DDC and Parkinsonism: Classic radiotracers, targeting presynaptic dopaminergic function such as dopamine transporters (DAT), vesicular monoamine transporter type 2 (VMAT2), and aromatic L-amino acid decarboxylase (AADC), have proven valuable in supporting the diagnosis of PD and distinguishing it from non-degenerative causes of parkinsonism [3,4,5].