Browsing by Author "Matias, Mariana"
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- Image upsampling algorithms applied on Nuclear Medicine: comparision of hqnx and nxSaI algorithms families with two interpolation algorithms - nearest neighbour and bicubic interpolationPublication . Nogueira, Fábio; Matias, Mariana; Soares, Sofia; Cunha, Lídia; Metello, Luís F.Introduction: Image resizing is a normal feature incorporated into the Nuclear Medicine digital imaging. Upsampling is done by manufacturers to adequately fit more the acquired images on the display screen and it is applied when there is a need to increase - or decrease - the total number of pixels. This paper pretends to compare the “hqnx” and the “nxSaI” magnification algorithms with two interpolation algorithms – “nearest neighbor” and “bicubic interpolation” – in the image upsampling operations. Material and Methods: Three distinct Nuclear Medicine images were enlarged 2 and 4 times with the different digital image resizing algorithms (nearest neighbor, bicubic interpolation nxSaI and hqnx). To evaluate the pixel’s changes between the different output images, 3D whole image plot profiles and surface plots were used as an addition to the visual approach in the 4x upsampled images. Results: In the 2x enlarged images the visual differences were not so noteworthy. Although, it was clearly noticed that bicubic interpolation presented the best results. In the 4x enlarged images the differences were significant, with the bicubic interpolated images presenting the best results. Hqnx resized images presented better quality than 4xSaI and nearest neighbor interpolated images, however, its intense “halo effect” affects greatly the definition and boundaries of the image contents. Conclusion: The hqnx and the nxSaI algorithms were designed for images with clear edges and so its use in Nuclear Medicine images is obviously inadequate. Bicubic interpolation seems, from the algorithms studied, the most suitable and its each day wider applications seem to show it, being assumed as a multi-image type efficient algorithm.
- Study of the Influence of Patient Hydration in Bone ScintigraphyPublication . Ferreira, Sara; Cunha, Lídia; Osório, Soraia; Matias, Mariana; Lemos, Joana; Vieira, Domingos; Soares, Sofia; Fonseca, Abigaíl; Silva, José Alexandre; Amorim, Inês; Castro, Rosa; Metello, Luís F.The bone scintigraphy is a diagnosis method noninvasive and sensitive in detecting early bone lesions, constituting about 35% of all tests performed in the Service of Nuclear Medicine, of the Hospital of Santo Antonio, in the city of Porto, where the following study took place. One of the important technical details in preparing the patient for this examination is the hydration following the administration of the radiopharmaceutical. The aim of this study focused on assessing the value of hydration on the quality of the image in a bone scintigraphy.