Marshal Brucer was born in 1913 in Chicago and Started his career in Nuclear Medicine. In 1948 Marshall Brucer joined the Oak Ridge Institute of Nuclear Studies. He was put to work investigating the use of radioactive materials in diagnosing and treating diseases. Grimmet Leonardo and Marshall began building the Colbalt-60 a machine designed to kill tumors with radiation. Grimmet Leonardo and Marshall continue to build the Colbalt-60. Marshall and Grimmet finish the Colbalt-60.