In 1972, positron emission tomography (PET) imaging was invented by researchers at Washington University – St. Louis including Michel Ter-Pogossian, Michael Phelps, and Edward Hoffman.

Later that same year, neuroradiology and Ben Mayes come together to create the Mallinckrodt Institute of Radiology’s (MIR) first fellowship.

In 1984, MIR researchers develop fluoroestradiol (FES), the first radioactive form of estrogen used as a PET imaging agent for detecting breast cancer.