In 1941, Washington University in St. Louis received the first cyclotron installed at a U.S. academic medical center. Built on the university campus in 1940, it was used for medical research until it was commandeered by the government in 1942 for the Manhattan Project. 

The first isolated plutonium in the world, which would barely fit on the head of a pin, was accomplished with this cyclotron. In the summer of 1943, Frank O. Bubb, head of applied mathematics, took charge of the cyclotron as it once again fell under University auspices.

Another cyclotron was built in 1964, when Mallinckrodt Institute researchers designed and installed it at the Washington University Medical Center. It was the first cyclotron to be located in a U.S. medical facility.