Inveon acquisition workplace

Mouse PET/CT imaging was performed using a Siemens Inveon PET/CT Multi Modality system (Siemens Medical Solutions, Knoxville, TN) with effective spatial resolution of 1.4 mm at the center of field of view (FOV). All animals were fasted for 12 h prior to PET imaging. Each mouse received 140 μCi of 2-deoxy-2-(18F)fluoro-D-glucose (FDG) in 150 μL in saline intravenously via tail vain injection. The mice were placed on a heat pad before and during image acquisition. PET images were acquired 1h post-injection (p.i.), for 15 min, with animals under 2.5% isoflurane. PET images were reconstructed into a single frame using the 3D Ordered Subsets Expectation Maximization (OSEM3D/MAP) algorithm. CT images were acquired immediately after PET with the FOV centered at the shoulder of the mouse. CT projections (360 steps/rotation) were acquired with a power of 80 kVp, current of 500 μA, exposure time of 145 ms, binning of 4, and effective pixel size of 102 μm. The CT reconstruction protocol used a downsample factor of 2, was set to interpolate bilinearly, and used a Shepp-Logan filter. PET and CT images were co-registered in Inveon Acquisition Workplace (Siemens Medical Solutions) for analysis. Regions of interest (ROI) were drawn manually, encompassing the thyroid in all planes containing the organ. The target activity was calculated as percentage injected dose per gram.

Experiments started 2-3 weeks after intrasplenic injection of tumor cells. To demonstrate tumor-specific NIS expression in vivo, mice received polyplexes systemically via the tail vein (i.v.) at a DNA dose of 2.5 mg/kg (50 μg DNA in 250 μL HBG). Mice were treated as follows: (1) LPEI-PEG-GE11/NIS (n=5); (2) LPEI-PEG-Cys/NIS (n=3); (3) LPEI-PEG-GE11/NIS + NaClO₄ (n=2): pretreatment with an i.p. injection of 2 mg of the competitive NIS inhibitor sodium perchlorate (NaClO₄) 30 min before PET tracer administration. 48 h after polyplex injection the novel NIS PET tracer ¹⁸F-TFB (10 MBq; synthesized by the Radiopharmacy, Klinikum rechts der Isar, TU Munich, as described previously [40 (link)]) was applied i.v. and tracer accumulation in metastatic liver areas was determined by small-animal PET (Inveon, SIEMENS Preclinical Solutions, Erlangen, Germany). Regions of interest were analyzed with the software Inveon Acquisition Workplace (Siemens) and quantified using Inveon Research Workplace (Siemens) and expressed as a fraction of the total amount of initial dose (% of ID). The retention time of the tracer ¹⁸F-TFB within metastases was determined by serial scanning after 0.5 h, 1 h and 2 h. To suppress thyroidal iodide uptake, a 10-day pretreatment with L-thyroxin (L-T4; 5 mg/ml; Sigma-Aldrich) in drinking water was conducted before PET-imaging.

Degradation experiments were carried out using with better. The presented material was implanted in adult Japanese white rabbits (provided by Tianjin Institute of Medical Sciences) to examine its corrosion resistance in vivo. The extrusion rods with a diameter of 8 mm were machined into cylindrical implants with a diameter of 2 mm and a length of 6 mm, which were sterilized by Co60 radiation before surgery. During the operation, the rabbit was anesthetized and the fur on the hind limbs was removed. A hole defect was made in the left femoral condyle with a diameter of about 2 mm. The implant was inserted into the hole and the sutured the myofascial membrane and skin after operation. The operation process was shown in Figure 2. The rabbits were euthanized at 6- and 13-weeks post operation. The Femoral tissues (including implant) were then fixed in 4% paraformaldehyde solution.
The micro-CT scanning was then carried out by Inveon MM CT (SIEMENS, Munich, Germany). The Inveon Acquisition Workplace (SIEMENS, Munich, Germany) and Inveon Research Workplace (SIEMENS, Munich, Germany) software were then used for scanning and data analysis. The COBRA_Exxim (EXXIM Computing Corp., Livermore, CA) software was used for 3D reconstruction and bone parameter analysis.

The left knee joints were then scanned using micro-CT (Inveon, Siemens Medical Solutions, IL, USA) with the following sets: 13-μm isotropic voxel, 80-kV voltage, 500-μA current, 300-ms settling time, 360 projections per 360° and 200-ms exposure time. The obtained raw data were reconstructed using Inveon Acquisition Workplace (Version 5.0, Siemens Medical Solutions USA, Inc., IL, USA). For subchondral trabecular bone analysis, covering the whole subchondral bone in tibial plateaus was selected as the ROI. Bone volume/tissue volume (BV/TV), trabecular number (Tb. N), trabecular thickness (Tb. Th) and trabecular separation (Tb. Sp) were calculated using Inveon Research Workplace (Version 5.0, Siemens Medical Solutions, IL, USA).