Recently, we developed a radiotracer using a 64Cu-labeled antibody, [64Cu]Cu-NODAGA-ATV:4D9 (ATV is antibody transport vehicle), which uses the human transferrin receptor as a blood–brain barrier transport vehicle for a TREM2 antibody (8) to image TREM2-associated microglial activation in the CNS of an AD mouse model using PET (9). This evidence concerns the gene TREM2 and Alzheimer disease.