Radiopharmaceuticals that bind to the serotonin transporter (SERT), such as [11C]-(3-amino-4-(2-dimethylamino-methyl-phenyl-sulfonyl)-Benzonitrile) ([11C]-DASB), or to Acetylcholinesterase (AChE) enzyme as [11C]-methyl-4-piperidyl acetate ([11C]-MP4A), allow to map brain SERT in patients with different degrees of PD severity, or cholinergic denervation associated with progressive cognitive decline and loss of odor discrimination (Politis et al., 2010). Here, ACHE is linked to Mental deterioration.