Thèses : « Radiologic image »

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Vercillo, Richard 1953. « Very high resolution video display memory and base image memory for a radiologic image analysis console ». Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276707.

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Digital radiographic images are created by a variety of diagnostic imaging modalities. A multi-modality workstation, known as the Arizona Viewing Console (AVC), was designed and built by the University of Arizona Radiology Department to support research in radiographic image processing and image display. Two specially designed VMEbus components, the base image memory and the video display memory, were integrated into the AVC and are the subject of this thesis. The base image memory is a multi-ported, 8 megabyte memory array based on random access memory used for raw image storage. It supports a 10 megapixel per second image processor and can interface to a 320 megabit per second network. The video display memory utilizes video memories and is capable of displaying two independent high resolution images, each 1024 pixels by 1536 lines, on separate video monitors. In part, these two memory designs have allowed the AVC to excel as a radiographic image workstation.

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Chun, Hee. « Auditory sensory feedback tool to supplement visual data perception in radiologic imaging a demonstration using MR mammography / ». Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1148594830.

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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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Ullman, Gustaf. « Quantifying image quality in diagnostic radiology using simulation of the imaging system and model observers ». Doctoral thesis, Linköping : Department of Medicine and Health, Linköping University, 2008. http://www.bibl.liu.se/liupubl/disp/disp2008/med1050s.pdf.

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Sampedro, Santaló Frederic. « Automatic image quantification strategies in clinical nuclear medicine and neuroradiology ». Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/402270.

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Amb la revolució de la tecnologia digital d’obtenció d’imatges radiològiques i l’increment de la potència computacional, el camp de la quantificació d’imatges mèdiques ha sorgit. El fet de poder programar un ordinador per a que detecti patrons d’interès en imatges radiològiques i pugui derivar-ne d’aquests indicadors numèrics amb valor clínic fa que, sens dubte, aquest àmbit de coneixement tingui un gran potencial en entorns mèdics i de recerca. En aquesta tesi es presenten un conjunt de contribucions científiques en aquest context. En particular, es descriu el disseny i la implementació d’una sèrie d’estratègies computacionals de quantificació d’imatges de medicina nuclear i neuroradiologia. A continuació es detalla com aquestes tècniques han demostrat ser d’utilitat per a l’estudi de malalties molt rellevants en l’actualitat com són el càncer de mama, el limfoma no-Hodgkin, la pielonefritis, la malaltia d’Alzheimer, la malaltia de Parkinson i l’abús de cànnabis.
Con la revolución de la tecnología digital de obtención de imágenes radiológicas y el aumento de la potencia computacional, el campo de la cuantificación de imágenes médicas ha emergido. El hecho de poder programar un ordenador para que detecte patrones de interés en imágenes radiológicas y pueda derivar de ellos una serie de indicadores numéricos con valor clínico hace que, sin duda, este ámbito de conocimiento tenga un gran potencial en el entorno médico y de investigación. En esta tesis se presentan un conjunto de contribuciones científicas en este contexto. En particular, se describe el diseño y la implementación de una serie de estrategias computacionales de cuantificación de imágenes de medicina nuclear y neuroradiología. A continuación se detalla cómo estas técnicas han demostrado ser de utilidad en el estudio de patologias muy relevantes en la actualidad como son el cáncer de mama, el linfoma no-Hodgkin, la pielonefritis, la enfermedad de Alzheimer, la enfermedad de Parkinson i el abuso de cánnabis.
With the revolution of digital medical imaging and the increasing computational power, the field of quantitative medical image analysis emerged. By programming a computer to detect patterns of interest in medical images and derive clinically meaningful numerical indicators from them, this field shows promising potential for healthcare and medical research systems. In this thesis, the design and implementation of computer-based quantification techniques in nuclear medicine and neuroradiological images led to several contributions in this field. These image-derived indicators contributed to complement the visual diagnosis and to further understand the pathophysiology of important health issues such as breast cancer, non-Hodgkin lymphoma, pyelonephritis, Alzheimer’s disease, Parkinson’s disease and cannabis abuse.

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Alejaldre, Monforte Aída. « Uutilidad de los estudios de imagen muscular en el diagnóstico de un grupo de miopatías con debilidad axial ». Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/399847.

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Las miopatías hereditarias son enfermedades de alta complejidad diagnóstica y pueden presentarse con diferentes fenotipos. Un fenotipo emergente es el fenotipo axial. La enfermedad de Pompe (EP) del adulto es una glicogenosis que provoca una debilidad muscular que generalmente afecta a las cinturas y la musculatura axial. Se asocia a una afectación respiratoria entre otras complicaciones. Las miopatías secundarias a mutaciones en el gen EMD y LMNA pueden cursar con debilidad de cinturas o causar una distrofia tipo Emery-Dreifuss (EDMD). La EDMD cursa con debilidad escapulo-humero-peroneal asociada a contracturas articulares en codos, tobillos y columna. En los últimos años la Tomografía computerizada (TC) y la Resonancia magnética nuclear (RMN) están siendo usadas para el estudio de algunas patologías neuromusculares. La hipótesis de la presente tesis es que la imagen muscular puede ser un buen biomarcador diagnóstico en la EP del adulto y en la miopatía producida por mutaciones en el gen EMD o LMNA. La existencia de un patrón característico en la radiología permitiría un diagnóstico eficaz y precoz. Los objetivos fueron: 1) la descripción del patrón de infiltración grasa muscular en estas miopatías. 2) Estudiar la infiltración muscular en el área paravertebral y abdominal en 30 pacientes con EP. 3) Correlacionar la debilidad muscular con en el grado de infiltración en la radiología en la EP. 4) Describir las características clínicas y de imagen muscular en 42 pacientes con mutaciones en el gen EMD y LMNA. 5) Buscar diferencias radiológicas según el genotipo (EMD o LMNA). En el estudio de la EP, realizado sobre 30 pacientes con RMN o TC del área del tronco, encontramos que los pacientes asintomáticos presentaban infiltración grasa muscular en al menos un músculo y que existía un patrón de infiltración muscular en el área del tronco que además seguía un patrón evolutivo según avanzaba la gravedad clínica. Objetivamos que existía una correlación entre el grado de infiltración muscular y el estadio clínico de los pacientes. En el estudio de las miopatías secundarias a mutaciones en el gen LMNA y EMD, realizado sobre 42 pacientes con RMN o TC de tronco y extremidades inferiores, los pacientes con EDMD no presentaron diferencias clínicas según su genotipo. Describimos un patrón de infiltración en los pacientes con EDMD que afectaba al área paravertebral, compartimento anterior y posterior de muslo y posterior de pierna. Encontramos una diferencia significativa en el grado y la frecuencia de infiltración del músculo Peroneo siendo mayor en las mutaciones del gen EMD. Observamos infiltración de la musculatura paravertebral en los pacientes asintomáticos y una progresión en el patrón radiológico según el estadio clínico. Se puede concluir que la imagen muscular es un biomarcador eficaz para el diagnóstico de la EP del adulto y de la miopatía producida por mutaciones en el gen EMD y LMNA. La imagen muscular puede ser útil para guiar el estudio genético en pacientes que comparten un mismo fenotipo.
Hereditary myopathies are diseases with a complex diagnosis. They may present with different phenotypes of muscle weakness. A relatively new phenotype is the axial phenotype. Adult Pompe’s disease (PD) is a glycogenosis. Glycogen accumulation in lysosomes causes muscle weakness that usually involves girdles and axial muscles associated with respiratory insufficiency. Myopathies due to mutations in EMD and LMNA genes may present with girdles weakness or with Emery-Dreifuss muscular dystrophy phenotype (EDMD). EDMD patients present a scapular-humeral-peroneal weakness associated with joint contractures at elbows, ankles and spine. In recent years computed tomography (CT) and magnetic resonance imaging (MRI) are being used for the study of some neuromuscular diseases. The hypothesis of this thesis is that muscular imaging could be a good diagnosis biomarker of Adult PD and EMD o LMNA genes related myopathy. A characteristic radiological pattern would allow an effective and early diagnosis. Aims were: 1) to describe the pattern of fatty muscle infiltration in these myopathies. 2) to study muscle infiltration in the paravertebral and abdominal area in 30 patients with PD. 3) to correlate muscle weakness with the degree of muscle infiltration in radiology in PD. 4) To describe clinical and radiological characteristics in 42 patients with mutations in EMD and LMNA genes. 5) to search radiological differences according to genotype (EMD o LMNA). PD study was performed in 30 patients with MRI or CT at the trunk level. We found that asymptomatic patients had fatty muscle infiltration in at least one muscle. There was a specific infiltration pattern in trunk area. Moreover this pattern makes evolves according to the clinical severity. There was a correlation between the degree of muscle infiltration and clinical stage. The study of myopathies due to mutations in EMD and LMNA genes was perfomed in 42 patients with MRI or CT of trunk and lower extremities area. We found EDMD patients showed no clinical differences according genotype. We described an infiltration pattern in these patients that affects paravertebral area, anterior and posterior compartment in the thigh and posterior compartment in the leg. Significative difference was found in the degree and frequency of infiltration in peroneal muscle. Peroneal Infiltration was greater in patients with mutations in EMD gene. We showed paravertebral infiltration in asymptomatic patients. We found an evolutive radiological pattern according to the clinical stage evolution. In conclusion muscular radiology is an effective biomarker for the diagnosis of adult PD and myopathies caused by mutations in the LMNA or EMD genes. In patients who share the same phenotype muscle imaging could be a useful tool to guide genetics studies.

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Silva, Thiago Rodrigues da. « Dosimetria em radiologia diagnóstica digital : Uso dos indicadores de exposição de sistemas digitais como estimadores de dose absorvida ». Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-06112014-143320/.

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Os sistemas de radiologia digital, entre eles os baseados em fósforos fotoestimuláveis (sistemas CR como sao conhecidos em radiologia), são cada vez mais comuns na pratica radiológica da cidade de Sao Paulo, seguindo uma tendência mundial. O uso desta tecnologia, que vem substituindo o conjunto tela-filme como sistema de detecção e produção de imagem, permite o uso de uma faixa dinâmica de detecção mais ampla e pode ser prejudicial ou benéfico do ponto de vista da dose absorvida pelo paciente, pois possibilita a obtenção de imagens para superexposições ou subexposições. Para avaliar o contraste obtido na imagem, e, ao mesmo tempo, obter uma estimativa da dose absorvida pelo paciente, todos os fabricantes de sistemas CR incluem no software de analise da imagem um indicador de exposição, que deve se relacionar com a dose absorvida pela placa de fosforo foto-estimulável (Image Plate IP). Estudos que relacionam a razão sinal ruído (SNR) e Dose de Entrada na Pele (DEP), avaliada com câmara de ionização e dosimetria TL, para radiografias de torax (frente e perfil) foram conduzidos empregando técnicas clinicas. Valores de dose (DEP e dose de saída) foram comparados com valores de níveis de cinza e de indicadores de exposição obtidos para as imagens com o CR Agfa CR30-X. Para isso foram utilizados dois simuladores: um simulador homogêneo, com paredes PMMA e preenchido com agua; e um simulador antropomórfico sem os membros superiores e inferiores (RANDO Phantom), no qual foi possível também medir doses internas com dosimetria TL, com irradiações realizadas em laboratório e em ambiente hospitalar. Os resultados mostraram uma relação logarítmica entre o indicador de exposição da Agfa (log of median of histogram - lgM) e a dose de saída do simulador, e uma relação logarítmica da DEP com a mediana dos níveis de cinza de uma regiao da imagem (SAL - Scan Average Level) para ambas as projeções. Também foi possível relacionar o lgM com a DEP, porem, tal relação e dependente da qualidade do feixe. Com o uso de filtros, verificamos que e possível diminuir a DEP mantendo a mesma qualidade da imagem. Neste trabalho foram obtidos valores de DEP na faixa de 0,0995(50) 1,657(51) mGy, e de doses internas entre 0,0074(18) e 0,90(13) mGy. Com isso concluímos que e possível relacionar os indicadores de exposição com a dose absorvida (DEP e dose de saída), e usar o CR como um avaliador de dose absorvida no paciente, quando a qualidade do feixe e conhecida.
The digital radiology systems, among them the system based on photostimulable phosphors (CR systems as they are known in radiology) are increasingly common in radiological practice in Sao Paulo, following a worldwide trend. Using this technology, which is replacing the screen-film as detection system for production of the image, can be detrimental or beneficial in terms of the absorbed dose to the patient, because the dynamic range of these detectors is much wider than the radiographic films, and it is possible to obtain an image with overexposure or underexposure. To evaluate the contrast obtained in the image, and at the same time, obtain an estimate of the absorbed dose to the patient, all manufacturers of CR systems include the evaluation of an exposure index in the image analysis software. This index should be related to the absorbed dose to the phosphor plate (Image Plate- IP). Studies that relate the signal to noise ratio (SNR) and Entrance Skin Dose (ESD), measured with ionization chamber and TL dosimetry for chest X-rays were conducted using clinical techniques, and typical values of dose (ESD and exit dose) were compared with values of gray levels and exposure index obtained with the CR. For this we used two simulators: a homogeneous one made with PMMA walls and filled with water, and an anthropomorphic phantom without the upper and lower limbs (RANDO Phantom), in which it was also possible to measure internal doses with TL dosimetry. The results showed a logarithmic relationship between the Agfa index IgM (log of median of histogram) and the simulator exit dose, and a log relationship between the ESD and the mean gray level of a region of the image (SAL - Scan Average Level ). It was also possible to relate the IgM with ESD, but the relation is dependent on the beam quality. With the use of different filtrations, we verified the possibility of decrease the ESD keeping the same image quality. In this work we obtained ESD values in the range 0.0995(50) 1.657(51) mGy, and internal doses from 0.0074(18) to 0.90(13) mGy.

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Ovando, Cortés Paloma Andrea. « Variabilidad en el diagnóstico de caries proximales con radiología convencional e imagen radiológica digitalizada estandarizadas ». Tesis, Universidad de Chile, 2006. http://repositorio.uchile.cl/handle/2250/144973.

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Trabajo de Investigación Requisito para optar al Título de Cirujano Dentista
La detección de caries proximales incipientes es uno de los problemas a los que todavía se enfrentan los odontólogos debido principalmente a la difícil inspección de dichas superficies1. En la actualidad el diagnóstico radiológico es fundamental ya que aproximadamente la mitad de las lesiones proximales no son visibles clínicamente y sólo pueden ser detectadas mediante radiografías5,6, sin embargo, para que una lesión de caries sea detectada radiológicamente debe producirse una desmineralización del 30%4,5. Esta limitación en la detección de caries proximales incipientes ha hecho que nuevas tecnologías sean desarrolladas, sistemas digitales tienen gran aceptación en la evaluación y diagnóstico de lesión de caries oclusales por permitir durante la interpretación radiográfica, la manipulación del contraste, brillo y densidad, sin embargo no hay estudios similares para la detección de caries proximales10. En este estudio se comparó la efectividad de los métodos de diagnóstico radiográfico convencional, radiográfico digitalizado normal y radiográfico digitalizado invertido en la detección de caries proximales. Además se comparó el diagnóstico de caries realizado por alumnos egresados de Odontología, odontólogos generales y especialistas en radiología máxilo-facial. La muestra consistió en un total de 41 dientes entre premolares y molares con superficies proximales o al menos una de ellas con tinción evidente; mancha blanca o mancha café. La toma radiográfica convencional de todos los dientes fue realizada por un docente de la cátedra de Radiología de la Universidad de Chile. Con el objeto de estandarizar la toma radiográfica se creó un soporte que mantuvo siempre el tubo de rayos X en la misma posición y distancia con respecto a la película y al objeto a radiografiar Los dientes fueron montados en grupos de 3 dientes cada uno para crear las superficies de contacto y fueron fijados con cera rosa. Las imágenes digitalizadas se obtuvieron mediante el escaneo de las radiografías tomadas previamente en forma convencional. Las imágenes digitalizadas se manipularon computacionalmente en brillo y contraste y se invirtió la imagen para obtener el negativo de ésta. Las imágenes radiográficas convencional, digitalizadas normal y digitalizada invertida fueron analizadas por 9 observadores, 3 alumnos de pregrado egresados de la carrera de Odontología de la Universidad de Chile, 3 odontólogos generales y 3 radiólogos máxilo-faciales titulados en la Universidad de Chile. Cada uno de los observadores evaluó presencia o ausencia de caries proximales en las superficies dentarias y la profundidad de éstas respondiendo a una pauta de observación. Cada uno analizó las imágenes radiográficas en forma independiente, en el mismo lugar físico y bajo condiciones estándar. Para validar la comparación entre las distintas modalidades radiográficas los dientes fueron sometidos a cortes en zonas que involucraran la lesión y fueron examinados por un observador calibrado previamente, bajo condiciones estándar y evaluados en base al mismo criterio usado en el examen radiográfico. El porcentaje de acierto de todos los observadores en las distintas técnicas radiográficas fue 42% con radiología convencional, 40,2% con radiología digitalizada normal y 41,1% con radiología digitalizada invertida. El grupo de radiólogos máxilo-faciales tuvo un 44,1% de coincidencia con radiología convencional, 36% con radiología digitalizada normal y 39,2% con radiología digitalizada invertida. El grupo de odontólogos generales tuvo un 42,3% de aciertos con radiología convencional, un 39,6% con radiología digitalizada normal y un 40,5% con radiología digitalizada invertida. El grupo de estudiantes egresados tuvo un porcentaje de acierto de 39,6% con radiología convencional, 45% con radiología digitalizada normal y 43,7% con radiología digitalizada invertida. El test aplicado para el análisis estadístico fue el de Anova, no hubo diferencia significativa entre los resultados obtenidos. En este estudio se concluye que la efectividad de la radiografía digitalizada normal y digitalizada invertida en el diagnóstico de caries proximales es similar al de la radiografía convencional y que al comparar la precisión diagnóstica entre estudiantes egresados, odontólogos generales y radiólogos máxilo-faciales no hay evidencias de mejorías significativas en la interpretación diagnóstica en detección de caries proximales con la experiencia del examinador.

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Cros, Olivier. « Image Analysis and Visualization of the Human Mastoid Air Cell System ». Licentiate thesis, Linköpings universitet, Medicinsk informatik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-122179.

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From an engineering background, it is often believed that the human anatomy has already been fully described. Radiology has greatly contributed to understand the inside of the human body without surgical intervention. Despite great advances in clinical CT scanning, image quality is still related to a limited amount X-ray exposure for the patient safety. This limitation prevents fine anatomical structures to be visible and, more importantly, to be detected. Where such modality is of great advantage for screening patients, extracting parameters like surface area and volume implies the bone structure to be large enough in relation to the scan resolution. The mastoid, located in the temporal bone, houses an air cell system whose cells have a variation in size that can go far below current conventional clinical CT scanner resolution. Therefore, the mastoid air cell system is only partially represented on a CT scan. Any statistical analysis will be biased towards air cells of smaller size. To allow a complete representation of the mastoid air cell system, a micro-CT scanner is more adequate. Micro-CT scanning uses approximately the same amount of X-rays but for a much longer exposure time compared to what is normally allowed for patients. Human temporal bone specimens are therefore necessary when using such scanning method. Where the conventional clinical CT scanner lacks level of minutes details, micro-CT scanning provides an overwhelming amount of fine details. Prior to any image analysis of medical data, visualization of the data is often needed to learn how to extract the structures of interest for further processing. Visualization of micro-CT scans is of no exception. Due to the high resolution nature of the data, visualization of such data not only requires modern and powerful computers, but also necessitates a tremendous amount of time to adjust the hiding of irrelevant structures, to find the correct orientation, while emphasising the structure of interest. Once the quality of the data has been assessed, and a strategy for the image processing has been decided, the image processing can start, to in turn extract metrics such as the surface area or volume and draw statistics from it. The temporal bone being one of the most complex in the human body, visualization of micro-CT scanning of this bone awakens the curiosity of the experimenter, especially with the correct visualization settings. This thesis first presents a statistical analysis determining the surface area to volume ratio of the mastoid air cell system of human temporal bone, from micro-CT scanning using methods previously applied for conventional clinical CT scannings. The study compared current resul s with previous studies, with successive downsampling the data down to a resolution found in conventional clinical CT scanning. The results from the statistical analysis showed that all the small mastoid air cells, that cannot be detected in conventional clinical CT scans, do heavily contribute to the estimation of the surface area, and in consequence to the estimation of the surface area to volume ratio by a factor of about 2.6. Such a result further strengthens the idea of the mastoid to play an active role in pressure regulation and gas exchange. Discovery of micro-channels through specific use of a non-traditional transfer function was then reported, where a qualitative and a quantitative preanalysis was performed are described. To gain more knowledge about these micro-channels, a local structure tensor analysis was applied where structures are described in terms of planar, tubular, or isotropic structures. The results from this structural tensor analysis, also reported in this thesis, suggest these micro-channels to potentially be part of a more complex framework, which hypothetically would provide a separate blood supply for the mucosa lining the mastoid air cell system.

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Andersson, Kristina. « Evaluation of uncertainties in sub-volume based image registration : master of science thesis in medical radiation physics ». Thesis, Umeå universitet, Institutionen för fysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-38638.

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Physicians often utilize different imaging techniques to provide clear, visual information about internal parts of the patient. Since the different imaging modalities give different types of information, the combination of them serves as a powerful tool while determining the diagnosis, planning of treatment or during therapy follow-up. To simplify the interpretation of the image information, image registration is often used. The goal of the registration is to put different images in a common coordinate system. It is essential that the registration between the images is accurate. Normalized Mutual Information (NMI) is a metric that quantifies the conformity between images. Even though NMI is a robust method it is often dominated by large structures as the external contour of the patient as well as by the structures of the bones. The prostate is an organ that does not have a fixed position relative to the other organs and host small amounts of image information. The accuracy of the registration is therefore limited with respect to the prostate when using the whole image volume. This master thesis investigates the possibility to restrict the part of the image used for registration to a small volume around the prostate with goal to receive a better registration of the prostate than if full sized images are used. A registration program, utilizing NMI, was written and optimized in MatLab. Four Magnetic Resonance (MR) series and one Computed Tomographic (CT) series where taken over the pelvic area of five patients with the diagnosis prostate cancer. The prostate were delineated by a physician. By adding margin to the delineations five different sized Regions of Interest (ROI) where created. The smallest ROI precisely covered the prostate while the largest covered the whole image. The deviation in Center of Mass (CoM) between the images and the Percentage Volume Overlap (PVO) were calculated and used as a measure of alignment. The registrations performed with sub-volumes showed an improvement compared to those that used full-volume while registering a MR image to another MR image. In one third of the cases a 2 cm margin to the prostate is preferable. A 3 cm margin is the most favorable option in another third of the cases. The use of sub-volumes to register MR images to CT series turned out to be unpredictable with poor accuracy. Full sized image registration between two MR image pairs has a high precision but, due to the motion of the prostate, poor accuracy. As a result of the high information content in the MR images both high precision as well as high accuracy can be achieved by the use of sub-volume registration. CT images do not contain the same amount of image information around the prostate and the sub-volume based registrations between MR and CT images are hence inconsistent with a low precision.

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Fermor, Paul Elliot. « Image driven fluoroscopy for interventional radiology ». Thesis, University of Surrey, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250820.

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Leão, Tiago Freire Carneiro. « Sistema de avaliação de qualidade de imagem em radiologia digital odontologica ». [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258950.

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Orientador: Eduardo Tavares Costa
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: Novas tecnologias e sistemas de detecção de radiação para a geração de imagens radiográficas odontológicas vêm sendo disponibilizados como alternativa aos filmes radiográficos. Sistemas baseados em tecnologia do tipo PSPL parecem superar algumas das restrições encontradas nos sistemas baseados em tecnologia CCD, tais como volume do detector, cabos de conexão, tamanho limitado da imagem e limitação da latitude. É importante que seja possível comparar sistemas de imagem concorrentes (diferentes tecnologias ou diferentes fabricantes com mesma tecnologia), utilizando ferramentas e protocolos de controle e certificação de qualidade. Foi desenvolvido um pacote computacional e um conjunto de simuladores e foi realizada a análise de dois sistemas comerciais baseados na tecnologia PSPL, de forma a validar o sistema desenvolvido. O programa desenvolvido permite obter e analisar: curva sensitométrica, função de transferência de modulação (MTF), densidade espectral de potência (NPS), quanta equivalente de ruído (NEQ) e eficiência na detecção de quanta (DQE). Os resultados mostraram que o pacote computacional e o conjunto de simuladores permitem realizar o controle de qualidade de sistemas de radiografia digital odontológica de maneira quantitativa e objetiva, facilitando a análise comparativa entre diferentes sistemas comerciais. Palavras-chave: Radiologia digital odontológica, controle de qualidade em radiodiagnóstico, curva sensitométrica, detecção equivalente de quanta, função de transferência de modulação, densidade espectral de ruído, quanta equivalente de ruído.
Abstract: New systems and technologies for radiation detection intended for dental radiology have become available as an alternative to dental radiographic film. Systems based on PSPL technology seems to overcome some of the restrictions of systems based on CCD technology such as the bulky detector, connecting wire, limited image size and limited exposure latitude. It is important that competing imaging systems can be compared (different technologies or different manufacturers of the same technology) by means of quality control tools and quality certification protocols. A software package and a set of specific phantoms were developed and the analyses of two competing PSPL systems were conducted to validate the developed system. The software allows the user to obtain and analyze: the characteristic curve, modulation transfer function (MTF), noise power spectrum (NPS), noise equivalent quanta (NEQ) and detective quantum efficiency (DQE). The results have shown that the developed software and phantom set allow quality control of digital dental radiology systems in a very objective and quantitative way, facilitating comparative analysis of competing commercial systems. Keywords: Digital dental radiology, quality assurance in radiodiagnostic, characteristic curve, detective quantum efficiency, modulation transfer function, noise power spectrum, noise equivalent quanta.
Mestrado
Engenharia Biomedica
Mestre em Engenharia Elétrica

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Brucoli, Henrique Cesar Purchio. « Análise da imagem radiográfica de raízes apicetomizadas e irradiadas com laser de Nd:YAG por meio do processamento de imagem de radiografias digitais diretas ». Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/23/23139/tde-24102009-112749/.

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Nesta pesquisa foi realizada a análise da imagem radiográfica digital da técnica periapical de raízes cujos ápices foram irradiados com laser de Neodymium Yttrium Aluminum Garnet (Nd:YAG) após a ressecção apical. Com intuito de encontrar alterações da imagem radiográfica digital das raízes causadas pela irradiação laser, desenvolvemos um modelo experimental in vitro. Foram realizadas as apicectomias de 39 raízes de dentes unirradiculares a dois milímetros do limite apical, com posterior fixação dos dentes em dispositivo que conferiu uma rígida padronização das radiografias, cujas imagens foram capturadas por meio de um sistema de radiografia digital direta (Dixi® Planmeca). Com a fixação das raízes no dispositivo de padronização, realizamos uma radiografia inicial, irradiamos os ápices radiculares com o laser de Nd:YAG e em seguida fizemos uma radiografia final, sem manipulação do sistema de padronização durante todo o processo. Os parâmetros de irradiação laser utilizados foram baseados no protocolo de pesquisa clínica para cirurgias apicais desenvolvido no Laboratório Especial de Laser em Odontologia (LELO-FOUSP). Foram eles 100mJ, 15Hz, 1,5W e diâmetro da fibra óptica de 320m. As radiografias foram obtidas com três tempos de exposição diferentes (0,05s, 0,08s e 0,14s). As imagens radiográficas antes e depois a irradiação laser, obtidas em 12 bits, foram convertidas para 8 bits e exportadas para o programa de análise de imagens ImageTool 3.0.0. A análise das imagens digitais foi executada por meio de histogramas e subtração de imagem digital quantitativa. Foi possível detectar por meio dos dois métodos uma menor quantidade de dentina na superfície apical após a irradiação com o laser de Nd:YAG. A variável tempo de exposição não apresentou diferenças estatísticas significantes, porém foi observada uma tendência de melhor desempenho dos métodos com imagens obtidas com exposição de 0,05s. Apesar de termos observado remoção de tecido dentinário, não foi possível detectar a presença de uma camada de dentina mais radiopaca nas imagens radiográficas da superfície irradiada.
In this research, we carried out an evaluation of the digital radiographic image of dental root-ends irradiated with Neodymium Yttrium Aluminum Garnet (Nd:YAG) laser after apical resection. With the intention of founding alterations in the digital radiographic image of the roots caused by laser irradiation, we developed an in vitro experimental model. We made apicectomy in 39 single-root teeth, 2 milimeters below the apical limit and then we fixed these teeth in a standardization device. The radiographic images were captured thru a direct digital radiographic system (Dixi® Planmeca). After positioning of the teeth in the standardization device, we made an initial radiograph, Nd:YAG laser irradiation of the apex and a final radiograph, without manipulation of the standardized system during the whole process. The laser parameters applied in this research followed the clinical research protocol for apical surgeries developed in the LELO- FOUSP. They were 100mJ, 15Hz, 1,5W and a 320m diameter optic fiber. The radiographs were made within three different exposure times (0,05s, 0,08s and 0,14s). The obtained 12 bit radiographic images before and after laser irradiation were converted to 8 bit images and exported to the ImageTool 3.0.0 image analysis software. With this software wee analyzed the digital images in the methods of histogram analysis and quantitative digital image subtraction. The two methods indicated less amount of dentin in the apical surface after Nd:YAG laser irradiation. The variable exposure time did not present statistical differences. However, we observed a tendency of better performance of the methods with images obtained with 0,05s exposure time. Although we observed dental tissue ablation, it was not possible to detect the presence of a more radiopac dentin layer in the irradiated surface radiographic images.

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Linder, Tova, et Ola Jigin. « Organ Detection and Localization in Radiological Image Volumes ». Thesis, Linköpings universitet, Artificiell intelligens och integrerade datorsystem, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-138944.

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Using Convolutional Neural Networks for classification of images and for localization and detection of objects in images is becoming increasingly popular. Within radiology a huge amount of image data is produced and meta data containing information of what the images depict is currently added manually by a radiologist. To aid in streamlining physician’s workflow this study has investigated the possibility to use Convolutional Neural Networks (CNNs) that are pre-trained on natural images to automatically detect the presence and location of multiple organs and body-parts in medical CT images. The results show promise for multiclass classification with an average precision 89.41% and average recall 86.40%. This also confirms that a CNN that is pre-trained on natural images can be succesfully transferred to solve a different task. It was also found that adding additional data to the dataset does not necessarily result in increased precision and recall or decreased error rate. It is rather the type of data and used preprocessing techniques that matter.

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AKBAR, MUHAMMAD USMAN. « Deep Learning Approaches Targeting Radiological Images ». Doctoral thesis, Università degli studi di Genova, 2022. http://hdl.handle.net/11567/1069387.

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Artificial Intelligence (AI) algorithms have remarkably improved their performance in the recent years in various domains, thanks to the introduction of deep learning approaches. Indeed they have shown a tremendous potential when solving tasks involving image analysisThe problem of deep learning is its requirement for huge datasets, nonetheless, DL approaches have proved to be helpful in the domain of medical imaging as well. Automated segmentation and classification in different biomedical tasks have proven to be faster and more cost effective. In this thesis we study deep learning approaches used for segmentation and classification of different radiological images mainly CT Scans, MRI Scans and CXR images. In particular, we explored some issues like the multi-modality, and the small dataset problem We first discuss about how the small datasets can be exploited to improve the performance of the deep model in the proposed architectures and then in the next work we train the model with multi modal data consisting of both CT and MRI images together and consider the corresponding opposite modality of CT and MRI as missing data problem. We use Cycle-GAN to generate the synthetic data for the missing data and further train the model with original and synthetic data together. Then we focus on the classification of COVID exploiting the multi-modality data available. We proposed an architecture that is capable of handling multi modal data and extract feature representation from available modalities before concatenation and further use them for final classification. Then we exploit joint learning to train a small dataset from scratch. Finally, this thesis concludes with open questions that may benefit from future work. This thesis demonstrate the potential role of CNNs to address the tasks of segmentation and classification.

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ANDRE, MARC. « Exploitation d'images numeriques en radiologie en vue d'un enseignement ». Aix-Marseille 2, 1988. http://www.theses.fr/1988AIX20374.

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Cocklin, M. L. « Digial chest radiology : image processing requirements and applications ». Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/38264.

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Fontes, David Manuel Carvalho de Abreu. « Web system for workflow optimization in radiology service ». Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/18015.

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Mestrado em Engenharia de Computadores e Telemática
A ampla adoção de imagens médicas em formato digital nos diversos tipos de instituições de saúde, levantou novos problemas ao nível da gestão de dados e processos. A normalização destes cenários tem sido alvo de atenção nas últimas décadas, esforço que resultou no desenvolvimento e dinamização de normas como DICOM e HL7. Atualmente coexistem dois tipos de sistemas de informação num laboratório de imagem médica que devem funcionar de forma integrada, os RIS que são responsáveis pela gestão das tarefas administrativas e os PACS que fazem a gestão das imagens e informação associada. Esta dissertação teve como objetivo desenhar e implementar uma solução RIS baseada em ferramentas de utilização livre ou código aberto. Assim, começamos por estudar detalhadamente o estado da arte, incluindo soluções do domínio público e proprietárias, destacando os pontos fortes e fraquezas de cada uma. Para além da análise das tecnologias utilizadas no desenvolvimento de cada solução, este estudo teve contributos determinantes na análise de requisitos efetuada. Nomeadamente, permitiu-nos identificar funcionalidades inovadoras e com elevado valor para os utilizadores. O resultado é um sistema de informação capaz de gerir todas as operações de um departamento de radiologia, incluindo gestão administrativa de utentes, agendamento de exames, realização de relatórios clínicos, entre outras. Em termos de características inovadoras destaca-se o módulo de relatório que permite carregar novos modelos de relatórios com o sistema em produção e a sua exportação para o formato standard DICOM-SR, permitindo desta forma a sua integração com as imagens no repositório PACS. Em termos tecnológicos, desenvolveu-se uma aplicação web multiplataforma que segue uma arquitetura modular orientada a serviços e que oferece uma abstração relativamente à camada de persistência de dados.
The widespread adoption of digital medical images in various types of health institutions, has raised new problems regarding data and processes management. The standardisation of these scenarios has been subject of attention in the last decades, resulting in the development and promotion of standards such as DICOM and HL7. Currently, there are two kinds of information systems in medical imaging laboratories, that must operate in a collaborative manner, RIS which is responsible for managing the administrative tasks and PACS that manage images and associated information. This dissertation aimed to design and implement an RIS solution based on tools with no use restriction or open source. We begin by studying in detail the state of the art, including the open source and proprietary solutions, highlighting the strengths and weaknesses of each one. In addition to analysing the technologies used in the development of each solution, this study provided decisive contributions, regarding the project requirements. In particular, it allowed us to identify innovative features with high value to users. The achieved solution is an information system capable of managing all operations in a radiology department, including administrative management of patients, exam scheduling, conducting clinical reports, among others. Regarding innovative features, the reporting module stands out, since it allows to upload new report templates into the system and export these clinical reports in the DICOM-SR standard, thus allowing their integration with the images in a PACS repository. Regarding the technologies aspect, it was developed a multi-platform web application that follows a modular service-oriented architecture and also provides an abstraction in regard to the data persistence layer.

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Richardson, Richard Thomas. « Image Enhancement of Cancerous Tissue in Mammography Images ». NSUWorks, 2015. http://nsuworks.nova.edu/gscis_etd/39.

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This research presents a framework for enhancing and analyzing time-sequenced mammographic images for detection of cancerous tissue, specifically designed to assist radiologists and physicians with the detection of breast cancer. By using computer aided diagnosis (CAD) systems as a tool to help in the detection of breast cancer in computed tomography (CT) mammography images, previous CT mammography images will enhance the interpretation of the next series of images. The first stage of this dissertation applies image subtraction to images from the same patient over time. Image types are defined as temporal subtraction, dual-energy subtraction, and Digital Database for Screening Mammography (DDSM). Image enhancement begins by applying image registration and subtraction using Matlab 2012a registration for temporal images and dual-energy subtraction for dual-energy images. DDSM images require no registration or subtraction as they are used for baseline analysis. The image data are from three different sources and all images had been annotated by radiologists for each image type using an image mask to identify malignant and benign. The second stage involved the examination of four different thresholding techniques. The amplitude thresholding method manipulates objects and backgrounds in such a way that object and background pixels have grey levels grouped into two dominant and different modes. In these cases, it was possible to extract the objects from the background using a threshold that separates the modes. The local thresholding introduced posed no restrictions on region shape or size, because it maximized edge features by thresholding local regions separately. The overall histogram analysis showed minima and maxima of the image and provided four feature types--mean, variance, skewness, and kurtosis. K-means clustering provided sequential splitting, initially performing dynamic splits. These dynamic splits were then further split into smaller, more variant regions until the regions of interest were isolated. Regional-growing methods used recursive splitting to partition the image top-down by using the average brightness of a region. Each thresholding method was applied to each of the three image types. In the final stage, the training set and test set were derived by applying the four thresholding methods on each of the three image types. This was accomplished by running Matlab 2012a grey-level, co-occurrence matrix (GLCM) and utilizing 21 target feature types, which were obtained from the Matlab function texture features. An additional four feature types were obtained from the state of the histogram-based features types. These 25 feature types were applied to each of the two classifications malignant and benign. WEKA 3.6.10 was used along with classifier J48 and cross-validation 10 fold to find the precision, recall, and f-measure values. Best results were obtained from these two combinations: temporal subtraction with amplitude thresholding, and temporal subtraction with regional-growing thresholding. To summarize, the researcher's contribution was to assess the effectiveness of various thresholding methods in the context of a three-stage approach, to help radiologists find cancerous tissue lesions in CT and MRI mammography images.

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Roger, Étienne. « Image organization and navigation strategies for a radiological workstation ». Thesis, University of Ottawa (Canada), 1989. http://hdl.handle.net/10393/6046.

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Lindskog, Maria. « Clinical Investigations of Image Guided Radiation Therapy for Prostate Cancer with an On-Board Imager ». Thesis, Stockholm University, Medical Radiation Physics (together with KI), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8320.

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The daily uncertainty concerning tumor localization is one of the major problems during the course of radiation therapy. Image guided-radiation therapy (IGRT) can be used to improve the localization and adjustment of the planning target volume. The aim of this work was to evaluate both the IGRT technique used for prostate cancer patients at the department of the Karolinska University Hospital and an alternative on-line adaptive radiation therapy (ART) method with an On-Board Imager (OBI).

In the first part of the thesis 2D and 3D image registration with an OBI were compared. Ten prostate cancer patients were involved in the analyses. Two different statistical tests were used to determine significant systematic deviations between the two methods. The second part concerns daily dose verifications and dose plan reoptimization of one intensity modulated radiation therapy (IMRT) prostate cancer patient treated with IGRT. The study was based on cone-beam computed tomography (CBCT) images acquired at 6 different treatment fractions. The risk of developing late rectal and bladder toxicity was quantified using normal tissue complication probability (NTCP) calculations. Additional measurements on an Alderson phantom were performed to verify the accuracy of using the CBCT images for dose calculations.

A statistically significant difference between the 2D-2D and the 3D-3D match applications could be observed in lateral and longitudinal direction. However, the effect differed among the patients. The phantom measurements showed small dose deviations between the CT and CBCT image, with a mean dose increase to the prostate and seminal vesicles (SV) of 2.5 %. The daily dose to the prostate and SV of the IMRT patient showed to be satisfactory. The daily dose to the rectum did not exceed the prescribed rectal dose except at one treatment fraction and the highest risk of developing late rectal toxicity was about 10.4 %. Large daily bladder dose variations were observed and at two treatment fractions the bladder dose restrictions were exceeded. With a reoptimization process of the dose plan, the dose to the bladder could be reduced while conserving the dose to the target.

This work shows that for these specific patient cases appropriate doses to the prostate and SV can be delivered with IGRT. However, introducing a suitable ART method could lead to a reduction of inter-fractional rectal and bladder dose variations.

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Schomer, Barbara Greene. « Cost effectiveness in telemedicine : conventional versus digital delivery of radiologic images / ». Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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Djordjevic, Milos. « Evaluation of Geometric Accuracy and Image Quality of an On-Board Imager (OBI) ». Thesis, Stockholm University, Medical Radiation Physics (together with KI), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-6967.

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In this project several tests were performed to evaluate the performance of an On-Board Imager® (OBI) mounted on a clinical linear accelerator. The measurements were divided into three parts; geometric accuracy, image registration and couch shift accuracy, and image quality. A cube phantom containing a radiation opaque marker was used to study the agreement with treatment isocenter for both kV-images and cone-beam CT (CBCT) images. The long term stability was investigated by acquiring frontal and lateral kV images twice a week over a 3 month period. Stability in vertical and longitudinal robotic arm motion as well as the stability of the center-of-rotation was evaluated. Further, the agreement of kV image and CBCT center with MV image center was examined.

A marker seed phantom was used to evaluate and compare the three applications in image registration; 2D/2D, 2D/3D and 3D/3D. Image registration using kV-kV image sets were compared with MV MV and MV-kV image sets. Further, the accuracy in 2D/2D matches with images acquired at non-orthogonal gantry angles was evaluated. The image quality in CBCT images was evaluated using a Catphan® phantom. Hounsfield unit (HU) uniformity and linearity was compared with planning CT. HU accuracy is crucial for dose verification using CBCT data.

The geometric measurements showed good long term stability and accurate position reproducibility after robotic arm motions. A systematic error of about 1 mm in lateral direction of the kV-image center was detected. A small difference between kV and CBCT center was observed and related to a lateral kV detector offset. The vector disagreement between kV- and MV-image centers was  2 mm at some gantry angles. Image registration with the different match applications worked sufficiently. 2D/3D match was seen to correct more accurately than 2D/2D match for large translational and rotational shifts. CBCT images acquired with full-fan mode showed good HU uniformity but half fan images were less uniform. In the soft tissue region the HU agreement with planning CT was reasonable while a larger disagreement was observed at higher densities. This work shows that the OBI is robust and stable in its performance. With regular QC and calibrations the geometric precision of the OBI can be maintained within 1 mm of treatment isocenter.

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Nayak, Aman Kumar. « Segmenting the Left Atrium in Cardic CT Images using Deep Learning ». Thesis, Linköpings universitet, Institutionen för datavetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-176592.

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Convolution neural networks have achieved a state of the art accuracy for multi-class segmentation in biomedical image science. In this thesis, a 2-Stage binary 2D UNet and MultiResUNet are used to segment the 3D cardiac CT Volumes. 3D volumes have been sliced into 2D images. The 2D networks learned to classify the pixels by transforming the information about the segmentation into latent feature space in a contracting path and upsampling them to semantic segmentation in an expanding path. The network trained on diastole and systole timestamp volumes will be able to handle much more extreme morphological differences between the subjects. Evaluation of the results is based on the Dice coefficient as a segmentation metric. The thesis work also explores the impact of the various loss function in image segmentation for the imbalanced dataset. Results show that2-Stage binary UNet has higher performance than MultiResUnet considering segmentation done in all planes. In this work, Convolution neural network prediction uncertainty is estimated using Monte Carlo dropout estimation and it shows that 2-Stage Binary UNet has lower prediction uncertainty than MultiResUNet.

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Bittar-Cortez, Juliana Araujo. « Radiografia digital e a tecnica de subtração no monitoramento da desmineralização e remineralização do esmalte dentario ». [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288985.

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Orientador: Francisco Haiter Neto
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo deste estudo in vitro foi comparar dois protocolos de remineralização em lesões de cárie no esmalte dentário, avaliados por meio de análises de cálcio (Ca) e fósforo (Pi), dureza do esmalte, microscopia de luz polarizada e subtração radiográfica digital (SRD); avaliar a viabilidade da utilização de dois diferentes sistemas de radiografias digitais, placa PSP (photostimulable storage phosphor) e sensor CMOS (complementary metal oxide semicondutor), no diagnóstico de desmineralizações, e a acurácia das radiografias digitais convencionais (RDC) e três métodos de SRD (linear, avançada e logarítmica) no diagnóstico de mudanças minerais; e comparar o ruído e reprodutibilidade das imagens de SRD lineares e logarítmicas produzidas a partir de dois sistemas de radiografias digitais. Para isso, lesões de cárie artificiais foram criadas em 100 superfícies proximais de dentes hígidos. Vinte dentes foram mantidos como controle e oitenta foram submetidos a dois diferentes protocolos de remineralização em 4 e 8 semanas, com a contínua imersão em saliva artificial e um tratamento adicional com flúor. Radiografias digitais foram realizadas antes e depois dos protocolos de remineralização. Cinco examinadores avaliaram a desmineralização e as mudanças minerais nas RDC, dispostas lado a lado, e três métodos da SRD. As análises de Ca / Pi e a colocação dos dentes na solução remineralizante foram considerados como padrão ouro. A média dos tons de cinza e o desvio padrão (DP) no histograma foram também mensurados. As concentrações de Ca e Pi na saliva artificial após os tratamentos foram significativamente menores do que a solução original (p<0,05); e por meio da SRD foi possível verificar diferenças entre as imagens. Entretanto, o teste de dureza e a microscopia de luz polarizada não detectaram nenhuma alteração. O sistema CMOS foi significativamente mais acurado do que a sistema PSP no diagnóstico da desmineralização e mudanças minerais, assim como a SRD linear no diagnóstico de mudanças minerais. Também foram estatisticamente diferentes os valores da média dos níveis de cinza e do DP entre os dois sistemas. Foi concluído que (a) o tratamento adicional de flúor promoveu valores maiores de ganho mineral; (b) a análise de Ca / Pi na saliva artificial foi o método mais sensível na avaliação de alteração mineral; (c) a imagem de SRD linear é um método válido na detecção do aumento de intensidade, como sinal de ganho mineral; e (d) as imagens de SRD utilizando as placas PSP tiveram um menor ruído do que nas imagens geradas pelo sensor CMOS
Abstract: The aim of this in vitro study was to compare two remineralization protocols of artificial carious lesions in enamel, evaluated by Calcium (Ca) and Phosphorus (Pi) analysis, cross-section hardness test, polarized light microscopy and digital subtraction images (DSR); to assess the feasibility of using two different systems of digital radiography, photostimulable storage phosphor (PSP) plate and complementary metal oxide semiconductor (CMOS) sensor on the demineralization diagnosis, and the accuracy of digital conventional radiographs (DCR) and three methods of DSI (linear, advanced and logarithmic) on mineral changes diagnosis; and, to compare noise and reproducibility in linear and logarithmic DSI produced from two digital radiography systems. Artificial caries-like lesions on 100 approximal surfaces of sound teeth were produced. Twenty teeth were kept as control and eighty teeth were subjected to two different remineralization protocols for 4 and 8 weeks, with continuous immersion in artificial saliva, and additional fluoride treatment. Digital radiographs were taken before and after the remineralization protocols. Five examiners assessed demineralization and mineral changes on DCR, placed side by side, and three methods of DSI. Ca / Pi analysis and the placement of the teeth on the remineralization solution was the gold standard. The mean shades of gray and the standard deviation (SD) of the histogram were also assessed. The concentrations of Ca and Pi in the artificial saliva after the treatments were significantly lower than the original solution (p<0.05); and DSR showed differences between the images. However, the Hardness test and polarized light microscopy did not detect any changes. CMOS system was significantly more accurate than PSP system on demineralization and mineral changes diagnosis, and also linear DSR on mineral changes diagnosis. It was also statistically significant different the values of mean shades of gray and SD between both systems. It was concluded that (a) the additional Fluoride treatment provided higher values of mineral gained; (b) Ca / Pi analysis in the artificial saliva were the most sensitive method of mineral change evaluation; (c) linear DSI is a valuable method to disclose an intensity increase, as a sign of mineral gained; and (d) DSR images created from PSP plates had less noise than images produced from CMOS sensor
Doutorado
Radiologia Odontologica
Doutor em Radiologia Odontológica

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Holta, Camilla. « Fördelar och nackdelar med vismutskydd över bröst vid datortomografiundersökning : En litteraturstudie ». Thesis, Örebro universitet, Hälsoakademin, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-16475.

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Sammanfattning Bakgrund Stråldosen vid en datortomografiundersökning (CT-undersökning) kan vara 100 gånger större än vid en konventionell röntgenundersökning [1]. På 10 år har antalet CT-undersökningar nästan fördubblats [2], vilket också innebär att stråldosen till patienterna ökar [1]. Bröstkörtlarna är ett av de mest strålkänsliga organen och är därför viktiga att skydda [3, 4]. Material som dämpar röntgenstrålning kraftigt och som lämpar sig för strålskydd är t.ex. bly och vismut [5]. Vismutskydd är ett tungt, metalliskt grundämne som absorberar röntgenstrålning och därmed reducerar stråldosen till vävnaderna under skyddet [6, 7]. Syfte Syftet med studien är att genom en litteraturstudie undersöka vismuts strålskyddande effekt för bröstvävnad och eventuell påverkan på bildkvalitén. Metod Artikelsökningarna gjordes i databasen PubMed med sökorden Radiation protection, Reduced radiation dosage, Radiography, Bismuth, Breasts, Bismuth shielding och image quality i olika kombinationer. Totalt valdes åtta artiklar ut. Resultat Samtliga studier har kommit fram till att vismutskyddet ensamt [8, 9, 10, 11] eller tillsammans med automatisk exponeringskontroll (AEC) reducerar stråldosen till brösten [7, 8, 12, 13, 14]. Fem studier hävdar också att bildkvalitén inte påverkas nämnvärt [7, 10, 12, 13, 14] medan två av studierna visar på en brusökning [8, 9]. Slutsats Vismutskyddet har en stråldosreducerande effekt men det bidrar även till sämre bildkvalité. Studien visar att skyddet ska användas med försiktighet och om inte tekniken utvecklas så att mAs-värdet (milliAmperesekund) lokalt över brösten kan reduceras, rekommenderas användandet av AEC istället. Nyckelord: Vismut, datortomografi, bröst, bildkvalité och stråldosreducering.

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Cantell, Gillian Diane. « Measurement of image quality in nuclear medicine and radiology ». Thesis, University of Aberdeen, 1995. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU078704.

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The imaging process can be thought of as the acquisition of data and the processing and display of data. The image quality of the acquired data is assessed using objective methods. The spatial transfer characteristic was measured using the MTF, and the noise properties assessed using Wiener spectra for gamma camera and film-screen systems. An overall measure of image quality, noise equivalent quanta, can then be calculated. The image quality of the displayed data is assessed using subjective methods. Contrast detail test objects have been used for film-screen systems and forced choice experiments for nuclear medicine data. The Wiener spectrum noise measurement has been investigated as a measure of uniformity. Simulated and gamma camera flood images were produced. Observer tests were carried out to give a contrast at which the non-uniform flood images could be distinguished from the uniform flood images. Wiener spectra were produced and single number indices derived. Statistical tests were performed to determine the contrast at which the uniform and non-uniform Wiener spectra can be distinguished. Results showed that Wiener spectra measurements can be used as a measure of uniformity under certain conditions. The application of resolution and noise measurements to the evaluation of film-screen systems and radiographic techniques has been considered. The results follow the trends presented in the literature. Provided that the scanning equipment is available tests on film-screen systems are practical to perform and are an important addition to other evaluation tests. Results show the ideal observer approach of measuring the resolution, noise and hence noise equivalent quanta, is a practical method of assessing image quality in a hospital environment.

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Mello, Juliana Mariano da Rocha Bandeira de. « Qualidade de imagem radiológica : calculando sensibilidade e especificidade em mamografias digitais diagnósticas do HCPA – auditoria interna ». reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/139762.

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OBJETIVOS: Avaliar a certeza de qualidade dos resultados mamográficos em uma instituição de referência para diagnóstico e tratamento do câncer de mama na Região Sul do Brasil, considerando as recomendações da quinta edição do BIRADS (“Breast Imaging Reporting and Data System”) para propósitos de auditoria. MATERIAL E MÉTODOS: Foi realizado um estudo de coorte observacional retrospectivo e transversal com 4911 pacientes que foram submetidas a pelo menos uma mamografia durante o ano de 2013 em um hospital público regional, ligado a uma universidade pública federal na Região Sul do Brasil. Essas pacientes foram acompanhadas até 31 de dezembro de 2014, para checar as taxas de desempenho dos resultados mamográficos na instituição em estudo, incluindo verdadeirospositivos (VP), verdadeiros-negativos (VN), falso-positivos (FP), falso-negativos (FN), valores preditivos positivos (VPP), sensibilidade e especificidade com um intervalo de confiança de 95%. RESULTADOS: O estudo demonstrou alta certeza de qualidade nos resultados das mamografias digitais diagnósticas, especialmente em relação à sensibilidade (90,21%) e especificidade (98,97%). O valor preditivo positivo (VPP) geral foi estimado em 65,3%. A taxa de interpretação anormal (ou reconvocação) foi de 12,26% e a razão de verossimilhança (“likelihood ratio”) das mamografias diagnósticas obtida foi 86,68%. CONCLUSÕES: Conclui-se que os resultados de mamografias digitais diagnósticas foram apropriados e similares aos valores pospostos pelo BIRADS. Além disso, o estudo proporcionou auto-reflexão e auto-avaliação da prática radiológica no serviço, o que é essencial para o melhoramento e processo de colaboração mais efetivo entre todos os profissionais envolvidos com o diagnóstico e tratamento do câncer de mama. Esses resultados podem incentivar outras instituições a atingirem altas taxas de qualidade de desempenho nos resultados mamográficos, apesar de possíveis limitações estruturais quando comparadas a instituições de países desenvolvidos.
OBJECTIVES: To evaluate the quality assurance of the mammography results in a reference institution for breast cancer diagnosis and treatment in southern Brazil, considering the BIRADS (Breast Imaging Reporting and Data System) 5th edition recommendations for auditing purposes. MATERIAL AND METHODS: We performed a retrospective cohort observational and cross-sectional study with 4911 patients who underwent at least one mammography throughout the year of 2013 in a regional public hospital, linked to a federal public university in southern Brazil. These patients were followed until 31st December, 2014 to check the performance rates of mammography results in our institution, including true-positives (TP), true-negatives (TN), false-positives (FP), false-negatives (FN), positive predictive values (PPV), sensitivity and specificity with a confidence interval of 95%. RESULTS: The study has showed high quality assurance on digital diagnostic mammographic results, especially regarding sensitivity (90,21%) and specificity (98,97%). The overall positive predictive value (PPV) was estimated in 65,3%. The abnormal interpretation rate (recall rate) was 12,26% and the likelihood ratio of diagnostic mammograms obtained was 86,68%. CONCLUSIONS: We concluded that our digital diagnostic mammography results were appropriate and similar to values proposed by the BIRADS. Also, the study provided self-reflection and insights on our radiological practice, which is essential to the improvement and more effective collaboration process between all the professionals involved with breast cancer diagnosis and treatment. These results may incentivize other institutions to achieve high quality performance rates in mammography results, despite possible infrastructure and facilities limitations when comparing to developed countries.

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Inácio, Luís Miguel Coelho. « Sistema de informação e processamento para radiologia odontológica ». Master's thesis, Universidade de Aveiro, 2007. http://hdl.handle.net/10773/1896.

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Mestrado em Engenharia Electrónica e Telecomunicações
As técnicas imagiológicas assumem-se como os meios complementares de diagnóstico e terapêutica (MCDT) de maior relevância no cenário clínico actual. O recurso crescente a estas técnicas surge no sentido de maximizar a acuidade do diagnóstico, procurando correlacionar a informação imagiológica com outros dados clínicos, previamente identificados. A imagiologia médica compreende um vasto conjunto de técnicas de recolha de dados e de equipamentos tecnológicos, usados como complemento ao diagnóstico e tratamento de algumas patologias. A odontologia recorre cada vez com mais proeminência à radiologia projectiva, considerando-a como parte constituinte de um exame dentário. Este trabalho surge no âmbito duma iniciativa a nível europeu, visando a obtenção de dados de um arquivo de radiografias dentárias e a aplicação de técnicas de análise e processamento digital que permitam identificar e correlacionar as estruturas morfológicas dentárias com diversas patologias do foro estomatológico. No âmbito desta dissertação, abordaram-se temas inerentes à formação e visualização de radiografias dentárias, assim como da qualidade expectável para este tipo de imagens. A melhoria da qualidade da imagem em radiologia, enquanto técnica de préprocessamento, reflecte-se credibilidade qualidade dos resultados produzidos pelos métodos de segmentação, usados na identificação dos contornos dos dentes. As técnicas de pré-processamento estudadas neste trabalho podem classificar-se em dois níveis: técnicas de minimização de ruído e técnicas de manipulação do contraste. Neste universo, foram estudados quatro métodos de segmentação orientados ao contorno, os quais foram designados por: método do gradiente; método MAP (maximum aposteriori); GVF – Snakes; e método interactivo baseado em Live Wire. Estas técnicas foram testadas em radiografias dentárias, propondose como principal aplicação prática a avaliação quantitativa da periodontite, baseada na medição da perda de massa óssea alveolar. A depuração e validação dos métodos foi fundamentada pelo estudo estatístico da variabilidade inter observador registada durante a tarefa de medição da perda de massa óssea alveolar. Finalmente, e no sentido de integrar as técnicas estudadas no âmbito desta dissertação, propôs-se um protótipo de um sistema de informação e processamento para radiologia odontológica. ABSTRACT: Image analysis techniques are the most important complementar means of diagnosis and therapeutics (MCDT) in the actual clinical scenery. The growing resource to these techniques appears in order to maximize the diagnosis acuity and to establish a relation between the information of the images with other clinical data, previously identified. Medical imaging contains a large set of data acquirement techniques and of technological equipments, used as complement to the diagnosis and treatment of some pathologies. The dentistry uses the projective radiology with more prominence, considering it as an auxiliary tool of dental exam. This work appears in an European initiative with two main goals. The first is the acquirement of a large data file of dental x-ray images and the second is to construct a software tool, which contains several techniques of digital image analysis and processing that can be used to identify and correlate the morphology of dental structures with several stomatological pathologies. In this dissertation, are presented themes about the formation and visualization of dental x-ray images, as well as about the expected quality for this kind of images. In radiology, the improvement of the image quality as preprocessing technique is reflected in the reliability of the results produced by the segmentation methods and used in the teeth contours identification. The preprocessing techniques that were studied in this work can be classified in two types: techniques of noise minimization and techniques of contrast enhancement. Therefore, were studied four contour oriented segmentation methods, which were designated as: gradient method; MAP method (maximum aposteriori); GVF - Snakes; and interactive method based on Live Wire. These techniques were tested in dental x-ray images, and was proposed as main practical application, the quantitative evaluation of periodontitis, based on the alveolar bone loss measurement. The depuration and validation of the implemented methods was based on the statistical study of the inter-observer variability, observed during the measurement of the alveolar bone loss. Finally, it was proposed a prototype of an information and processing system for odontological radiology, in order to integrate the techniques that were studied in the context of this dissertation.

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Jeffery, Nathan. « Computer assisted tutoring in radiology ». Thesis, De Montfort University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391237.

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Oliveira, Aparecido Ferreira de [UNIFESP]. « Gestão na formação do residente de radiologia ». Universidade Federal de São Paulo (UNIFESP), 2012. http://repositorio.unifesp.br/handle/11600/22230.

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Made available in DSpace on 2015-12-06T23:45:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2012
O medico radiologista atua num campo que utiliza um parque tecnologico com equipamentos modernos, de alto custo e de renovacao intensa em software (programas computadorizados dedicados) e hardware (equipamentos, acessorios e insumos), provocando uma evolucao constante na forma de produzir os servicos na especialidade. Este panorama realca a importancia da Gestão na pratica cotidiana desta especialidade. Objetivo: Investigar, a partir de residentes, docentes e preceptores de radiologia, a aprendizagem sobre Gestão na residencia em radiologia da Escola Paulista de Medicina da UNIFESP, procurando subsidios para o aprimoramento da formacao do medico radiologista. Metodo: Desenvolveu-se uma pesquisa de carater exploratorio, com abordagens quantitativa e qualitativa junto ao universo de residentes, docentes e preceptores atuantes no programa de residencia do Departamento de Diagnostico por Imagem, utilizando-se um questionario no formato de Likert e posterior aprofundamento por meio de entrevistas gravadas, que foram transcritas e categorizadas a partir das suas unidades de significado, por meio de uma analise tematica. Resultados e Discussao: Os resultados apontam para a necessidade da residencia em radiologia estar mais atenta para as diferentes habilidades de Gestão do seu egresso. Residentes, docentes e preceptores concordam que o programa capacita seus residentes para gerir o proprio conhecimento u aprender a aprender, habilidade essencial para a continuidade do processo formativo apos a Residencia. A clareza de papeis e o grau de autonomia dos residentes vao aumentando durante o processo de formacao, e o preparo para participar de equipes multiprofissionais ocorre na interacao diaria entre os residentes e as equipes. No entanto, a Gestão da tecnologia, incluindo uso eficiente, compras e manutencao de equipamentos, mostrou-se pouco contemplada, assim como o aprendizado sobre o SUS
The radiology field uses modern high cost technolog ical equipment, with intense renewal of software (computer-based programs) and h ardware (equipment, accessories and supplies), causing continuous evolu tion to produce services in this specialty. It highlights the management importance on a daily basis of this area of expertise. Objective : To investigate the radiology residents, teachers and tutors’ learning about management in their residency progra m at the EscolaPaulista de Medicina , UNIFESP, seeking for grants to improve the radiol ogist ́s education. Methodology : an exploratory quantitative and qualitative study was developed with residents, faculty staff and tutors working in the residency program of the Department of Diagnostic Imaging. The Likert scale questionnai re was used and further taped interviews were then transcribed and categorized f rom their units of meaning, through the thematic analysis technique. Resultsand Discussion : The results showed that the radiology residency program needs t o be more attentive to different management skills of its egress students. Residents , faculty staff and tutors agreed that the program enables residents to manage their own knowledge - learning how to learn, an essential skill for the continuing traini ng process after residency. Definition of roles and residents ́ autonomy will increase duri ng the training process, and preparing to participate in multidisciplinary teams occurs in daily interaction between residents and the teams. However, management of tec hnology, including efficient use, purchase and equipment maintenance was rarely considered as well as the learning on the Unique Health System (SUS).
BV UNIFESP: Teses e dissertações

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Mubarak, Suhayla Walsh Laurence J. « Design, implementation and assessment of an instructional cd-rom in dental radiology / ». [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16692.pdf.

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Oram, Louise Carolyn. « Scrolling in radiology image stacks : multimodal annotations and diversifying control mobility ». Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45508.

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Advances in image acquisition technology mean that radiologists today must examine thousands of images to make a diagnosis. However, the physical interactions performed to view these images are repetitive and not specialized to the task. Additionally, automatic and/or radiologist-generated annotations may impact how radiologists scroll through image stacks as they review areas of interest. We analyzed manual aspects of this work by observing and/or interviewing 19 radiologists; stack scrolling dominated the resulting task examples. We used a simplified stack seeded with correct or incorrect annotations in our experiment on lay users. The experiment investigated the impact of four scrolling techniques: traditional scrollwheel, click+drag, sliding-touch and tilting to access rate control. We also examined the effect of visual vs. haptic annotation cues’ on scrolling dynamics, detection accuracy and subjective factors. Scrollwheel was the fastest scrolling technique overall for our lay participants. Combined visual and haptic annotation highlights increased the speed of target-finding in comparison to either modality alone. Multimodal annotations may be useful in radiology image interpretation; users are heavily visually loaded, and there is background noise in the hospital environment. From interviews with radiologists, we see that they are receptive to a mouse that they can use to map different movements to interactions with images as an alternative to the standard mouse usually provided with their workstation.

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Bicudo, Alexandre Luiz da Costa [UNESP]. « Avaliação ultra-sonográfica convencional e dopplerfluxométrica de ovário de cadelas, durante a fase folicular do ciclo estral ». Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/99370.

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Made available in DSpace on 2014-06-11T19:30:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-05Bitstream added on 2014-06-13T20:07:36Z : No. of bitstreams: 1 bicudo_alc_dr_botfmvz.pdf: 403167 bytes, checksum: 90885c2effdcd34acfe70d5474be4d99 (MD5)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Nenhuma avaliação clínica ou a receptividade à cobertura pelo macho é suficientemente rigorosa para detectar com exatidão a ocorrência e o dia das ovulações nas cadelas. Algumas cadelas podem ovular no quinto dia do ciclo estral, enquanto outras, ovulam mais tardiamnente, como no trigésimo dia. A técnica mais recente para determinar a ovulação na cadela é a exploração ovariana por ultrasonografia. Portanto, o presente trabalho tem por objetivo avaliar o grau de confiabilidade e rigor do exame ultra-sonográfico, em modo B e a possibilidade de avaliações dopplerfluxométricas de artérias intra-ovarianas para uma detecção segura da ovulação nas cadelas. Para tanto foram utilizadas 5 cadelas, SRD, adultas, com peso de até 10 Kg e em início de fase folicular do ciclo estral. Durante a fase de proestro e estro foram realizados exames ultra-sonográficos (Logic 3, GE) com transdutor de 10Mhz, seriados, com no máximo 48horas de intervalo. Foram realizados cortes sagitais e transversais para se detectar e mensurar os folículos ovarianos. A partir da detecção do colapso folicular ou da substituição da imagem circunscrita anecóica de parede regular por uma estrutura hipoecogênica de contornos irregulares foi monitorado o início de formação luteal. Na fase luteal do ciclo foram realizadas mensurações dos corpos lúteos. Foram realizadas também imagens com o doppler colorido e espectral. Para avaliação do Doppler espectral o cursor foi colocado sobre a artéria ângulo insonação ≤ 60º, procedendo-se a avaliação da velocidade máxima do pico sistólico (VPS), dos índices de resistividade (IR) e pulsatilidade (IP). Foi realizada uma análise descritiva dos resultados obtidos. Pela imagem ultra-sonográfica convencional foi possível detectar 100% dos ovários das cadelas estudadas, possibilitando acompanhar o desenvolvimento folicular, colapso e formação de corpo lúteo em 85,7% dos folículos. A presença de corpos lúteos foi identificada em 100% das cadelas. A média da velocidade máxima do pico sistólico foi de 26,41cm/s, observada desde 120horas até 24horas após a ovulação. O IR apresentou declínio no dia da ovulação ou 24horas após, e o seu valor variou de 0,44 – 0,59 neste período. O IP apresentou muitas oscilações durante o proestro e estro, apresentando declínio desde 120horas antes até 24horas após a ovulação e seu valor nesse período foi de 0,57-1,1.
No clinical evaluation or the receptivity to the male can be rigorous enough to detect precisely the occurrence and the day of the ovulations in dogs. Some dogs can ovulate on the fifth day of the estral cycle, while others, ovulate later, on the thirtieth day. The latest technique to determine the ovulation in dogs is the ovarian exploration with ultrasound. Therefore, the present work evaluates the degree of dependability and accuracy of the ultrasound examination, in B mode and the possibility of dopplerfluxometric evaluations of intra-ovarian arteries for a safe detection of the ovulation in dogs. Therefore 5 mongrel adult bitches, with weight of up to 10 kg and at the onset of follicular phase, were used. During proestrus and estrus ultrasound examinations (Logic 3, GE) with transducer of 10Mhz were carried out in series with the maximum of 48-hour intervals. Sagittal and transversal cuts were taken to detect and measure the ovarian follicules. From the detection of the folicular collapse or the substitution of the anecoiccircumscribed image of regular wall for a hipoecogenic structure of irregular outline was monitored the beginning of luteal formation. In the luteal phase of the cycle measurements of the luteum bodies were carried out. Images with the spectral doppler had been carried also through colorful and. For evaluation of the spectral Doppler the cursor was placed on the artery angle insonation = 60º, proceeding it evaluation from the maximum speed of the systolic peak (SSP), of the resistivity rate (RR) and pulsatility rate (PR). A descriptive analysis of the results was carried out. For the conventional ultrasound image it was possible to detect 100% of the ovarius of the studied dogs, making possible to follow the development of the follicule, collapse and formation of luteum body in 85.7% of the follicules. The presence of luteum bodies was identified in 100% of the dogs. The average of the maximum speed of the systolic peak was of 26.41cm/s, observed since 120 hours until 24hours after the ovulation. RR presented decline on the day of the ovulation or 24 hours, and its value varied 0.44 - 0.59 in this period. The PR presented many oscillations during proestrus and estrus, presenting decline from 120 hours before until 24horas after the ovulation and its value in this period was of 0.57-1.1.

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Cruz, Carla Weidle Marques da. « Construção de instrumento de medida do tempo de trabalho da enfermagem em Centro de Diagnóstico por Imagem ». Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/7/7140/tde-21082012-155557/.

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O objetivo deste estudo foi construir um instrumento para medir o tempo despendido pela equipe de enfermagem em intervenções realizadas nos setores de Tomografia Computadorizada, Ressonância Nuclear Magnética, Ultrassonografia, Mamografia e Radiologia Convencional em Centros de Diagnóstico por Imagem. Trata-se de estudo de abordagem quantitativa, observacional, transversal e descritivo, realizado em um CDI de um Hospital privado, localizado na cidade de São Paulo. Os dados foram coletados, de outubro a novembro de 2011, e organizados seguindo as etapas: (1) identificação das atividades de enfermagem nos cinco setores por meio de levantamento em revisão bibliográfica e observação em campo; (2) mapeamento das atividades identificadas em intervenções de enfermagem, conforme a Classificação das Intervenções de Enfermagem (NIC); (3) validação das intervenções de enfermagem em uma oficina de trabalho por meio da validação de conteúdo; (4) teste piloto do instrumento de medida da distribuição do tempo dos profissionais de enfermagem em CDI por meio da técnica de amostragem do trabalho, em intervalos de 10 minutos. Participaram da observação em campo e do teste piloto 17 profissionais de enfermagem. Foram relacionadas, por meio de revisão bibliográfica e observação direta, 126 atividades de enfermagem. Após o mapeamento cruzado, 54 intervenções de enfermagem corresponderam a 126 atividades. Como resultado da oficina de trabalho, os sete juízes participantes reduziram o número de intervenções para 32 e de atividades para 92. A intervenção Reunião Administrativa foi criada, pois não há intervenção na NIC que corresponda à atividade Participar de reuniões. As 92 atividades de enfermagem do instrumento corresponderam a 32 intervenções, 15 classes e sete domínios da NIC. As principais intervenções observadas nos cinco setores foram, em ordem de frequência: Assistência em Exames, Documentação, Gerenciamento de Caso, Acompanhamento por telefone, Cuidados na admissão e Troca de informações sobre cuidados de saúde. O instrumento mostrou-se adequado à realidade assistencial da equipe de enfermagem no CDI estudado. Com esta pesquisa, foi possível propor um instrumento de intervenções, fundamentado na NIC, para se obter a distribuição do tempo despendido pela equipe de enfermagem em cada intervenção nos setores de Tomografia, Ressonância Magnética, Ultrassonografia, Mamografia e Radiologia Convencional.
The purpose of this study was to build an instrument that could measure the time spent in nursing interventions performed in the CT, MRI, Ultrasound, Mammography and X-ray sectors of a radiology department. This was an observational, transversal and descriptive study with a quantitative approach. The survey was conducted in a private Radiology Service located in São Paulo, Brazil. The data was collected from October to November, 2011. The steps of the study were: (1) identification of nursing activities in each sector by direct observation and literature review; (2) cross-mapping with the NIC taxonomy; (3) face validation of interventions by nurses and technical specialists in radiology and in the use of NIC; (4) pilot testing of the instrument by using work sampling technique, in 10 minutes intervals. Seventeen nursing professionals participated in the observational and pilot testing steps of the study. 126 nursing activities were identified, based on literature review and direct observation. After the cross-mapping technique, 54 nursing interventions corresponded to the 126 activities. As a result of the workshop technique, the seven judges reduced the number of interventions to 32 and the activities to 92. The 92 nursing activities corresponded to 32 nursing interventions, 15 classes and 7 domains of the NIC. The most frequent interventions were: Examination Assistance, Documentation, Case Management, Telephone Follow-up, Admission Care and Health Care Information Exchange. The instrument was shown to be appropriated to the nursing staff reality in the Radiology Center where the study was conducted. As a result of this study, it seemed possible to propose an instrument capable of assessing the workload and information relevant to staffing, by measuring the distribution of time spent by nursing staff interventions in CT, MRI, Ultrasound, Mammography and X-ray sectors

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Hethener, Eric. « The design of a multimedia workstation (image/voice/data) for radiological applications ». Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/4813.

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Rawashdeh, Mohammad. « Radiologist and image characteristics that affect the accuracy of breast cancer diagnosis ». Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/12790.

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Aims Variations in the performance of mammography readers are well reported, but key lesion and reader features explaining such variations are not fully explored. This PhD study aims to: 1) measure the diagnostic accuracy of breast radiologists, 2) identify parameters linked to higher levels of performance, and 3) establish the key mammogram morphological features that impact upon the detection of breast cancer. Methods All studies received institutional ethics approval. There were two studies, Study A: a test set of mammograms was developed compromising 60 cases, 20 containing cancer, and these were shown to 129 readers. Each reader was asked to locate any malignancies and provide a confidence rating using a scale of 1-5. Details were obtained from each reader regarding experience and training and these were correlated with jackknifing free response operating characteristic (JAFROC) figure of merit. Cancers were ranked according to the “detectability rating”, that is, the number of readers who accurately detected and located the lesion divided by the total number of readers, and this was correlated with various mathematical lesion descriptors. Study B: to validate the methods used in the previous studies, another test set compromising 40 mammographic images, each containing a single lesion, were presented to nine expert breast radiologists using a high specification interactive digital drawing tablet with stylus. Each reader was asked to manually delineate the breast masses using the tablet and stylus and then classify the lesion according to the American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS) lexicon. Delineated shapes were quantified using v Matlab software. Intraclass Correlation Coefficient (ICC) was used to assess interobserver agreement for delineation, and nonparametric ICC (Kendall's W) for classification parameters. Results Higher reader performance was positively correlated with number of years reading mammograms (P≤0.01), number of mammogram readings per year (P≤0.001), and hours reading mammogram per week (P≤0.04). For readers with annual volumes of less than 1000 mammograms per year, JAFROC values was negatively related to years’ post-qualification as a radiologist (P≤0.004) and number of years reading mammograms (P≤0.002). For readers reading more than 5000 mammograms per year, JAFROC values was positively linked to years qualified as a radiologist (P≤0.01), number of mammograms readings per year (P≤0.002) and number of hours readings per week (P≤0.003). Number of mammograms readings per year was positively related with JAFROC scores for readers with an annual volume between 1000 and 5000 (P≤0.03). For image features and lesion descriptors there were correlations between “detectability rating” and lesion size (P≤0.005), breast density (P≤0.007), perimeter (P≤0.0004), eccentricity (P≤0.02), and solidity (P< 0.0001). Poor inter-observer agreement was found for BI-RADS shape (W= 0.50) and margin (W= 0.40) assessments. However, agreement for computer-based measures was excellent for compactness (ICC = 0.93) and good for lesion elongation (ICC = 0.82). Conclusions Radiologist experience and lesion morphology contributes significantly to cancer detection efficacy. Poor levels of agreement were found when readers classified lesions using BI-RADS, however, using computer metrics, good inter-observer agreement was found for lesion delineations. These studies have provided new information regarding factors that impact upon radiologists’ performance. The data provided should contribute to an improvement to the service women receive and help reduce radiology reporting variability in the future.

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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
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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Velo, Alexandre França [UNESP]. « Otimização de imagem de torax para radiografia computadorizada ». Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/87750.

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Made available in DSpace on 2014-06-11T19:23:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-10-30Bitstream added on 2014-06-13T19:28:41Z : No. of bitstreams: 1 velo_af_me_botib.pdf: 2027153 bytes, checksum: 75d4e59757a87a168a8558deb0356dce (MD5)
Os métodos que utilizam radiações ionizantes ainda são os mais empregados por serem considerados mais “baratos” e sobretudo, muito eficientes quando utilizados com controle e qualidade. Novos sistemas de aquisição, registro e armazenamento de imagens estão sendo desenvolvidos, dentre os quais podemos citar a radiologia computacional e digital. Este método de diagnóstico pode proporcionar maior qualidade da imagem, favorecendo a não repetição de exames de modo a contribuir com a redução de dose para o paciente, quando utilizado com controle e qualidade. A otimização da relação risco-benefício é considerada de grande avanço no que diz respeito à radiologia convencional, entretanto essa não é a realidade da radiologia computacional e digital, onde não dispomos de normas e protocolos estabelecidos para otimização da imagem, dose e custo para a rotina clinica de radiodiagnóstico. Esta pesquisa teve como objetivo a otimização de imagens radiográficas computacionais de tórax (na projeção Póstero Anterior - PA). A escolha por essa modalidade de exame se deve ao fato deste ser o exame convencional mais realizado na rotina clínica. Para atingir esse objetivo foram utilizados fantomas homogêneos que simulam características de absorção e espalhamento da radiação próxima à do tórax de um paciente padrão, com aproximadamente 1,73m e 75 kg. Neste estudo o Fantoma homogêneo Equivalente ao Paciente (FEP) foi utilizado na calibração do sistema de imagem computacional, de modo a obter índices de exposições (lgMs) previamente definidos para cada tensão (kVp). As técnicas calibradas foram aplicadas em um fantoma antropomórfico (RANDO). As imagens obtidas foram avaliadas, por um especialista da área de radiologia, o qual identificou a melhor imagem (imagem ótima), para cada kVp, para determinadas possíveis anomalias no pulmão...
The ionizing radiation methods are still the most commonly used for being considered cheaper and very efficient when used with control and quality. New acquisition, recording and image storage systems are being developed among which we can mention the Computed Radiography and Digital Radiography. This method of diagnosis might provide higher image quality, favoring unrepeated examinations in order to contribute to the patient dose reduction when used with control and quality. The risk-benefit rate optimization is considered a breakthrough in computed radiology, however it’s not the reality of the computed and digital image, which do not have well established norms and protocols for image, dose and expense optimization in the radiodiagnostic clinical routine. This research had as objective the optimization of computed radiographic images of the chest (anterior - posterior projection). The choice of this modality exam was due the fact that it is the most realized on clinical routine. To achieve this objective it was used an homogeneous phantom that simulates spreads and absorption characteristics of radiation next to a standard patient, with 1, 73 m and 75 Kg approximately. On this study, the Phantom Equivalent of Patient (PEP) was used to calibrate the computational image system, acquiring exposure index (lgMs) previously defined to each kVp. The calibrated techniques were applied on an Anthropomorphic Phantom (RANDO). The images were evaluated by a radiology specialist whose identified the best image (optima image) for each kVp to determine possible anomalies on lung / bones lesions using the Visual Gradual Assessment (VGA). After the optima images selection, the radiologist used the VGA relative to select the image standard, where it stood out by its “image beauty”. Based on 3D principle (Dose, Diagnostic, Dollar), respecting this order... (Complete abstract click electronic access below)

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Velo, Alexandre França. « Otimização de imagem de torax para radiografia computadorizada / ». Botucatu, 2012. http://hdl.handle.net/11449/87750.

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Orientador: Jose Ricardo de Arruda Miranda
Coorientador: Diana Rodrigues de Pina
Banca: Sério Marrone Ribeiro
Banca: Homero Schiabel
Resumo: Os métodos que utilizam radiações ionizantes ainda são os mais empregados por serem considerados mais "baratos" e sobretudo, muito eficientes quando utilizados com controle e qualidade. Novos sistemas de aquisição, registro e armazenamento de imagens estão sendo desenvolvidos, dentre os quais podemos citar a radiologia computacional e digital. Este método de diagnóstico pode proporcionar maior qualidade da imagem, favorecendo a não repetição de exames de modo a contribuir com a redução de dose para o paciente, quando utilizado com controle e qualidade. A otimização da relação risco-benefício é considerada de grande avanço no que diz respeito à radiologia convencional, entretanto essa não é a realidade da radiologia computacional e digital, onde não dispomos de normas e protocolos estabelecidos para otimização da imagem, dose e custo para a rotina clinica de radiodiagnóstico. Esta pesquisa teve como objetivo a otimização de imagens radiográficas computacionais de tórax (na projeção Póstero Anterior - PA). A escolha por essa modalidade de exame se deve ao fato deste ser o exame convencional mais realizado na rotina clínica. Para atingir esse objetivo foram utilizados fantomas homogêneos que simulam características de absorção e espalhamento da radiação próxima à do tórax de um paciente padrão, com aproximadamente 1,73m e 75 kg. Neste estudo o Fantoma homogêneo Equivalente ao Paciente (FEP) foi utilizado na calibração do sistema de imagem computacional, de modo a obter índices de exposições (lgMs) previamente definidos para cada tensão (kVp). As técnicas calibradas foram aplicadas em um fantoma antropomórfico (RANDO). As imagens obtidas foram avaliadas, por um especialista da área de radiologia, o qual identificou a melhor imagem (imagem ótima), para cada kVp, para determinadas possíveis anomalias no pulmão... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The ionizing radiation methods are still the most commonly used for being considered cheaper and very efficient when used with control and quality. New acquisition, recording and image storage systems are being developed among which we can mention the Computed Radiography and Digital Radiography. This method of diagnosis might provide higher image quality, favoring unrepeated examinations in order to contribute to the patient dose reduction when used with control and quality. The risk-benefit rate optimization is considered a breakthrough in computed radiology, however it's not the reality of the computed and digital image, which do not have well established norms and protocols for image, dose and expense optimization in the radiodiagnostic clinical routine. This research had as objective the optimization of computed radiographic images of the chest (anterior - posterior projection). The choice of this modality exam was due the fact that it is the most realized on clinical routine. To achieve this objective it was used an homogeneous phantom that simulates spreads and absorption characteristics of radiation next to a standard patient, with 1, 73 m and 75 Kg approximately. On this study, the Phantom Equivalent of Patient (PEP) was used to calibrate the computational image system, acquiring exposure index (lgMs) previously defined to each kVp. The calibrated techniques were applied on an Anthropomorphic Phantom (RANDO). The images were evaluated by a radiology specialist whose identified the best image (optima image) for each kVp to determine possible anomalies on lung / bones lesions using the Visual Gradual Assessment (VGA). After the optima images selection, the radiologist used the VGA relative to select the image standard, where it stood out by its "image beauty". Based on 3D principle (Dose, Diagnostic, Dollar), respecting this order... (Complete abstract click electronic access below)
Mestre

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Tacher, Vania. « Optimisation du guidage tri-dimensionel en radiologie interventionnelle ». Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC0020.

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L’optimisation du guidage en radiologie interventionnelle implique de simplifier les gestes, d’améliorer la qualité d’images et leur précision tout en réduisant l’exposition aux rayons X du personnel soignants et des patients et l’usage du produit de contraste iodé, néphrotoxique. Elle implique un travail sur chacune des quatre étapes fondamentales de chaque intervention que sont : « voir », « atteindre », « intervenir » et « contrôler » le succès de l’intervention et l’absence de complication.L’étape « voir » la cible a fait l’objet de 3 études : la première, animale, portait sur l’amélioration de la qualité d’images de cone-beam computed tomography (CBCT) et la seconde, clinique, sur la précision de la segmentation des tumeurs hépatiques mise en évidence sur les images de CBCT lors de chimioembolisations (CHE). Et enfin, la troisième, clinique, sur le repérage des artères épigastriques inférieures profondes en réalité augmentée avant lambeau.L’étape « atteindre » la cible a fait l’objet de 5 études. Deux études ont validé la précision du ciblage des tumeurs hépatiques lors des CHE utilisant des logiciels de détection automatique des artères nourricières et de perfusion virtuelle du territoire tumoral à traiter sur les images de CBCT lors de CHE. Trois autres études portaient sur les cartographies 3D par la technique de fusion d’images 3D projetées sur la fluoroscopie 2D. Les deux premières premières ont montré que l’usage de la fusion d’images lors des traitements endovasculaires des anévrismes complexes de l’aorte abdominale utilisant les images d’angioscanner ou d’angioIRM préopératoires permettant de réduire voire de s’affranchir de l’usage de produit de contraste iodé dans la prise en charge de ces pathologies. Le développement de la fusion d’images notamment lors du placement de shunt porto-systémique trans-hépatique par voie trans-jugulaire a permis de faciliter ces interventions tout en limitant l’usage des rayons X dans une troisième étude.La troisième étape « interventir » a fait l’objet de trois études. Une étude, fantôme, a montré la possibilité d’obternir une imagerie sélective et quantitative des structures iodées par l’imagerie spectrale des microsphères chargées d’huile iodée. Une seconde étude préclinique animale a attesté la radioopacité de ces mêmes microsphères chargées lorsqu’elles s’accumulent dans les capillaires ou néovaisseaux et sont le reflet de la nécessité de combiner une recherche commune sur le couple imagerie/matériel. Et enfin l’étude sur la rentabilité des biospies des tumeurs guidées par l’image qui a permis de mettre fin à des dogmes.La quatrième étape « contrôler » le succès des traitements comprend deux études. La première, est une revue de la littérature et a permis de proposer une standardisation de l’usage du CBCT lors des CHE et la seconde a évalué différents facteurs prédicteurs de réponse tumorale en IRM après CHE avec un intérêt particulier porté sur l’usage de nouveaux critères d’analyse 3D (vRECIST et qEASL).Le guidage en radiologie et notamment par le CBCT est encore confronté à la limitation majeure qu’est d’utiliser des rayons X et des produits de contraste iodé mais également à un champ de vue limité et à une qualité d’images sensibles aux artéfacts. D’ou le développement d’autre moyen de guidage comme l’IRM, éléctromagnétisme, fibroptique ou encore la réalité augmentée. Ces derniers éléments font partis de projets de recherche en cours ou à venir
Optimizing image guidance in interventional radiology involves simplifying procedures, improving image quality and accuracy while reducing X-rays exposure, and the use of iodinated contrast media, which is nephrotoxic. It involves to improve each of the four fundamental steps of each intervention: "see", "reach", "intervene" and "control" the success of the intervention and the absence of complication.To "see" the target was the subject of 3 studies: the first study, was an animal study focused on improving the quality of images of cone-beam computed tomography (CBCT). The second study was a clinical study about the precision of the tumor segmentation of on CBCT images during chemoembolization (TACE). And finally, the third study was a clinical study and described the identification of the lower deep epigastric arteries in augmented reality before flap.To "reach" the target was the subject of 5 studies. Two studies investigated the accuracy of hepatic tumor targeting in TACE using automatic feeding detection and virtual tumor perfusion software on CBCT images. Three other studies were focused on 3D roadmap using the image fusion technique overlaid onto 2D fluoroscopy. The two first studies were about endovascular treatments of complex abdominal aortic aneurysms using images fusion based on angiography of computed tomography or IRM to reduce or even eliminate the use of iodinated contrast agent in the management of such disease. The development of image fusion, particularly during trans-hepatic porto-systemic shunt placement, was shown to facilitate these interventions while limiting the use of X-rays published in to a thrid study.To "intervene" step included three studies. A phantom study showed that spectral imaging displayed selective and quantitative images of iodine content of iodine-loaded microspheres. A preclinical study demonstrated their visibility on x-ray based imaging when they accumulated in capillaries or neovessels and reflected the need to combine a common search for the couple imaging / biomaterials. And finally the study on the rentability of the image guided biospies of tumors which allowed to end dogmas.To "control" the success of treatments included two studies. The first study is a review of the literature and allowed a standardization of the use of the CBCT during the TACE and the second evaluated the factors predictors of tumor response on MRI images after TACE by the use of new 3D criteria. Image guidance with the use of CBCT, is still confronted with the major limitation of the use of X-rays and iodinated contrast media, but also to a limited field of view and a sentitive images quality to artefacts. Hence the development of other image guidance types such as MRI, electromagnetism, fibroptic or augmented reality are on its way. These last elements are part of a research projects in progress or to come

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Proença, José de Aguiar. « A contribuição da implementação do controlo da qualidade da imagem radiológica digital para a melhoria contínua da qualidade num serviço de imagiologia : o estudo de caso no serviço de imagiologia do HFF ». Master's thesis, [s.n.], 2008. http://hdl.handle.net/10284/1086.

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Dissertação de Mestrado apresentada à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Qualidade.
O presente trabalho de investigação aborda a importância da implementação do controlo da qualidade da imagem radiológica digital no processo da melhoria contínua da qualidade do Serviço de Imagiologia do Hospital Fernando Fonseca. O objectivo geral deste estudo consistiu em implementar um referencial de controlo da qualidade da imagem radiológica digital no Serviço de Imagiologia do Hospital Fernando da Fonseca. Formulou-se a seguinte questão de investigação: Qual o referencial de controlo da qualidade da imagem radiológica digital no Serviço de Imagiologia do HFF e, em que medida contribui para a melhoria contínua da qualidade da imagem radiológica digital? A parte empírica desta investigação decorreu em meio natural nas instalações do Serviço de Imagiologia – Urgência do Hospital Fernando da Fonseca no período compreendido entre 15 de Janeiro e 30 de Setembro de 2008. A população foi constituída pelo conjunto de exames radiológicos digitais realizados nos períodos de 15 de Janeiro a 20 de Fevereiro de 2008, de 1 a 31 de Maio de 2008, de 7 de Junho a 7 de Julho e de 1 a 30 de Setembro do mesmo ano. A amostra foi retirada da população recorrendo a uma selecção aleatória simples. Como instrumento de colheita de dados recorreu-se à elaboração de uma folha de verificação. Os resultados foram apresentados em cartas de controlo, gráficos de barras, tabelas de Pareto e de frequências. Os resultados obtidos concluíram que a implementação do controlo da qualidade da imagem radiológica digital contribuiu para a melhoria contínua da qualidade da imagem radiológica digital obtendo-se uma redução de cerca de 39,78% do número de exames radiológicos não conformes. The present research work is about the importance of the implementation of the digital radiologic image quality control in the process of a continuous improvement of the Imagiology Service quality at Fernando Fonseca Hospital. The main purpose of this study consisted in implementing a referential of the digital radiologic image control quality in the Imagiology Service of Fernando Fonseca Hospital. The following research question was set: Which is the referential of the digital radiologic image quality control in the Imagiology Service of Fernando Fonseca Hospital and in what way did it contribute to a continuous improvement of the digital radiologic image quality? The empirical part of this research took place in the natural environment of the Imagiology Service facilities - Emergency Services of Fernando Fonseca Hospital from 15ht January to 30th September 2008. The population was formed by the whole of the digital radiologic exams held from 15th January to 20th February 2008, from 1st to 31st May 2008, from 7th June to 7th July and from 1st to 30th September of the same year. The sample was got from the population using a simple random selection. As a tool for the data collection we applied a check list. The results were presented in control charts, bar charts, Pareto tables and frequency tables. The final results concluded that the implementation of the digital radiologic image quality control contributed to a continuous improvement of the digital radiologic image and a reduction of 39.78% was obtained in the number of non compliant radiologic exams. Ce travail de recherche c’est à propos de l’importance de l’implémentation du contrôle de la qualité de l’image radiologique digital dans le procédé de l’amélioration continue de la qualité au Service d’Imagiologie de l’ Hôpital Fernando Fonseca. L’objectif général de cette étude a consisté à implémenter un référentiel de contrôle de la qualité de l’image radiologique digital au Service d’Imagiologie de l’Hôpital Fernando Fonseca. On a formulé la question suivante : Quel est le référentiel de contrôle de la qualité de l’image radiologique digital au Service de l’Imagiologie du HFF et, comme a contribué à améliorer continuellement la qualité de l’image radiologique digital ? La partie empirique de cette recherche s’est passée en ambiance naturel dans les installations au Service d’Imagiologie – Urgence de l’Hôpital Fernando Fonseca au période contenu entre le 15 janvier et le 30 septembre 2008. La population a été formé par ensemble d’examens radiologiques digitales réalisés entre le 15 janvier et le 20 février 2008, le 1 jusqu’à 31 mai 2008, le 7 juin jusqu’à 7 juillet et le 1 jusqu’à 30 septembre du même année. L'essai a été donné par la population en recourant à une sélection aléatoire simple. Comme outil de récolte de donnés on a recouru á l’élaboration d’une feuille de vérification. Les résultats ont été présentés en cartes de contrôle, de graphiques à barres, de tables de Pareto et de fréquences. Les résultats obtenus ont conclu comme l’implémentation du contrôle de la qualité de l’image radiologique digital a contribué pour une amélioration continue de la qualité de l’image radiologique digitale, en obtenant une réduction près de 39,78% du nombre d’examens radiologiques non conformes.

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Lee, SangKyu. « Image-based dose correlation studies on radiation- induced lung injury ». Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97013.

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The goal of this work is to develop an accurate and automatic tool to evaluate normal lung tissue response to radiotherapy (RT) and its correlation with local dose. Manifestation of radiation-induced lung disease (RILD)in radiography is a measurable endpoint for RT-induced normal tissue complication. Follow-up CT images from RT-received non-small-cell lung cancer patients were registered to a corresponding planning CT image. Followingimage intensity calibration, the extent of RILD was segmented based on the change in physical density during the follow-up period. Dose coverage to the RILD segmentation and healthy lung was calculated based on retrievedtreatment plans. Normal tissue response in terms of RILD volume and local dose-response showed dependency on patients and follow-up periods. Monte-Carlo dose calculation was found to be important to obtain bettercorrelation. Provided the improved accuracy in CT calibration and image registration, this tool can facilitate further normal tissue toxicity studies.
Le but de ce travail est de développer un outil automatisé de haute précision permettant d'evaluer la réponse de tissus de poumons sains à la radiothérapie (RT), ainsi que leurs corrélation avec la dose locale. Les complications de tissus de poumons sains induites par RT peuvent être mesurées à l'aide des manifestations de maladies pulmonaires induites par radiations (MPIR) en radiographie. Le suivi des images CT par des cellules de poumons cancéreuses provenant de la RT a été enregistré à leur image CT de planication correspondante. à l'aide du suivi de la calibration de l'intensité de l'image, l'etendue des MPIR a été segmentée en se basant sur le changement de densité physique durant la période de suivi. La dose reliée à la segmentation des MPIR et aux tissus de poumons sains a été calculée en se basant sur des planications de traitements établis. La réponse des tissus sains en termes de volume MPIR et la réponse de la dose locale ont démontrées une dépendance signicative par rapport aux patients et aux périodes de suivi. Le calcul de dose par simulations Monte-Carlo sest révélé être important an d'obtenir de meilleures corrélations. En tenant compte de l'amélioration de l'exactitude des calibrations CT et des enregistrements d'image, cet outil peut faciliter le déroulement des futures études de toxicité des tissus sains.

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Patefield, Steven. « The diagnostic efficacy of JPEG still image compression in three radiological imaging modalities ». Thesis, Lancaster University, 2002. http://eprints.lancs.ac.uk/12092/.

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Franck, Flávia Aparecida. « Estudo da interferência da caixa de localização na qualidade da imagem tomográfica e no cálculo da dose de radiação em tratamentos de radiocirurgia ». Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/521.

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CAPES
Tratamentos de radiocirurgia requerem elevada precisão, pois envolvem lesões de pequenas dimensões, as quais são tratadas em poucas frações de altas doses de radiação. Sendo assim, a localização precisa da região de interesse é de grande importância para o sucesso do tratamento radioterápico. Neste trabalho foi investigada a interferência da caixa localizadora do alvo em tais procedimentos, utilizando imagens tomográficas do crânio de um phantom antropomórfico para simular um tratamento de radiocirurgia utilizando duas técnicas de exposição conforme protocolo do Hospital Israelita Albert Einstein. Todo o processo de planejamento radioterápico de um tratamento de radiocirurgia foi executado, incluindo o cálculo da dose média de radiação com e sem diferenças de heterogeneidades para todas as exposições realizadas, utilizando os algoritmos de cálculo de dose AAA e PBC. Foi realizada também uma análise da variância dos valores dos pixels nos histogramas dos números CT para analisar a interferência do uso da caixa de localização na qualidade das imagens tomográficas adquiridas. Os experimentos realizados indicam que o algoritmo AAA é menos susceptível a diferenças no cálculo dos valores das doses médias. Quanto ao ruído, os experimentos realizados com a caixa localizadora do alvo demostraram maior perda na qualidade da imagem tomográfica.
Radiosurgery treatments require high precision because they involve lesions of small dimensions, which are treated with elevated radiation doses in a few fractionated sessions. Thus, the localization accuracy of the region of interest is very important for successful radiation therapy. In this study, the interference of the target localizer box in such procedures was investigated using tomographic images of the skull of an anthropomorphic phantom in order to simulate a radiosurgery treatment using two exposure techniques according to a protocol of the Albert Einstein Hospital. The radiosurgery treatment process was performed, including the calculation of the average radiation dose with and without tissue inhomogeneity considerations for all exposures, using the AAA and PBC dose calculation algorithms. An analysis of the variance of pixel values in the CT number histogram was also conducted in order to analyze the interference of the target localization box on the quality of the acquired tomographic images. The experiments indicate that the AAA algorithm is less susceptible to differences in the calculation of the average doses. Regarding noise, the experiments performed with the target localization box demonstrated greater loss in tomographic image quality.

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Lilja, Johan. « [18F]Flutemetamol PET image processing, visualization and quantification targeting clinical routine ». Doctoral thesis, Uppsala universitet, Radiologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-317688.

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Alzheimer’s disease (AD) is the leading cause of dementia and is alone responsible for 60-70% of all cases of dementia. Though sharing clinical symptoms with other types of dementia, the hallmarks of AD are the abundance of extracellular depositions of β-amyloid (Aβ) plaques, intracellular neurofibrillary tangles of hyper phosphorylated tau proteins and synaptic depletion. The onset of the physiological hallmarks may precede clinical symptoms with a decade or more, and once clinical symptoms occur it may be difficult to separate AD from other types of dementia based on clinical symptoms alone. Since the introduction of radiolabeled Aβ tracer substances for positron emission tomography (PET) imaging it is possible to image the Aβ depositions in-vivo, strengthening the confidence in the diagnosis. Because the accumulation of Aβ may occur years before the first clinical symptoms are shown and even reach a plateau, Aβ PET imaging may not be feasible for disease progress monitoring. However, a negative scan may be used to rule out AD as the underlying cause to the clinical symptoms. It may also be used as a predictor to evaluate the risk of developing AD in patients with mild cognitive impairment (MCI) as well as monitoring potential effects of anti-amyloid drugs.Though currently validated for dichotomous visual assessment only, there is evidence to suggest that quantification of Aβ PET images may reduce inter-reader variability and aid in the monitoring of treatment effects from anti-amyloid drugs.The aim of this thesis was to refine existing methods and develop new ones for processing, quantification and visualization of Aβ PET images to aid in the diagnosis and monitoring of potential treatment of AD in clinical routine. Specifically, the focus for this thesis has been to find a way to fully automatically quantify and visualize a patient’s Aβ PET image in such way that it is presented in a uniform way and show how it relates to what is considered normal. To achieve the aim of the thesis registration algorithms, providing the means to register a patient’s Aβ PET image to a common stereotactic space avoiding the bias of different uptake patterns for Aβ- and Aβ+ images, a suitable region atlas and a 3-dimensional stereotactic surface projections (3D SSP) method, capable of projecting cortical activity onto the surface of a 3D model of the brain without sampling white matter, were developed and evaluated.The material for development and testing comprised 724 individual amyloid PET brain images from six distinct cohorts, ranging from healthy volunteers to definite AD. The new methods could be implemented in a fully automated workflow and were found to be highly accurate, when tested by comparisons to Standards of Truth, such as defining regional uptake from PET images co-registered to magnetic resonance images, post-mortem histopathology and the visual consensus diagnosis of imaging experts.

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Bercier, Yanic. « Image fusion for radiosurgery treatments of arteriovenous malformations ». Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82830.

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An interactive 3D target localisation and delineation tool has been developed for radiosurgery planning of arteriovenous malformations (AVMs). With this system, magnetic resonance (MR), MR angiography (MRA) and computed tomography (CT) volumes can be fused in stereotactic space. Stereotactic angiography (SA) images can be linked to the MRA volume by recovering the SA acquisition geometry. The MRA and SA images can be correlated (1) by ray-tracing through the MRA volume with the recovered SA acquisition geometry and overlaying the images onto the SA images and (2) by localising the AVM onto a volume rendered representation of the MRA with a 3D cursor and projecting its position onto the SA images. Target contours can then be drawn on the MRA/MR/CT images and simultaneously projected onto the SA images.
The plans of patients who had previously undergone radiosurgery at our institution employing SA images for localisation and MR images for delineation were investigated. MRA datasets were also acquired at the time of MR scanning employing the 3D TOF technique. Some ray-traced MRA images correlated well visually with the SA images, others presented inconsistencies which suggest that MRA should be used only as complement to SA images.
The role of the different modalities (M-RA, MR and SA) in the definition of target volumes is investigated by defining the target contours with different combinations of modalities within the interactive system. The target volumes drawn with different modalities were compared to a reference volume, drawn using MRA, MR and SA images, and presented underestimation and overestimation of target volumes ranging from 20% to 92% and from 3% to 40%.
The dosimetric implications of image fusion for target delineation are investigated by retrospective evaluation of the dose coverage of the reference target volume by the original treatment plan. Target coverage inferior to 60% of the reference target volumes by the original treatment plans was obtained for the patients. Treatment plan optimisation was performed to evaluate the possible dosimetric improvements resulting from image fusion for AVM target delineation. The plans were improved by employing three, eight and four isocentres for the 3 patients, and resulted in target coverage equal or superior to 98% for all three patients.

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Santos, Milton Rodrigues dos. « A gestão da informação imagiológica na formação em radiologia ». Master's thesis, Universidade de Aveiro, 2007. http://hdl.handle.net/10773/4589.

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Mestrado em Gestão da Informação
A evolução tecnológica vivida nas últimas décadas revolucionou o ambiente formativo e os recursos utilizados nos processos de ensino e aprendizagem. A utilização das Tecnologias de Informação e Comunicação para a disseminação de informação em ambiente educativo promoveu o surgimento de metodologias de ensino fortemente dependentes da tecnologia disponível. Esta evolução tecnológica repercutiu-se também na formação dos profissionais de imagiologia médica, nomeadamente dos técnicos de radiologia. A existência de sítios web com material formativo, a par com o crescente desenvolvimento da formação baseado em e-learning, tornaram o acesso a estes recursos de informação uma mais valia no processo educativo. Mas, a utilização de grande parte destes recursos implica que o utilizador conheça os conceitos adjacentes ao domínio do problema. Por outro lado, o utilizador tem, geralmente, dificuldade em obter uma perspectiva integrada. No âmbito no trabalho aqui apresentado, é proposto um modelo de informação genérico designado como Caso de Estudo (CE), o qual se pretende que seja a base para o desenvolvimento de sistemas de informação de suporte ao ensino da radiologia. O CE constitui o repositório de dados para o que foi definido um modelo de informação genérico que permite a utilização de narrativas de estudos de caso de forma integrada com outros conteúdos de apoio à formação em ambiente digital. O modelo de informação genérico é baseado nos conceitos entrada, colecção e item, os quais são estruturados segundo arquétipos. Estes conceitos foram validados a partir da informação que faz parte da narrativa de um estudo de caso em radiologia convencional.
The technological evolution lived in the last few decades have revolutionized the teaching/learning process and the used resources. The use of information and communication technologies for the information dissemination in learning scenarios has promoted the birth of new methodologies of teaching, strongly dependent of the available technology. This technological evolution had also effects in the formation of radiology professionals, such as x-ray technologists. The existence of sites with radiology formative material, along with the increasing development of the e-learning, makes the access to these new information resources, of a great importance for the teaching/learning process. However, the use of great part of these new resources is dependent of the user knowledge of the problem domain, and, on the other hand, these resources do not give an integrated perspective of the learning materials. This work pretends to propose a generic information model named Caso de Estudo (CE) that may be used on the construction of new information systems that will support radiology teaching and learning activities. The CE is a data repository and for that it was developed a generic information structure witch provides the utilization of a study case narrative integrated with other digital resources. The generic information structure is based on the concepts entry, collection, and item, which are organised by archetypes. These concepts were validated with the information of a conventional radiography case study narrative.

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Nordquist, Andrew L. « Image-based tissue growth modeling and prediction ». Thesis, The University of Texas at San Antonio, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1550349.

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The goal of this research is to study tissue growth via developing mathematical formulations and computational modeling. Tissue growth modeling has many applications --- including tumor growth, wound healing, bone remodeling, epithelial tissue remodeling, and other problems in developmental biology. Key to this study is incorporating the results of the analysis of non-destructive medical images that augment the models. Quantitative image analysis for the purpose of providing input parameters for and validation of tumor growth models (TGMs) is discussed. Two types of computational TGMs are studied in detail: one is based on the logistic equation, the other is based on the theory of porous media, or mixture theory. For the mixture-based model, we developed an algorithm that couples a level set method to track tumor boundaries while the tissues themselves are treated as a perfused mixture. After the mathematical foundation of each of the TGMs is formulated, we discuss implementation aspects, along with computational results. Finally, we validate the computational results with experimental observations of tumor volume versus time via imaging data acquired from animal models. The RMS deviation between predicted and observed values is as close as 11\% of the time-averaged volume.

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Hafiz, Nirupama. « Comparison of the quality of images of pelvic soft tissues when a standard and two different dose minimisation protocols are used in helical CT scanning of the pelvis of children / ». [St. Lucia, Qld.], 2000. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16246.pdf.

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Thèses sur le sujet « Radiologic image »

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