18F-FDOPA PET Acquisition and Reconstruction

All patients fasted for at least 4 h before ¹⁸F-FDOPA PET acquisition and some patients received Carbidopa, to help increase tracer uptake in the brain, 1 h prior to their exam, which was the institutional procedure effective between February 2018 and September 2020 [19 (link)]. Acquisitions were performed on the same digital PET/computed tomography (CT) device (Vereos, Philips Healthcare^®, Eindhoven, The Netherlands). First, a CT scan was obtained for each patient. A 30 min dynamic PET acquisition was performed following the injection of 2MBq ¹⁸F-FDOPA per kg of body weight. One static image based on the last 20 min of the acquisition (2 iterations, 10 subsets, 256 × 256 × 164 voxels of 1 × 1 × 1 mm³) and 30 frames of 1 min each (3 iterations, 15 subsets, 128 × 128 × 82 voxels of 2 × 2 × 2 mm³) for dynamic images were reconstructed using an OSEM 3D algorithm [16 (link),20 (link)]. All static and dynamic PET images were reconstructed with and without PSFd. Images were corrected for CT attenuation and dead time, as well as random and scattered coincidences during the reconstruction process.