Striatal Dopamine Transporter Quantification

PET imaging data were obtained on a GE Healthcare system (Chicago, Illinois) for one dataset (PROD) and a Siemens Biograph 6 HiRez PET scanner (Erlangen, Germany) for the second dataset (NEUTOP), in 3D mode. These two PET datasets were previously published by our group in the context of separate independent questions (PROD [30 (link)]; NEUTOP [10 (link)]). The PET data acquisition and preprocessing procedures are explained in detail in those two previous reports and in the Supplementary Methods. Our primary measure was the whole striatal influx constant (K_i^cer, min⁻¹). Time-activity curves were visually inspected and K_i^cer was calculated using the Patlak–Gjedde graphical approach adapted for a reference tissue input function [31 (link)]. This approach has previously been shown to have good reliability, with intraclass correlation coefficients for the whole striatum of over 0.8 [32 (link)].