Michael Phelps is the scientist most often identified as the inventor of PET, a technique that permits the imaging of biological processes in the organ systems of living individuals. Phelps has advanced biomedical imaging by producing four generations of PET scanners, including the prototypes on which all of today's commercial PET scanning systems are based. Michael Phelps is the scientist most often identified as the inventor of PET, a technique that permits the imaging of biological processes in the organ systems of living individuals. Phelps has advanced biomedical imaging by producing four generations of PET scanners, including the prototypes on which all of today's commercial PET scanning systems are based. Michael E. Phelps was born in Cleveland, Ohio, in 1939. He earned his B.S. in Chemistry and Mathematics from Western Washington State University in 1965, and his Ph.D. in Chemistry from Washington University, St. Louis, in 1970. He began his faculty career at Washington University School of Medicine, 1970-1975. From 1975-1976, Phelps was a member of the faculty at the University of Pennsylvania, Philadelphia. In 1976, he moved to the University of California School of Medicine, where he has held the following positions: Professor of Radiological Sciences, 1976-1992; Professor of Biomathematics, 1980-present; Chief, Division of Biophysics, 1981-1984; Jennifer Jones Simon Professor, 1983-1996; Norton Simon Professor, 1996-present; Chief, Division of Nuclear Medicine, 1984-1992; Associate Director, UCLA/DOE Laboratory of Structural Biology & Molecular Medicine, and Chief, Division of Nuclear Medicine, 1984-present; Director, Crump Institute for Biological Imaging, 1989-present; and Chairman, Department of Molecular & Medical Pharmacology, 1992-present; and Chief, Division of Nuclear Medicine, Department of Molecular & Medical Pharmacology, 1992-present.