[Radioimmunoimaging of hepatocellular carcinoma with 131I labeled antihepatoma monoclonal antibody Fab fragment].

OBJECTIVE: To study the effects of radioimmunoimaging (R11) of hepatocellular carcinoma with 131I labeled antihepatoma monoclonal antibody (HAb18) Fab fragment. METHODS: HAb18Fab was prepared by papain digesting HAb18, and it was radioiodinated with iodine-131 using high efficiency iodination method. The experiment consisted of two parts: ten nud mice bearing human hepatocellular carcinoma xenograft were injected intravenously with 131I-HAb18Fab 3,700 kBq/mouse, and six patients with hepatocellular carcinoma were injected intravenously with 131I-HAb18Fab 111-166.5 mBq/body. RESULTS: Ten nud mice bearing hepatocellular carcinoma, showed positive image. The optimum imaging time was 4.5-12 h after injection, and was 21.07 +/- 0.05 for tumor/liver higher than 5.83 +/- 0.05 of intact HAb18, and the reported 3.03. No tumor image was found in the control group of mice. Six patients with hepatocellular carcinoma, after injecting 131I-HAb18Fab 16 h, showed positive image. The optimum imaging time was 16-24 h earlier than 96 h of the reported 131I. CONCLUSION: R11 with 131I-HAb18Fab possesses the advantages of the location, qualitative analysis and earlier diagnosis. It is prospective in clinical application.