11C-Deuterium-L-deprenyl (11C-DED) (often synthesized without deuterium as 11C-L-deprenyl) is a well-established PET radiotracer used in AD research that targets monoamine oxidase B (MAO-B) for the imaging of astrocytes [4,8,9,10,11,12,13,14,15,16,17,18,19,20,21]. Here, MAOB is linked to Alzheimer disease.