Inveon preclinical pet ct system

⁸⁹Zr radiolabeling was performed as described in the work of Zeglis and Lewis⁴⁰ and radiochemical yield and purity were determined by thin layer chromatography (TLC). Doses were administered if the radiochemical purity was more than 95%. PET–CT images were acquired 24 h post-FUS using an Inveon Preclinical PET-CT system (Siemens). Mice were anesthetized and maintained using 2% isoflurane in oxygen at a flow rate of 2 L/min and positioned in an in-house manufactured 4-mouse scanning bed. A 30 min PET image was acquired followed by a CT for attenuation correction and co-registration to the MRI data. The PET images were reconstructed using the OSEM-2D reconstruction algorithm in the Inveon Acquisition Workspace (IAW, Siemens) correcting for attenuation and ⁸⁹Zr detector efficiency.

PET/CT scanning was performed using an Inveon preclinical PET/CT system (Siemens Medical Solutions, Knoxville, TN) with a spatial resolution of ~1.5 mm full width at half maximum at the center of the field of view. Mice were placed in a restrainer and administered 250 µCi (9.25 MBq) of [¹⁸F]favipiravir in ~150 µL volume via IV tail vein injection and immediately anesthetized with isoflurane (4% induction, 2% maintenance) delivered in oxygen. The mice were positioned in the center of the PET field of view and PET imaging initiated for a period of 2 h. Upon completion of the PET imaging session, a 5 minute CT scan (80 kV, 500 µA, 98 µm, and 360° rotation in 220 steps) was initiated. During all imaging procedures, animal respiration rate and body temperature were monitored and maintained using an M2M-BioVet™ small animal physiological monitoring system (M2M imaging, Cleveland, OH). When scanning was completed, mice were heavily sedated under isoflurane and organs removed as described above for assessment of radiotracer distribution by gamma counting.

On days 3, 6, and 10 post-infection, mice (n = 5/group/day) were bled for determination of viremia by qRT-PCR and then PET/CT scanned. PET/CT scanning was performed using an Inveon preclinical PET/CT system (Siemens Medical Solutions, Knoxville, TN) with a spatial resolution of ~ 1.5 mm full width at half maximum at the center of the field of view. Mice were anesthetized with isoflurane (4 % induction, 2 % maintenance) delivered in oxygen. Once anesthetized, animals were administered ~ 8.0 MBq of [¹⁸F]DPA-714 in ~ 150 μl volume via IV tail vein injection and were allowed to wake in their home cages for a 60-min radiotracer uptake phase. Just prior to scanning, mice were reanesthetized with isoflurane and PET imaging was performed (details are provided in the ESM).