title: Portable gamma probe for radioimmune localization of experimental colon tumor xenografts.
abstract: Tumor radioimmune detection as presently practiced utilizes a gamma scintillation camera to image tumors. A major clinical limitation is the inability to detect tumors smaller than 2 cm. This limitation is due in part to the inverse square law which states: the number of detected radioactive counts is inversely proportional to the square of the distance separating a radioactive source from the detecting device. A hand-held gamma-detecting probe (GDP) suitable for intraoperative use has been developed. The GDP can be placed near radioactive tumors and take advantage of the inverse square law in a way not possible with external scanning cameras. The use of radiolabeled baboon carcinoembryonic antigen (CEA)-specific antisera produced increased tumor isotope localization in CEA-producing tumors compared to the injection of nonspecific antisera. Tumor isotope-antisera localization was not influenced by tumor volume or time since tumor implantation. The GDP probe counts demonstrated a high degree of correlation with gamma well tissue counts. The probe was able to detect preferential tumor localization in doses lower than could be detected with external scintillation cameras.
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000276:immunology; D000818:Animals; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging* / Q000276:immunology; D005260:Female; D006801:Humans; D007106:Immune Sera; D007457:Iodine Radioisotopes; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010215:Papio / Q000276:immunology; D011877:Radionuclide Imaging / Q000295:instrumentation*
chemical_list: D002272:Carcinoembryonic Antigen; D007106:Immune Sera; D007457:Iodine Radioisotopes