Abstract
Optimised information can be extracted from diuretic renography studies by careful interpretation of the sequential images coupled to the parameters derived from the time activity curves TAC's. This work is mainly concerned with the quantitative aspects of radionuclide renography. The various quantitative parameters in radionuclide renography are defined after reviewing the anatomy and physiology of the renal system and the radiopharmaceuticals used and assessing the performance of the gamma camera employed. The two computer programs developed through this work to analyse renography data are described and include deconvolution analysis. The effect of several factors on the quantitation of radionuclide renography studies are investigated. The linearity and efficiency of the gamma camera iamging system, with respect to input count rate and the methods by which net syringe counts and corrected kidney counts are obtained, were studied. Emphasis was placed on the effect of these factors on the measurement of GFR using the Gates' method. The various parameters which may be obtained from radionuclide renography were evaluated in the presence of complete unilateral obstruction induced in sheep. Follow-up renography studies were performed for a variable number of weeks post obstruction as well as post release of obstruction. The excretory function of the kidney can be evaluated by renal transit times. However, their estimation is susceptible to various errors. Using the matrix inversion method, errors due to kidney function, extrarenal background and statistical noise were investigated in a simulation study. The effect of these errors on the estimation of the relative kidney function was also studied. The effect of the region of interest ROI delineation on deconvolution analysis was assessed using normal renography studies done on patients. The choice of the left ventricle or the aorta as an input ROI, liver and spleen contribution to the kidney ROIs and the delineation of the parenchymal ROIs were studied. Finally, the inter- and intra-observer reproducibiity in drawing kidney ROIs was also assessed.