Maximum intensity micro-PET images were obtained on a Siemens INVEON small-animal PET/CT scanner (Siemens Medical Solutions USA, Inc., Malvern, PA). The unit has a gantry diameter of 21 cm, a transverse field of view (FOV) of 12.8 cm, and an axial length of 11.6 cm. The scanner operated in a 90 min dynamic, three-dimensional (3D) volume imaging acquisition mode. The mice were laser aligned at the center of the scanner FOV for subsequent imaging. Mice were administered 1.48–15.5 MBq (averaging ~ 7.4 MBq) of [18F]1 in 100 μL of 10% EtOH in saline containing sodium ascorbate via tail vein injection. Immediately after injection, the mice were anesthetized using a 1 L oxygen flow of 3% isoflurane and imaged within 2–5 min of injection. Micro-PET image reconstruction was obtained with an OSEM3D algorithm without tissue attenuation correction. The micro-PET data was analyzed using Siemens Inveon Research Workplace, General Analysis software.
The micro-CT images were obtained on a MILabs VECTor6CTUHROI unit (Houten, Utrecht, Netherlands) immediately after micro-PET for the purpose of anatomic/molecular data fusion. The accurate total body, full scan angle micro-CT images were acquired for ~ 8–10 min, and concurrent image reconstruction was achieved using a Hann projection filter algorithm at 100 μm voxel size. Reconstructed DICOM (digital imaging and communication in medicine) micro-CT images were created using PMOD 4.1 software and imported into the Siemens Inveon Research Workplace software for subsequent image fusion with micro-PET for the ROIs overlay to create TACs to access radioisotope uptake and distribution.
The second PET/CT scan followed the same imaging protocol as the first PET/CT scan except for the blocking agent (5 mg/kg) was administered intravenously 5 min prior to [18F]1 injection. All mice were sacrificed 24 hours following the completion of the second PET/CT scan, and their hearts and descending aortas were harvested and preserved in 4% paraformaldehyde in phosphate-buffered saline (PBS) solution until further analysis.
Free full text: Click here