TC-99M-ENS, A NEW RADIOPHARMACEUTICAL FOR AERIAL LUNG SCINTIGRAPHY - COMPARATIVE-STUDIES IN RATS

The biological behavior of Tc-99m-Labeled exogenous natural surfactant (Tc-99m-ENS) was studied and compared to Tc-99m-diethylene-triaminepe ntaacetate (Tc-99m-DTPA) and (TCO4-)-T-99m. The Labeling yield percent ages for Tc-99m-DTPA and Tc-99m-ENS were higher than 95%. Biodistribut ion studies performed after aerosolization showed that the percentage of activity concentration in lungs for Tc-99m ENS was 98.7 +/- 1.3%, f or Tc-99m-DTPA 77.8 +/- 20.6%, and 22.4 +/- 7.5% in the case of (TcO4- )-Tc-99m. These results suggest that this new radiopharmaceutical show s an optimal lung concentration, and therefore it can be considered fo r clinical trials.