Les dernières années des innovations technologiques ont été développées pour optimiser la dose au scanner ; la plus importante et la plus récente étant la reconstruction itérative (RI). La RI permet d’améliorer les index de qualité image avec une dose abaissée ou à dose équivalente reconstruite avec la classique rétroprojection filtrée, mais restituant enfin une qualité d’image modifiée. L’objectif de cette thèse était d’établir un protocole TDM du thorax délivrant une dose similaire à celle d’une radiographie du thorax de face et une de profil (ULD-CT_Ultra-low-dose-Computed Tomography) pour des indications de douleurs thoraciques en urgence sans injection de produit de contraste. La réaction des radiologues non habitués a été investiguée pour considérer la modification de l’image liée à la réduction de la dose et de l’emploi de la RI. Pour atteindre cet objectif les travaux de cette thèse se sont déroulés selon trois phases. La première phase représente une approche globale à la RI, testée sur fantômes pour optimiser les protocoles TDM de notre département. À partir des résultats obtenus, la deuxième phase a débuté. Des protocoles TDM thorax standard, à basse dose (LD-CT_Low-dose) et à très basse dose (ULD-CT) ont été testés sur des cadavres humains. La troisième phase a été caractérisée par l’application du protocole ULD-CT en pratique clinique aux urgences. Quatre articles scientifiques ont été rédigés pour représenter les trois phases de cette thèse. En conclusion, le protocole ULD-CT reconstruit avec des hauts niveaux de RI a délivré une dose inférieure à celle du niveau de référence diagnostique national pour une radiographie du thorax de face et une de profil. Ce type de protocole à très faible dose reconstruit avec RI est une alternative valable à la radiographie pour certaines indications sélectionnées pour l’exploration du thorax en urgence. En outre les radiologues malgré des remarques critiques sur la qualité d’image de l’ULD-CT ont toujours déclaré un niveau de confiance diagnostique élevé. / Computed Tomography (CT) improved patients' health care. However CT has a major drawback, which is the ionizing irradiation of the patient with an ensuing radiation-induced cancer risk. This issue is particularly observed in emergency settings, where the CT is increasingly becoming a dominant tool for the care decision-making, often after a radiographic study. Although this attitude is justified in the majority of the cases, it could be deleterious. Thus the principles of radiation safety obligate to the optimization of radiation dose delivered to the patients. The main problem is that the chest is the most radiation sensitive region of the human body. Hence the research of the better trade-off between the dose reduction and a diagnostic image quality is mandatory. Recently, several technological improvements have been developed to optimize the radiation dose at CT. The newest and most important innovation is the iterative reconstruction (IR). IR improves the quality image indexes of a CT image generated with a lowered dose or equivalent to that reconstructed with filtered back projection. Finally this reconstruction method renders a modified CT image. The goals of this PhD thesis were: i) to establish an unenhanced CT protocol, delivering a dose in the range of a radiographic study (ULD_ultra-low-dose-CT), for chest pain indications with no need of contrast media administration and ii) to investigate the reaction of unaccustomed radiologists to ULD-CT imaging. To accomplish these tasks the work of this thesis has been split in three phases. In the first phase a study approaching globally the IR was carried out testing several CT protocols on phantoms, in order to optimize the CT protocols of our institution. The outcomes of this study opened the second phase. A standard dose CT, a low-dose-CT and an ULD-CT protocols were acquired on the chest of human cadavers. The third phase was characterized by the application of ULD-CT in clinical practice in emergency settings. Four scientific articles were produced to communicate the results of this doctorate work. In conclusion, the ULD-CT protocol, reconstructed with high strengths of IR, conveyed a dose lower than the one of the national diagnostic reference level for a double projections chest X-ray. This ULD-CT protocol with IR is a valid alternative to the radiography for the study of the chest, for selected indications in emergency settings. Moreover, despite the radiologists were censorious about the ULD-CT image quality, they demonstrated always a high diagnostic confidence level.