Tc-99m-alafosfalin: an antibiotic peptide infection imaging agent

摘要

The radiolabeled antibiotic peptide Tc-99m-alafosfalin was assessed as an infection imaging agent in a rat model by comparison with Tc-99m-DTPA and Tc-99m-leukocytes. Tc-99m-alafosfalin was prepared via an instant cold kit and Tc-99m-leukocytes were prepared using Tc-99m-stannous fluoride colloid in an ex vivo labeling procedure of whole blood. In separate experiments, the three radiotracers were administered to rats infected with staphylococcus aureus. Quantitative biodistribution studies were performed as well as scintigraphic images and histopathology. Tc-99m-alafosfalin is a stable product, obtained in high radiochemical purity (>95%). This agent was mainly renally excreted, with low liver, spleen and bone uptake, and resulted in a mean ratio of infectedon-infected thighs of 4.3/1.0 at 4 hr post radiotracer injection. Tc-99m-DTPA gave a corresponding ratio of 1.9/1.0 and Tc-99m-leukocytes gave 20.0/1.0 at the same time point. An in vitro assay found the level of Tc-99m-alafosfalin binding to staphylococcus aureas higher than Tc-99m-DTPA (10% versus 1% respectively). Tc-99m-alafosfalin accumulates at sites of infection in a rat model better than the perfusion molecule Tc-99m-DTPA, yet less than Tc-99m-leukocytes. The distribution characteristics of this Tc-99m-antibiotic peptide would be an advantage in imaging abdominal and soft tissue infection. (C) 2003 Elsevier Science Inc. All rights reserved. [References: 32]