1. From the Yale University School of Medicine (A.J.S.), New Haven, Conn; Johns Hopkins University Medical Institutions (F.B.), Baltimore, Md; Massachusetts General Hospital, Harvard Medical School, Center for Molecular Imaging Research (M.N.), Boston, Mass; University of Virginia Health Sciences Center (F.H.E.), Charlottesville, Va; Stanford University School of Medicine (J.C.W.), Stanford, Calif; University of Pittsburgh School of Medicine (F.S.V.), Pittsburgh, Pa; Mount Sinai School of Medicine (Z.A...