Experimental study of internal radiation with yttrium-90 microspheres in the treatment of mouse transplanted hepatoma

The effect of yttrium-90 microspheres in the treatment of mouse transplanted hepatoma H22 was studied. Seventy BALB/C mice with hepatoma H22 were randomly divided into 7 groups (A, B, C, D, E, F, G) and treated respectively with 37, 18.5, 14.8, 11.1, 7.4, 3.7 and 0 MBq/cm3 internal radiation by intratumoral injection of Y-90 microspheres. Dose-dependent therapeutic effects were observed. In group A and B, the tumor growth was markedly retarded and eventually un-palpable. Histological examinations showed complete necrosis of the tumor. In groups C,D, E,F, the tumor growth was also inhibited. However, patchy necrosis could be seen amid apparently normal tumor cells. Only isolated, spotty foci of necrosis were present in the untreated control tumors. The results indicate that a tumor of 1 cm diameter can be effectively treated by internal radiation with 18.5MBq Y-90 microspheres injected into the tumor.