Kwantifisering van radionukliedverspreiding deur planare beelding met 'n sintillasiekamera

English: In this study attenuation and scatter correction techniques in planar imaging were investigated as well as the practical implementation of these techniques in clinical studies. The attenuation correction technique that was investigated was the geometrical mean method where an iterative method was used to determine the attenuation coefficient. This adaptation made the attenuation correction method independent of depth. In this study the depth dependence of the geometrical mean method was solved which is an important contribution. The three-energy window scatter correction technique was investigated with Monte Carlo methods for planar imaging. These simulations showed that the scatter correction method under corrects by approximately 10%. The scatter correction technique cannot be performed on it's own but must be used in conjunction with the attenuation correction method. The overall effect of the quantitation (attenuation and scatter correction) was determined in two ways. First a known amount of activity was imaged. Then the correction was applied to the images. Subsequently the corrected activity obtained from the latter images was compared to the known value. The calculated activity was 98,6 % of the known activity value. Secondly clinical studies were performed where the bladder activity was quantitated in vivo and correlated to the in vitro measured value. In this case the correlation coefficient was 0,996. The quantitation technique was applied to the clinical determination of the glomerular filtration rate. The quantitation technique was compared to the routine method that requires handling of urine. The correlation coefficient was 0.96 and the linear regression line had a slope ofO.91 and a y-axis intercept of4.8l. The quantitation of the bladder activity leads to a simplification of the clinical study procedure since the physical handling of urine can be eliminated. The accuracy of this method depends on the conversion factor that compensates for the difference between the sensitivity of the camera and the well counter. This factor must be checked on a regular basis to ensure the accuracy of this method. The bladder as source organ was used in this study. The bladder is a relative isolated organ and therefor the influence of radioactive uptake in other organs is relatively small. If these quantitations are applied to organs that are not isolated, i.e. the heart where the liver can influence it, this problem has to be address. In this project a quantitative planar imaging technique was investigated that corrects for attenuation and scatter and thereby facilitates depth independent corrections.