DUBLIN, OHIO--(BUSINESS WIRE)--Navidea Biopharmaceuticals, Inc. (NYSE MKT: NAVB), a biopharmaceutical company focused on precision diagnostic radiopharmaceuticals, today announced that enrollment has commenced at two sites participating in its Phase 2, open-label, safety and efficacy PET imaging study of [18F]NAV4694 for detection of cerebral ß-amyloid plaque in subjects diagnosed with probable Alzheimer’s disease (AD). The study is designed to compare images from subjects with probable AD with similarly aged and young healthy volunteers (HV). Two trial sites are currently enrolling subjects: Molecular NeuroImaging, LLC in New Haven, CT, which dosed the first patient in the study; and the Alzheimer’s Disease Center at Quincy Medical Center in Quincy, MA.