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1
Leal, James Andrew 1963. "Automated radiographic inspection of through-hole electronic circuit board solder defects." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276672.
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A study has been carried out to investigate the use of "real-time" radiography as a method of automated inspection of through-hole electronic circuit board solder joints. By evaluating five major solder defects it has been found that film radiography employing high contrast film results in a definite distinction between a good solder joint and a defective solder joint. The same five defects were also found to be distinguishable from a good solder joint when evaluated by a real-time radiographic inspection unit using digital image processing. Although the type of defect being investigated was not discernible, the ability to distinguish a good solder joint from a defective solder joint is a major step in the implementation of automated solder joint inspection for military electronics.
2
Hayek, Jorge Elie. ""Avaliação da densidade ótica perimplantar cervical em controle longitudinal de implantes com função oclusal imediata em maxila"." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/23/23139/tde-11112005-115646/.
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A proposta neste estudo foi avaliar as alterações da densidade ótica do osso alveolar perimplantar cervical em controle longitudinal, por meio de radiografias periapicais digitalizadas de dez pacientes, nos quais foram instalados seis implantes na maxila submetidos à função oclusal imediata, mediante a instalação de uma prótese fixa 24 horas após a cirurgia. Todos os pacientes foram avaliados clinicamente, com exames da análise da freqüência de ressonância, além de controle radiográfico. Foi utilizada a técnica radiográfica intrabucal do parale lismo, com cone longo, sendo que o feixe de raios X incidiu perpendicularmente ao longo eixo do implante. Os controles radiográficos foram realizados na instalação da prótese, após 6 meses e após 12 meses. As radiografias obtidas foram então capturadas por uma câmera de vídeo (preto e branco) por meio de um microscópio ótico (40 vezes de aumento). Devido à ampliação utilizada, os implantes tiveram suas imagens digitalizadas em 2 etapas (metade direita e metade esquerda), sendo consideradas como amostras independentes. Após a sobreposição de um gabarito sobre a imagem, com a finalidade padronizar as áreas a serem estudadas, foram analisadas as densidades óticas na área de interesse osso + implante e na área de controle implante (onde não é esperada alteração) por meio do software ImageLab. Para a correção de possíveis variações na densidade da radiografia e projeção geométrica oriundas da metodologia empregada, foi utilizada uma equação matemática para validar a análise dos dados obtidos. Os resultados mostraram que ocorreu variação percentual da densidade ótica na área de interesse (osso + implante) nos primeiros seis meses (T2) com diminuição de aproximadamente 5% para o lado direito e diminuição de aproximadamente 6% para o lado esquerdo em relação às radiografias iniciais (T1) e após doze meses, a diminuição da densidade ótica estabilizou-se, não sendo encontradas alterações estatisticamente significantes em relação ao período correspondente entre T2 (seis meses) e T3 (doze meses). Os resultados da análise digital das radiografias periapicais demonstraram coincidência com os resultados da análise da freqüência de ressonância e exame clínico dos implantes e demonstraram um aspecto compatível com o sucesso dos implantes osteointegrados com função imediata na maxila.<br>The aim in this study was the evaluation of the variations of the perimplantar optical bone density at the cervical region in a longitudinal control, by the use of digitized radiographs of ten patients, who received six implants installed in the maxilla and submitted to immediate occlusion function, through fixed prosthesis installed 24 hours after the surgery. All the patients were observed in clinical control, with resonance frequency analysis and also radiographic control. It was performed a intraoral radiograph using the paralleling technique, with the long cone and the beam of x-ray aimed perpendicular to the long axis of the implant. The radiographic controls were done at the time of the installation of the prosthesis, after six months and after twelve months after the first control. The obtained radiographs were captured by a black and white video camera by an optical microscope (40 times of magnification). Due to the utilized magnification, the implants have their images digitized in two steps: half right and half left, and they were considered as independent samples. After the superimposition of a standardized pattern, to help the standardization of the areas of the study, it was analyzed the optical density at the areas of interest bone + implant and at areas of control bone (where it is not hope changes) through the software ImageLab. To correct possible variations of the effect of the absence of standardization of the geometric projection and the radiographic density, it was realized a mathematic equation and it was obtained a correction factor of density in order to compensate. The results sho wed that there were percentage variation of the optical density at the area of interest (bone + implant) at six months (T2) showed a decreased of about 5% for the right side and showed a decreased of about 6% for the left side when analyzed the first control and after twelve months no significant statistical difference was observed between the T2 period (six months) and T3 period (twelve months). The results of digital analysis from the intraoral radiographs showed as the same as the results of resonance frequency analysis and the clinic examination of the implants and showed a success of implants installed in the maxilla with immediate occlusion function.
3
Schneider, Uwe. "Proton radiography : a tool for quality control in proton therapy /." [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10780.
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Ariga, Eiji, Shigeki Ito, Shizuhiko Deji, Takuya Saze, and Kunihide Nishizawa. "Development of dosimetry using detectors of diagnostic digital radiography systems." American Association of Physicists in Medicine, 2007. http://hdl.handle.net/2237/8818.
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Bickerton, M. L. "Development of improved techniques for the neutron radiography of CF188 flight control surfaces." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0006/MQ44833.pdf.
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Beldjoudi, Guillaume Nordine. "Approche multi-énergies associée à un détecteur spectrométrique rayons X pour l’identification de matériaux." Thesis, Lyon, INSA, 2011. http://www.theses.fr/2011ISAL0082/document.
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Le développement des détecteurs de rayons X en comptage à base de semiconducteurs est en plein essor depuis une dizaine d’années, et des applications aussi bien dans le domaine médical que dans le domaine du contrôle non destructif sont envisagées. Ces détecteurs permettent en effet de réaliser des mesures à des énergies multiples en une seule acquisition, et ce avec une excellente séparation énergétique. Depuis les années 2008-2009, il semble qu’une véritable course se soit lancée pour le développement de détecteur permettant des mesures multi-énergies sur un nombre toujours plus nombreux de bandes d’énergies. Cependant, à ce jour, parmi l’ensemble des travaux qui ont été réalisés, l’intérêt de réaliser des mesures sur un grand nombre d’énergies n’a pas été démontré pour l’identification de matériaux. Dans le cadre d’une étude en sécurité, nous avons évalué l’intérêt lié à l’utilisation de détecteurs de rayons X en comptage permettant la réalisation de mesures sur plusieurs bandes d’énergies. Le domaine applicatif étudié concerne l’identification de matériaux dans les bagages des voyageurs. Nous avons tout d’abord développé une méthode originale d’identification de matériaux homogènes applicable à tout type de détecteur multi-énergies. Dans un premier temps, nous avons étudié, en simulation, l’évolution des performances d’identification de matériaux avec l’augmentation du nombre de bandes d’énergies de comptage. Un processus d’optimisation a été réalisé dans le but de déterminer, pour certaines configurations, une géométrie optimale des bandes d’énergies de comptage. Dans un second temps, les conséquences résultant de la prise en compte de la fonction de réponse du détecteur ont été quantifiées par la simulation de différents effets détecteurs (partage de charge, résolution en énergie). Une validation expérimentale a enfin pu être effectuée en utilisant un détecteur spectrométrique en comptage. À partir des mesures réalisées avec un tel détecteur, un regroupement des données nous a permis d’évaluer les performances d’identification de détecteurs possédant un nombre de bandes d’énergies de comptage différent. Enfin, nous avons mené une étude préliminaire sur la transposition à la tomographie multi-énergies de la méthode d’identification de matériaux homogènes développée initialement en radiographie. Cette modalité d’imagerie permet alors l’identification de matériaux superposés<br>The development of X-ray photon counting detectors based on semiconductors has grown up over the last ten years, and applications in medicine, in security and in nondestructive testing are under study. These detectors make it possible to perform measurements at multiple energies in a single acquisition, with an excellent energetic separation. Since the years 2008-2009, it seems that a real race started for the development of detectors performing multi-energetic measurements on an increasing number of energy bands. However, today, within the works already done, the interest of performing measurements on a large number of energies has not been demonstrated for material identification. As part of a study in homeland security, we assessed the interest of using Xray counting detectors that perform measurements on multiple energy bands. The considered field of interest is material identification in the luggage of travelers. We first developed an original method for identifying single materials. This method is applicable to any type of multi-energy detector. In a first time, we studied in simulation the evolution of the performance for identifying materials with the increasing number of energy bands. An optimization process was carried out to determine, for certain configurations, an optimal geometry of the energy bands.In a second step, the consequences of taking into account the detector response function were quantified by simulating different sensors effects (charge sharing, energy resolution). An experimental validation has been performed by using a counting spectrometric detector. From the measurements experimentally obtained with such a detector, combining the data allowed us to evaluate the identification performance that would have detectors possessing a different number of energy bands. Finally, we conducted a preliminary study on the transposition of the identification method initially developed for radiography to the multi-energy computed tomography. This imaging modality allows to identify superimposed materials
7
Tisseur, David. "Contrôle par imagerie X de combustible nucléaire pour les centrales à haute température." Villeurbanne, INSA, 2008. http://www.theses.fr/2008ISAL0015.
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Ce travail s'inscrit dans le cadre d'une thèse CIFRE entre AREVA NP et le laboratoire CNDRI de I'INSA de Lyon dans le contexte du développement d'une centrale de quatrième génération dite High Temperature Reactor (HTR). Dans ces futures centrales nucléaires, le combustible se présentera sous la forme de petites billes multicouches de 1 mm de diamètre appelée particule TRISO (TRistructuraiiSOtropic). Pour des raisons de sûreté divers contrôles de ces particules doivent être mis en place. Le premier objectif de ce travail est de développer une méthode de mesure de la densité des couches entourant les particules HTR par rayons X et la conception d'un démonstrateur industriel. La technique de mesure, que nous avons mise en place, est fondée sur une méthode inverse qui repose sur l'imagerie X en contraste de phase. Le second objectif de ce travail est de quantifier la répartition spatiale des particules dans un assemblage combustible nommé "compact". Après un état de l'art sur la mesure de l'homogénéité, nous montrons qu'une tomographie à haute énergie associée à un traitement de l'image adapté permet d'obtenir la position dans l'espace de chaque particule constituant le compact. L'approche proposée consiste à comparer un histogramme multiéchelle de répartition expérimental des particules à un modèle théorique à l'aide d'un test du chi2. Ceci nous permet de dégager un critère permettant de quantifier l'homogénéité des compacts<br>This PhD the. Sis is the result ot a collaboration between AR EVA NP and laboratory CNDRI of the INSA of Lyon in the context of the development of a 4\textsuperscript{th} generation nuclear power plant, named as High Temperature Reactor (HTR). In these future nuclear power plants, the fuel consists of small multi-layer spheres of 1 mm diameter called TRISO particle (TRistructural ISOtropie). For safety reasons various controls of these particles must be developed. The first objective of this study is to develop a measurement method of the density of the layers surrounding HTR particles by x-rays and to install an industrial demonstrator. The measurement technique is founded on an inverse method based on X-ray phase contrast imaging. The second objective is to quantify the space distribution of the particles in a fuel assembly named "compact". After a state of the art to the measure of the homogeneity, we demonstrate that a high energy tomography associated with a suitable image processing enables to obtain the position in the space of each particle constituting the compact. The suggested approach consists in comparing an experimental multiscale histogram of particle distribution with an ideal model using a chi2 test. This allows to suggest a criterion to quantify the homogeneity of the compact
8
Yao, Min. "Computed radiography system modeling, simulation and optimization." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0128/document.
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Depuis plus d’un siècle, la radiographie sur film est utilisée pour le contrôle non destructif (CND) de pièces industrielles. Avec l’introduction de méthodes numériques dans le domaine médical, la communauté du CND industriel a commencé à considérer également les techniques numériques alternatives au film. La radiographie numérique (en anglais Computed radiography -CR) utilisant les écrans photostimulables (en anglais imaging plate -IP) est une voie intéressante à la fois du point de vue coût et facilité d’implémentation. Le détecteur (IP) utilisé se rapproche du film car il est flexible et réutilisable. L’exposition de l’IP aux rayons X génère une image latente qui est ensuite lue et numérisée grâce à un système de balayage optique par laser. A basse énergie, les performances du système CR sont bonnes ce qui explique son utilisation importante dans le domaine médical. A haute énergie par contre, les performances du système CR se dégradent à la fois à cause de la mauvaise absorption de l’IP mais également de la présence de rayonnement diffusé par la pièce qui, étant d’énergie plus faible, est préférentiellement absorbée par l’IP. Les normes internationales préconisent l’utilisation d’écrans métalliques pour améliorer la réponse des systèmes CR à haute énergie. Néanmoins, la nature et l’épaisseur de ces écrans n’est pas clairement définie et la gamme des configurations possibles est large. La simulation est un outil utile pour prévoir les performances d’une expérience et déterminer les meilleures conditions opératoires. Les méthodes Monte Carlo sont communément admises comme étant les plus précises pour simuler les phénomènes de transport de rayonnement, et ainsi comprendre les phénomènes physiques en jeu. Cependant, le caractère probabiliste de ces méthodes implique des temps de calcul importants, voire prohibitifs pour des géométries complexes. Les méthodes déterministes au contraire, peuvent prendre en compte des géométries complexes avec des temps de calcul raisonnables, mais l’estimation du rayonnement diffusé est plus difficile. Dans ce travail de thèse, nous avons tout d’abord mené une étude de simulation Monte Carlo afin de comprendre le fonctionnement des IP avec écrans métalliques à haute énergie pour le contrôle de pièces de forte épaisseur. Nous avons notamment suivi le trajet des photons X mais également des électrons. Quelques comparaisons expérimentales ont pu être menées à l’ESRF (European Synchrotron Radiation Facility). Puis nous avons proposé une approche de simulation hybride, qui combine l'utilisation de codes déterministe et Monte Carlo pour simuler l'imagerie d'objets de forme complexe. Cette approche prend en compte la dégradation introduite par la diffusion des rayons X et la fluorescence dans l'IP ainsi que la diffusion des photons optiques dans l'IP. Les résultats de différentes configurations de simulation ont été comparés<br>For over a century, film-based radiography has been used as a nondestructive testing technique for industrial inspections. With the advent of digital techniques in the medical domain, the NDT community is also considering alternative digital techniques. Computed Radiography (CR) is a cost-efficient and easy-to-implement replacement technique because it uses equipment very similar to film radiography. This technology uses flexible and reusable imaging plates (IP) as a detector to generate a latent image during x-ray exposure. With an optical scanning system, the latent image can be readout and digitized resulting in a direct digital image. CR is widely used in the medical field since it provides good performance at low energies. For industrial inspection, CR application is limited by its poor response to high energy radiation and the presence of scattering phenomena. To completely replace film radiography by such a system, its performance still needs to be improved by either finding more appropriate IPs or by optimizing operating conditions. Guidelines have been addressed in international standards to ensure a good image quality supplied by CR system, where metallic screens are recommended for the case of using high energy sources. However, the type and thickness of such a screen are not clearly defined and a large panel of possible configurations does exist. Simulation is a very useful tool to predict experimental outcomes and determine the optimal operating conditions. The Monte Carlo (MC) methods are widely accepted as the most accurate method to simulate radiation transport problems. It can give insight about physical phenomena, but due to its random nature, a large amount of computational time is required, especially for simulations involving complex geometries. Deterministic methods, on the other hand, can handle easily complex geometry, and are quite efficient. However, the estimation of scattering effects is more difficult with deterministic methods. In this thesis work, we have started with a Monte Carlo simulation study in order to investigate the physical phenomena involved in IP and in metallic screens at high energies. In particular we have studied separately the behavior of X-ray photons and electrons. Some experimental comparisons have been carried out at the European Synchrotron Radiation Facility. Then, we have proposed a hybrid simulation approach, combining the use of deterministic and Monte Carlo code, for simulating the imaging of complex shapes objects. This approach takes into account degradation introduced by X-ray scattering and fluorescence inside IP, as well as optical photons scattering during readout process. Different simulation configurations have been compared
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Guu, Adam Cheng-show. "Study of weld pool formation by real-time radiography with application for sensing and control of arc welding /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487688507503345.
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Silva, Sabrina Donato da. "Estabelecimento de requisitos de desempenho em dosimetria e proteção radiológica nos serviços de mamografia digital de Minas Gerais." CNEN - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, 2014. http://www.bdtd.cdtn.br//tde_busca/arquivo.php?codArquivo=310.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Segundo dados do Cadastro Nacional de Estabelecimentos de Saúde (CNES), o Estado de
Minas Gerais possui aproximadamente 477 mamógrafos em uso. Destes, estima-se que em
torno de 200 são digitais utilizando, principalmente, sistemas de radiografia computadorizada
(CR) ou radiografia direta (DR). A mamografia é insubstituível no diagnóstico e detecção
precoce do câncer de mama, principal causa de morte entre mulheres no mundo. Um alto padrão
de qualidade da imagem, aliada com uma dose tão baixa quanto razoavelmente exequível, são
essenciais para esta detecção precoce de forma segura, levando a necessidade de controle de
qualidade através do processo de otimização dos procedimentos.
Dentro deste contexto este estudo teve como objetivo determinar a dosimetria e a qualidade da
imagem em 72 combinações mamógrafo/CR e DRs em 68 serviços de mamografia do Estado
de Minas Gerais, o que corresponde aproximadamente 14% do total de mamógrafos atualmente
em uso no Estado de Minas Gerais e a cerca de 34% dos mamógrafos digitais em uso (CRs e
DRs).
O teste que avalia a linearidade da resposta do detector mamógrafico atendeu aos critérios de
desempenho especificados pela Sociedade Espanhola de Física médica em 85% dos
equipamentos avaliados. Porém dos serviços que apresentaram não conformidade nesse quesito
apenas dois apresentaram menos de quatro anos de uso do mamógrafo. Possivelmente o tempo
de utilização dos mamógrafos esteja relacionado a não conformidade apresentada por esses
serviços. A relação contraste ruído mostrou-se ser um ponto crítico na cadeia de produção da
imagem em sistemas digitais, principalmente para maiores espessuras de acrílico.
Mais da metade dos serviços avaliados nessa pesquisa obtiveram um bom desempenho na
relação sinal ruído (SNR), e na avaliação da imagem através do simulador de contraste e detalhe
CDMAM. Em relação ao ruído da imagem a maioria dos serviços ficaram não conformes.
Na avaliação da dose glandular média realizada com simuladores de mama, a média geral dos
valores de doses obtidos ficaram dentro dos limites considerados aceitáveis na literatura, para
a maioria das espessuras simuladas de mama. Porém os resultados obtidos nesse teste são
preocupantes, pois a maioria dos sistemas digitais avaliados ficaram não conformes nesse
quesito em pelo menos uma espessura de acrílico avaliada, e além disso houve um aumento
considerável da dose glandular média em comparação a medidas anteriores realizadas no Estado
de Minas Gerais. Já na comparação da dose glandular média entre sistemas CR e DR os sistemas
DR apresentaram doses consideravelmente menores para maiores espessuras, em comparação
com os sistemas CR. Em relação à comparação entre avaliações subsequentes a amostra seguiu
o comportamento geral dos serviços avaliados nesta pesquisa, com exceção da SNR que
apresentou um pior desempenho entre as avaliações subsequentes e o ruído, que apesar do baixo
índice de conformidade obteve uma melhora entre uma avaliação e outra.
Apesar dos potenciais benefícios que podem ser alcançados com o uso do sistema CR e DR, o
emprego dessa tecnologia precisa ser revisto e otimizado para que possa oferecer imagens de
qualidade utilizando a menor dose possível de radiação.<br>According to the National Registration of Health Establishments (CNES), there are
approximately 477 mammographs operating in the state of Minas Gerais, of which, roughly
estimating, 200 are digital apparatus using mainly computerized systems of radiography (CR)
or direct radiography (DR). Mammography is irreplaceable in the diagnosis and early detection
of breast cancer, the main cause of death in women worldwide. A high standard of image quality
coupled with a dose as low as reasonably practicable, are essential for early detection of this
disease with safely, leading to the need for quality control through optimization of process
procedures.
Within this context, this study aimed to determine dosimetry and image quality on 72
mammography combinations / CR and DR in 68 mammography services in the State of Minas
Gerais, which represents approximately 14% of mammography units currently in use in the
State of Minas Gerais and about 34% in use of digital mammography (CRs and DRs).
The test evaluates the linearity of response of the detector mammographic met the performance
criteria specified by the Spanish Society of Medical Physics in 85% of evaluated equipment.
However, the services they showed non-compliance in this regard, only two were less than four
years of use of mammography. Possibly the time of use of mammography is related to noncompliance
by these services. The contrast noise ratio proved to be a critical point in the
production chain image in digital systems, especially for thicker acrylic. More than half of the
services evaluated in this study showed good performance in signal noise, and image evaluation
by the phantom contrast and detail CDMAM. Regarding the image noise, most services were
non-compliance. In evaluating the average glandular dose with breast phantom, the overall
average dose values obtained were within acceptable limits in the literature for most of the
simulated breast thicknesses. However the results of that test are troubling, since most digital
systems evaluated were non-compliant in this regard at least one thick acrylic evaluated, and in
addition there was a considerable increase in the average glandular dose compared to previous
measurements performed in the State of Minas Gerais. In comparison between the average
glandular dose in CR and DR systems, the DR systems showed significantly lower doses for
greater thickness as compared with the CR systems.
Regarding the comparison between subsequent reviews, the sample followed the general
behavior of the services evaluated in this study, except the SNR had a worse performance
between subsequent evaluations and noise, which despite the low level of compliance achieved
an improvement between evaluation and other. Therefore, despite the potential benefits that can
be attained with the use of the CR and DR systems, the employment of this technology has to
be revised and optimised so that a better quality image can be achieved and the radiation dose
reduced as much as possible.
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Wibowo, Gatot Morti Chavalit Wongse-ek Manus Mongkolsuk. "Factors affecting image quality and entrance skin exposure when using automatic exposure control (AEC) /." Abstract, 2004. http://mulinet3.li.mahidol.ac.th/thesis/2547/cd370/4537449.pdf.
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Silva, Renan Lucio Berbel da. "Avaliação da densidade ótica peri-implantar cervical em controle longitudinal de implantes na região anterior de maxila." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/23/23139/tde-15082018-094151/.
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As complicações peri-implantares, posteriormente a colocação do implante em função, são frequentes e sua identificação precoce pode significar uma terapêutica adequada e consequentemente garantir o sucesso do terapêutica. A proposta neste trabalho foi avaliar longitudinalmente a densidade ótica do osso alveolar peri-implantar na região cervical, analisada, por meio da técnica de subtração radiográfica de um acervo de radiografias digitais adquiridas de pacientes previamente reabilitados com trinta e sete implantes osteointegrados imediatos na região anterior da maxila. Os controles radiográficos foram realizados em cinco momentos: na instalação das próteses, após 15,90,180 e 360 dias, e as radiografias intrabucais foram obtidas pela técnica do paralelismo de cilindro longo, com posicionadores do tipo Hanshin individualizados de forma a garantir a padronização das imagens. As imagens digitais obtidas foram alinhadas e equalizadas e por fim submetidas ao procedimento de subtração radiográfica. Os resultados indicaram que a metodologia de subtração radiográfica é válida para a avaliação da perda óssea peri-implantar, assim como demonstra a literatura. No entanto, a reprodução das angulações verticais e horizontais, apresentam-se como críticas na avaliação da densidade óptica da crista óssea e demandam grande habilidade do operador para a correta aplicação. Por meio dessa técnica, conseguimos avaliar de forma quantitativa e qualitativa as alterações na faces proximais nas imagens radiográficas do acervo analisado. A subtração radiográfica, por meio da ferramenta de histograma, permitiu quantificar de forma objetiva as diferenças encontradas nas análises.<br>The peri-implant complications, in addition to implant placement in function, are frequent and their early identification could mean a therapy appropriately and consequently guarantee the success of the treatment. The aim of this research was to longitudinally evaluate of the optical density of the peri-implant alveolar bone at the cervical region, analyzed by means of the radiographic subtraction technique, a collection of digital radiographs acquired from patients previously rehabilitated with thirty seven osseointegrated implants. The radiographic controls performed in five moments, at the installation of the prostheses, after 15,90,180 and 360 days, and the intraoral radiographs were obtained by parallelism technique, with Hanshin-type positioners individualized in order to guarantee the standardization of the images. The obtained digital images were aligned and equalized and finally submitted to radiographic subtraction procedure. The results indicated that the methodology of radiographic subtraction is valid for an evaluation of the peri-implant bone loss, as well as to demonstrated at the literature. However, the reproduction of the vertical and horizontal angles, are presented as critical in the evaluation of the optical density, and demand a great ability of the operator for a correct application. Through the technique we obtained a quantitative and qualitative evaluation in the area of proximal images in the radiographic images of the analyzed data. The histogram tool applied on the radiographic subtraction images allowed to quantify objectively as the differences found in the analyzes.
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Mickus, Joice. "Elaboração de um guia de referência com imagens radiográficas para aplicação em exames extraorais odontológicos." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2792.
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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.<br>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.
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Al-Khateeb, Susan. "Studies on the remineralization of white spot lesions : longitudinal assessment with quantitative light-induced fluorescence /." Stockholm, 1998. http://diss.kib.ki.se/1998/19980331alkh.
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Gomes, Danielle Soares. "Estudo de desempenho de sistemas de visualização de imagens mamográficas correlacionados com qualidade de imagem." CNEN - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, 2014. http://www.bdtd.cdtn.br//tde_busca/arquivo.php?codArquivo=329.
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Para as análises de imagens mamográficas, médicos radiologistas fazem uso de monitores médicos especializados, capazes de proporcionar laudos seguros, uma vez que devem oferecem resolução adequada, níveis corretos de luminância e contraste dentro do padrão DICOM - Digital Imaging and Communications in Medicine (Comunicação de Imagens Digitais na Medicina). Este trabalho teve como objetivo avaliar a qualidade dos monitores específicos para mamografia digital, através de testes propostos pelo Report N 3 da American Association of Physicists in Medicine AAPM usando medidores calibrados de luminância (fotômetro) e padrões TG18 em testes quantitativos e qualitativos. Avaliou-se as condições de luz ambiente e outros indicadores básicos de desempenho, como, distorção geométrica, ruído, resolução, reflexão, uniformidade da luminância, o cumprimento resposta contraste de luminância para padrão DICOM e padrão anatômico das mamas. Em resposta, o teste que mais apresentou não conformidade foi à variação excessiva com o padrão de resposta contraste DICOM Grayscale Standard Display Function (GSDF), apresentando não conformidade em (100%) dos monitores analisados. Nos demais testes, todos os monitores de 5MP e o de 3MP apresentaram conformidade nos parâmetros avaliados. Em uma ação corretiva para as não conformidades, indica-se a realização de calibrações e procedimentos de verificação de controle de qualidade feitas por profissionais capacitados ou orientados.<br>For the analysis of mammographic images, radiologists make use of specific medical monitors, able to provide insurance reports, as they offer appropriate resolution, correct levels of luminance and contrast within the standard DICOM - Digital Imaging and Communications in Medicine (Communication Images digital in Medicine). This study aims to evaluate the quality of specific monitors for digital mammography, by testing the calibrated luminance meters (photometer) and TG18 standards in quantitative and qualitative methods proposed by Report No. 3 of American Association of Physicists in Medicine AAPM. It was evaluated the ambient light conditions and other basic performance indicators, such as, the as geometric distortion, noise, resolution, reflection, luminance uniformity, contrast luminance response compliance to DICOM standard and anatomical pattern of the breasts. The results showed that non-compliance test fails when visualizing low-contrast objects (100% of monitors analyzed) in the response pattern contrast DICOM Grayscale Standard Display Function (GSDF). For the other tests, all monitors of 5 and 3MPixel presented in agreement to the evaluated parameters. For a further corrective action for instance, non-compliance, it may be indicate to perform calibrations and verification of quality control developed by trained or oriented professionals.
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Costa, Hamilton Baptista da. "Investigação de qualidade para comparação de sistemas de imagem em radiologia odontológica." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-26122005-185903/.
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O presente trabalho de pesquisa trata da investigação de parâmetros de qualidade aplicados a sistemas de imagem em radiologia odontológica. Para isso, foram levantados parâmetros propostos pela Portaria nº 453 de 1998 da Secretaria de Vigilância Sanitária do Ministério da Saúde em aparelhos de raios X odontológicos e determinadas funções de transferência de modulação (FTM), como método para a avaliação da resolução espacial de sistemas de radiologia odontológica digital. Com base nesses dados, comparou-se três sistemas digitais diretos (DIGORA, DENOPTIX e CygnusRay) e um sistema digital indireto, baseado no scanner Umax PowerLook 1120. Essa comparação evidenciou, para esse caso, a melhor qualidade, em termos de resolução espacial, do sistema indireto estudado e a relativa equivalência dos sistemas digitais entre si, quando comparados em suas resoluções máximas (em número de pontos por polegada). Também foi possível validar o uso do método de simulação computacional para a obtenção da FTM de sistemas radiográficos odontológicos<br>This work has investigated quality parameters applied to odontologic radiographic image systems. In order to achieve this purpose, parameters related to the Portaria nº 453 of 1998 of Secretaria de Vigilância Sanitária do Ministério da Saúde have been checked and modulation transfer functions (MTF) have been determined. These information has been used to compare three differents direct radiographic images systems (DIGORA, DENOPTIX e CygnusRay) and one indirect, based on scanner Umax PowerLook 1120. The obtained data has showed, in this case, the better performance, in terms of spatial resolution, of the indirect system and the relative equivalency of the direct systems, when configured with the maximum resolution (in term of dpi). The work has validated the computer simulation process in order to generate the MTF of odontologic radiographic image systems
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SILVA, JONAS O. da. "Desenvolvimento de câmaras de ionização especiais para controle de qualidade em mamografia." reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10507.
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FURQUIM, TANIA A. C. "Metodologia para correlação entre doses e detectabilidade em imagens mamográficas padrões: aplicação no estado de Sao Paulo." reponame:Repositório Institucional do IPEN, 2005. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11290.
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Fiani, Myriam. "Reconstruction 3D à partir d'un nombre limité de radiographies : application au contrôle non destructif des soudures." Paris 11, 2001. http://www.theses.fr/2001PA112312.
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Nous nous intéressons à la reconstruction 3D d'objets métalliques à partir d'un nombre limité de projections. L'application traitée est le contrôle non destructif des soudures par gammagraphies. A cause des contraintes in situ et des contraintes liées aux types de pièces et de défauts contrôlés, les informations disponibles sont pauvres et en nombre limité. De ce fait, le problème de reconstruction est mal posé. Afin d'obtenir une solution acceptable, nous choisissons de le régulariser dans le formalisme bayésien. L'estimateur retenu est le maximum a posteriori. C'est aussi le minimiseur d'un critère pénalisé. A partir de l'existant développé à EDF, nous apportons des améliorations qui sont, en particulier, adaptées à la reconstruction de soudures à partir de gammagraphies. D'un point de vue modélisation, nous exploitons des informations a priori originales, notamment la géométrie de la pièce supposée exempte de défauts et des contraintes d'appartenance à un intervalle. Nous affinons également la modélisation de la formation des données en prenant en compte le phénomène de flou. .<br>This work deals with the 3D reconstruction of metal objects from a limited number of projections. The application is the nondestructive evaluation of welds from X-ray data. The information are few and of poor quality due to the in situ constraints and to constraints related to the type of objects and its faults. Reconstruction is then an ill-posed inverse problem. In order to obtain an accurate solution, it is regularised in the Bayesian framework. The selected estimator is the maximum a posteriori. It is also the value that minimises a penalised criterion. We make improvements to the existing method developed at EDF well suited particularly for the reconstruction of welds from radiographies. Modelling contribution involves original prior information concerning the object geometry, constraints of belonging to an interval. We also enhance modelling of the data by taking the blurring phenomenon into account. The 3D reconstructions we get using our method, from simulated and real data, validate these improvements. .
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HONDA, CRISTIANE J. de C. "Aplicação de câmaras de ionização especiais para controle de qualidade em mamografia." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23915.
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Submitted by Maria Eneide de Souza Araujo (mearaujo@ipen.br) on 2015-10-07T19:13:10Z
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CORREA, EDUARDO de L. "Metodologia de controle de qualidade e implantacao de campos padroes de radiacao X, nivel mamografia, seguindo a norma IEC 61267." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9603.
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PIRES, JOAO dos S. J. "Avaliação da grandeza tensão de pico prática em equipamentos clínicos utilizados em radiodiagnóstico." reponame:Repositório Institucional do IPEN, 2007. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11716.
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Santana, Priscila do Carmo. "Desenvolvimento de metodologia para avaliação automatizada da qualidade de imagens digitalizadas em mamografia." CNEN - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, 2010. http://www.bdtd.cdtn.br//tde_busca/arquivo.php?codArquivo=121.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>O processo de avaliação da qualidade de imagens radiográficas em geral, e de mamografia em
especial, pode ser muito mais preciso, prático e rápido com o auxílio de ferramentas de análise
computacional.
A proposta deste trabalho é o desenvolvimento de uma metodologia computacional para
automatizar o processo de avaliação da qualidade das imagens mamográficas por meio de
técnicas de processamento digital de imagens (PDI), utilizando um ambiente de processamento
de imagens já existente (ImageJ).
Com a aplicação de técnicas de PDI foi possível determinar características geométricas e
radiométricas das imagens avaliadas. Os parâmetros avaliados incluem resolução espacial,
detalhes de alto contraste, limiar de baixo contraste, detalhes lineares de baixo contraste, massas
tumorais, índice de contraste e densidade óptica de fundo.
Os resultados obtidos por esta metodologia foram comparados com os resultados apresentados
nas avaliações visuais realizadas pela Vigilância Sanitária de Minas Gerais. Por meio desta
comparação foi possível demonstrar que esta metodologia automatizada apresenta-se como uma
promissora alternativa para redução ou supressão da subjetividade existente na metodologia de
avaliação visual, atualmente em uso.<br>The process of evaluating the quality of radiographic images in general, and mammography in
particular, can be much more accurate, practical and fast with the help of computer analysis
tools.
The purpose of this study is to develop a computational methodology to automate the process of
assessing the quality of mammography images through techniques of digital imaging processing
(PDI), using an existing image processing environment (ImageJ).
With the application of PDI techniques was possible to extract geometric and radiometric
characteristics of the images evaluated. The evaluated parameters include spatial resolution,
high-contrast detail, low contrast threshold, linear detail of low contrast, tumor masses, contrast
ratio and background optical density.
The results obtained by this method were compared with the results presented in the visual
evaluations performed by the Health Surveillance of Minas Gerais. Through this comparison was
possible to demonstrate that the automated methodology is presented as a promising alternative
for the reduction or elimination of existing subjectivity in the visual assessment methodology
currently in use.
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LAMMOGLIA, PATRICIA. "Elaboracao e implementacao de testes de controle de qualidade em equipamentos de angiografia por subtracao digital." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10962.
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Alvarenga, Frederico Ladeia. "Análise de parâmetros e controle da qualidade de sistemas de radiologia computadorizada para mamografia." CNEN - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, 2008. http://www.bdtd.cdtn.br//tde_busca/arquivo.php?codArquivo=96.
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Nenhuma<br>O desenvolvimento e a consolidação de novas tecnologias na radiologia vêm se constituindo
em uma estratégia permanente das empresas, uma vez que resulta em ganhos de
produtividade, qualidade dos produtos e serviços, redução de custos, conscientização
ambiental, eliminação de desperdícios, melhoria em atendimento e diagnósticos para os
pacientes.
O programa de controle da qualidade em mamografia é um instrumento para o gerenciamento
da qualidade dos serviços que são oferecidos à população. A radiografia computadorizada
(CR) em mamografia surge como uma importante ferramenta nas ações sistematizadas de
controle do câncer de mama, na detecção precoce através de programas de rastreamento de
segmentos populacionais, com exames periódicos. Para que se tenham mamografias de
qualidade ótima na detecção do câncer de mama é necessário seguir critérios de qualidade da
imagem e desempenho dos equipamentos.
Os sistemas de radiografia computadorizada (CR) constituem um método eficiente e
econômico de captura e conversão de radiografia em formato digital. Desde que as soluções
digitais em mamografia vêm sendo utilizadas comercialmente, mostrou-se evidente que os
sistemas de avaliação dos métodos analógicos não são apropriados para as tecnologias
digitais.
Por se tratar de um sistema novo no processo de aquisição de imagens médicas, ainda não se
tem um método definido de avaliação estabelecido pelos órgãos reguladores nacionais.
Os ensaios foram realizados no Laboratório de Calibração e Dosimetria do Centro de
Desenvolvimento da Tecnologia Nuclear onde foi possível avaliar a cadeia da formação da
imagem e parâmetros de qualidade da imagem como: contraste, resolução espacial, ruído,
densidade ótica, razão sinal ruído, razão sinal contraste, distorção, artefatos e processamento.
Esses parâmetros influenciam na capacidade de interpretação e visualização da imagem radiográfica, sendo estes determinantes para a tomada de decisão do diagnostico final.
O propósito deste trabalho é o de analise de parâmetros e controle da qualidade de sistemas de
radiologia computadorizada para mamografia a fim de apresentar indicadores que refletem a
exposição à radiação em um detetor de imagem. O resultado final dos testes de caracterização
do sistema digital avaliado foi satisfatório em todos os aspectos relativos à metodologia
aplicada para avaliação dos testes, comprovando assim os benefícios dos sistemas digitais de
aquisição de imagens médicas.
O trabalho sugere um modelo de metodologia para avaliação do sistema de radiografia
computadorizada em mamografia.<br>The development and the consolidation of new technologies in radiology became a permanent
strategy of companies since they contribute to the increase of productivity, the upgrade of the
quality of products and services, reduction of costs, environmental consciousness, elimination
of waste and improvement of the diagnosis.
The quality control program for mammography is an instrument for the management of the
quality of services provided to the population. The Computed Radiography (CR) in
mammography appears to be an important tool in the systematic actions for controlling the
breast cancer; it also has an important role in the early detection through screening programs
of population segments by periodic exams. Good mammography images are achieved if the
criteria for image quality and equipment performance are complied with standards.
The Computed Radiography systems are an efficient and economical method of capture and
conversion of the diagnostic image to digital format. Since digital solutions in mammography
have been used, it became evident that evaluation systems of analogical methods are not
adequate to digital technologies.
The CR is a new system for the acquisition process of medical images; therefore there are not
yet standards with an established quality control evaluation method provided by national
regulatory authority.
Measurements were carried out in a CR of the Dosimetry and Calibration Laboratory of the
Development Center of Nuclear Technology; it was possible to evaluate the image formation
chain and image quality parameters as contrast, spatial resolution, noise, optical density,
signal-noise ratio, signal-contrast ratio, distortion, test objects and processing method. The
visualization and interpretation ability of the radiographic image are highly influenced by
those parameters; they are determinant for taking decision of the final diagnostic. The purpose of this work was to analyze the image parameters and the quality control
procedure of CR systems for mammography; indicators that reflect the radiation exposure in
an image detector were recommended. The final result of the characterization tests in this
digital system was statistically significant relative to all aspects to the applied methodology
for tests evaluation, proving the benefits of this digital system for acquisition of medical
images.
This work suggests a methodology model for evaluating the computed radiography systems
used for mammography purposes.
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Baradi, Divyank. "Control strategies and inspection methods for welded part." Thesis, Karlstads universitet, Avdelningen för maskin- och materialteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-16383.
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Present and future demonstrator designs were used to demonstrate the quality assurance of welds. The NDT methods tested on prototype demonstrator parts are: visual inspection, radius gauges, throat size gauge, liquid-penetrant testing, magnetic particle testing and ultrasonics with pulse echo and phased array. The other methods like eddy current, time of flight diffraction, radiography, impression test, macro test and infrared thermographs are currently being analyzed along with their inspection costs. The control plans for present and future designs with corresponding present and future NDT methods are suggested to minimize a shift in process. Magnetic particle testing revealed a lack of fusion and cracks for fillet welds, whereas ultrasonic pulse echo and phased array identified an internal lack of fusion, inner pores/slag inclusions on butt welds. Ultrasonic PAUT & TOFD could be used for accurate defect identification and thermography for online identification of lack of penetration, depth of penetration and weld parameters.<br>Weight reduction by improved weld quality (WIQ)
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Tolazzi, Ana Lucia. ""A influência do controle de qualidade em telerradiografias em norma lateral e na obtenção de pontos cefalométricos"." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/23/23139/tde-11112005-124011/.
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Os objetivos deste estudo foram: 1- avaliar a influência dos fatores energéticos e da posição de cabeça, no sentido vertical e horizontal, na qualidade das radiografias cefalométricas e na interpretação dos resultados para diagnóstico e plano de tratamento; 2- verificar as implicações oriundas da determinação de pontos cefalométricos equivocados pela falha no controle de qualidade nas radiografias cefalométricas. Telerradiografias em norma lateral, padronizadas em condições reprodutíveis, foram realizadas em um crânio seco e em um fantoma. Realizou-se simulações de falhas técnicas relacionadas a quilovoltagem, miliamperagem, tempo de exposição e posição do filtro de alumínio, e a modificações horizontais e verticais de 3º, 6º, e 9º do fantoma em relação ao plano sagital mediano e ao plano de Frankfurt, respectivamente. Vinte e seis radiografias cefalométricas foram selecionadas e encaminhadas para seis examinadores (3 ortodontistas e 3 radiologistas), para executarem manualmente a análise cefalométrica de McNamara. ANOVA comparou as medidas de onze variáveis nas 26 análises cefalométricas. Quando ocorreu diferença, aplicou-se o teste de comparações múltiplas de Games-Howell (variâncias heterogêneas) e o de Tukey HSD (variâncias homogêneas), ao nível de probabilidade 5%. Não houve diferenças estatisticamente significantes entre os seis examinadores e entre as onze variáveis estudadas (p > 0,05). Observou-se pouca influência dos fatores energéticos na qualidade das imagens e reprodutibilidade dos pontos cefalométricos estudados. As variações horizontais da posição da cabeça em relação ao plano sagital mediano apresentaram discrepâncias significativas na qualidade da imagem radiográfica para cefalometria. Pontos cefalométricos inadequados comprometeram o diagnóstico, mesmo com examinadores experientes. A interpretação das cefalometrias precisa estar associada com aspectos clínicos, fotografias, modelos gnatostáticos e outras radiografias, para estabelecer o diagnóstico e plano de tratamento.<br>The aims of this study were to evaluate the influence of energetic factors and head position on the quality of cephalometric radiographs and on their interpretation, and to analyze the consequences of incorrect landmark identification due to errors in quality control in cephalometric radiographs. Standardized lateral cephalographs of a dry skull and a phantom were taken. There were made simulations of technical errors related to kilovoltage, milliampereage, exposition time and position of Al filter, and to horizontal and vertical changes of 3°, 6° and 9° of the phantom in relation to sagital plane and Frankfurt plane, respectively. Twenty-six cephalometric radiographs were selected and 6 examiners (3 orthodontists and 3 radiologists) performed the manual cephalometric analyses of McNamara. ANOVA compared the measurements of 11 variables in the 26 cephalometric analyses. Significant statistically differences were not found among the 6 examiners and among the 11 variables (p > 0.05). Energetic factors had low influence in the quality of the images and on the reproducibility of the cephalometric landmarks. Horizontal variations of head position in relation to sagital plane influenced the quality of cephalometric radiographs. Incorrect cephalometric landmarks compromised the diagnosis, even with experienced examiners. Cephalometry should be complimented by clinical examination, photographs, gnathostatics models and others radiographs to establish diagnosis and treatment.
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Freud, Nicolas. "Modélisation et simulation de systèmes d'imagerie par rayons X ou gamma." Lyon, INSA, 2003. http://theses.insa-lyon.fr/publication/2003ISAL0061/these.pdf.
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Cette thèse est consacrée à la mise au point d'un code de calcul permettant de simuler rapidement des images radiologiques réalistes en prenant en compte les principaux paramètres physiques à l'œuvre dans une chaîne d'imagerie par rayons X ou gamma. Dans la première partie, nous effectuons un tour d'horizon de l'état de l'art en matière de simulation des phénomènes de transport de rayonnement. Cette étude nous conduit à choisir une approche déterministe et à rechercher des solutions algorithmiques spécifiques, dédiées à la simulation d'images radiologiques et limitées dans un premier temps à la prise en compte du rayonnement directement transmis. Les solutions proposées, qui mettent l'accent sur la vitesse d'exécution et la robustesse, sont implémentées dans un code appelé VXI (Virtual X-ray Imaging). VXI permet d'effectuer aisément des simulations dans des configurations d'imagerie réalistes (spectre polychromatique, objets de géométrie complexe. . . ). La deuxième partie de cette thèse aborde la simulation du rayonnement diffusé par les objets inspectés. Nous proposons une méthode déterministe pour simuler le rayonnement diffusé d'ordre 1 sans recourir à une architecture de calcul parallèle. Cette méthode est validée en comparant les résultats qu'elle fournit avec ceux que donne le code de Monte Carlo Geant4<br>This PhD thesis is devoted to the development of a computer code enabling to simulate in a short time realistic radiological images, taking into account the main physical parameters acting in an X- or gamma-ray imaging chain. In the first part, we carry out a general survey of the state of the art in the field of radiation transport simulation. This study leads us to choose a deterministic approach and to seek specific algorithms, devoted to the simulation of radiological images and, at first, accounting only for the directly transmitted radiation. The proposed solutions, which emphasize execution speed and robustness, are implemented in a code named VXI (Virtual X-ray Imaging). VXI makes it easy to carry out simulations in realistic imaging configurations (polychromatic spectrum, objects with complex geometry. . . The second part of this thesis broaches the simulation of the radiation scattered by the inspected objects. We propose a deterministic method to simulate first-order photon scattering without having recourse to a parallel computing architecture. This method is validated by comparing its results with the ones given by the Monte Carlo code Geant4
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Freud, Nicolas Babot Daniel. "Modélisation et simulation de systèmes d'imagerie par rayons X ou gamma." Villeurbanne : Doc'INSA, 2005. http://docinsa.insa-lyon.fr/these/pont.php?id=freud.
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Thèse doctorat : Génie des Matériaux : Villeurbanne, INSA : 2003.<br>Chap. 2 et 4 rédigés en anglais. En appendice, 1 article rédigé en anglais intitulé "Optimal calibration via virtual X-ray imaging for dual-energy techniques : application to glass wool", issu du Colloque "Six international Conference on quality control by artificial vision" et paru dans la revue "SPIE", vol. 5132, 2003, p. 422-432. Titre provenant de l'écran-titre. Bibliogr. p. 143-155.
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Ravanbod, Hossein. "Numérisation et prétraitement d'image : application à la radiographie industrielle en contrôle non destructif : réalisation d'un système performant d'acquisition, traitement et visualisation d'image radiographique de très forte densité." Paris 11, 1987. http://www.theses.fr/1987PA112463.
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La première préoccupati0n de cette étude a été d'atteindre avec un microdensitomètre classique des performances de mesure comparables à celles d'un de densitomètre : extraire de l'information significative dans un fond de densité optique (D. O. ) souvent supérieure à 5. Nous avons dû spécialiser le microdensitomètre dans le domaine particulier de la mesure des clichés radiographiques de très forte densité. L'étude et la réalisation d'un système d'acquisition nettement plus performant ont abouti à : une augmentation de la dynamique de mesure de 3. 5 D. 0 à 5. 5 D. 0, une augmentation de la vitesse d'acquisition (gain de 1 à 8. 2), la possibilité d'extraire des informations dans des clichés à contraste local faible. L'étude systématique de la formation de double couches sensible et l’étude du processus de numérisation ont permis de trouver le compromis optimal dans le choix des valeurs des trois paramètres fondamentaux de la numérisation d’un image : échantillonnage spatial, fréquence de prélèvement, quantification. La restitution d'une image de grande dynamique sur une console de visualisation de dynamique réduite exige pour détecter un défaut d'une manière optimale, des prétraitements spécifiques. Suivant les types d'information recherchée, deux méthodes sont proposées : Méthode globale, toute l'image est traitée, cette méthode permet de localiser rapidement les zones critiques sur le cliché. Méthode locale, dans une zone restreinte contenant le défaut, repéré mais mal défini par la méthode globale on soustrait le fond conti. Nu de l'image pour mettre en évidence le défaut<br>Nondestructive testing of parts of wide thickness of the nuclear plants is inspected by radiography. It requires long exposure of a double photosensible of layer emulsion to X or gamma rays. Consequently the radiography image shows high densities and law local contrast. The acquisition of the digital image requires the extraction of significant information from background density which is often above optical density (O. D. ) 5. Our first aim has been to measure these very high densities with classical microdensitometers. The microdensitometer measures a small area. The limit of measurement is more rapidly attained than with the densitometer and the maximum values possible are below O. D. 4. Our works are resulted in a substantial reduction of electronic noises increasing the dynamic range of measurement form O. D. 3. 5 to 0. D. 5. 5, in an appreciable reduction of the acquisition time (gain of 8. 2 to 1) and the possibility of extracting information in law contrasting images. The systematic study of image formation on a double photosensible layer emulsion and the study of digitalization process have enabled us to find the optimal compromise in the choice of the values of the three fundamental parameters of digitalization of the image (spatial sampling, temporal sampling frequency, quantification). The acquired information is a wide dynamic range image. The restoration of this image on a visualization console of limited dynamic range, requires specific preprocessing. According to the types of informations required, two methods are proposed: global method, the whole image is processed to rapidly localize the critical zone of the image, local method, in a limited zone containing a defect, located but badly defined by the global method, we subtract the continuous background of the image in order to see the defect
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Massa, Bruno Sergio Ferreira. "O uso da radiografia inlet no controle radiográfico do quadril na displasia do desenvolvimento do quadril." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/5/5140/tde-13062018-104951/.
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Introdução: A displasia do desenvolvimento do quadril (DDQ) acomete de 1,5 a 2,5, em cada 1000 nascidos vivos. O tratamento pode variar desde o uso do suspensório até a redução cruenta, associada ou não a osteotomias da bacia e do fêmur. A avalição da redução, após as reduções incruentas ou cruentas, é feita por meio de radiografias uniplanares e complementada com imagens de tomografia ou de ressonância magnética. Uma incidência radiográfica, geralmente não usada para essa finalidade, pode ajudar nessa avaliação: a radiografia Inlet. Este estudo tem como objetivo avaliar a eficácia da radiografia Inlet, em comparação com a tomografia, método utilizado atualmente em nosso serviço para essa avaliação. Secundariamente, busca avaliar a reprodutibilidade da avaliação, através de correlações intra e inter observadores. Métodos: Foram avaliados pacientes com diagnóstico de DDQ, operados entre 2013 e 2015. Todos os pacientes foram submetidos à incidência radiográfica Inlet pós-operatória e a tomografia. Foram realizadas avaliações cegas, em imagens distribuídas randomicamente intra e entre avaliadores, correlacionadas pelo índice Kappa (IC 95%). Foi também realizado um consenso entre os avaliadores que foi comparado com os resultados da tomografia. Essa correlação foi avaliada pelo índice Kappa ponderado (IC 95%) e assim foram obtidas as medidas diagnósticas: sensibilidade, especificidade, valor preditivo positivo (VPP), valor preditivo negativo (VPN), likelihood positivo (LR+) e likelihood negativo (LR). Resultados: Foram obtidas 25 radiografias de um total de 22 pacientes, que foram incluídas neste estudo. A idade média de tratamento foi de 2,95 anos e variou entre um e cinco anos, com maior prevalência no sexo feminino e maior incidência no lado esquerdo. As avaliações intra e inter-observadores tiveram valores semelhantes e com índice Kappa alto, 0,834 (IC 95%). A correlação entre o consenso e a tomografia mostrou alta concordância Kappa = 0,834 (IC95%), com 100% de sensibilidade, especificidade de 95,5% e valor preditivo negativo de 100 (83,9-100). Conclusão: A incidência radiográfica Inlet se mostrou um método viável e confiável, em comparação com a tomografia computadorizada para a avaliação pós-operatória da redução, na displasia do desenvolvimento do quadril<br>Introduction: Development dysplasia of the Hip (DDH) affects 1.5 to 2.5 per 1000 live births. The treatment varies according to the age and can range from the use of the suspensory to open reduction associated with pelvic osteotomies and, or femur osteotomies. The evaluation of the reduction after the surgeries is done by means of uniplanar radiographs and complemented with tomography or magnetic resonance images. A complementary radiograph not used for this purpose may help in this evaluation: Inlet radiography. This study aims to evaluate the effectiveness of the Inlet radiography in comparison to the Tomography method currently used in our service for this evaluation. Secondarily, it seeks to evaluate the reproducibility of the evaluation through intra and inter-observer correlations. Methods: Patients with a diagnosis of DDQ operated between 2013 and 2015 were evaluated. All patients underwent postoperative inlet radiography and tomography. Blind evaluations were performed on images randomly distributed intra and between evaluators correlated by Kappa index (95% CI). A consensus was also reached among the evaluators and this was compared with the results of tomography as a gold method. This correlation was evaluated by the weighted Kappa index (95% CI) and the diagnostic measures, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood (LR +) and negative likelihood (LR) were obtained. Results: A total of 25 radiographs obtained from 22 patients were included in the study. The mean age of treatment was 2.95 years and ranged from one to five years, with a higher prevalence in females and a higher incidence on the left side. Intra and interobserver evaluations obtained similar values and high Kappa = 0.834 (95% CI). The correlation between consensus and tomography showed high Kappa agreement = 0.834 (95% CI), with 100% sensitivity, 95.5% specificity and negative predictive value of 100 (83.9-100). Conclusion: Inlet radiography proved to be a viable and reliable method compared with CT for postoperative evaluation of hip reduction in Developmental Hip Dysplasia
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Oliveira, Bruno Beraldo. "Protocolo experimental de testes de desempenho e dosimetria para tomossíntese digital de mama." CNEN - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, 2014. http://www.bdtd.cdtn.br//tde_busca/arquivo.php?codArquivo=343.
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Nenhuma<br>O sistema de tomossíntese digital de mama (Digital Breast Tomosynthesis, DBT) é uma modalidade de imagem emergente que fornece informações estruturais quase tridimensionais (3D) da mama. Este sistema possui um grande potencial para substituir ou complementar a mamografia padrão no diagnóstico do câncer de mama. A melhoria na diferenciação de tecidos normais e massas suspeitas é uma das principais vantagens do sistema DBT, que proporciona uma redução das sobreposições dos tecidos, principal problema da mamografia.
No Brasil, os testes de desempenho e a dosimetria para mamógrafos convencionais são estabelecidos pela Portaria n 453/98 do Ministério da Saúde e pela Agência Nacional de Vigilância Sanitária. Porém, não há nenhum protocolo nacional que estabeleça os testes para o controle de qualidade de equipamentos digitais.
A proposta deste trabalho foi investigar os resultados dos testes de desempenho e da dosimetria de um mamógrafo que utiliza o sistema DBT a fim de elaborar um documento que contenha testes de qualidade e o procedimento adequado de dosimetria para avaliar fisicamente estes equipamentos.
Para determinar o adequado desempenho do mamógrafo, foi avaliada a estrutura do equipamento através dos testes de força e alinhamento da bandeja de compressão. Para avaliar o detector, foram realizados testes de linearidade e uniformidade da sua resposta. A fim de verificar a imagem produzida, o mamógrafo foi submetido aos testes de ruído, resolução espacial e qualidade da imagem utilizando objetos simuladores. Por fim, foi realizada a dosimetria do equipamento visando à otimização do procedimento. A otimização significa manter o nível de radiação tão baixo quanto razoavelmente exequível, considerando a qualidade da imagem, para proporcionar um diagnóstico preciso.
A fim de garantir a confiabilidade dos resultados de dosimetria, os equipamentos utilizados foram submetidos a testes de fuga, repetibilidade, reprodutibilidade e dependência angular.
Os resultados dos testes de desempenho realizados no equipamento com sistema DBT estavam em conformidade com a maioria dos valores de referência estabelecidos. Considerando as incertezas nas medições, todos os valores calculados na dosimetria estavam de acordo com os níveis de referência adotados internacionalmente.
Este trabalho contribuiu para estabelecer o procedimento adequado dos testes de controle de qualidade e dosimetria em mamógrafos que utilizam o sistema DBT. A metodologia e os resultados obtidos são importantes, pois fazem parte de um documento pioneiro para avaliação destes equipamentos.<br>The Digital Breast Tomosynthesis (DBT) system is an emerging image modality that provides almost three-dimensional (3D) structural informations of the breast. This system has a great potential to replace or complement the standard mammography in the diagnosis of the breast cancer. The improvement in differentiation of normal tissues and suspicious masses is one of the main advantages of the DBT system, which provides a tissue overlap reduction, the main problem of mammography.
In Brazil, the performance tests and dosimetry for analogic mammography units are established by the Ministry of Health Ordinance n 453/98 and the National Health Surveillance Agency. However, there is no national protocol establishing tests for the quality control of digital equipments.
The purpose of this study was to investigate performance and dosimetry results of a mammography unit that uses the DBT system to elaborate a document that contains quality tests and the proper dosimetry procedure to evaluate these equipments physically.
For the determination of the adequate performance of the mammographic unit, the structure of this equipment was evaluated through tests of strength and alignment of the compression paddle. For the detector assessment, tests of linearity and uniformity of its response were performed. In order to verify the image produced, the mammographic unit was submitted to noise, spatial resolution and image quality tests using phantoms. Finally, the dosimetry of this equipment was performed in order to optimize the procedure. The optimization means to maintain the level of radiation as low as reasonably achievable, considering the image quality to provide an accurate diagnosis.
The equipments used were submitted to leakage current, repeatability, reproducibility and angular dependence tests to ensure the reliability of dosimetry results.
Results of performance tests performed in the equipment with DBT system were in accordance with the most of reference values established. Considering the uncertainties in the measurements, all calculated values in dosimetry were in agreement with the reference levels adopted internationally.
This work contributed to establish the proper procedure of quality control tests and dosimetry in mammographic units that use DBT systems. The methodology and results obtained are important because they are part of a pioneer document to evaluate these equipments.
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Salim, Rodrigo. "Estudo para validação de um referencial anatômico para controle fluoroscópico na preparação do túnel tibial em cirurgia de reconstrução do ligamento cruzado posterior." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/17/17142/tde-29072015-083926/.
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O objetivo primário deste estudo foi identificar parâmetros anatômicos que permitissem ao cirurgião, durante o ato cirúrgico, localizar com o auxílio de fluoroscopia o centro de inserção do ligamento cruzado posterior (LCP) na tíbia. O objetivo secundário foi propor ao cirurgião um método reprodutível e seguro para realizar a perfuração do túnel tibial na cirurgia de reconstrução do LCP. Vinte joelhos de cadáveres frescos congelados foram, inicialmente, submetidos à tomografia computadorizada de alta resolução (TC). Os joelhos foram, a seguir, dissecados e a inserção tibial do LCP digitalizada por um sistema de rastreamento óptico. A digitalização óptica da inserção do LCP resultou em modelos tridimensionais que permitiram localizar o centroide virtual dessa inserção. Paralelamente à analise virtual, inseriu-se um fio de Kirschner (FK) no centro anatômico da inserção tibial do LCP sob visualização direta. Foi realizado exame fluoroscópico no plano sagital desta tíbia e o ponto correspondente à inserção do FK foi registrado na imagem. Os locais definidos como o centro do LCP, nos dois métodos, foram plotados em uma linha imaginária paralela à faceta tibial de inserção do mesmo. Para fins de referência, essa linha foi dividida em uma escala centesimal, tendo o seu ponto zero correspondente à margem anterior/proximal da faceta e o ponto 100, correspondente à margem posterior/distal da faceta. O centro do LCP esteve situado em um ponto correspondente a 70% da distância, a partir da borda anterior/proximal da faceta do LCP, quando tomada como referência uma imagem de fluoroscopia em perfil do joelho (plano sagital). Essa medida mostrou ser reprodutível e pode ser um parâmetro útil para orientar a perfuração e inserção do fio guia tibial na confecção do túnel tibial nas cirurgias de reconstrução do LCP.<br>The primary objective of this study was to determine the center of the anatomical tibial insertion of the posterior cruciate ligament in cadaver knees and correlate this point to anatomical references as seen on fluoroscopic images of the same specimens. We aimed to describe a reproducible and safe method to place the tibial tunnel at the most anatomical position during posterior cruciate ligament reconstructions. Twenty fresh frozen cadaver knees were initially submitted to a high-resolution computadorized tomography (CT). Then, the knees were dissected and the PCL tibial insertion was digitalized with an optical tracking system. The optical digitalization of the PCL insertion resulted in tridimensional models that allowed the identification of the virtual centroid of this insertion. After the virtual analysis by CT scan, a Kirschner wire was inserted at the anatomical center of the PLC tibial insertion under direct visualization. Fluoroscopic views of the tibia on the sagittal plane were acquired and the correspondent point of the Kirschner wire insertion was registered. The points defined as the posterior cruciate ligament center by the two methods were plotted in an imaginary line parallel to the tibial facet of the PCL insertion. As a reference, this line was divided in a centesimal scale, with the zero point corresponding to the anterior/proximal margin of the facet and the 100-point, corresponding to the posterior/distal margin of the facet. The PCL center was found in one point corresponding to approximately 70% of the distance from the anterior/proximal border of the PCL facet when a lateral fluoroscopic image of the knee was utilized as a reference (sagittal plane). This measure was found to be consistently reproducible and may be a useful parameter to guide the positioning of the tibial guide wire during tibial tunnel drilling in posterior cruciate ligament reconstructions.
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GUERRA, ALINE B. "Estabelecimento e controle de qualidade de feixes padroes de radiacao X para calibracao de instrumentos, nivel mamografia." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10849.
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ALCANTARA, MARCELA C. "Avaliacao dos criterios de qualidade de imagem e estudo das doses em um departamento de mamografia." reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9470.
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Melyukov, Dmitry. "Etude et développement d'une méthode de caractérisation in-situ et à distance de dépôts en couches minces par pyrométrie active laser." Ecole nationale d'ingénieurs (Saint-Etienne), 2011. http://www.theses.fr/2011ENISE004.
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Les matériaux revêtus sont utilisés partout dans l’industrie actuelle. L’objectif principal pour assurer la qualité pendant la fabrication comme pendant l’exploitation est un contrôle des propriétés de ces couches essentiellement son épaisseur mais aussi son homogénéité et son adhésion au substrat. Idéalement, la technique permettant ce contrôle ne doit pas changer l’état de notre couche, c'est-à-dire être non-destructive. Il existe plusieurs méthodes du contrôle non-destructif (CND) comme les ultrasons, les courants Foucault, la radiographie… Dans le cadre de cette thèse on a concentré nos efforts sur la méthode de thermographie active (TA) qui présente, par rapport aux autres technique de CND l’avantage de pouvoir être effectuée à distance, sans contact, rapidement et avec une haute résolution spatiale. On a étudié le cas du chauffage de la surface par un faisceau laser couplé avec les mesures du rayonnement thermique par détecteur infrarouge au centre de la tache laser. Tout d’abord nous avons accompli l’analyse théorique pour mieux comprendre quelles propriétés des couches pouvaient être déterminée par la méthode de TA et sous quelles conditions. Le résultat de cette étude théorique est le développement de méthodes de caractérisation complète de notre couche et particulièrement une méthode de mesure de l’épaisseur indépendamment de toutes autres propriétés (optique, thermique). La partie expérimentale de ce travail a montré le bon fonctionnement de la méthode de mesure de l’épaisseur d’une feuille des matériaux différents (INOX, titane, tungstène et al. ). On a ainsi vérifié la faisabilité de la méthode de mesure de l’épaisseur sans contact (et à distance) et sans calibration (et sans connaître les propriétés du matériau)<br>Layered materials are used throughout the industry today. The main objective to ensure quality during manufacturing as well as during operation is the control of the properties of these layers mainly its thickness but also its homogeneity and adhesion to the substrate. The most desirable technique is a technique that does not change the state of our film, i. E. Non-destructive. There are several methods of non-destructive testing (NDT) such as ultrasound, eddy current, radiography etc. As part of this thesis we focused our efforts on the active thermography method (TA) which has some advantages over other NDT techniques such as the possibility to put some distance between the test piece and the device, the absence of contact, the speed of the measurements and the high spatial resolution. We studied the case of heating of the surface by a laser beam coupled with measurements of thermal radiation by infrared detectors in the center of the laser spot. First of all we have done theoretical analysis to understand what properties of the layers can be determined by the method of TA under what conditions. As the result of this theoretical study we developed a number of methods for complete characterization of the layer and especially the methods for measuring the thickness independently of all other properties (optical, thermal). The experimental part of this work has shown the proper functioning of the method for measuring the thickness of a sheet of different materials (stainless steel, titanium, tungsten et al. ). By this way it was verified the feasibility of the method for measuring the layer thickness without contact (and at a distance) and without calibration (and without knowing the material)
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Messias, Pricila Cordeiro. "Controle de qualidade, medição de dose glandular média e protocolo de rotina para tomossíntese digital mamária." Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/1881.
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No Brasil, o câncer de mama é o mais frequente e a principal causa de morte entre as mulheres, para o ano de 2016 foram estimados 57.960 mil novos casos. A Tomossíntese Digital Mamária (TDM) reduz os efeitos da sobreposição do tecido da mama, oferecendo uma melhor caracterização dos achados mamográficos e diminuindo a necessidade de incidências adicionais. A recente introdução da TDM na prática clínica requer manutenção dos requisitos de dose e qualidade da imagem, além de rotinas de Controle de Qualidade (CQ) e monitoração da Dose Glandular Média (DGM), e também uma equipe técnica qualificada para executar o procedimento. A prática de monitoração da qualidade da imagem e da dose de radiação é uma solução para assegurar continuamente a alta qualidade de exames de radiodiagnóstico. São poucos os estudos relacionados ao CQ em TDM no Brasil, e ainda não foram estabelecidos protocolos nacionais e internacionais específicos; sendo assim, os testes de CQ utilizados são baseados naqueles utilizados pela National Health Service Breast Screening Programme (NHSBSP), European Reference Organisation for Quality Assured Breast Screening and Diagnostic Service (EUREF), American Association of Physicists in Medicine (AAPM), Internacional Atomic Energy Agency (IAEA). Este estudo propõe e apresenta os resultados dos testes de CQ e DGM para mamografia e TDM, e um Protocolo de Rotina para exames de TDM. Os testes de CQ para TDM foram realizados conforme as recomendações do fabricante, da Portaria 2898/13 e de protocolos internacionais. O Protocolo de Rotina foi elaborado visando sanar as dúvidas mais frequentes da equipe técnica, assim como otimizar a qualidade do exame em sala. Para atestar a qualidade da imagem diagnóstica para todas as espessuras, foi realizado o teste de Qualidade de Imagem do simulador padrão do American College of Radiology (ACR). Na avaliação da DGM todos os valores obtidos para mamografia e TDM se mantiveram em conformidade com os limites de referência utilizados, exceto para a espessura de 20 mm em TDM. Para todos os outros testes de CQ, os resultados se mantiveram em conformidade com os limites de referência. Os resultados adquiridos nas avaliações reforçam a importância do controle de qualidade aplicado de forma adequada no processo de obtenção das imagens, assegurando baixa dose e boa qualidade da imagem, cumprindo o princípio ALARA.<br>In Brazil, breast cancer is the most common and the leading cause of death among women; in 2015, 57,120,000 new cases. Digital Breast Tomosynthesis (DBT) reduces the effects of overlapping breast tissue, offering a better characterization of mammographic findings and decreasing the need of additional views. The recent introduction of DBT in clinical practice requires, in order to maintain the dose requirements and image quality, aside from routine Quality Control (QC) procedures and monitoring the Mean Glandular Dose (MGD) also a qualified technical team to perform the procedure. The practice of monitoring the image quality and the radiation dose is a solution to continuously ensure high quality diagnostic radiology exams. Few studies related to CQ TDM in Brazil, and national and international specific protocols have not been established, Thus, QC tests used are based on those used by the National Health Service Breast Screening Programme (NHSBSP), European Reference Organization for Quality Assured Breast Screening and Diagnostic Service (EUREF), American Association of Physicists in Medicine (AAPM), International Atomic Energy Agency (IAEA). This study proposes and presents the results of the QC tests and DGM for mammography and TDM, and routine protocol for TDM tests. The QC tests for TDM were performed according to the manufacturer's recommendations, of Portaria 2898/13 and international protocols. The Routine Protocol was elaborated aiming to resolve the most frequent doubts of the technical team, as well as optimize the room examination. In order to certify the quality of the diagnostic image for all thicknesses, a imagine quality test from the standard simulator of American College of Radiology (ACR) was performed. In the DGM evaluation, all values mammography and TDM remained in accordance with the reference range used except for 20 mm TDM. For all other QC tests, the results remained in accordance with the reference limits. The results obtained in the assessments emphasize the importance of quality control applied properly in obtaining the imaging process, ensuring low dose and good image quality, fulfilling the ALARA principle.
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Miguel, Cristiano. "Avaliação das condições de radioproteção em radiologia intraoral." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1159.
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Este estudo apresenta a avaliação das condições de radioproteção em radiologia intraoral. A pesquisa foi realizada em parceria com o Instituto de Radioproteção e Dosimetria da Comissão Nacional de Energia Nuclear (IRD/CNEN). A coleta de dados foi feita por meio de pesquisa de campo quantitativa de caráter descritivo durante o período de setembro de 2013 a dezembro de 2014. Participaram voluntariamente do estudo, odontólogos da cidade de Curitiba - PR que atuam com equipamentos de raios X intraorais. A amostra da pesquisa consistiu em 97 odontólogos e 130 equipamentos intraorais instalados em 74 locais de atendimentos distribuídos em 39 bairros da cidade de Curitiba - PR. Foram avaliadas 21 clínicas odontológicas, 40 consultórios odontológicos, 1 hospital universitário, 8 unidades municipais de atendimento odontológico e 4 instituições de ensino. Os dados foram coletados por meio de formulários preenchidos pelo pesquisador, pelos odontólogos, e pela avaliação de controle de qualidade dos equipamentos de raios X. As avaliações de dose de entrada na pele, tamanho de campo de radiação e filtração total foram realizadas com kits dosimétricos fornecidos e avaliados pelo IRD/CNEN. As medidas do tempo de exposição e da tensão dos equipamentos de raios X foram realizadas com detectores não invasivos. A dose ocupacional dos odontólogos foi verificada com dosímetros termoluminescentes. Por meio de formulários e de um questionário (aprovado pelo Comitê de Ética em Pesquisa de Seres Humanos - UTFPR) foi possível identificar as características técnicas dos equipamentos, avaliar os procedimentos de trabalho e o conhecimento dos odontólogos em relação à radioproteção. Com os resultados da pesquisa é possível destacar que apenas 10% dos equipamentos avaliados atendem a todas as exigências das normas de radioproteção do Brasil. Entretanto, 84,5% das doses de entrada na pele dos pacientes foram consideradas como conforme. Em relação à exposição ocupacional, a radiologia intraoral mostra-se segura, porém os procedimentos de trabalho dos odontólogos, referentes à radioproteção podem ser otimizados. Grande parte dos odontólogos não utiliza posicionador na sua rotina, fazem o processamento químico das radiografias através do método visual, usam sempre o mesmo tempo de exposição para todas as regiões anatômicas e não observam os pacientes durante a aquisição das imagens. O estudo sugere que a falta de conhecimento e de interesse dos odontólogos em relação à radioproteção, a falta de manutenção periódica dos equipamentos e a falta de fiscalização da agência regulamentadora são os responsáveis pelas não conformidades observadas.<br>This study presents an evaluation of the radiation protection conditions in intraoral radiology. The survey was conducted in partnership with the Radiation Protection and Dosimetry Institute of the National Commission of Nuclear Energy (IRD/CNEN). Data collection was performed using quantitative field research in a descriptive way during the period of september 2013 to december 2014. The study had the voluntarily participation of dentists in the city of Curitiba – PR, working with intraoral X-ray equipment. The research sample consisted of 97 dentists and 130 intraoral equipments which are installed in 74 care locations distributed in 39 neighborhoods in the city of Curitiba - PR. The study evaluated 21 dental clinics, 40 dental offices, 1 hospital, 8 municipal units of dental care and 4 educational institutions. Data were collected through forms checked out by the researcher, by dentists and the quality control evaluation of X-ray equipment. The evaluation of the entrance skin dose, radiation field size and total filtration were performed with dosimetric kits supplied and evaluated by IRD/CNEN. The exposure time and voltage measures of X-ray equipment were performed with noninvasive detectors. Occupational dose was measured with thermoluminescent dosimeters. Through appropriate forms and a questionnaire (approved by the Ethics Committee of Human being Research - UTFPR) it was possible to identify the technical characteristics of the equipment, review the working procedures and knowledge of the dentists in relation to radiation protection. Among the search results it is important to emphasize that only 10% of the evaluated equipment reaches all requirements of the Brazilian radiation protection standards. However, 84,5% of the entrance skin dose delivered to the patients was considered in accordance. Regarding occupational exposure, the intraoral X-rays seem to be safe, but the dentist’s working procedures, related to the radiation protection, can be optimized. Most dentists do not use positioners in their routine, make the chemical processing of X-rays through the visual method, routinely use the same exposure time for all anatomic regions and do not observe patients during image acquisition. The study suggests that the dentists’s lack of knowledge and interest in radiological protection, the lack of equipment regular maintenance and the lack of regulatory agency supervision are the responsible for the nonconformities observed.
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Le, Meur Yann. "Analyse automatique de la qualité des images issues de détecteurs plats à rayons X." Phd thesis, Grenoble INPG, 2009. http://www.theses.fr/2009INPG0023.
Full textAbstract:
Durant les dix dernières années, l'imagerie médicale a profité pleinement de l'essor technologique des techniques d'imagerie numérique. Dans le domaine de la radiographie X, les nouveaux détecteurs, possédant un encombrement réduit et une meilleure sensibilité, détrônent progressivement les anciennes techniques à film ou à tube. Cette thèse, préparée en partenariat avec l'entreprise Trixell, leader mondial des détecteurs plats pour radiographie médicale, traite du contrôle qualité des images issues de ces détecteurs. L'exigence du domaine médical impose un contrôle strict des défauts pouvant apparaître sur les images. Cette thèse est donc axée sur la conception d'une chaîne complète d'analyse de la qualité des images issues des détecteurs numériques. Un éclairage particulier est donné à la détection des défauts, parfois peu visibles, à l'aide de techniques de détection adaptées à notre contexte de défauts spatialement corrélés dans un fort bruit de fond<br>Since last decade, medical imaging has grown up with the development of new digital imaging techniques. In the field of X-ray radiography, new detectors replace progressively older techniques, based on film or x-ray intensifiers. These digital detectors offer a higher sensibility and reduced overall dimensions. This PhD thesis has been prepared with Trixell, the world leading company in flat detectors for medical radiography. It deals with quality control on digital images stemming from these detectors. High quality standards of medical imaging impose a close analysis of the defects that can appear on the images. This PhD thesis describes a complete process for quality analysis of such images. A particular focus is given on the detection task of the defects, thanks to methods well adapted to our context of spatially correlated defects in noise background
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Le, Meur Yann. "Analyse automatique de la qualité des images issues de détecteurs plats à rayons X." Phd thesis, Grenoble INPG, 2009. http://tel.archives-ouvertes.fr/tel-00424459.
Full textAbstract:
Durant les dix dernières années, l'imagerie médicale a profité pleinement de l'essor technologique des techniques d'imagerie numérique. Dans le domaine de la radiographie X, les nouveaux détecteurs, possédant un encombrement réduit et une meilleure sensibilité, détrônent progressivement les anciennes techniques à film ou à tube. Cette thèse, préparée en partenariat avec l'entreprise Trixell, leader mondial des détecteurs plats pour radiographie médicale, traite du contrôle qualité des images issues de ces détecteurs. L'exigence du domaine médical impose un contrôle strict des défauts pouvant apparaître sur les images. Cette thèse est donc axée sur la conception d'une chaîne complète d'analyse de la qualité des images issues des détecteurs numériques. Un éclairage particulier est donné à la détection des défauts, parfois peu visibles, à l'aide de techniques de détection adaptées à notre contexte de défauts spatialement corrélés dans un fort bruit de fond.
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Wege, Stefan. "Wiederauffindung von Objektbereichen vorgeprüfter Gepäckstücke für eine weitere Inspektion: Positionswiederfindung mit Momenten." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-33205.
Full textAbstract:
Zur schnellen und sicheren Gepäckabfertigung ist eine Automatisierung der Gepäckprüfung zweckmäßig. Es wird eine mehrstufige Prüfung des Gepäcks durchgeführt. In der ersten Stufe werden vom Gepäckstück mehrere Röntgendurchstrahlungbilder angefertigt. Bei einem Teil der Gepäckstücke wird ein kritischer Bereich festgestellt, welcher mit einer zweiten Maschine genauer untersucht werden muss. Aus diesem Grund muss durch die zweite Maschine anhand nur eines weiteren Röntgendurchstrahlungsbildes erkannt werden, wo sich der kritische Bereich nach dem Transport durch das Förderband befindet. Zur Lösung dieses als Positionswiederfindung bezeichneten Problems wurde ein Verfahren entwickelt, welches auf einer Beziehung zwischen den Momenten der Grauwertverteilung des Durchstrahlungsbildes und den Momenten der Schwächungskoeffizentenverteilung des Objektes beruht. Das Verfahren wurde anhand von simulierten Beispielen getestet<br>Automatic explosive detection is advantageous for fast and secure baggage control. The baggage is controlled by a multi level system. In level 1 the baggage will be inspected by a multi view x-ray radiography machine. The machine divides the baggage into secure and rejected bags and finds in the rejected bags a critical region for further inspection by a level 2 machine. For this reason the level 2 machine has to identify by only one additional x-ray view the new position of the critical region of the bag after the transport to the level 2 machine. To solve this problem a method was developed, which uses a relation between the moments of the grey-value of x-ray scan and the moments of the x-ray attenuation coefficient of the inspected object. The method was tested with simulated scans
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Wege, Stefan. "Wiederauffindung von Objektbereichen vorgeprüfter Gepäckstücke für eine weitere Inspektion: Positionswiederfindung mit Momenten." Doctoral thesis, Bundesanstalt für Materialforschung und -prüfung (BAM), 2009. https://tud.qucosa.de/id/qucosa%3A25280.
Full textAbstract:
Zur schnellen und sicheren Gepäckabfertigung ist eine Automatisierung der Gepäckprüfung zweckmäßig. Es wird eine mehrstufige Prüfung des Gepäcks durchgeführt. In der ersten Stufe werden vom Gepäckstück mehrere Röntgendurchstrahlungbilder angefertigt. Bei einem Teil der Gepäckstücke wird ein kritischer Bereich festgestellt, welcher mit einer zweiten Maschine genauer untersucht werden muss. Aus diesem Grund muss durch die zweite Maschine anhand nur eines weiteren Röntgendurchstrahlungsbildes erkannt werden, wo sich der kritische Bereich nach dem Transport durch das Förderband befindet. Zur Lösung dieses als Positionswiederfindung bezeichneten Problems wurde ein Verfahren entwickelt, welches auf einer Beziehung zwischen den Momenten der Grauwertverteilung des Durchstrahlungsbildes und den Momenten der Schwächungskoeffizentenverteilung des Objektes beruht. Das Verfahren wurde anhand von simulierten Beispielen getestet.<br>Automatic explosive detection is advantageous for fast and secure baggage control. The baggage is controlled by a multi level system. In level 1 the baggage will be inspected by a multi view x-ray radiography machine. The machine divides the baggage into secure and rejected bags and finds in the rejected bags a critical region for further inspection by a level 2 machine. For this reason the level 2 machine has to identify by only one additional x-ray view the new position of the critical region of the bag after the transport to the level 2 machine. To solve this problem a method was developed, which uses a relation between the moments of the grey-value of x-ray scan and the moments of the x-ray attenuation coefficient of the inspected object. The method was tested with simulated scans.
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Alves, João Carlos Agostinho. "Evaluation of the efficacy of four intra-articular therapeutic protocols for the control and treatment of osteoarthritis in a Canis familiaris model." Doctoral thesis, Universidade de Évora, 2021. http://hdl.handle.net/10174/29955.
Full textAbstract:
A osteoartrite (OA) é uma doença que afecta que afecta todos os mamíferos, com uma expressão clínica e económica muito importante. No cão, a sua fisiopatologia clínica, médica e terapêutica são muito semelhantes às do Homem, tornando esta espécie num modelo natural de excelência para o estudo da OA no Homem. Associando-se a doença predominantemente ao aparecimento de sinais e sintomas clínicos envolvendo a(s) articulação(ões) afetada(s), o uso de terapêuticas locais administradas por via intra-articular (IA), possibilitam reduzir a quantidade da substância activa a utilizar para obter o efeito médico desejado, assim como os potenciais efeitos sistémicos colaterais. Desde há muito tempo que o uso de corticosteróides e ácido hialurónico têm assumido um papel relevante na terapia IA da OA. Actualmente, terapias inovadoras como o uso de concentrados de plaquetas autologas ou de anabolizantes, como o Estanozolol, têm-se revelado promissoras no controlo local da doença. Contudo, os seus mecanismos de ação não estão ainda totalmente esclarecidos, o que se traduz na dificuldade em obter consenso entre os clínicos para o estabelecimento de protocolos padronizados, fazendo-se assim a sua utilização com base na medicina de evidência resultante da experiência individual do clínico. A monitorização da OA no que respeita à sua evolução e resposta à terapeutica instituída é actualmente monitorizada com o recurso a marcadores de inflamação, técnicas de imagem como a radiografia e termografia digitais, ao estudo e análise da biomecânica do doente em placas ou plataformas de força, que adicionam informação muito importante à colhida durante o exame clínico objectivo do doente.
O presente estudo realizado na espécie Canis familiaris com OA na articulação coxofemoral apresenta como principais objetivos: 1) Determinar o efeito de quatro substâncias administradas por via IA no maneio da OA da anca; 2) Avaliar a variação na concentração dos marcadores inflamatórios Proteína C-Reativa (PCR) e Interleucina-1 (IL-1) no líquido sinovial de doentes com OA coxofemoral; 3) Avaliar a relação entre a medicina laboratorial, a medicina de imagem e o exame médico objectivo do doente; 4) Validar o uso da termografia digital e da plataforma de pressão na avaliação da OA; e 5) Delinear um protocolo terapêutico para os doentes com OA coxofemoral utilizando o cão como modelo animal, sob o conceito geral de - Uma Única Saúde (One Health). O estudo foi desenvolvido numa amostra de cem articulações coxo-femorais (N = 100), de doentes com OA de ocorrência natural. A amostra estudada foi dividida aleatoriamente em cinco (5) grupos cada um com vinte (20) articulações, de acordo com o tipo de terapêutica IA administrada. Assim, consideraram-se: grupo de controlo (GC, n=20), grupo de hexacetonido de triancinolona (THG, n=20), grupo de concentrado de plaquetas (Grupo PCG, n=20), grupo de estanozolol (SG, n=20) e o grupo de acido hialurónico - Hylan GF 20 (HG, n=20). Cada doente foi avaliado em nove (9) tempos diferentes ao longo do estudo: dia 0 (dia do tratamento) e dias 8, 15, 30, 60, 90, 120, 150 e 180 após tratamento. As avaliações de cada doente e articulação foram realizadas com a análise da biomecânica do doente em plataforma de força, goniometria da articulação (amplitude articular em flexão e extensão), perímetro da coxa, termografia digital, radiografia digital, análise do líquido sinovial e quatro instrumentos de metrologia clínica, nomeadamente: Escala Rápida de Avaliação de Dor Canina (Canine Brief Pain Inventory), Escala de Osteoartite Canina de Liverpool (Liverpool Osteoarthritis in Dogs), Índice Ortopedico Canino (Canine Orthopedic Index) e Escala Analógica Visual de Hudson (Hudson Visual Analogue Scale). O trabalho estatístico dos dados foi realizado com o programa IBM SPSS Statistics version 20. Foram realizados vários testes estatísticos, de acordo com a análise pretendida: teste t de amostras emparelhadas, ANOVA de medidas repetidas, com correcção Huynh-Feldt, ou o teste de Wilcoxon. O teste de Kaplan-Meier, comparado com o teste log-rank, e a regressão de Cox foram conduzidos para avaliar sobrevivência. Todos os resultados obtidos forma considerados como estatisticamente significativos para o valor de P<0,05.
Os grupos PCG e HG foram aqueles que registaram melhorias mais significativas e duradouras, de acordo com os resultados da regressão de Cox para as diferentes avaliações realizadas. Considerando as avaliações objectivas, PCH e HG apresentaram uma melhora de 81% e 69%, e de 61% e 57% para os índices de simetria e diminuição de suporte de peso em estação, respetivamente. De acordo com os resultados obtidos, o uso de concentrado de plaquetas autologas e de ácido hialurónico de alta densidade parecem ser os tratamentos preferenciais para a melhoria das alterações registadas nos doentes com OA, melhorando a qualidade de vida dos doentes. Os resultados obtidos permitiram verificar também uma redução no nível da dor nos doentes do grupo THG, o que pode ser atribuído ao marcado efeito anti-inflamatório dos corticosteróides; Title: Evaluation of the efficacy of four intra-articular therapeutic protocols for the control and treatment of osteoarthritis in a Canis familiaris model.
ABSTRACT:
Osteoarthritis (OA) affects all mammals, being an important and costly disease. The pathologic process, clinical presentation, and response to treatment are very similar in humans and dogs, making the naturally occurring canine osteoarthritis model the closest to a gold standard for the study of human osteoarthritis. Since OA is mainly symptomatic in the affected joint while lacking obvious extra-articular manifestations, it is well suited to have a local therapy administered by intra-articular (IA) injection, reducing the total amount required to produce an effect as well as systemic adverse effects. There are several substances used in the IA management of OA, some used for a long time, like corticosteroids and hyaluronan, while others have gained more recent attention, as autologous platelets and stanozolol. In common, regardless of how long they have been used, their action mechanisms and effects are not fully known, as the protocol for their use is usually based on the clinician’s individual experience. Disease evolution and response to treatment can be monitored through inflammation markers, different clinical evaluation modalities, as digital thermography, digital radiography, or stance analysis, which all add relevant information to the clinical examination.
This study set four goals: 1) to determine the effect of four IA substances in the management of hip OA; 2) assess variations in C-reactive protein and IL-1 in the synovial fluid of patients with OA; 3) evaluate the relationship between laboratory medicine, with imaging results and clinical assessment; 4) validate the use of digital thermography and weight bearing evaluation in OA assessement; and 5) to outline a treatment protocol for patients with OA, with the dog as an animal model, under the One Health concept. One hundred (N=100) hip joints were selected from patients with naturally occurring osteoarthritis and randomly assigned to five groups: control group (CG, n=20), triamcinolone hexacetonide group (THG, n=20), platelet concentrate group (PCG, n=20), stanozolol group (SG, n=20) and Hylan G-F 20 group (HG, n=20). Evaluations were conducted on days 0 (treatment day), 8, 15, 30, 60, 90, 120, 150, and 180 days post-treatment. They consisted of the evaluation of weight distribution, joint range of motion at flexion and extension, thigh girth, digital thermography, radiographic signs, synovial fluid analysis, and four clinical metrology instruments were collected: Canine Brief Pain Inventory, Liverpool Osteoarthritis in Dogs, Canine Orthopedic Index and the Hudson Visual Analogue Scale. All results were analyzed with IBM SPSS Statistics version 20. Several statiscal tests were conducted, according to the intended analysis: Paired Samples T-Test, Repeated Measures ANOVA, with a Huynh-Feldt correction, or Wilcoxon Signed Ranks Test. Kaplan-Meier estimators were conducted and compared with the log-rank test. Cox proportional hazard regression analysis was performed to determine treatment survival. A significance level of P<0.05 was set.
PCG and HG registered longer lasting effects, and better improvements according to the Cox hazard regression with the different assessments made. Considering objective parameters, PCH patients showed a 69%-81% improvement in symmetry and weight-bearing reduction, respectively, while HG showed 61% and 57% improvements. These seem to be the preferred treatments for functional impairments due to OA. In addition to these evaluations, PCG and HG also registered more significant improvements in several scores as Hudson Visual Analogue Scale, stiffness, function, gait of the Canine Orthopedic Index. Better impact on pain interference was observed in THG, which could be attributed to the high anti-inflammatory effect of corticosteroids, and the relation between pain and inflammation.
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Rizzo, Andrea. "Advanced N.D.T.: analisi e studio di componenti in materiale composito." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/4596/.
Full textAbstract:
Numerose evidenze dimostrano che le proprietà dei materiali compositi sono strettamente legate ai processi produttivi, alle tipologie di fibra e resina impiegate nel materiale stesso. Proprietà caratterizzate anche dai difetti contenuti nel materiale stesso. Nella tesi si presta particolare attenzione al processo produttivo con prepreg e autoclave trattando anche il tema della stesura di un ply-book. Si valutano in modo teorico e critico alcuni tra i metodi N.D.T. più avanzati tra cui: P.T.(Penetrant Test), Rx(Radiography Test), UT (Ultrasound Test in Phased Array) e IRT (InfraRed Termography - Pulsata). Molteplici sono i componenti testati che variano tra loro per: tipologia di resina e fibra impiegata, processo produttivo e geometria. Tutti questi componenti permettono di capire come i singoli parametri influenzino la visualizzazione e l'applicabilità delle tecniche N.D.T. sopra citate. Su alcuni provini è stata eseguita la prova meccanica Drop Weight Test secondo ASTM D7136 per correlare le aree di delaminazione indotte e la sensibilità di ogni singolo metodo, visualizzando così la criticità indotta dagli urti con bassa energia di impatto (BVID Barely Invisible Impact)di cui i materiali compositi soffrono durante la "service life".
A conclusione del lavoro si potrà comprendere come solo l'analisi con più metodi in parallelo permetta di ottenere una adeguata Probability Of Detection.
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Liukkonen, E. (Esa). "Radiologisten kuvien katselussa käytettävien näyttöjen laatu:näyttöjen laitekanta, suorituskyky ja laadunvalvonta sekä kuvankatseluolosuhteet radiologisissa yksiköissä ja terveyskeskuksissa." Doctoral thesis, University of Oulu, 2010. http://urn.fi/urn:isbn:9789514262180.
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Abstract The purpose of this study was to investigate the quality of displays at radiology departments and healthcare centers, viewing conditions, quality control practices and user experiences of viewing radiological images from displays during 2007. The study aimed to provide guidelines to improving the quality of image viewing from displays and viewing conditions in healthcare. The data was gathered from radiology departments at university hospitals in Finland and healthcare centers in the treatment area of responsibility of the Oulu University Hospital. Display technology, quality control practices and users experiences of viewing were determined using questionnaires. Technical measurements were performed in order to acquire information on displays performance and viewing conditions. In addition, observation was used to evaluate viewing conditions. Almost all displays at radiological departments were applicable for diagnostics. At healthcare centers all displays were inapplicable for diagnostics. Both organization groups had displays using obsolete cathode ray tube technology and these displays did not pass current acceptance criteria. Most radiology departments had viewing conditions which were compatible with existing guidelines, whereas at healthcare centers lighting conditions were too bright for viewing radiological images from displays. Acceptance testing was done only for few of the displays and quality control was not performed regularly. Personnel responsible for quality assurance felt they were provided with inadequate resources for performing display quality control. Clinicians at healthcare centers did not identify the poor performance of displays. Radiologists and clinicians at healthcare centers rarely performed quality assurance for displays. The quality of displays, viewing conditions and the assessment of display performance at healthcare organizations was not at the level required by the existing guidelines. Both the cathode ray tube displays and uncalibrated liquid crystal displays should either be replaced with new ones or calibrated. Lighting and positioning of displays ought to be rearranged in order to diminish reflections. Furthermore, doctors ought to be able to rearrange lighting conditions with ease. More resources ought to be directed to display quality control and different quality control practices should be unified. Both the users and the quality control personnel should also be provided with more training in display quality control. Regular display quality control should be extended to all healthcare organizations. Clinicians working at healthcare centers should be provided with adequate training in the use of image viewing software<br>Tiivistelmä Tämän tutkimuksen tarkoituksena oli selvittää vuoden 2007 aikana radiologisten yksiköiden ja terveyskeskusten radiologisten kuvien katseluun tarkoitettujen näyttöjen laatu, kuvankatseluolosuhteet ja laadunvalvontakäytännöt sekä käyttäjien kokemuksia röntgenkuvien katselusta näytöiltä. Tutkimuksen tavoitteena oli antaa toimenpide-ehdotuksia kuvankatselun ja kuvankatseluolosuhteiden kehittämiseksi terveydenhuollossa. Aineisto muodostui otoksesta viiden yliopistollisen sairaalan radiologisista yksiköistä ja Oulun yliopistollisen sairaalan erityisvastuualueen terveyskeskuksista. Näyttöjen laitekanta, laadunvalvontakäytännöt ja lääkäreiden kokemuksia näyttötyöskentelystä selvitettiin kyselyllä. Mittausten ja havainnoinnin avulla saatiin tietoa näyttöjen suorituskyvystä ja kuvankatselutilojen valaistusolosuhteista. Radiologisten yksiköiden näytöt olivat teknisesti pääosin radiologisista kuvista tehtävään diagnostiikkaan soveltuvia. Terveyskeskuksissa käytettiin näyttöjä, jotka eivät soveltuneet diagnostiikkaan. Molemmissa ryhmissä poistuvaan katodisadeputkitekniikkaan perustuvia näyttöjä oli vielä käytössä, eikä yksikään mitatuista näytöistä saavuttanut hyväksyttävyyskriteereitä kaikkien suorituskyvyn mittaustulosten osalta. Suurimmassa osassa radiologisten yksiköiden työpisteissä huoneen valaistus oli suositusten mukainen, kun taas terveyskeskuksissa huoneiden valaistus oli liian voimakas radiologisten kuvien katseluun käytetyillä näytöillä. Vastaanottotarkastus oli tehty vain pienelle osalle näytöistä ja säännöllistä laadunvalvontaa tehtiin näytöille vähän. Laadunvalvojat kokivat resurssit riittämättömiksi näyttöjen laadunvalvontaan. Terveyskeskuslääkärit eivät itse tunnistaneet näytön huonoa suorituskykyä. Radiologit ja terveyskeskuslääkärit tekivät laadunvalvontaa käyttämilleen näytöille hyvin vähän. Tutkimuksen kohteena olleissa radiologisissa yksiköissä ja terveyskeskuksissa röntgenkuvien katseluun tarkoitettujen näyttöjen laatu, valaistusolosuhteet ja laadunvalvonta eivät vastanneet suosituksia. Katodisädeputkinäytöt ja kalibroimattomat nestekidenäytöt tulisi vaihtaa uusiin tai kalibroida. Valaistusta ja näyttöjen sijoittelua tulisi muuttaa heijastusten vähentämiseksi. Lisäksi lääkärillä tulisi olla mahdollisuus muuttaa valaistusta helposti. Näyttöjen laadunvalvontaan tulisi saada enemmän resursseja, laadunvalvontakäytännöt tulisi yhtenäistää ja käyttäjille sekä laadunvalvojille tulisi antaa lisää koulutusta näyttöjen laadunvalvontaan. Säännöllinen näyttöjen laadunvalvonta tulisi ulottaa kaikkiin terveydenhuollon organisaatioihin. Terveyskeskuslääkäreille tulisi antaa koulutusta kuvankatseluohjelmien käyttöön
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Stolidi, Adrien. "Développement de méthodes d'imagerie par contraste de phase sur source X de laboratoire." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS076/document.
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L'imagerie par rayons X est fortement développée dans notre société et notamment dans les domaines industriels, médicaux ou sécuritaires. L'utilisation de cette méthode d'imagerie des structures internes (pour la détection d'irrégularité, de contrôle non destructif de pièces ou de menaces) est quotidienne. En radiographie, le contraste produit sur les images est relié à la variation de l'atténuation du flux de rayons X, qui est fonction de la densité, de l'épaisseur du matériau étudié ainsi que de la longueur d'onde utilisée. Ainsi par exemple, des gaines métalliques, des os ou des armes amènent du contraste sur l'image. Mais en plus de leur atténuation, les rayons X vont subir un déphasage qui est d'autant plus important que le matériau est peu atténuant. Ce phénomène va amener du contraste, dit de phase, permettant d'imager des matériaux peu denses tels que des plastiques, composites, tissus mous ou explosifs. Ce travail de thèse présente le développement et l'adaptation, dans le domaine des rayons X, de méthodes d'imagerie par contraste de phase sur des équipements de laboratoire. Le but est de compléter, d'une manière plus accessible et quotidienne, les demandes d'évaluation non destructives. Ce manuscrit se découpe suivant deux axes portant sur la simulation d'une part et sur le développement instrumental d'autre part. Un outil de simulation a été développé portant sur une description hybride alliant optique géométrique et optique ondulatoire. Les limites du modèle et des validations sont présentées. La partie instrumentale se focalise sur l'étude de deux techniques d'imagerie différentielle de phase. La première technique est de l'interférométrie à décalage multilatéral, dont l'adaptation sur tube à rayons X est réalisée pour la première fois. Une exploitation intéressante de la redondance de la mesure que produit la technique sera notamment introduite. La deuxième approche est une technique d'interférométrie de suivi de tavelure, dont nous présenterons une nouvelle exploitation<br>X-ray imaging is widely used in non-destructive testing dedicated to industry, medical or security domain. In most of the radiographic techniques, the image contrast depends on the attenuation of the X-ray beam by the sample. This attenuation is function of the density and thickness of the object and of the wavelength. Therefore, objects like metal covers, bones or weapons bring contrast on the image. In addition to attenuation, phase shifting happens, in particular for low-attenuating material. This phenomenon brings contrast, called phase contrast, and allows a X-ray image of low-attenuating material as plastics, composites, soft tissues or explosives. This work presents development and adaptation, in the X-ray domain, of phase contrast imaging techniques on laboratory equipment. The goal is to bring phase contrast imaging in daily use. This manuscript is split in two parts, simulation and instrumentation. A simulation tool has been developed, mixing geometrical optic and wave optic. Limits of the model and validation are presented. For the instrumental part, two interferometric techniques have been considered. The first one is multi-lateral interferometry where adaptation on X-ray tube is presented for the first time. Interesting use of the measurement recurrence will be introduced. The second one is speckle tracking interferometry, recently adapted on X-ray tube, for which we present new advancements
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Esteves, Cristiane Linge Exposito. ""Influência da técnica de desobturação e do limite de obturação na extrusão apical"." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/23/23135/tde-21012005-102925/.
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O controle da extrusão apical durante a reintervenção endodôntica é essencial para o sucesso do novo tratamento. Nesse contexto, o presente estudo teve como objetivo comparar a quantidade de material sólido extruído na desobturação de canais radiculares variando-se a técnica de esvaziamento e o limite de obturação. Foram utilizados 40 incisivos inferiores previamente tratados divididos em dois grupos de acordo com o limite de obturação estabelecido. Cada grupo foi subdividido em dois subgrupos levando-se em conta a técnica de desobturação empregada; manual (subgrupos A1 e B1) e mecânico-rotatória com limas de Ni-Ti (Quantec LX) (subgrupos A2 e B2). O material sólido extruído foi coletado por meio do sistema de filtração Millipore, levado à secagem em dessecador de sílica e pesado em balança analítica de precisão. Os resultados obtidos foram submetidos a ANOVA para dois fatores de variação sendo em seguida empregado o Teste de Tukey (α = 5%). A técnica de desobturação mecânico-rotatória produziu menor extrusão (0,66mg) que a manual (1,11mg), havendo diferença estatística significante entre elas (p < 0,05). Os canais preenchidos até o vértice radiográfico apresentaram maior quantidade de extrusão (1,38mg) do que os obturados 1 mm aquém do forame (0,39mg), observando-se diferença estatística significante entre eles (p < 0,05). A menor quantidade extrusão foi observada no subgrupo A2 (0,20mg), em que foi empregada a técnica rotatória de desobturação em canais obturados 1mm aquém do forame apical, sendo constatada diferença estatisticamente significante deste subgrupo com os demais (p < 0,05). A extrusão de material sólido durante a desobturação de canais radiculares é influenciado pela técnica empregada e pelo limite apical de obturação.<br>The apical extrusion control during the endodontic retreatment is essential for the success of the new treatment. The purpose of this study was to compare the quantity of solid apically extruded material during filling removal according the gutta-percha removal technique and root filling limit. Forty mandibular incisors with a single straight canal were selected. The canals were previously endodontically treated and then divided into two groups according the filling level. Each group was subdivided in two groups considering the retreatment technique: stainless steel hand files (subgroups A1 and B1) versus niquel-titanium rotatory instruments (subgroups A2 and B2). The extruded solid material was collected by Millipore filtration system, dried in silica desiccators and weighed in an eletrobalance. The results were analyzed using ANOVA with two variation factors and Tukey Test (α = 5%). The niquel-titanium rotatory instruments produced less extrusion (0,66mg) than the stainless steel hand files (1,11mg), with significant statistical difference between them (p < 0,05). The canals filled until the radiographic apex showed larger amount of extruded material (1,38mg) than those filled 1 mm beyond the foramen (0,39mg). It was observed significant statistical difference between them (p < 0,05). The smaller extruded debris amount was observed in subgroup A2 (0,20mg), in which one the rotary technique was used to remove the gutta-percha of canals filled 1mm beyond the apical foramen. It was verified significant statistical difference of this subgroup with the other ones (p < 0,05). The extrusion of solid material during the gutta-percha removal is influenced by the technique as well as the apical filling limit.
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Teschke, Kay, Yat Chow, Michael Brauer, et al. "Exposures and their control in radiographic film processing in British Columbia." 2000. http://hdl.handle.net/2429/825.
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Νιώτης, Δημήτριος. "Quality control on dental panoramic radiography units." Thesis, 2010. http://nemertes.lis.upatras.gr/jspui/handle/10889/4330.
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Quality control on panoramic radiography units, calculation of effective dose, principles of function of panoramic units, QC protocols, radio-protection issues.<br>Έλεγχος ποιότητας οδοντιατρικών πανοραμικών συστημάτων ακτινογράφησης, υπολογισμός ενεργού δόσης, αρχές λειτουργίας πανοραμικών συστημάτων, πρωτόκολλα ποιοτικού ελέγχου, ζητήματα ακτινοπροστασίας.
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McLeod, Robert William. "An experimental approach to Automatic Exposure Control testing." 2009. http://hdl.handle.net/2440/57898.
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A New Zealand Qualified Health Physicist (QHP) is required, under the Radiation Protection Act of 1965 and the Radiation Protection Regulations 1982, to perform auditing compliance tests on x-ray equipment at regular intervals to ensure that this equipment conforms to the Code of Safe Practice with the use of x-rays. The protocol for these tests must be approved by the National Radiation Laboratory (NRL). One of these test protocols sets out the requirements for the functionality testing of the x-ray machine Automatic Exposure Control (AEC). The current NRL protocol for AEC testing is based on the radiographic film environment (NRL C5 1994). This protocol was tested to determine its applicability to the digital computed radiography (CR) imaging systems which are replacing screen-film systems. To begin this process a comparison of the different exposure indexes for each image medium was required. This proved to be achievable using a system of exposure dose comparison. The AEC test process for both image modalities follows identical requirements but differ slightly in the test methods used to achieve these. The most significant finding throughout this stage was not the differences between protocols but was the requirement to achieve consistent exposure index values over the clinical kVp range for each image medium. This requirement, applicable to any x-ray image medium, became the focus of this thesis. The thesis has explored through experimentation, the effect of optimisation of AEC kVp compensation for the variable kVp response of an image medium, on image consistency. At Christchurch Hospital where this investigation took place the work has shown that the performance of AEC devices can be optimised to improve image consistency, indicated by a more consistent exposure index over the clinical kVp range. The optimisation process also achieves a more consistent dose response to the image plate. A dose variation of 8.3% from the average was achieved compared to 26% in the unoptimised version. No clinically significant changes to image quality were apparent in test images. Under these conditions it was found that AEC functionality could be assessed solely by the measurement of AEC dose to the image plate (IP). Use of this test method provides quantifiable time management benefits for the Medical Physicist and for the radiology departments in which they work.<br>http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1369625<br>Thesis (M.Sc.(Med.Physics)) - University of Adelaide, School of Chemistry and Physics, 2009