It has been confirmed that dynamic PET imaging of SV2A is sensitive to synaptic loss in patients with brain disorders, including temporal lobe epilepsy (Finnema et al2016), Alzheimer’s disease (AD) (Chen et al2018, Mecca et al2020, O’Dell et al2021), and Parkinson’s disease (PD) (Matuskey et al2020). Here, SV2A is linked to Parkinson disease.