"Magnetic resonance imaging (MRI) has increasingly become the preferred imaging modality in modern day research to study disease. MRI presents an imaging technique that is practically non-invasive and without any ionizing radiation. This dissertation presents the use of contrast agents in MRI studies to differentiate compartments, to study dose dependence of relaxation times, and to characterize tumors using signal amplifying enzymes in the brain. Differentiating compartments in the brain can be useful in diffusion studies to detect stroke at an early stage. Diffusion-weighted NMR techniques have established that the apparent diffusion coefficient (ADC) of cerebral tissue water decreases during ischemia. However, it is unclear whether the ADC change occurs due to changes in the intracellular (IC) space, extracellular (EC) space, or both. To better understand the mechanism of water ADC changes in response to ischemic injury, making IC and EC compartment specific measurements of water diffusion is essential. The first study was done where manganese (Mn2+) was used as an IC contrast agent. Mn2+ uptake by cells causes shortening of the T1 relaxation time of IC water. The relative difference in T1 relaxation times between the IC and EC compartments can be used to discriminate between the MR signals arising from water in the respective compartments. Mn2+ is also widely used in manganese-enhanced MRI (MEMRI) studies to visualize functional neural tracts and anatomy in the brain in vivo. In animal studies, the goal is to use a dose of Mn2+ that will maximize the contrast while minimizing its toxic effects. The goal of dose study was to investigate the MRI dose response of Mn2+ in rat brain following SC administration of Mn2+. The dose dependence and temporal dynamics of Mn2+ after SC injection can prove useful for longitudinal in vivo studies that require brain enhancement to persist for a long period of time to visualize neuroarchitecture like in neurodegenerative disease studies. Contrast agents, in addition to their use in compartmental differentiation and dose studies, can be used for imaging tumors. The last study in this dissertation focuses on imaging EGF receptors in brain tumors. We tested a novel pretargeting imaging approach that includes the administration of humanized monoclonal antibody (anti-EGFR mAb, EMD72000) linked to enzymes with complementing activities that use a low-molecular weight paramagnetic molecule (diTyr-GdDTPA) as a reducing substrate administered following the mAb conjugates. We analyzed the differential MR tumor signal decay in vivo using orthotopic models of human glioma. The patterns of MR signal change following substrate administration revealed differences in elimination patterns that allowed distinguishing between non-specific and specific modes of MR signal decay. "

Inúmeros trabalhos avaliando as exigências de lisina podem ser encontrados na literatura, mas seus resultados são heterogêneos. Revisões sistemáticas e a meta-análise permitem integrar diferentes variáveis, gerar novos resultados e obter respostas ajustadas a uma maior diversidade experimental. Objetivou-se explorar as relações da lisina digestível com as variáveis de desempenho, estabelecer a exigência e avaliar a eficiência marginal da lisina segundo a lei de rendimentos decrescentes para suínos em crescimento e terminação. Para os estudos I e II, foram compilados 36 artigos publicados entre 2002 e 2013 avaliando 2.399 suínos pesando entre 15-120 kg. Para o estudo III, foram utilizados 26 artigos que avaliaram 1.820 suínos pesando entre 20-120 kg. No estudo I, o consumo diário de lisina apresentou correlações maiores com a ingestão de energia metabolizável e proteína bruta e com as deposições de proteína e lipídios. O consumo diário de lisina apresentou melhor ajuste nas equações de variância-covariância do que o nível percentual de lisina. No estudo II, o aumento no consumo diário de lisina melhorou o ganho de peso e a deposição de proteína na fase de 70-120 kg. Nas fases de 15-30; 30-70 e 70-120 kg os níveis de lisina digestível determinados para obter as melhores respostas de ganho corresponderam ao consumo diário de 14,8; 20,2 e 18,3 g lisina/dia. Os níveis de lisina digestível determinados para obter as melhores respostas de deposição de proteína corresponderam ao consumo diário de 16,3 e 24,1 g lisina/dia nas fases 15-30 e 30-70 kg. No estudo III, observamos que a medida que o animal se aproxima ou atinge o ponto de máximo desempenho, a eficiência de uso da lisina digestível diminui segundo a lei de rendimentos decrescentes. Dietas formuladas para atender 95% da máxima resposta de ganho de peso permitem uma melhora na eficiência marginal de uso da lisina da ordem de 2,4; 2,5 e 1,5 g de ganho de peso para cada g de lisina ingerida nas faixas de peso vivo 20-50; 50-70 e 70-120 kg. Sugerimos a inclusão de variáveis como a eficiência alimentar e o ganho de peso nas análises de determinação de exigências de lisina, também a escolha de metodologias analíticas adequadas e a inclusão da lei de rendimentos decrescentes da eficiência marginal de uso da lisina nos atuais modelos de determinação de exigência para evitar a superestimação observada nas tabelas de recomendação nutricional. / Several studies evaluating the lysine requirements are avaible in the literature, but its results are heterogeneous. Systematic reviews and meta-analysis allows integrating different variables, generating new results and producing answers adjusted to experimental diversity. This objective of this study was to explore the relationship among dietary lysine and the performance variables, establishing the requirement and assessing the marginal efficiency of dietary lysine according to the law of diminishing returns for growing-finishing pigs. For studies I and II, 36 articles published from 2002 to 2013 evaluating 2399 pigs weighing between 15-120 kg were compiled. And for the study III 26 articles evaluating 1820 pigs weighing between 20-120 kg were used. In the study I, daily intake of lysine showed higher correlations with the metabolizable energy intake and crude protein, with the protein deposition and lipid deposition. The daily intake of lysine showed better adjustment in the variance-covariance equations than the dietary level of lysine. In Study II, increasing the daily intake of lysine improved the weight gain and protein deposition in the 70-120 kg phase. In 15-30; 30-70 and 70-120 kg phase the levels digestible lysine that maximized weight gain reponse corresponded to the daily intake of 14.8; 20.2 and 18.3 g lysine/day. Lysine levels that maximized protein deposition reponse corresponded to daily intake of 16.3 and 24.1 g lysine/day in the phases 15-30 and 30-70 kg. In the study III, it was observed that, as the animal approaches or reaches the maximum performance the efficiency of lysine use decreases according to the law of diminishing returns. Diets formulated to meet 95% of the maximal weight gain response permit a marginal improvement in efficiency of use of the lysine the order of 2.4; 2.5 and 1.5 grams of weight gain for each lysine grams ingested in live weight phases 20-50; 50-70 and 70-120 kg respectively. It suggest the inclusion of variables feed efficiency and weight gain in analysis for the determination of lysine requirements, also the choice of appropriate analytical methods and the inclusion of diminishing returns law of marginal efficiency the dietary lysine in current models for the determination of requirements to avoid the overestimation observed in nutritional recommendation tables.

Esse trabalho apresenta um estudo sobre os efeitos de radiação em circuitos analógicos de baixa e ultra baixa potência e tensão, identificando as fragilidades destes circuitos (e das respectivas técnicas de projeto) quando aplicados em ambientes radioativos, como, por exemplo, os circuitos em satélites, e em equipamentos de instalações nucleares. Foram realizados estudos de caso, via simulação elétrica utilizando o software HSPICE, considerando os efeitos de degradação elétrica correspondentes a doses de radiação acumulada de até 500krad(Si), além de eventos singulares considerando circuitos de baixa tensão e potência projetados para a tecnologia IBM (GF) de 130nm. Pôde-se observar que o uso de transistores de óxido mais fino, apesar de afetar negativamente o consumo estático, é recomendado para as aplicações estudadas, devido a menor sensibilidade à radiação. Ainda, foi discutido o aumento dos caminhos de fuga de corrente devido ao uso de layout distribuído. Possibilidades e estratégias de mitigação foram discutidas. Por fim, obteve-se um conjunto de sugestões e informações para auxiliar o projetista de circuitos de baixo consumo a obter soluções robustas à radiação. / This work studies the radiation effects in low-power and ultra-low power analog circuits, identifying the fragility of such circuits (and associated design techniques) when employed in radioactive environments, as for example, in satellites and nuclear facilities. Case studies were carried out using HSPICE software for electrical simulation of cumulative radiation effects, corresponding to doses up to 500krad(Si), as well as for single events simulation. We showed that, the use of thin oxide (core) MOSFETS, though increasing the static consumption, is recommended for the studied applications, because they are less sensitive to radiation. Then, we discussed the increase of current leakage paths by the distributed layout style. Mitigation strategies were also discussed. Finally, we obtained a set of suggestions and information to guide the designers of low power analog circuits towards obtaining radiation robust solutions.

This work aims to develop a theoretical power operations envelope for the PUR-1 reactor. Given the bulk coolant temperature, the reactor’s power level is limited primarily by the Onset of Nucleate Boiling. Additional limitations to the reactor power are explored including the dose rate at the top of the pool due to shine and the airborne effluent of argon and nitrogen. Operations in excess of the facility cooling capacity will be proposed and are already permitted at other US research reactor facilities, provided temperature limitations are met. The MCNP and NATCON code packages have been implemented to assist in power limitation measurement. A brief discussion on the licensing considerations is included to provide some framework for pursuit of these higher power levels. The maximum power consideration ensures continued full use of the facility while maximizing its effectiveness in the teaching laboratories and access to researchers. The final power level is limited by the administrative dose limit at the top of the reactor pool as well as the Onset of Nucleate Boiling power level as a function of bulk pool temperature. The result is an operational envelope which would allow operators to have the maximum neutron flux without changing the facility or creating phase transition within the light water coolant.

Computed tomography imaging has revolutionised modern medicine and we can now study the body in greater detail than ever before. Cardiac computed tomography has the potential to provide information not just on coronary anatomy, but also on myocardial function, perfusion and viability. This thesis addresses the optimisation and validation of computed tomography imaging of the heart using a wide volume 320-multidetector scanner. Computed tomography coronary angiography now has diagnostic accuracy comparable to invasive coronary angiography. However, radiation dose remains an important concern. It is therefore important to minimise computed tomography radiation dose while maintaining image quality. I was able to demonstrate that iterative reconstruction and patient tailored imaging techniques led to a 39% reduction in radiation dose in computed tomography coronary angiography, while maintaining subjective and objective assessments of image quality. In addition, I demonstrated that diagnostic images can be obtained in 99% of unselected patients presenting with suspected coronary artery disease when using single heart-beat 320- multidetector computed tomography coronary angiography. Computed tomography myocardial perfusion imaging can provide additional and complementary information as compared to computed tomography coronary angiography that can aid diagnosis and management. I established both quantitative and qualitative assessment of computed tomography myocardial perfusion imaging and validated it against both a clinical “gold-standard”, fractional flow reserve during invasive coronary angiography, and a physiological “gold-standard”, positron emission tomography with oxygen-15 labelled water. Finally, I was able to show that techniques to reduce radiation dose can also be applied to computed tomography myocardial perfusion imaging, leading to a 60% reduction in radiation dose, while maintaining image quality. In my thesis, I have established that comprehensive cardiac angiographic and perfusion imaging can be performed with wide volume computed tomography in a broad generalizable population of patients with relatively low radiation exposure. These techniques provide both structural and functional assessments from a single imaging modality that are valid and readily applicable to the clinic in the assessment and management of patients with suspected coronary artery disease.

La scintillation organique correspond au phénomène d’émission de lumière par un matériau moléculaire à la suite de l’excitation de celui-ci par un rayonnement externe d’énergie donnée. Lors de l’interaction, le dépôt d’énergie induit des transitions électroniques peuplant des états dont la plupart se désexcite de manière non radiative, à l’exception d’une, entre le premier état électronique singulet et l’état fondamental de la molécule. Lors de cette relaxation, un photon de fluorescence est émis. Cette émission a deux origines : i) l’excitation directe par le rayonnement primaire et les électrons secondaires ; elle donne lieu à une émission dite rapide ou prompte ; ii) l’ionisation par le rayonnement primaire et les électrons secondaires ; elle donne lieu à une émission dite lente ou différée. Ce travail de recherche fondamentale, à la fois théorique et expérimental, fait l’analyse de toutes les étapes du processus, de l’interaction primaire à l’émission de fluorescence, de manière à relier la dose déposée à la quantité de lumière émise, à des fins d’applications en dosimétrie médicale. Il repose sur la mesure des déclins de fluorescence de deux molécules modèles, l’anthracène et le paraterphényle, excitées par un flux continu de rayons X, et la séparation des contributions rapide et lente de la lumière émise, aux énergies médicales. Une modélisation analytique des processus physiques conduisant à l’émission de lumière, au regard de la dose déposée, a ensuite été effectuée, faisant apparaître de nombreux résultats originaux. Dans un premier temps, un dispositif expérimental original a été développé, basé sur la technique TCSPC (Time-Correlated Single Photon Counting), afin de pouvoir mesurer des déclins temporels de fluorescence en résolution nanoseconde et sous flux d’irradiation continu. Dans un second temps, nous avons développé une nouvelle approche mathématique permettant d’extraire finement les composantes rapides et lentes du signal. L’analyse des résultats a montré, pour la première fois, l’existence d’un rapport R constant et uniquement fonction du matériau, entre les rendements d’excitation et d’ionisation. Le caractère constant de ce rapport ne peut être attribué qu’à un mécanisme d’autoionisation moléculaire au sein d’un matériau se comportant intrinsèquement comme une chambre d’ionisation proportionnelle pour l’ionisation secondaire de basse énergie. Ceci est en accord total avec la linéarité observée entre l’intensité totale de lumière différée (ionisation) et la dose mesurée par une chambre d’ionisation proportionnelle. Une étude plus approfondie des mécanismes d’excitation, au regard du rapport R, a également permis de montrer, pour la première fois, une proportionnalité directe entre l’intensité totale de la lumière prompte et le dépôt d’une dose que nous avons baptisé dose d’excitation. Cette dose a été observée comme étant de 4 à 14 fois supérieure à celle mesurée par une chambre d’ionisation. Ce résultat original majeur devra impérativement conduire à des études futures afin de mieux comprendre les dégâts infligés à la matière organique et biologique par les excitations. / Organic scintillation is the emission of light by an organic scintillator when irradiated by an external source of radiation depositing enough energy to excite the molecule. Electronic states are populated by the electronic transitions generated by the deposited energy. The states de-excite through radiationless transitions, except for one, the transition between the first electronic state and the ground state where a photon of fluorescence is emitted. This light has two different origins: i) direct excitation caused by primary radiation or secondary electrons which leads to an emission knows as prompt; ii) ionization caused by primary radiation or secondary electrons generate what is known as the delayed component. This fundamental research was based on both theoretical and experimental work. We studied all the different processes in organic scintillation, from the interaction between the incident radiation and matter to the emission of light in order to find the relationship between fluorescence and the deposited dose, to the application to medical dosimetry. Two well known organic scintillators, anthracene and p-terphenyl, were excited using an X-ray source set at typical medical imaging parameters. The light emitted was acquired and an analytical model was used to describe the different processes that led to light emission revealing interesting new results.An experimental setup, based on the Time Correlated Single Photon Counting (TCSPC) technique, was developed to acquire fluorescence decay curves with nanosecond resolution using a continuous X-ray source. Afterwards, these curves were analyzed using an innovative mathematical approach in order to determine the prompt and delayed components.Results showed the ratio, defined as R, between the prompt and delayed components of fluorescence was constant and independent of the energy of the incident X-rays and that the response of the delayed component of fluorescence was linear to an ionization chamber. These observations were explained by considering that the only process taking place within the molecule after excitation was autoionization. Hence, the response of organic scintillator was the same as the one of an ionization chamber. Furthermore, due to the constant ration R, the response of prompt component of fluorescence was linear to the ionization chamber as well. This was the first time this behavior was observed and we referred to it as excitation dose. This dose was between 4 and 14 times bigger than the one measured with the ionization chamber. These original results suggested that energy is deposited mainly through excitation processes, suggesting the need for further studies to better understand the damage caused by excitation to the living.

Existem evidências na literatura de que a administração de medicações, como corticosteróides inalatórios e broncodilatadores, utilizando inaladores pressurizados dosimetrados, é mais eficaz e segura do que com os nebulizadores convencionais. Entretanto, há evidências de que não só pacientes, mas também profissionais de saúde têm dificuldade no manejo dos inaladores pressurizados dosimetrados. A hipótese do presente estudo é que o conhecimento da técnica inalatória entre os profissionais da nossa Instituição é heterogêneo, sendo que não há informações sobre o nível deste conhecimento entre as diversas categorias profissionais. OBJETIVOS: Avaliar o conhecimento prático e teórico de profissionais da área médica, de enfermagem e fisioterapia sobre a utilização do inalador dosimetrado através de testes padronizados. MÉTODOS: Avaliações teóricas e práticas sobre o conhecimento do uso de inaladores pressurizados dosimetrados foram realizadas com médicos, fisioterapeutas, enfermeiras e auxiliares de enfermagem, atribuindo-se uma nota de 0 a 10 para cada avaliação. Calcularam-se as medianas das notas obtidas pelos profissionais de cada categoria, as questões com maiores e menores índices de erros e feita a comparação descritiva do desempenho das diversas categorias profissionais. Após as avaliações, instrução verbal e escrita sobre a utilização correta dos dispositivos foi fornecida a todos os participantes. A análise estatística foi feita através do método de Kruskal-Wallis de comparação de medianas. Também foi realizada a análise através de regressão logística múltipla seqüencial. RESULTADOS: foram avaliados 30 médicos residentes ou estagiários da pediatria, 23 médicos assistentes, 29 fisioterapeutas, 33 enfermeiras e 31 auxiliares de enfermagem, em um total de146 profissionais. Não foram entrevistados residentes ou assistentes do grupo de Pneumologia. Os médicos residentes, fisioterapeutas e os médicos assistentes obtiveram desempenho significativamente superior que os enfermeiros e auxiliares de enfermagem. Apenas os médicos residentes obtiveram mediana superior a seis. As questões práticas com maiores índices de erros foram as relativas à limpeza do espaçador. Questões relativas à agitação do inalador antes do uso e à limpeza da cavidade oral após a sua utilização também obtiveram alto índice de erros. A questão teórica mais errada foi a respeito do tempo necessário entre dois jatos em aplicações sucessivas do inalador pressurizado dosimetrado. CONCLUSÕES: O conhecimento teórico-prático dos profissionais de saúde da Instituição a respeito do uso de inaladores pressurizados dosimetrados é heterogêneo. Os médicos residentes, fisioterapeutas e médicos assistentes obtiveram desempenho significativamente melhor que os enfermeiros e auxiliares de enfermagem sendo que estes últimos estão diretamente envolvidos na aplicação prática destes dispositivos na rotina hospitalar. / There are data in the literature indicating that the administration of medications such as inhaled corticosteroids and bronchodilators, using metered-dose inhalers, is more effective and safer than its dispensation by conventional nebulizers. However, there is evidence that not only patients but also health care professionals have difficulty in dealing with pressurized dose inhalers. The hypothesis of the present study is that the knowledge of inhalation techniques among health professionals of our Institution is heterogeneous, and there is no information about this knowledge among the diverse categories of professionals. OBJECTIVE: To assess the practical and theoretical knowledge of medical professionals, nursing and physiotherapy on the use of metereddose inhalers by standardized testing. METHODS: Practical and written tests on the use of metered-dose inhalers were applied to physicians, physical therapists, nurses and nursing assistants. A score from 0 to 10 was assigned to each evaluation. Median scores were calculated for each professional category. Questions with higher and lower correct values were identified, and a descriptive comparison was made regarding the performance of the diverse professional categories. Following the examination, oral and written instructions on the correct use of the devices were provided for all participants. Statistical analysis was performed using the Kruskal-Wallis method for comparison of medians. A sequential logistic multiple regression analysis was also performed. RESULTS: A total of 146 professionals were assessed, including 30 fellows in pediatrics, 23 attending physicians, 29 physical therapists, 33 nurses and 31 nursing assistants. Fellows or attending physicians of the Pediatric Pulmonology Unit were not included in the study. Fellows, physical therapists and attending physicians performed significantly better than did nurses and nursing assistants. Only fellows had a median score greater than six. On the practical tests for infants and toddlers, the step most often missed was that related to cleaning the spacer. On practical tests, the steps related to shaking the inhaler and cleaning the mouth also presented high error indices. On the written tests, the question most often answered incorrectly was that related to the waiting time between puffs. CONCLUSIONS: The theoretical and practical knowledge of health professionals of our Institution on the use of metered-dose inhalers is heterogeneous. The performance of fellows, physical therapists and attending physicians was significantly better than that of nurses and nursing assistants who are directly involved in the practical application of these devices in the hospital routine.

Existem evidências na literatura de que a administração de medicações, como corticosteróides inalatórios e broncodilatadores, utilizando inaladores pressurizados dosimetrados, é mais eficaz e segura do que com os nebulizadores convencionais. Entretanto, há evidências de que não só pacientes, mas também profissionais de saúde têm dificuldade no manejo dos inaladores pressurizados dosimetrados. A hipótese do presente estudo é que o conhecimento da técnica inalatória entre os profissionais da nossa Instituição é heterogêneo, sendo que não há informações sobre o nível deste conhecimento entre as diversas categorias profissionais. OBJETIVOS: Avaliar o conhecimento prático e teórico de profissionais da área médica, de enfermagem e fisioterapia sobre a utilização do inalador dosimetrado através de testes padronizados. MÉTODOS: Avaliações teóricas e práticas sobre o conhecimento do uso de inaladores pressurizados dosimetrados foram realizadas com médicos, fisioterapeutas, enfermeiras e auxiliares de enfermagem, atribuindo-se uma nota de 0 a 10 para cada avaliação. Calcularam-se as medianas das notas obtidas pelos profissionais de cada categoria, as questões com maiores e menores índices de erros e feita a comparação descritiva do desempenho das diversas categorias profissionais. Após as avaliações, instrução verbal e escrita sobre a utilização correta dos dispositivos foi fornecida a todos os participantes. A análise estatística foi feita através do método de Kruskal-Wallis de comparação de medianas. Também foi realizada a análise através de regressão logística múltipla seqüencial. RESULTADOS: foram avaliados 30 médicos residentes ou estagiários da pediatria, 23 médicos assistentes, 29 fisioterapeutas, 33 enfermeiras e 31 auxiliares de enfermagem, em um total de146 profissionais. Não foram entrevistados residentes ou assistentes do grupo de Pneumologia. Os médicos residentes, fisioterapeutas e os médicos assistentes obtiveram desempenho significativamente superior que os enfermeiros e auxiliares de enfermagem. Apenas os médicos residentes obtiveram mediana superior a seis. As questões práticas com maiores índices de erros foram as relativas à limpeza do espaçador. Questões relativas à agitação do inalador antes do uso e à limpeza da cavidade oral após a sua utilização também obtiveram alto índice de erros. A questão teórica mais errada foi a respeito do tempo necessário entre dois jatos em aplicações sucessivas do inalador pressurizado dosimetrado. CONCLUSÕES: O conhecimento teórico-prático dos profissionais de saúde da Instituição a respeito do uso de inaladores pressurizados dosimetrados é heterogêneo. Os médicos residentes, fisioterapeutas e médicos assistentes obtiveram desempenho significativamente melhor que os enfermeiros e auxiliares de enfermagem sendo que estes últimos estão diretamente envolvidos na aplicação prática destes dispositivos na rotina hospitalar. / There are data in the literature indicating that the administration of medications such as inhaled corticosteroids and bronchodilators, using metered-dose inhalers, is more effective and safer than its dispensation by conventional nebulizers. However, there is evidence that not only patients but also health care professionals have difficulty in dealing with pressurized dose inhalers. The hypothesis of the present study is that the knowledge of inhalation techniques among health professionals of our Institution is heterogeneous, and there is no information about this knowledge among the diverse categories of professionals. OBJECTIVE: To assess the practical and theoretical knowledge of medical professionals, nursing and physiotherapy on the use of metereddose inhalers by standardized testing. METHODS: Practical and written tests on the use of metered-dose inhalers were applied to physicians, physical therapists, nurses and nursing assistants. A score from 0 to 10 was assigned to each evaluation. Median scores were calculated for each professional category. Questions with higher and lower correct values were identified, and a descriptive comparison was made regarding the performance of the diverse professional categories. Following the examination, oral and written instructions on the correct use of the devices were provided for all participants. Statistical analysis was performed using the Kruskal-Wallis method for comparison of medians. A sequential logistic multiple regression analysis was also performed. RESULTS: A total of 146 professionals were assessed, including 30 fellows in pediatrics, 23 attending physicians, 29 physical therapists, 33 nurses and 31 nursing assistants. Fellows or attending physicians of the Pediatric Pulmonology Unit were not included in the study. Fellows, physical therapists and attending physicians performed significantly better than did nurses and nursing assistants. Only fellows had a median score greater than six. On the practical tests for infants and toddlers, the step most often missed was that related to cleaning the spacer. On practical tests, the steps related to shaking the inhaler and cleaning the mouth also presented high error indices. On the written tests, the question most often answered incorrectly was that related to the waiting time between puffs. CONCLUSIONS: The theoretical and practical knowledge of health professionals of our Institution on the use of metered-dose inhalers is heterogeneous. The performance of fellows, physical therapists and attending physicians was significantly better than that of nurses and nursing assistants who are directly involved in the practical application of these devices in the hospital routine.

A radioterapia de feixe de intensidade modulada (IMRT) no seu modo dinâmico é uma forma de radioterapia tri-dimensional (3D), na qual modula-se um feixe de forma a obter-se a irradiação com campos que possuem perfil variável. Os campos são gerados por um sistema de otimização matemático e transformado em seqüências de movimento ou abertura de lâminas dos colimadores terciários de múltiplas folhas (MLC) ou feixe colimado helicoidal, reproduzindo a fluência de radiação adequada. No processo o operador atribui valores limitantes de dose ao alvo e aos órgãos de risco circunvizinhos para que o sistema de planejamento inverso realize a otimização possível. Após a aprovação do plano de tratamento o mesmo deve ser conferido, através de um controle de qualidade (CQ), onde são verificadas as doses que deverão ser administradas ao paciente, comprovando-se as doses obtidas e aprovadas no plano do sistema de planejamento (SPC). Para este controle os mesmos feixes e campos são medidos em termos de dose absorvida e perfis, através de dosimetria na qual comprova-se que não há erro físico ou dosimétrico no plano que irá tratar o paciente com diferença aceitável de até 5%, também utilizada como tolerância para a aprovação dos 460 casos avaliados nesta tese. Foram apresentados as metodologias para a aceitação no primeiro serviço a utilizá-la no Brasil e os testes de controle de qualidade de dois serviços de radioterapia, desde agosto de 2001 à maio de 2006 e no outro serviço de outubro de 2007 a maio de 2008, com controle de qualidade que permitiram os respectivos tratamentos clínicos com dados de 4 anos, ou seja, 460 casos com 3935 campos de tratamento verificados individualmente por dosimetria. Isto possibilitou o aperfeiçoamento da metodologia e garantia da qualidade nos tratamentos de IMRT dinâmico destes pacientes. / The intensity modulated radiation therapy (IMRT) is a type of radiation therapy using dynamic sliding window which modulated the beamlets of each field which are thus obtained as a variable profile. The multiple fields are obtained by mathematic optimization in special treatment planning system. In this way, the resulted field is generated by leaf sequencing using the multi-leaf collimator (MLC) or helicoidally beam. The optimization is an interactive process with operator and planning system where the dose prescription to target and dose limit for organ of risk are inserted to obtain the acceptable beam fluence and this process is named as inverse planning. The planning approved by physician should checked by means of dosimetry in order to assure the correct dose delivery; this action is the main task of a quality control (QC) program. The QC is performed by measurements of total absorbed dose and profile for each field planned for the patient. The acceptance level is 5% for total dose and was used for all 460 cases and 3935 fields analyzed between August 2001 to May 2006 at Albert Einstein Hospital and October 2007 to May 2008 at the Centro Infantil Dr. Boldrini. This work performs an analysis of the QC of treatments plans for all patients treated with IMRT. During four years the methodologies were frequently improved and upgradated for each tumor site and could thus be assured for the required quality of all treatments with dynamic IMRT.

Neste trabalho, estão descritos os métodos de seleção, calibração e de determinação dos fatores de correção, as características físicas dos dosímetros termoluminescentes, o procedimento de cálculo para converter a leitura do dosímetro em dose absorvida e a metodologia para se determinar a dose de entrada. Foram investigadas a praticidade e a utilidade das medidas de dose de entrada com os dosímetros termoluminescentes, bem como a exatidão e a reprodutibilidade no fornecimento da dose diária. As medidas de dose de entrada foram realizadas em cinco pacientes com diagnóstico de câncer de mama tratadas com um feixe de fótons de 6 MV. Não foram detectados grandes desvios entre a dose medida e a dose esperada (os valores concordaram em ± 5%), devido à excelente estabilidade do equipamento de tratamento, ao sistema automático de verificação e à boa exatidão no ajuste diário do tratamento. Uma boa precisão pode ser alcançada quando os fatores de correção para cada parâmetro de influência na resposta do dosímetro são cuidadosamente determinados e aplicados para converter o sinal termoluminescente em dose absorvida. O estudo demonstrou a viabilidade do uso dos dosímetros termoluminescentes para a dosimetria in vivo e sua utilidade como parte de um programa de garantia de qualidade em um serviço de radioterapia. / Selection, calibration procedure to convert TLD signal into absorbed dose and physical characteristics at the thermoluminescent dosimeters, as well as the determination of correction factors and the methodology to determine expected entrance dose, are described in this work. Practical aspects and the utility of entrance dose measures with thermoluminescent dosimeters were investigated, as well as the exactness and the reproducibility of the daily dose release. The entrance dose measures were performed in five patients with diagnosis of breast cancer treated with a 6 MV photon beam. The measured dose and the expected dose values agreed in ± 5%, due to excellent treatment equipment stability, to automatic verification system and the good exactness in the daily treatment adjustment. Good precision can be achieved when the correction factors for each parameter of influence in the dosimeter response are carefully determined and applied to convert the thermoluminescent signal into absorbed dose. The study demonstrates the viability of thermoluminescent dosimeters use for in vivo dosimetry and its utility as part of a quality assurance program in a radiation therapy service.