131I-Cholylglycyltyrosine （CGT） was used for the study of radiolocalization and targeting therapy in nude rats bearing human hepatocellular carcinoma （HCC） （nude rat-HCC）. The nude rats were sacrificed at various intervals after intravenous injection of 131I-CGT

and radioactivity in major organs was determined. The uptake rate of 121I-CGT in tumor was remarkably higher than that of other tissues

especially on the phase of 24 hours. Tumor imaging was clearly observed 24 hours after the injection in all of the three rats. Dynamic scanning in nude rat-HCC model showed that 131I-CGT can be selectively taken up by hepatoma

and detained up to 7 days. Of the six rats treated

complete remission was observed in one rat three months later

while partial remission observed in the others.