Cancer diagnostic imaging and theranostics by using radionuclide-encapsulated liposomes

Abstract

In cancer diagnosis and therapy, radionuclide imaging and radionuclide therapy by using their radiation energy are informative and promising. Large tumor accumulation is needed for their success. Liposomes, one of the nanoparticles of drug delivery system, have a potential to deliver drugs to the tumor via the enhanced permeability and retention (EPR) effect. We have been studying application of radionuclide-encapsulated liposomes for tumor imaging and therapy. It is also attractive as "theranostic" agent, because both radionuclides for imaging and therapy can be encapsulated in the same liposomes. However, conventional radionuclide-encapsulated liposomes also accumulate in the normal tissues, such as the liver and spleen, hindering their clinical application. I herein present a new strategy focusing on the radionuclide-ligand complexes inside the liposomes that is able to escape from the liver after the accumulation and be rapidly excreted into urine.