Dr. Lewellen obtained his doctorate in Experimental Nuclear Physics from the University of Washington in Seattle , Washington . He currently holds the position of Director, Physics and Instrumentation Development as well as Professor of Radiology at the University of Washington and is also an Adjunct Professor of Electrical Engineering and Bioengineering. Dr. Lewellen is considered the leading researcher in the field of high resolution PET system development. He is conducting advanced research in the area of position-sensitive PET scanners. Moreover, Dr. Lewellen has been and is a principal investigator for many NIH grants in the areas of PET and SPECT development, simulations of imaging systems, and improvement of image quality. Dr. Lewellen’s group at the University of Washington has also conducted contract research for several major corporations, including General Electric Medical Systems.

Additionally, Dr. Lewellen has undertaken consulting tasks for many commercial firms, including most of the major medical imaging companies. Dr. Lewellen has received various honours from the National Honors Physics Society, NASA, and the National Mathematical Honors Society among others. In 2005 he chaired the Nuclear Science Symposium (NSS) and Medical Imaging Conference (MIC) held in Puerto Rico.