- Professor of Radiology, Biomedical Engineering, and Pharmacy at the University of Southern California
- Director of the USC PET Imaging Science Center since its inception in 1981
- Served as President of the Society of Nuclear Medicine and has been a major contributor to the development of clinical PET and molecular imaging
- Board Certified in both Diagnostic Radiology and Nuclear Medicine
- Received his M.D. and Ph.D. degrees from Cornell University