The Missed Tc-99m Radiopharmaceuticals for Cardiac Imaging

Despite the success of 99mTc-sestamibi and 99mTc-tetrofosmin, the search for 99mTc heart imaging agents having a pharmacokinetic behavior much closer to that of an ideal perfusion tracer has been never interrupted. This short review illustrates advances in this field that have been made using the class of 99mTc complexes characterized by the presence of a terminal technetium-nitrogen multiple bond. This category of 99mTc compounds has proven to be particularly useful for cardiac imaging and a number of highly interesting compounds have been developed. The main chemical and biological properties of these agents are briefly summarized here.