SYNTHESIS OF 5-[I-123]IODONICOTINAMIDE AND BIODISTRIBUTION IN RAT

5-[I-123]iodonicotinamide (NAM) was prepared by halogen exchange iodin ation from 5-bromonicotinamide. In order to study biodistribution and brain accumulation I-123-NAM was injected into rats. Dynamic gamma cam era images were collected. The rats were sacrificed and tissue specifi c activities were measured. From dynamic images the maximum brain (hea d) activity after 30 minutes was 8.3 % of the injected dose and after 110 minutes, 4.5 %. I-123-NAM was cleared by the kidneys. Radioactivit y in the tissue samples of brain, kidney, blood, liver, spleen, lung, muscle, heart, bone and thyroid decreased over the course of 110-160 m inutes, indicating rapid washout of the tracer. In conclusion the upta ke in the brain and washout of I-123-NAM was rapid. I-123-NAM may be u seful as a brain imaging agent.