Inveon dpet

[¹⁸F]florbetaben radiosynthesis was performed as previously described (Rominger et al., 2013 (link)). This procedure yielded a radiochemical purity exceeding 98% and a specific activity of 80 ± 20 GBq/μmol at the end of synthesis. Mice were anesthetized with isoflurane (1.5%, delivered via a mask at 3.5 L/min in oxygen) and received a bolus injection [¹⁸F]florbetaben 12 ± 2 MBq in 150 μL of saline to a tail vein. Following placement in the tomograph (Siemens Inveon DPET), a single frame emission recording for the interval 30–60 min p.i., which was preceded by a 15-min transmission scan obtained using a rotating [⁵⁷Co] point source. The image reconstruction procedure consisted of three-dimensional ordered subset expectation maximization (OSEM) with four iterations and twelve subsets followed by a maximum a posteriori (MAP) algorithm with 32 iterations. Scatter and attenuation correction were performed and a decay correction for [¹⁸F] was applied. With a zoom factor of 1.0 and a 128 × 128 × 159 matrix, a final voxel dimension of 0.78 × 0.78 × 0.80 mm was obtained.

¹⁸F-FDG labeling provides a clinically translational approach for PET/MRI tracking of ADSCs. The efficiency of the labeling procedure was investigated for two approaches, microfluidics-based mechanoporation and conventional passive co-incubation. A single-cell suspension of ADSCs (5×10⁶) was mixed with medical-grade ¹⁸F-FDG (57 MBq/ml; 1 ml ¹⁸F-FDG [344 MBq] mixed with 2 ml FACS buffer [3x] and 3 ml PBS) and passed once through the microfluidic device (5 channels, flow rate 0.5 ml/min). We measured the cell processing time through the device for every experiment. Another batch of ADSCs (1×10⁶) was incubated with ¹⁸F-FDG (30 MBq/ml; 0.1 ml ¹⁸F-FDG [33 MBq] mixed with 1 ml glucose-free DMEM) for 12 min at 37°C. The labeled cells were washed twice with PBS to remove residual radioactivity and 5×10⁴ cells were transferred to a 24-well plate for PET imaging (Inveon D-PET, Siemens Preclinical Solutions, Knoxville, TN) using an acquisition time of 10 min and an energy window of 425-650 keV. Unlabeled ADSCs (5×10⁴) were used as control. After PET acquisition, the radioactivity per well was quantified by region of interest (ROI) analysis using the Inveon Research Workplace (IRW) software. Another set of 1×10⁴ labeled cells was measured using an automatic gamma counter (Hidex, Turku, Finland).