USEFULNESS OF TC-99M N,N'-ETHYLENE-1-DICYSTEINE COMPLEX FOR DYNAMIC KIDNEY INVESTIGATIONS

To assess the usefulness of the Tc-99m-ethylene-1-dicysteine (Tc-99m-EC) complex for examination of kidney function, dynamic kidney scintigraphy with Tc-99m--EC and clearance determinations were performed. During renoscintigraphy the kidney images were of superb quality, with overlying organs (liver, spleen) not visualized. Renograms showed typical shapes, their T(max) and T1/2 values being unsignificantly different from the values obtained with other radiopharmaceuticals used in renoscintigraphy (mercaptoacetyl triglycine, hippuran). Very strict correlations were found between values of Tc-99m-EC and I-131-iodohippurate (OIH) clearances (r=0.91) and excretion rate constants (r=0.92) for both radiopharmaceuticals. The correlation enabled the formulation of an equation by which effective renal plasma flow (ERPF) could be established from Tc-99m-EC clearance: ERPF(OIH) = 1.245 X CI(EC) + 51.52. On the basis of this equation a lower boundary of the normal Tc-99m-EC clearance was established; it amounts to 300 ml min-1 1.73 m-2.