EVALUATION OF TC-99(M)-HIG AS A LYMPHOSCINTIGRAPHIC AGENT IN RABBITS

In this pilot study, Tc-99(m)-labelled human immunoglobulin G (Tc-99(m )-HIG) was evaluated as a lymphoscintigraphic agent in five rabbits. I t was injected intradermally into the web space of the hind legs of th e rabbits (37 MBq/0.1 ml). Sequential scintigrams were obtained using a gamma camera for 120 min. The injection site and the hind legs were massaged post-injection. Blood samples were obtained at 5, 15, 30, 60, 90 and 120 min. Two of the rabbits were killed after 2 h. Their organ s were weighed and tissue specimens were obtained, weighed and counted against a standard using a gamma counter. The lymph channels and the lymph nodes were well visualized on the scintigrams. The background ac tivity was very low making interpretation easier. About 30% of the inj ected dose migrated from the injection site by 2 h. The mean popliteal lymph node uptake was 5.71 +/- 4.62% per gram of tissue. The lymph no de to other tissue concentration ratios were very high, ranging from 6 3:1 for the kidneys to 1099:1 for the heart. We conclude that Tc-99(m) -HIG is a promising new agent for the visualization of the lymphatic s ystem due to its easy labelling procedure, the stability of the label, its widespread availability and good image quality. It may potentiall y be useful in detecting and evaluating inflammatory lymph nodes. ((C) 1998 Lippincott-Raven Publishers).