Development and evaluation of iodinated tracers targeting amyloid plaques for SPECT imaging.

Successful development of iodinated ligands for various neurotransmitter receptors prompted us to explore the feasability of having iodinated ligands to target amyloid plaques of Alzheimer's disease. Several potential iodinated tracers based on various chemical backbone structures have been successfully prepared and evaluated toward this purpose. High binding affinities for Abeta aggregates were consistently observed for those ligands. However, the desirable in vivo properties were generally missing in the majority of those iodinated ligands. Only ligands with the promising in vitro and in vivo characteristics such as IMPY will likely warrant their success to be potential imaging agents mapping amyloid plaques in living human brain.