Evaluation of [99mTc] liposomes as lymphoscintigraphic agents: comparison with [99mTc] sulfur colloid and [99mTc] human serum albumin

This study investigates the use of [99mTc] liposomes for the detection of sentinel lymph nodes. A variety of [99mTc] liposome formulations were compared with common lymphoscintigraphic agents including [99mTc] regular-sulfur colloid (SC), [99mTc] 0.22 μ-filtered-SC, [99mTc] reduced heating time 0.22 μ-filtered-SC, and [99mTc] human serum albumin (HSA) in rabbits. Images were acquired for the first 60 minutes and at 24 hours, followed by tissue biodistribution study. All agents except [99mTc] regular SC demonstrated good migration from the injection site. Agents were retained in the popliteal node at 24 hours to varying degrees as follows: both [99mTc] filtered SC preparations > [99mTc] regular SC > [99mTc] liposomes > [99mTc] HSA. [99mTc] liposome imaging can be used to develop novel liposome compositions with improved lymph node diagnostic and drug delivery characteristics.