Inveon multimodality pet computed tomography scanner

The design of the PET study is presented in Fig. 1b using black and red text. [¹⁸F]FDG PET scans at predefined time points of 6 months (both models), 12 months (APP_Swe-PS1_dE9), and 17 months (Tg2576) were performed with an Inveon Multimodality PET/computed tomography (CT) scanner (Siemens Medical Solutions USA, Knoxville, TN) for isoflurane-anaesthetized mice. All PET scans were performed during the light phase between 9 a.m. and 1 p.m., and environmental conditions were standardized throughout the study as illustrated in Fig. 1b. CT scan was first acquired for attenuation correction, then, dynamic PET data were collected for 60 min in 3D list mode with an energy window of 350–650 keV. The data were then reconstructed using Fourier rebinning and a two-dimensional filtered back-projection reconstruction algorithm, and divided into 51 time frames (30 × 10 s, 15 × 60 s, 4 × 300 s, and 2 × 600 s) and decay corrected to the time of injection.

The same 9-month-old WT (n = 6) and TG (n = 6) mice were imaged using [¹¹C]PBR28 [¹⁸F]DPA-714 and [¹⁸F]F-DPA within a period of 10 days. The mice, anesthetized with a 2.5% isoflurane/oxygen mixture 30 min prior to tracer injection, were injected via a tail vein with [¹⁸F]F-DPA (injected dose 6.9 ± 0.2 MBq; 43 ± 18 μg/kg), [¹⁸F]DPA-714 (injected dose 6.8 ± 0.3 MBq; 0.8 ± 0.3 μg/kg), or [¹¹C]PBR28 (injected dose 10.3 ± 0.8 MBq; 0.4 ± 0.1 μg/kg) for 60-min dynamic scanning using an Inveon multimodality PET/computed tomography (CT) scanner (Siemens Medical Solutions, Knoxville, TN, USA). A few drops of Oftagel (2.5 mg/g; Santen, Tampere, Finland) were applied to the eyes of the animals to prevent eye dryness. The scanner has an axial 12.7-cm field of view and 10-cm transaxial field of view, generating images from 159 transaxial slices of voxel size of 0.78 × 0.78 × 0.8 mm³. CT preceded the PET modality for attenuation correction and anatomical reference. One of the TG animals imaged with [¹⁸F]F-DPA died during the scan, and hence this animal was excluded from the analysis.