[Simultaneous determination of kidney glomerular and tubular partial functions with 99mTc-DTPA and 131I-hippuran using a partially shielded whole body counter].

The methodical prerequisitis and the clinical results-of simultaneous double-radionuclide determinations of renal clearances of 99mTc-DTPA (Sn) and 131I-Hippuran, using a partially shielded whole-body counter, are reported. Examination of the in vitro stability of the 99mTc-DTPA (Sn) complex by radiochromatographic separation revealed an unbound 99mTc fraction of 4.7%. The whole body measurement geometry was found over the non-shielded regions of the body to be independent of the various physiological distribution volumes of the clearance substances. The simultaneously determined clearances of 51Cr-EDTA and 99mTc-DTPA resulted in a strong linear correlation (r = 0.96; n = 20). The relation between serum creatinine concentration and 99mTc-DTPA clearance was approximately hyperbolic (r = 0.89; n = 154). In a group of normals (n = 102) the renal filtration fraction (FF - ClTc-DTPA/ClOIH) was 0.18 +/- 0.04. In a group of urological patients (n = 72) this fraction did not change appreciably before and after operations, whereas it was found increased to 0.25 and 0.24, respectively, in patients with diabetes and albuminuria or urinary tract infection (n = 37). The relative error of the clearance determination with a partially shielded whole-body counter was about 15% down to clearances of some 50 ml/min, and higher than 50% with clearances below 20 ml/min.