However, earlier in vivo PET studies have shown that the regional pattern of MAO-B tracer (i.e., [3H]deuterium-L-deprenyl) binding is different from that of [18F]THK5317 binding, and MAO-B tracer binding appears to be less extensive in later stages of the AD (i.e., dementia-stage) in contrast to what seen with [18F]THK5317 [10, 39, 40]. This evidence concerns the gene MAOB and Alzheimer disease.