Biodistribution and scintigraphic studies of 153Sm-labeled anti-CEA monoclonal antibody for radioimmunoscintigraphy and radioimmunotherapy.

The anti-CEA monoclonal antibody, which selectively localizes in colon cancer, was labeled with Samarium-153 (153Sm). 153Sm is mainly a beta-emitter which can be used for therapeutic purposes, while its gamma-ray facilitates imaging studies. Labeling was achieved using the bicyclic anhydride of DTPA as chelator for Sm-153 tagging onto the antibody.