Abstract: Objective To investigate the radioimmunoimaging of 99mTc labelled humanized single-chain Fv dimmers （BDM3） and immunonanoparticles for hepatocellular carcinoma in nude mice bearing human hepatocellular carcinoma，and to study their application in diagnosis and therapy of hepatocellular carcinoma. Methods The label rate of 99mTc-BDM3 and 99mTc-BDM3 nanoparticles was determined by isotopic analyzer. The labelled BDM3 and BDM3 nanoparticles were injected intraperitoneally into the nude mice bearing human hepatocellular carcinoma. At intervals of 1 h，4 h and 8 h，the mice in each group were imaged on a SPECT，and then were sacrificed immediately to get various organs and tumors. Radioactivity ratio of tumor to non-tumor （T/NT） was measured. Results The label rates of 99mTc-BDM3 and 99mTc-BDM3 nanoparticle were 91% and 92%，respectively；The positive display rates by the antibody and its nanoparticle were both 100%；The ratio of T/NT were （1.63±0.17） and （3.63±0.21） 1 h，（3.82±0.24） and （5.63±0.26） 4 h，（0.48±0.21） and （1.41±0.32） 8 h after injection of 99mTc-BDM3 and 99mTc-BDM3 nanoparticle，respectively. The differences between two groups were statistical significance；Favorable images were obtained after 4 h. The labelled BDM3 and BDM3 nanoparticles concentrated in carcinoma and did not in nontumor，that showed an evident targeting effect in tumor. As a result of a double targeting effect，the BDM3 nanoparticles group had more concentration in tumor，and increased the imaging effect. Conclusions The humanized single-chain Fv dimmers （BDM3） and immunonanoparticles for hepatocellular carcinoma has high affinity to nude mice bearing human hepatocellular carcinoma xenografts. They could be target carrier for diagnosis and therapy of hepatocellular carcinoma.

Key words: Hepatocellular carcinoma, 99mTc label, Immunonanoparticles, Radioimmunoimaging