BACKGROUND: One of the reasons for the poor prognosis of pancreatic carcinoma is the difficulty of obtaining an early diagnosis of pancreatic carcinoma. One possibility is the application of radioimmunoscintigraphy using radiolabeled monoclonal antibodies (Mabs). METHODS: We labeled chimeric (human/mouse) Fab fragments of Mab A7 (chA7Fab) with (99m)Tc and examined the distribution of (99m)Tc-labeled chA7Fab in nude mice bearing human pancreatic carcinoma. RESULTS: The tumor accumulation of (99m)Tc-labeled chA7Fab was larger than that of (99m)Tc-labeled A7 from 2 to 6 hr after injection. (99m)Tc-labeled chA7Fab disappeared from blood more rapidly than (99m)Tc-labeled A7. For all resected normal tissues except kidney, the accumulation of (99m)Tc-labeled chA7Fab was low and similar to that of (99m)Tc-labeled A7. CONCLUSIONS: Because the half-life of (99m)Tc is short (6 hr), chA7Fab, which accumulates rapidly in tumors, may be a better carrier of (99m)Tc than intact Mab A7. Copyright 2003 Wiley-Liss, Inc.
BACKGROUND: One of the reasons for the poor prognosis of pancreatic carcinoma is the difficulty of obtaining an early diagnosis of pancreatic carcinoma. One possibility is the application of radioimmunoscintigraphy using radiolabeled monoclonal antibodies (Mabs). METHODS: We labeled chimeric (human/mouse) Fab fragments of Mab A7 (chA7Fab) with (99m)Tc and examined the distribution of (99m)Tc-labeled chA7Fab in nude mice bearing humanpancreatic carcinoma. RESULTS: The tumor accumulation of (99m)Tc-labeled chA7Fab was larger than that of (99m)Tc-labeled A7 from 2 to 6 hr after injection. (99m)Tc-labeled chA7Fab disappeared from blood more rapidly than (99m)Tc-labeled A7. For all resected normal tissues except kidney, the accumulation of (99m)Tc-labeled chA7Fab was low and similar to that of (99m)Tc-labeled A7. CONCLUSIONS: Because the half-life of (99m)Tc is short (6 hr), chA7Fab, which accumulates rapidly in tumors, may be a better carrier of (99m)Tc than intact Mab A7. Copyright 2003 Wiley-Liss, Inc.