Abstract

This study assessed the use of 99mTc-liposome agents for nuclear medicine purposes. Methods: A variety of 99mTc-liposome formulations were compared with common lymphoscintigraphic agents, including 99mTc-labeled regular sulfur colloid and 99mTc-labeled human serum albumin, besides assisting the use of positively charged liposomes in rabbits. Ten male rabbits (2-2.5 kg) were anesthetized with ketamine and xylazine intramuscularly. Then, they were injected with different 99mTc-liposome agents subcutaneously in the dorsum of each hind foot over the region of the metatarsals at the midline, as well as intravenously. Dynamic (1 min) scintigraphic γ-camera images were acquired in a 256 × 1,024 matrix both early and 60 min after injection. Afterward, the tissue biodistribution was determined by calculating the percentage injected dose per organ for each 99mTc agent and studying the heart-to-liver, heart-to-bone marrow, and heart-to-kidney ratios. Results: All agents demonstrated good migration from the injection site to the blood pool but not to lymphatic drainage. Agents were starting to clear out rapidly after 60 min. Conclusion: 99mTc-liposome imaging can be used to develop novel liposome compositions with improved cardiac diagnostic and drug delivery characteristics.

Keywords: human serum albumin; liposomes; nanocolloid; nanotechnology; nuclear medicine; tracer.