Radiographic Magnification
Mostrando 1-8 de 8 artigos, teses e dissertações.
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1. Evaluation of radiographic magnification in lateral cephalograms obtained with different X-ray devices: experimental study in human dry skull
OBJETIVO: avaliar a influência do fator de magnificação da imagem radiográfica nas grandezas angulares, lineares e proporcionais. MÉTODOS: a partir de um crânio seco humano, no qual foram fixadas esferas metálicas de dimensões pré-definidas (1,0mm de diâmetro), 14 telerradiografias foram obtidas em diferentes aparelhos de três fabricantes: Panoura
Dental Press J. Orthod.. Publicado em: 2013-04
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2. Distorção de imagens em radiografias panoramicas com relação a distancia intergoniaca / Distortion of images in panoramic radiographs in relation to the intergoniac distance
A realização de medidas precisas em radiografias panorâmicas é duvidosa, devido à distorção por ampliação de imagens. Por ser um método tomográfico, somente a porção do objeto localizada na camada de imagem do aparelho estará livre de distorção. O objetivo nesse trabalho foi determinar a camada de imagem do aparelho panorâmico Orthopantomogr
Publicado em: 2009
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3. SPIRO - sistema para processamento de imagem radiografica odontologica
The radiological digital image processing has been growing during the last 10 years due to the increasing technological development of microcomputers, to the image digitizing equipment and to the new digital radiographic equipments. In order to help the dentists, especialized on radiology, in improving their diagnosys, we have developed SPIRO (System for the
Publicado em: 1997
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4. Proposta de simulação computacional para avaliação de sistemas de imagem radiológica pelo método das funções de transferência. / A computer simulation proposal for radiographic systems evaluation by the transfer functions method.
From the conventional evaluation by the radiological systems Transfer Functions, this work shows that it is necessary to obtain slit images at several field orientations so that this annalysis has a more real significance for non-isotropic systems. This is achieved from the non-linearity on the variations among the MTFs obtained in several directions between
Publicado em: 1992
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5. Accuracy and precision of joint space width measurements in standard and macroradiographs of osteoarthritic knees.
OBJECTIVES--To improve the reproducibility and accuracy of joint space width (JSW) measurement as an assessment of cartilage loss in patients with osteoarthritis (OA) of the knee by determining how precision and accuracy of JSW measurement were altered by a computerised method of measurement, correction for radiographic magnification, radiography of the knee
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6. Diagnosis of pulmonary hypertension from radiographic estimates of pulmonary arterial size.
The reported accuracy of radiographic measurements in predicting pulmonary hypertension is very variable. Measurements of right and left descending pulmonary artery diameter have been reported to provide a correct diagnosis in as many as 98% of patients. A study was carried out to determine the predictive value of measurements made from the chest radiographs
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7. Effective DQE (eDQE) and speed of digital radiographic systems: An experimental methodology
Prior studies on performance evaluation of digital radiographic systems have primarily focused on the assessment of the detector performance alone. However, the clinical performance of such systems is also substantially impacted by magnification, focal spot blur, the presence of scattered radiation, and the presence of an antiscatter grid. The purpose of thi
American Association of Physicists in Medicine.
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8. Microfocal radiographic examination of erosions in the wrist and hand of patients with rheumatoid arthritis.
The microfocal x-ray unit, a new type of x-ray machine characterised by an extremely small x-ray source, enables great detail to be recorded in the projection radiographs owing to the high object magnification and resolution obtained with this system. Microfocal radiographic examinations were carried out on the wrists and hands of 26 patients with early or m