Therapeutic potential oflymph metastasis after 32P-chromicphosphate-poly L-lactic acid seeds implanted intohepatoma H22 xenograft model

：Objective To compare thetherapeutic potential of 32P-chromicphosphate-poly L-lactic acid (32P-CP-PLLA) seeds onregional lymph nodes in the KM mice model of hepatoma H22 lymph metastasis afterintratumoral implantation. Methods Ascitic hepatoma cells (H22) were injected into rightfat pad to establish lymph metastasis model in KM mice. Fifty-five KM mouse models wererandomly divided into different groups (n=5 each) through 32P-CP-PLLA implantion orcolloid 32 P-chromicphosphate ( 32P-CP) intravenous injection. Different doses at 18. 5,37. 0 or 74. 0 MBq per mouse were used immediately after establishing the tumor models.Different injection time points of 3, 7, 10 or 13 days were used as well at the dose of 37MBq per mouse. Dynamic imaging was performed by γ camera. Thereafter, all of KM mice were sacririced to separate popliteal lymphnode (PLN) and inguinal lymph nodes (ILN). The dose- and time-effect relation was observedby lymph node weight, light microscopy and electron microscopy. Results γ camera imaging demonstrated thatthe implantation points in 32P-CP-PLLA group had a limited and lasting radioactive uptakewhile the quality was the contrary, better than that in 32P-CP group. At the same dose thecolloidal group had a higher radioactivity than the seed group. At the same dose, the PLNquality of seed group and colloidal group was not significantly different ( P > 0. 05 ); The ILN quality of colloidal group is less than seed group (P < 0.05 ). Seedsimplanted at different times, PLN quality is significantly different ( F=31. 268 ,P <0.01 ). Conclusion 32P-CP-PLLA seeds implanted into tumor targeting position is better than32P-CP. There is a therapeutic effect to the lymph node metastasis as well as thetreatment of tumor. Key words: 32P-chromicphosphate-poly L-lacticacid; Carcinoma,hepatocelluar; Lymph metastasis