Cadmium telluride detectors in the external measurement of glomerular filtration rate using 99mTc-DTPA (Sn): comparison with 51Cr-EDTA and 99mTc-DTPA (Sn) plasma sample methods.

: GFR was determined in 16 patients using an external detector to monitor disappearance of a single injected dose of 99mTc-DTPA (Sn) simultaneously with determinations of GFR using plasma sample methods for 99mTc-DTPA (Sn) and 51Cr-EDTA. Values of GFR were correlated closely between the external determinations of GFR and the plasma sample methods of 51Cr-EDTA and 99mTc-DTPA (Sn) with correlation coefficients of 0.97 and 0.99, respectively. Although the external detector method is apparently accurate, its advantages are as yet insufficient to warrant its adoption as the method of choice for determination of GFR.