Positron Emission Tomography (PET) is a minimally-invasive diagnostic imaging procedure used to distinguish normal from diseased tissue in conditions such as cancer, ischemic heart disease, and some neurologic disorders. In amyloid PET imaging, a ligand that binds to a given targeted substrate (e.g., Aβ plaque aggregates) is labeled with a radioisotope (e.g., fluorine F18). The injected radiopharmaceutical (or "tracer") emits positrons when it decays. PET uses a positron camera (tomograph) to measure the decay of such tracers within human tissue. The injected radiopharmaceutical emits positrons when it decays. PET uses a positron camera (tomograph) to measure the decay of such tracers within human tissue. The relative differences in the rate of tracer decay among anatomic sites provide biochemical information on the tissue being studied. Amyloid PET imaging uses a class of radiopharmaceuticals that detect levels of amyloid in the human brain. Examples of these radiopharmaceuticals include Amyvid™ (florbetapir F18), Neuraceq™ (florbetaben F18) and Vizamyl™ (flutemetamol F18). Measurements of cerebral amyloid may be clinically useful in the work up and management of patients with cognitive impairment who are being evaluated for possible Alzheimer's disease or other causes of cognitive decline.