Autoradiography of lymph nodes with 99mTc-dextran in rabbits.

99mTc-dextran (D) was further evaluated in the present study as a lymphoscintigraphic agent compared to radiocolloids. It was injected intra-dermally into the web space between the second and third toes in both hind feet of two rabbits. 99mTc-nanocolloid (NC) was injected subcutaneously in both hind feet of two other rabbits. Popliteal lymph nodes were taken out and frozen in liquid nitrogen after the animals were sacrificed at 2 h post-injection. Three frozen sections in 10 microns thickness were prepared from each node for autoradiographic studies. The lymph node slices were exposed for 18 h using Ilford G 5 emulsion. The obtained autoradiographs showed that the distribution of 99mTc-D radioactivity within lymph nodes was more uniform indicating better tissue penetration compared to 99mTc-NC which remained mostly in the lymph canaliculi.