CLINICAL-EVALUATION OF TECHNETIUM-99M-L,L-ETHYLENEDICYSTEINE IN PATIENTS WITH CHRONIC-RENAL-FAILURE

Technetium-99m-L,L-ethylenedicysteine (Tc-99m-L,L-EC), a new renal rad iopharmaceutical, has been shown to have similar excretion characteris tics but a higher plasma clearance than Tc-99m-mercaptoacetyltriglycin e (Tc-99m-MAG3) in normal volunteers and patients with obstructive nep hropathy. This study evaluated Tc-99m-L,L-EC in patients with chronic renal failure. Methods: The clearance of Tc-99m-L,L,-EC was compared w ith that of I-125-hippuran in 26 patients with varying degrees of chro nic renal impairment (serum creatinine 168-1163 mu mol/liter). All 26 patients also were imaged with Tc-99m-L,L-EC (70-80 MBq). Fifteen pati ents had further imaging with Tc-99m-MAG3 (100 MBq) the following day. Results: A subjective analysis of the (TC)-T-99m-L,L-EC images reveal ed that all were of acceptable quality regardless of creatinine level. In the 15 patients who were imaged with both Tc-99m-L,L-EC and Tc-99m -MAG3, general image quality and target-to-background ratio were simil ar. Time-activity curves and mean parenchymal transit times obtained w ith the two agents were almost identical. Plasma clearance values (mea n +/- s.d.) of Tc-99m-L,L-EC and I-125-hippuran were 81 +/- 68 ml/min and 114 +/- 104 ml/min, respectively. Mean Tc-99m-L,L-EC clearance was 71% of the mean I-125-hippuran value. Conclusion: Technetium-99m-L,L- EC provides equally high-quality images to Tc-99m-MAG3 in patients wit h chronic renal failure. Technetium-99m-L,L-EC clearance more closely resembles that of hippuran than does Tc-99m-MAG3 clearance. These feat ures together with its ease of preparation make Tc-99m-L,L-EC an attra ctive alternative to Tc-99m-MAG3 in patients with chronic renal failur e.