Optimalizace scintigrafického zobrazení štítné žlázy – fantomová měření a klinické aplikace

Abstract

The aim of the thesis was to find the conditions in which the lesions in the scintigraphic image of the thyroid gland can be best recognized. First, the physical assumptions for the gamakamer and the conditions in which the camera works are described. The impact of individual parts of the gamakamer on the resulting image was examined and the appropriate acquisition parameters of the image were found. The possibilities of software image processing were also shown. In the practical part the distribution and the magnitude of radioactivity of the thyroid gland filled with radiopharmaceutical by technetium were measured. There were two gamakamers, one of which was equipped with a parallel collimator LEAP and a second pinhole collimator. For various distances of both collimators from the phantom, images were obtained, which were subsequently assessed for lesion recognizability. Described is the subjective lesion perception of images and the lesion recognizability by Rose's criterion according to the CNR (contrast to noise ratio) parameter. The result of this work was the finding that pinhole collimator is the most suitable for thyreological diagnostics. The best detectability of lesions in the image was achieved when Pinhole's collimator's forehead was closest to the phantom. The latest finding was that by selecting a low pass filter, lesion recognizability in clinical images can be improved slightly.