2.3.3. PET acquisition

The radioligand [¹⁸F]FE-PE2I was prepared in-house as previously described (Stepanov et al., 2012). List-mode data were acquired for 93 min following a 6-minute transmission scan with a Caesium-137 source for attenuation correction, as previously described (Fazio et al., 2018, Fazio et al., 2015, Kerstens et al., 2020). PET measurements were performed around the same time of day, and in all PD subjects in practically defined ‘OFF’ state (>12 h off levodopa medication, and > 24 h off dopamine agonists and MAO-B inhibitors).

PET data were reconstructed into 37 frames (8 × 10, 5 × 20, 4 × 30, 4 × 60, 4 × 180, 12 × 360 s) using 3D OP OSEM with 10 iterations and 16 subsets, including modeling of the PSF (Varrone et al., 2009). For both cohorts, data acquisition, and reconstruction were the same.