No description available.

Thesis (Ph.D.) OGI School of Science & Engineering at OHSU, July 2007. / Includes bibliographical references (leaves 202-216).

No description available.

The medical electron linear accelerator has been in general use for radiotherapy since the early nineteen-sixties, but in recent years a number of manufacturers have increased the maximum electron energy above the 8 MeV threshold for neutron production. The International Electrotechnical Commission (IEC) formed Sub Committee 62 C to institute safety recommendations for high energy machines, and in September 1975, the principle of a maximum neutron contamination level, was established. The level chosen was an arbitrary, interim value and it was recognised by the Committee that this value would change when more information became available. The lack of immediate information was due to the extreme difficulty in measuring pulsed neutrons of a wide range of energies in a very high gamma ray and RF environment. This thesis is a record of all aspects of neutron production of one particular make of machine, the MEL SL75-20, in order to satisfy the IEC requirement for information. The results show that the maximum interim value of neutron contamination was optimistically low, and unless measures were taken to reduce the neutron production, it was unlikely that any machine, irrespective of manufacturer, using standard target, primary collimator and flattening filter materials, could comply with the recommendations. The results also show that if a treatment room labyrinth was designed on traditional principles considering only high energy treatment beam gamma scattering, the facility would fail to meet the Sealed Sources regulations for an adequately shielded compound at typical treatment beam intensities, in view of the additional radiation from neutron streaming and subsequent neutron absorption effects. It is shown that both the patient dose and the hazard to staff, arising from neutron production, can be substantially reduced at very little cost. The ability to produce neutrons in a hospital environment could be most useful, and it is shown that using the experimental beam facilty as a neutron source, the linear accelerator could be used for diagnostic investigations on body tissues and fluids.

No description available.

O ruído articular é comumente reconhecido como um sinal de desarranjo articular, e a sua análise faz parte do conjunto de dados coletados em vários sistemas de classificação e diagnóstico, tanto em pesquisas como nas atividades clínicas. Apesar desta importância, existe ainda dificuldade na interpretação dos sons, em virtude da variação natural do fenômeno, do subjetivismo por parte de examinadores e dos métodos e equipamentos empregados para o diagnóstico. Visando uma análise mais objetiva, foi desenvolvido um dispositivo para gravar e analisar graficamente os sons. Este método permite o armazenamento e sucessivas análises, eliminando ainda diferenças de percepção de sons entre os examinadores. O objetivo da pesquisa é verificar a eficácia do dispositivo desenvolvido efetuando a comparação com exames de ressonância magnética (RM). A concordância entre os examinadores e as análises das gravações também foram feitas, para se verificar o subjetivismo das percepções. Pacientes com idade entre 14 a 75 anos e que reportaram dor muscular e/ou a presença de sons articulares foram incluídos na pesquisa. Foram excluídos aqueles que já tivessem recebido tratamento prévio, apresentassem dores de cabeça, infecções, traumas faciais recentes, patologias sistêmicas, gravidez ou marca passos. De acordo com estes critérios, uma amostra de 18 pacientes foi selecionada para a pesquisa. Os pacientes tiveram os ruídos articulares detectados com o método de palpação e por estetoscópios , por quatro examinadores, e os sons então foram gravados e analisados, com o dispositivo desenvolvido. Por fim, as percepções dos sons por todos os métodos realizados na pesquisa foram aplicadas ao protocolo RDC/TMD, e diagnósticos para cada paciente foram obtidos. Desta forma, foi feita a comparação com os exames de ressonância magnética (RM), adotado como padrão ouro na pesquisa. O critério estatístico de Altman mostrou uma concordância em termos de valores de kappa muito baixa entre os quatro examinadores. Nos ciclos de abertura, de acordo com os resultados obtidos no estudo, o examinador 2 (método de palpação) apresentou uma fraca concordância com os examinadores 3 e 4, (método de estetoscópios), (k=0.272 e k=0.397, respectivamente). O examinador 3 apresentou uma boa concordância com o examinador 4 (k=0.698). Nos ciclos de fechamento, o examinador 3 apresentou uma fraca concordância com o examinador 4 (k=0.398). Na comparação entre as gravações e os examinadores, verificou-se a falta de concordância entre estes, com valores de kappa muito baixos, quando possíveis de serem calculados (k=0.021 até k=0.147). Quando os diagnósticos obtidos pelo RDC/TMD por todos os métodos foram comparados com os laudos de RM, a gravação apresentou melhor percentual de concordância (55,6%), em relação à percepção de som pelos examinadores (36,1% a 52,8%). O dispositivo desenvolvido para análise e gravação dos ruídos articulares mostrou ser um método de fácil manuseio e visualização, conseguindo uma superior detecção de ruídos. A comparação com exames de RM confirmou esta melhora. / The joint noise is commonly recognized as a sign of an articular derangement, and its analysis is part of the data set collected in many systems of classification and diagnosis, both in research and clinical activities. Despite this importance, there is some difficulty in interpreting the sounds due to the natural variability of the phenomenon, subjectivism by examiners and the methods and equipments used for diagnosis. In order to get a more objective analysis, we developed a device to record and graphically analyze the sounds. This method allows the storage and subsequent analysis, even eliminating differences in perception of sound between the examiners. The present research aims to verify the effectiveness of the device developed by comparisons with magnetic resonance imaging (MRI). The agreement between the examiners and the analysis of the recordings were also made to verify the subjectivity of perception. Patients aged 14 to 75 years who reported muscle pain and / or the presence of joint sounds were included in the survey. We excluded those who had already received previous treatment, experience headaches, infections, recent facial trauma, systemic diseases, and pregnancy or pacemakers users. According to these criteria, a sample of 18 subjects was selected for the survey. The patients had joint noises detected with the methods of palpation and stethoscope by four examiners, and the sounds were recorded and then analyzed with the developed device. Finally, perceptions of the sounds made by all methods were applied in the research protocol RDC / TMD, and diagnoses for each patient were obtained. Finally, the comparison was made with magnetic resonance imaging (MRI), adopted as the gold standard in research. From the results, according to Altman criteria, there was an agreement in terms of very low kappa values among the four examiners. In cycles of opening, according to the results obtained in the study, the examiner 2 (palpation method) showed a poor agreement with the examiners 3 and 4 (method of stethoscopes), (k = 0272 k = 0397, respectively). The examiner 3 had good agreement with the examiner 4 (k = 0698). In closing cycles, the examiner 3 had a poor agreement with the examiner 4 (k = 0398). In the comparison between the recordings and the examiners, there was a lack of agreement among these, with very low kappa values when possible to be calculated (k = k = 0021 to 0147). When the diagnoses obtained by RDC / TMD by all methods were compared with the findings of MRI, the recording method showed the best percentage of agreement (55.6%) compared to the perception of sound by the examiners (36.1 to 52%, 8%). The device developed for recording and analyzing the joint sounds proved to be an easy method of handling and display, achieving a better detection of the noise. The comparison with MRI confirmed this improvement.

O ruído articular é comumente reconhecido como um sinal de desarranjo articular, e a sua análise faz parte do conjunto de dados coletados em vários sistemas de classificação e diagnóstico, tanto em pesquisas como nas atividades clínicas. Apesar desta importância, existe ainda dificuldade na interpretação dos sons, em virtude da variação natural do fenômeno, do subjetivismo por parte de examinadores e dos métodos e equipamentos empregados para o diagnóstico. Visando uma análise mais objetiva, foi desenvolvido um dispositivo para gravar e analisar graficamente os sons. Este método permite o armazenamento e sucessivas análises, eliminando ainda diferenças de percepção de sons entre os examinadores. O objetivo da pesquisa é verificar a eficácia do dispositivo desenvolvido efetuando a comparação com exames de ressonância magnética (RM). A concordância entre os examinadores e as análises das gravações também foram feitas, para se verificar o subjetivismo das percepções. Pacientes com idade entre 14 a 75 anos e que reportaram dor muscular e/ou a presença de sons articulares foram incluídos na pesquisa. Foram excluídos aqueles que já tivessem recebido tratamento prévio, apresentassem dores de cabeça, infecções, traumas faciais recentes, patologias sistêmicas, gravidez ou marca passos. De acordo com estes critérios, uma amostra de 18 pacientes foi selecionada para a pesquisa. Os pacientes tiveram os ruídos articulares detectados com o método de palpação e por estetoscópios , por quatro examinadores, e os sons então foram gravados e analisados, com o dispositivo desenvolvido. Por fim, as percepções dos sons por todos os métodos realizados na pesquisa foram aplicadas ao protocolo RDC/TMD, e diagnósticos para cada paciente foram obtidos. Desta forma, foi feita a comparação com os exames de ressonância magnética (RM), adotado como padrão ouro na pesquisa. O critério estatístico de Altman mostrou uma concordância em termos de valores de kappa muito baixa entre os quatro examinadores. Nos ciclos de abertura, de acordo com os resultados obtidos no estudo, o examinador 2 (método de palpação) apresentou uma fraca concordância com os examinadores 3 e 4, (método de estetoscópios), (k=0.272 e k=0.397, respectivamente). O examinador 3 apresentou uma boa concordância com o examinador 4 (k=0.698). Nos ciclos de fechamento, o examinador 3 apresentou uma fraca concordância com o examinador 4 (k=0.398). Na comparação entre as gravações e os examinadores, verificou-se a falta de concordância entre estes, com valores de kappa muito baixos, quando possíveis de serem calculados (k=0.021 até k=0.147). Quando os diagnósticos obtidos pelo RDC/TMD por todos os métodos foram comparados com os laudos de RM, a gravação apresentou melhor percentual de concordância (55,6%), em relação à percepção de som pelos examinadores (36,1% a 52,8%). O dispositivo desenvolvido para análise e gravação dos ruídos articulares mostrou ser um método de fácil manuseio e visualização, conseguindo uma superior detecção de ruídos. A comparação com exames de RM confirmou esta melhora. / The joint noise is commonly recognized as a sign of an articular derangement, and its analysis is part of the data set collected in many systems of classification and diagnosis, both in research and clinical activities. Despite this importance, there is some difficulty in interpreting the sounds due to the natural variability of the phenomenon, subjectivism by examiners and the methods and equipments used for diagnosis. In order to get a more objective analysis, we developed a device to record and graphically analyze the sounds. This method allows the storage and subsequent analysis, even eliminating differences in perception of sound between the examiners. The present research aims to verify the effectiveness of the device developed by comparisons with magnetic resonance imaging (MRI). The agreement between the examiners and the analysis of the recordings were also made to verify the subjectivity of perception. Patients aged 14 to 75 years who reported muscle pain and / or the presence of joint sounds were included in the survey. We excluded those who had already received previous treatment, experience headaches, infections, recent facial trauma, systemic diseases, and pregnancy or pacemakers users. According to these criteria, a sample of 18 subjects was selected for the survey. The patients had joint noises detected with the methods of palpation and stethoscope by four examiners, and the sounds were recorded and then analyzed with the developed device. Finally, perceptions of the sounds made by all methods were applied in the research protocol RDC / TMD, and diagnoses for each patient were obtained. Finally, the comparison was made with magnetic resonance imaging (MRI), adopted as the gold standard in research. From the results, according to Altman criteria, there was an agreement in terms of very low kappa values among the four examiners. In cycles of opening, according to the results obtained in the study, the examiner 2 (palpation method) showed a poor agreement with the examiners 3 and 4 (method of stethoscopes), (k = 0272 k = 0397, respectively). The examiner 3 had good agreement with the examiner 4 (k = 0698). In closing cycles, the examiner 3 had a poor agreement with the examiner 4 (k = 0398). In the comparison between the recordings and the examiners, there was a lack of agreement among these, with very low kappa values when possible to be calculated (k = k = 0021 to 0147). When the diagnoses obtained by RDC / TMD by all methods were compared with the findings of MRI, the recording method showed the best percentage of agreement (55.6%) compared to the perception of sound by the examiners (36.1 to 52%, 8%). The device developed for recording and analyzing the joint sounds proved to be an easy method of handling and display, achieving a better detection of the noise. The comparison with MRI confirmed this improvement.