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Localization of /sup 131/Ilabeled goat and primate anti-carcinoembryonic antigen(CEA) antibodies in patients with cancer

Journal Article · · Invest. Radiol.; (United States)
OSTI ID:6766100
Thirty patients with anti-carcinoembryonic antigen (CEA)-producing cancers of the colon, breast, or thyroid were intected with 1 to 2 mCi of Iodine-131 (/sup 131/I)-labeled, affinity-purified, goat or baboon anti-CEA antibodies. Images were obtained daily for four days. Computerized background subtraction using technetium 99m (/sup 99/mTC)-labeled compounds was used. Images obtained with and without background subtraction were correlated with other evidence of disease. Activity levels in plasma, urine, and thyroid gland were monitored. Significant deiodination of antibody occurred within the first 24 hours. The mean plasma half-disappearance-time of baboon antibody was significantly longer than the mean half-disappearance-time of goat antibody. With exogenous blockade, total thyroid uptake was less than 0.1% of the injected dose. Without background subtraction, scintigraphic localization of known tumor was possible in one of two patients with colon carcinoma, in three of 20 patients with breast cancer, and in one of five patients with medullary carcinoma of the thyroid. With background subtraction, potential false-positive results could be generated for every patients, depending on the normalization site chosen and the degree of subtraction used. In contrast to results of previous reports, CEA-producing tumor was found to be infrequently localized using highly purified goat or primate radiolabeled anti-CEA. Furthermore, the subtraction technique described by previous investigators may lead to a high false-positive rate.
Research Organization:
Departments of Surgery and Radiology, Duke University Medical Center, Durham, North Carolina
OSTI ID:
6766100
Journal Information:
Invest. Radiol.; (United States), Journal Name: Invest. Radiol.; (United States) Vol. 17:4; ISSN INVRA
Country of Publication:
United States
Language:
English