is a tenured Professor of Radiology, Medical Physics, Biomedical Engineering, Physics, and Electrical and Computer Engineering at Duke University, where he also serves as the director of Carl E. Ravin Advanced Imaging Laboratories and the founding director of the Clinical Imaging Physics Group. His expertise includes x-ray imaging, theoretical imaging models, simulation methods, and experimental techniques in medical image formation, analysis, assessment, display and perception. His current research includes methods to develop image quality and dose metrics that are clinically relevant and that can be used to design and utilize advanced imaging techniques towards optimum interpretive, quantitative and molecular performance. The main modalities of interest are computed tomography and tomosynthesis for breast, lung and abdominal imaging applications. He has been the recipient of 24 extramural grants, and has over 140 referred papers. He is certified by the American Board of Radiology, is a fellow of the American Association of Physicists in Medicine (AAPM), and is a fellow of the International Society of Optical Engineering (SPIE).

He was the founding Director of the Graduate Studies of the Duke Medical Physics Graduate Program. He has held leadership positions in the AAPM, the SPIE, and the Society of Directors of Academic Medical Physics Programs, and was appointed to the NCRP and serves on Program Area Committee 4.