David Greyson - Department of Medical Imaging, St. Michael&#۰۳۹;s Hospital, University of Toronto, Ontario, Canada

The role of the nuclear medicine has changed, from the early days when it was the only alternative to x-rays, to the present, when nuclear images are interpreted in light of specific metabolic processes, not anatomy. The development of specific receptor targeting radiopharmaceuticals, markers of viability using PETor SPECT, analogues of neurotransmitters etc., have placed the nuclear medicine physician into the realm of an in vivo biochemist or pharmacologist, or an applied physiologist. The current role of nuclear imaging is not merely to detect an abnormality, but to characterize the pathophysiology, risk stratify, direct therapy, and offer prognosis. As we recognize that the information obtained from a scintigram is occurring below the cellular level, we are entering the age of "Molecular Nuclear Medicine".