Albira si

Micro-PET/CT datasets were acquired using a preclinical micro-PET/CT (Albira Si, Bruker), made available by the CAPiR laboratory (Center for Advanced Preclinical Research in vivo), University of Catania, Italy. The CT datasets were acquired using 600 views in a low-resolution configuration, an initial horizontal position of 37 mm, an FOV of 64 mm, X-ray energy of 35 kV, a current of 200 μA, and the size of each CT-voxel was equal to 500 × 500 × 500 μm³. The DICOM (Digital Image Communications in Medicine) images were obtained using a 3D-based FBP algorithm. The PET images were re-constructed using the 3D-MLEM algorithm with a total of 12 iterations. PET-voxel was equal to 500 × 500 × 500 μm³.

PET/CT scans were performed on an Albira Si (Bruker). Mice were anaesthetized under 2–3% isoflurane, weighed and injected intravenously with 8.9 ± 2.3-MBq ¹⁸F-FDG in 200 μL via the lateral tail vein and flushed with saline, followed by a 1-h uptake period. Mice were scanned for 20-min static PET, followed by a 10-min CT protocol for anatomical registration. The CT scans were performed at a 35-kV tube voltage and 200 μA over 250 projections. Animal temperature was maintained and monitored throughout the procedure alongside the respiratory rate. PET/CT data were reconstructed using the Albira Reconstructor Software in PMOD (version 3.807, Bruker). PET data were reconstructed using a maximum likelihood expectation maximization iterative method at 25 iterations with scatter, random event, and radiotracer decay corrections. The PET data were fused with the CT data, which was reconstructed with filtered back projection. All PET and CT image data were analyzed in PMOD (version 3.807, Bruker). The methods used to calculate adiposity have been described previously⁶⁴ .

PET-CT imaging was performed on CT-2A tumour-bearing mice (n = 4), sham operated mice (n = 2), and healthy control mice (n = 1). ¹⁸F-fluciclovine PET tracer was provided by Blue Earth Diagnostics (Oxford, UK) through an agreement with University of Leeds. For pre-clinical administration, the radiotracer was reformulated by elution on chromatographic column to remove trisodium citrate to negate citrate poisoning in mice. The radiotracer was purified by elution on chromatographic column.
¹⁸F-fluciclovine (7.8 +/− 2.0 MBq, mean +/− standard deviation of injected activity) was intravenously injected (tail vein) at the beginning of a 90-min dynamic PET scan (Albira Si, Bruker), or 60 min before a 20-min static PET acquisition. All PET-CT acquisitions and injections were performed under 2% isoflurane anaesthesia at a flow rate of 2 L per minute. At the end of each PET acquisition, both dynamic and static, an extra 10-min Computed Tomography (CT) scan was performed. Dynamic and static PET scans were performed for evaluating ¹⁸F-fluciclovine biodistribution and uptake in healthy brains and tumours using an Albira Si PET/SPECT/CT scanner (Bruker, Ettlingen, Germany).