On the other hand, using RT-132 (a DAT tracer) PET imaging displacement in early PD patients (Guttman et al., 2001), a 22% change was observed after 3 weeks of treatment with 375 mg of L-DOPA corresponding to a doubling of the presynaptic DA release calculated from our receptor competition model. Here, SLC6A3 is linked to Parkinson disease.