William C. Klingensmith III, M.D. attended Cornell University in Ithaca, NY and then Cornell University’s College of Medicine in New York City. He completed an internship in medicine at the University of Oregon School of Medicine in Portland, OR, a residency in radiology at the University of Colorado School of Medicine in Denver, CO, and a fellowship in nuclear medicine at the Johns Hopkins University School of Medicine in Baltimore, MD. Then he returned to the University of Colorado School of Medicine as the head of nuclear medicine for seven years. He then joined Radiology Imaging Associates, a large academically oriented private practice radiology group in Denver. After 25 years in private practice he returned to the University of Colorado School of Medicine to again head nuclear medicine.Dr. Klingensmith has had an interest in the mathematics and biology of radiopharmaceutical localization throughout his career. During his nuclear medicine fellowship he determined the information content of first circulation time-activity curves. More recently he developed the clinically oriented equation for clearance of a radiopharmaceutical from blood into tissue, and the general algorithm for determining whether a physiologic measurement needs to be normalized for body size.