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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Elaboração de um guia de referência com imagens radiográficas para aplicação em exames extraorais odontológicos / Elaboration of a reference guide with radiograpich images for application in dental extraoral exams

Mickus, Joice 27 October 2017 (has links)
Os exames radiológicos são importantes recursos no auxílio da elaboração um diagnóstico odontológico preciso. Contudo, só devem ser realizados quando houver uma real indicação clínica, visto que os efeitos das radiações ionizantes no organismo humano são cumulativos. Falhas na execução de procedimentos radiológicos resultam em imagens com qualidade diagnóstica duvidosa, sendo necessária, muitas vezes, a repetição de exames. Desta forma, métodos para minimizar a rejeição imagens radiológicas devem ser observados. A fim de colaborar para a diminuição dos erros de posicionamentos e consequente rejeição de exames de imagem na área da odontologia, este estudo teve por objetivo a criação de um guia de referência para aplicação em exames extraorais odontológicos. Para a elaboração e estruturação deste guia, foi realizado um estudo com o intuito de identificar os motivos de rejeição de radiografias panorâmicas em um serviço de radiologia odontológica digital. O estudo foi retrospectivo e por meio de uma busca no software de aquisição de imagens, foram selecionadas 2306 radiografias panorâmicas digitais, correspondentes a 10% do total de exames realizados entre os anos de 2013 a 2015. A partir da amostra, foram identificados os exames rejeitados e as causas da rejeição. Ainda para colaborar com o desenvolvimento do guia de referência, foi aplicado um questionário aos profissionais técnicos/tecnólogos atuantes no setor de radiologia onde a pesquisa foi realizada. O questionário contou com nove perguntas relacionadas à rotina de trabalho do setor. Com os resultados obtidos na pesquisa foi possível a elaboração do guia de referência com imagens radiográficas para aplicação em exames odontológicos. / The radiological exams are important resources in aid of drafting a dental diagnosis. However, should only be performed when there is a real clinical indication, since the effects of ionizing radiation on the human body are cumulative. Flaws in the implementation of radiological procedures result in doubtful quality diagnostic images, being necessary, many times, the repetition of exams. In this way, methods to minimize radiological images rejection must be observed. In order to contribute to the reduction of errors of positioning and consequent rejection of imaging examinations in the area of dentistry, this study had as its objective the creation of a reference guide for application in dental extraoral examinations. For the preparation and structuring of this guide, a study was conducted with the aim of identifying the reasons for the rejection of panoramic radiographs in a digital dental radiology service. The study was retrospective and by means of a search in the software of image acquisition, were selected 2306 digital panoramic radiographs, corresponding to 10% of the total number of examinations performed between the years of 2013 and 2015. From the sample, were identified the rejected exams and the causes of rejection. To collaborate with the development of the reference guide, a questionnaire was applied at technical professionals working in the radiology sector where the research was conducted. The questionnaire was attended by nine questions related to routine work in the sector. With the results obtained in the study it was possible to do the preparation of the guide of reference with radiographic images for application in dental examinations.
82

Factors influencing patients' demand for x-ray examinations in rural Kwa-Zulu Natal

Mungomba, Bernard 02 1900 (has links)
The focus of this study was on the problem of unwarranted demand for radiological imaging by patients in rural KZN of South Africa. Literature in the context of this topic is scarce. Consequently the aim of this study was to describe sociodemographic factors that might influence patients demand for x-ray examinations. A quantitative in the form of a cross sectional survey was done. A convenient sample of 110 patients was surveyed using a structured questionnaire. Results of the study indicate that age, and educational level might influence patients’ demand for x-ray examinations. The study also revealed that very few respondents 10.9% (n=12) had knowledge about x-rays. The study further revealed that there might be other factors such as patients’ perceived benefits of x-rays, beliefs, lack of public health awareness as well as lack of effective communication between patients and health care providers. / Health Studies / M.A. (Public Health)
83

Core competencies of radiographers working in rural areas of South Africa

Mungomba, Bernard 02 1900 (has links)
Text in English / The contribution of general diagnostic imaging in the diagnosis and clinical management of patients in rural hospitals of South Africa is enormous. To provide high quality diagnostic imaging services for specific contexts requires radiographers who have up-to-date skills and expertise. Thus, rural radiographers require, over and above traditional radiographic expertise, additional competencies which are unique to rural practice. To date, however, little is known about additional core competencies and skills needed by radiographers working in rural areas. Previous studies have focused more attention primarily on other rural health professionals such as doctors and nurses. The aim of this mixed methods study was to investigate and identify additional core competencies required by radiographers working in rural district hospitals of KZN in order to propose a CPD strategy aimed at rural radiographers. An exploratory sequential design was utilised. There were seven participants in the qualitative phase of the study. In the quantitative phase a convenient sample of 109 respondents was surveyed using a structured questionnaire. Three major themes and seven categories emerged from Phase I of the study. These themes and categories were then used to develop a data collection instrument for Phase II of the study. Collectively, the findings of this mixed methods research revealed that there were a number of additional core competencies such as, but not limited to, teamwork, ability to do basic obstetric ultrasound scans, leadership, management, attitude and behaviours, and reporting on plain x-ray films, all of which are required by rural radiographers. Supporting evidence from the study indicated that the majority of these competencies were either partially or not at all covered in the audited curriculum. The study further revealed that the audited curriculum and the scope of radiography in its current form appear to focus attention on minimum competencies that do not promote the expansion and extension of the role of radiographers in rural areas. The study results also revealed a number of challenges faced by rural radiographers. / Health Studies / D. Litt. et Phil. (Health Studies)
84

Classificação de defeitos de soldagem em imagens radiográficas PDVD de tubulações de petróleo: uma abordagem com ensemble de Extreme Learning Machines / Classification of welding fedects in radiographic images DWDI of pipeline: an approach with ensemble of Extreme Learning Machines

Boaretto, Neury 27 April 2014 (has links)
A inspeção de defeitos de soldagem em imagens radiográficas de tubulações é bastante subjetiva e está sujeita a erros de interpretação por parte do inspetor laudista. Dentro desse contexto, nos últimos anos tem-se visto um grande esforço no desenvolvimento de métodos automáticos e semiautomáticos de detecção de defeitos em juntas soldadas. Este trabalho apresenta um método automatizado para detecção e classificação de defeitos em imagens radiográficas de juntas soldadas de tubulações obtidas pela técnica de exposição radiográfica parede dupla vista dupla (PDVD), obtidas em reais situações de campo e que, geralmente, têm uma qualidade mais baixa do que as imagens usadas em outros estudos. O método proposto identifica na imagem a região do cordão de solda, detecta as descontinuidades e classifica as mesmas em defeitos e não defeitos, destacando na imagem o resultado. São avaliados classificadores a partir de métodos de classificação por redes neurais Multilayer Perceptron (MLP), redes neurais Extreme Learning Machines (ELM) e classificador estatístico Support Vector Machines (SVM). O método proposto para identificação da região de interesse atingiu 100% de precisão na segmentação do cordão de solda. O classificador SVM apresentou um desempenho melhor que os classificadores MLP e ELM em todos os cenários testados. Com a utilização de ensembles de ELMs obteve-se um F-score de 85,7% para o banco de padrões de teste, resultados satisfatórios quando comprados com trabalhos semelhantes. O uso de ensembles de ELMs representa um ganho de apenas 0,5% no F-score em comparação com o melhor resultado de rede treinada individualmente, entretanto, com o uso de faixas de limiares de decisão do ensemble, o uso do método permite mostrar as descontinuidades sobre as quais o ensemble não tem certeza, destacando na imagem estas descontinuidades. A imagem resultate da aplicação do método serve como auxílio ao especialista na elaboração de laudos. / The inspection of radiographic images of welded joints is very subjective and is subject to errors of interpretation by the inspector. In this context, a great effort has been made in the last years to develop automatic and semiautomatic methods for detecting defects in welded joints. This research work presents an automated method for the detection and classification of defects in radiographic images of welded joints of pipes obtained by the double wall double image (DWDI) exposure technique obtained in real field situations and which generally have a lower quality than the images used in other studies. The proposed methos identifies the region of the weld bead, detects the discontinuities and classifies them as defects and non-defects, highlighting in the image the result. Classifiers are evalueted using methods of classification by multilayer perceptron (MLP) neural networks, extreme learning machines (ELM) neural networks, and Support Vector Machines (SVM). The proposed method for identifying the region of interest reached 100% precision in the segmentation od the weld bead. The SVM classifier performed better than the MLP and ELM classifiers in all scenarios tested. Using ELM ensembles, an F_score of 85,7% was obtained for a test patterns database, satisfactoryresults when compared to similar works. The use of ensembles of ELMs represents a gain of only 0,5% in the F-score compared to the best result of the individually trained network, however, with the use of ensemble decision threshold ranges, the presented method allows to show the discontinuities about which the ensemble is not sure, highlighting in the image these discontinuities as a region of uncertainty, leaving to the specialist the final evaluation of these discontinuities. The image resulting from the application of the method serves as an aid to the expert in the elaboration of reports.

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