Recent advances in 99mTc radio pharmaceuticals

Tc-99m radiopharmaceuticals play an important role in widespread applications of nuclear medicine, When Tc-99m radiopharmaceuticals first came into use, major efforts were directed toward the development of Tc-99m radiopharmaceuticals for bone imaging and for the excretory functions of the liver and kidneys. In the past 20 years, a significant advance has been made in technetium chemistry, which provided 99mTc radiopharmaceuticals for assessment of regional cerebral and myocardial blood flow. Recent efforts have been directed toward the design of Tc-99m-labeled compounds for estimating receptor or transporter functions. A number of bifunctional chelating agents that provide Tc-99m labeled proteins and peptides of high in vivo stability with high radiochemical yields have also been developed. More recently, organometallic technetium and rhenium compounds have been introduced as another class of 99mTc radiopharmaceutical design. In this manuscript, recent progress in Tc-99m radiopharmaceuticals is reviewed with the major emphasis laid on key innovations in this field to provide the 99mTc radiopharmaceuticals available today.