published_or_final_version / Dentistry / Master / Master of Dental Surgery

published_or_final_version / Dentistry / Master / Master of Dental Surgery

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / Computer Science / Master / Master of Philosophy

Neutron radiography is well suited to non-invasive imaging of water within metal containers. The goal of this work is to determine if neutron radiography can be used to image water freezing within a 1.6mm diameter capillary tube with the ultimate goal of observing this phenomena within fuel cells. In this work, radiography was completed at the Thermal Neutron Imaging Facility in the Nuclear Engineering Teaching Lab at The University of Texas at Austin. The source of neutrons was a TRIGA Mark II nuclear research reactor capable of 1.1 MW steady state power, which creates a neutron flux at the neutron imaging plane in beam port 5 of 5×10^6 neutrons/cm^2s. A scintillation screen and CCD camera are utilized to obtain digital radiographs, in which differences in pixel intensity are related to differences in neutron attenuation. An image processing algorithm was developed in Matlab to extract necessary data from each image, analyze water column images, and compare one to another. Also, a neutron flux model was implemented in Matlab in order to understand how a non-unidirectional neutron flux will affect final results. Raw image intensities of the water column in liquid and solid form were found to differ from expectations by at most 12.0% and 13.3%, respectively from the predictions of the Matlab flux model. A difference in pixel intensity comparing liquid water to solid water data is apparent and quantified. A ratio of pixel intensity for the ice image to the water image at full thickness of the water column is expected to be 1.038. Experimental results find a maximum ratio of 1.027, 1.1% off from expectations. / text

No description available.

An increase in the range and capability of imaging modalities has resulted in greater demands for radiology services. This research investigates how these changes have affected role requirements and role extensions of radiographers and the consequent implications for the educational needs of radiographers. Semi-structured interviews and three successive surveys of NHS radiography managers showed that the adoption and diffusion of extended roles in radiography had increased significantly over a ten year period. Role changes included additions both to the procedures carried out by radiographers, and to the reporting of procedures, e.g. film reporting, once the domain of radiologists, is now undertaken by radiographers in many trusts. Imaging managers’ views on the factors that encouraged or deterred the introduction of extended roles were explored. While many radiographers were keen to adopt new roles, implementation was unlikely without radiological support. Respondents believed the proposed ‘four-tier structure’ would help overcome staffing difficulties, while providing an improved career framework to advance the professional status of radiographers. A key theme was the need for greater clinical knowledge to facilitate transition to advanced practice. Three studies investigated radiography education. The first used a survey to investigate the preparedness for practice of three cohorts of newly qualified radiographers. Graduates recognised the importance of continuing professional development with extended role skills identified as a priority. The second study examined the relationship between contemporary practice and UK undergraduate radiography curricula. Most programmes had responded positively to developing technology. The third study used a survey to investigate the training for extended roles provided by employers. While most provided some training, much was unaccredited, and there was considerable variation in the duration of training for similar roles. The research has documented developments taking place at a time of enormous technological innovation. It provides key data on the changing practice of radiography that will be useful to all stakeholders planning improvements to radiography services. The data lead to a re-definition of practice and recommendations for supporting education and training.

by Chan Yiu Nam. / Chinese title: / Includes bibliographical references / Thesis (M.Phil.) -- Chinese University of Hong Kong, 1983

O pilar do sucesso do tratamento endodôntico é o diagnóstico e, para esse objetivo, a radiografia é um excelente recurso auxiliar, tanto pelo seu custo, como pela facilidade de obtenção. Contudo, ela tem suas limitações, pois trata-se da imagem bidimensional de um objeto tridimensional e daí a dificuldade encontrada no diagnóstico de lesões periapicais, fraturas radiculares e reabsorções dentais. Com o advento e o uso da tomografia computadorizada (TC), a partir de 1972, houve uma melhora na capacidade diagnóstica, com as imagens tridimensionais. Entretanto, a TC helicoidal tem limitações, na Odontologia, pelo seu custo, alta dose de radiação à qual o paciente é submetido pela presença de artefatos metálicos. Com a introdução da tomografia computadorizada na Odontologia, por meio do sistema de aquisição Cone Beam, essas desvantagens foram minimizadas, ocorrendo o aumento da qualidade diagnóstica da imagem tridimensional. O objetivo deste trabalho foi comparar a capacidade diagnóstica da tomografia computadorizada Cone Beam, utilizando o aparelho Accuitomo 3DX com as radiografias periapicais e ortopantomográficas (panorâmicas), em casos de lesões periapicais, fraturas radiculares e reabsorções dentais. Para isso, foram analisadas imagens obtidas por meio da tomografia e pelas técnicas radiográficas periapical e panorâmica de 150 casos clínicos, por dois examinadores calibrados, usando escores préestabelecidos. Os resultados permitiram afirmar que a técnica da tomografia apresentou diferença estatisticamente significante em relação às demais técnicas, no diagnóstico da extensão e localização de lesões periapicais, fraturas radiculares e reabsorções dentais. / Diagnosis is the basis of success of endodontic treatment; radiography is an excellent aid for that purpose, due to both cost and easy achievement. However, it also has limitations, since it is a bidimensional image of a three-dimensional object; this explains the difficulty in the diagnosis of periapical lesions, root fractures and tooth resorptions. The advent and use of computerized tomography (CT) since 1972 improved the diagnostic ability with utilization of three-dimensional images. However, helical CT is limited in Dentistry, due to its cost, high radiation dose and presence of metallic artifacts. These disadvantages were minimized by introduction of the cone beam system in dentistry, which improved the diagnostic quality of three-dimensional images. This study evaluated the diagnostic ability of cone beam computerized tomography using the appliance Accuitomo 3DX, compared to periapical and panoramic radiographs, in cases of periapical lesions, root fractures and tooth resorptions. Images of 150 clinical cases were obtained by tomography and by periapical and panoramic radiographic techniques and evaluated by two calibrated examiners, using pre-established scores. The results revealed that the tomography technique presented statistically significant difference in relation to the other techniques for diagnosis of the extent and location of periapical lesions, root fractures and tooth resorptions.

Durante o século passado, o diagnóstico por imagem na odontologia, foi dominado por radiografias, que são representações bidimensionais de estruturas tridimensionais, com sobreposição e distorções associadas. Com a introdução da tomografia computadorizada cone-beam (TCCB), houve um aumento no interesse por esta tecnologia dado às vantagens, como melhor qualidade de imagem, reconstrução tridimensional, possibilidade de visualização craniofacial, e as doses de radiação mais baixas em comparação com a tomografia computadorizada convencional (TC). A TCCB pode ser aplicada em diversas áreas da Odontologia, tais como: implantodontia, cirurgia, traumatologia, periodontia, endodontia, ortodontia, articulações temporomandibulares. Contudo, os profissionais da saúde devem estar cientes que os avanços tecnológicos terão implicações importantes sobre a prática clínica. Estes mesmos profissionais devem conhecer as indicações, limitações e implicações antes de considerar a utilização de tal equipamento. Sendo assim, o presente estudo pretende analisar, criticamente, a utilização e indicação do exame de imagem TCCB na Faculdade de Odontologia de Bauru USP. Ao mesmo tempo, pretende avaliar quantitativamente o uso deste equipamento em relação ao motivo da solicitação e a área bucal requisitada. / During the past century, the diagnostic for image in the dentistry, was dominated for radiographies, which are bidimensional representation of the tridimensional structure with superposition and distortion associated. With the introduction of cone-beam computed tomography (TCCB), there was an increased interest in this technology due to advantages such as better image quality, three-dimensional reconstruction, ability of craniofacial visualization and lower radiation doses compared with the conventional computed tomography (CT). The TCCB can be applied in various areas of dentistry such as dental implants, surgery, traumatology, periodontics, endodontics, orthodontics, temporomandibular joints. However, health professionals should be aware that technological advances have important implications for clinical practice. These same professionals should know the indications, limitations and implications before considering the use of such equipment. Thus, this study aims to analyze critically the use and indication of imaging examination TCCB in the Bauru Dental School - USP. At the same time, evaluate quantitatively the use of equipment for the purpose of the request.