PET Imaging Protocol for Tau Tracer [¹⁸F]PI-2620

The cohort of this study was scanned with a Biograph 64 or a mCT PET/CT scanner (both Siemens, Erlangen, Germany). A low-dose CT scan preceded the PET acquisition and served for attenuation correction. [¹⁸F]PI-2620 PET was performed in a full dynamic 0–60 min setting initiated upon intravenous injection (∼10 s) of 185 ± 10 MBq of the tracer in most of the patients and short imaging windows were used for a subset due to severe disability (11%). PET data were reconstructed iteratively (4 iterations, 21 subsets, 5.0 mm Gauss/ 5 iterations, 24 subsets, 5.0 mm Gauss) with a matrix size of 336 × 336 × 109/400 × 400 × 148, a voxel size of 1.018 × 1.018 × 2.027/1.018 × 1.018 × 1.500 mm³ / and a slice thickness of 2.027/ 1.500 mm. The previously evaluated single 20–40 min frame (Song et al., 2021 (link)) was used for all further analyses in order to allow inclusion of cases with short scans in severely disabled patients (20–40 min or 0–40 min scan).