Lymphoscintigraphy in regional lymph nodes on lower extremities of rabbits using ~(99m)Tc-injection of liposome of 5-fluorouracil by hypodermic injection

Objective To investigate lymphoscintigraphy and enrichment of 99mTc-FL in regional lymph nodes by SPECT to provide a basis for the regional lymph system targeted chemotherapy of malignant tumors. Methods 6 rabbits were hypodermically injected with 0.5 mCi of 99m Tc-FL in the first medial web on the dorsum of lower extremities. Lymphatic flow imaging was dynamically traced by SPECT in 30 or 60 minutes after injection. The diffusion and gathering of the radioisotope in the regional lymphatic vessels and lymph nodes were monitored by SPECT at different intervals within 8 h. The scintigraphy counting ratios(%) in injected sites or in the regional lymph system including lymph nodes in the popliteal fossa,in pelvic cavity,in the post-peritoneum and the cisterna chyli were measured respectively at 1 h,3 h and 6 h post-injection. Results The tracing of dynamic lymph flow in 30 or 60 minutes and imaging at different intervals in 8 h post-injection by SPECT showed that 99mTc-FL could slowly flow into the regional lymph system from injected sites and highly accumulated in their lymph nodes,but the radioactivity uptake ratios ofthe other organs were low. 1 h,2 h and 3 h post-injection,and the scintigraphy counting ratios of the three groups,in injected sites or the regional lymph system had statistical differences(P0.05). The scintigraphy counting ratios in injected sites were gradually decreasing,but rising in regional lymph nodes. The comparisons between the scintigraphy counting ratios in the regional lymph nodes and in the other organs (except injected sites) per group were significantly different(P0.05). The scintigraphy counting ratios in regional lymph system were sharply highly than in other organs. Conclusions 99mTc-FL can flow into regional lymphatic chains rather than directly enter blood circulation. 99m Tc-FL can be highly accumulated in the regional lymph nodes. Therefore,the regional lymph system targeted chemotherapy for malignant tumors is clinically feasible.