Radioimmunodetection of Gastrointestinal Neoplasms with Antibodies to Carcinoembryonic Antigen

Primary and secondary gastrointestinal tumors have been identified using sheep immunoglobulin G antibody to carcinoembryonic antigen radiolabeled with 131I. 99mTc-pertechnetate and 99mTc-human serum albumin were used to identify tissue spaces and blood pool and to facilitate external subtraction imaging. In 13 patients with tumors, 4 of 5 primary sites and 8 of 11 secondary sites were successfully demonstrated. Two patients with benign disease had negative scans. Comparison with conventional methods of scanning showed good correlation.