title: Biodistribution and scintigraphic studies of 153Sm-labeled anti-CEA monoclonal antibody for radioimmunoscintigraphy and radioimmunotherapy.
abstract: 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. [153Sm]anti-CEA was biologically evaluated in nude mice bearing tumors of different weight (0.5-2.5 g), at diverse time intervals (4-72 hours), by anatomic and imaging methods. Biodistribution studies showed slow blood clearance and high retention in the liver, kidneys and lungs. In nude mice bearing tumors of about the same weight, uptake increased with time, from 4 to 72 hours post injection (p.i.). Highest uptake was observed in 0.5-0.8 g tumors compared to those of 1.5-2.5 g. The results agreed with imaging studies performed on a gamma camera at 4 to 72 hours p.i. Tumor uptake depended on time and tumor weight. The tumor can be visualized 24 hours p.i. but, due to the high background, it can be clearly distinguished at 72 hours p.i.
authors.affiliation: Institute of Radioisotopes-Radiodiagnostic Products, National Center for Scientific Research Demokritos, 153 10, Athens, Greece.
authors.forename: Melpomeni
authors.initials: M
authors.lastname: Fani
authors.forename: Stavros
authors.initials: S
authors.lastname: Xanthopoulos
authors.forename: Spyridon C
authors.initials: SC
authors.lastname: Archimandritis
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Stratis
authors.forename: Penelope
authors.initials: P
authors.lastname: Bouziotis
authors.forename: George
authors.initials: G
authors.lastname: Loudos
authors.forename: Alexandra D
authors.initials: AD
authors.lastname: Varvarigou
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics* / Q000627:therapeutic use; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D005260:Female; D018796:Immunoconjugates / Q000493:pharmacokinetics* / Q000627:therapeutic use; D051379:Mice; D008819:Mice, Nude; D016499:Radioimmunotherapy; D011868:Radioisotopes / Q000493:pharmacokinetics* / Q000627:therapeutic use; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics* / Q000627:therapeutic use; D012493:Samarium / Q000493:pharmacokinetics* / Q000627:therapeutic use; D014018:Tissue Distribution
chemical_list: D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D018796:Immunoconjugates; D011868:Radioisotopes; D019275:Radiopharmaceuticals; D012493:Samarium