Clinical comparison of technetium-99m-N,N-bis(mercaptoacetyl)-2,3-diaminopropanoate with technetium-99m DTPA for renal imaging

We studied 14 patients having serum creatinines of 1.0 to 12.8 mg/dl with either Tc-99m-N,N'-bis(mercaptoacetyl)-2,3-diaminopropanoate (CO2-DADS) or Tc-99m DTPA, and within 48 hours with the other agent. Analog and digital images of the kidneys and bladder were acquired for 30 minutes after injection and after voiding. The kidney-to-background ratio at 3 minutes for Tc-99m CO2-DADS was 2.01 +/- 0.79 (mean +/- SD) times that for Tc-99m DTPA (P less than 0.001). The parenchymal transit time for Tc-99m CO2-DADS was 1.34 +/- 0.25 (mean +/- SD) times that for Tc-99m DTPA (P less than 0.005). The percent-excreted dose at 30 minutes for Tc-99m CO2-DADS was 2.57 +/- 1.24 (mean +/- SD) times that for Tc-99m DTPA (P less than 0.001). Analog Tc-99m CO2-DADS images showed spatial resolution comparable to that for Tc-99m DTPA. Hepatobiliary excretion was never seen. Tc-99m CO2-DADS appears to be generally superior to Tc-99m DTPA as a renal radiopharmaceutical.