Explora fdg4

The Eclipse RD cyclotron (Siemens AG, Germany) and FDG synthesis device (Siemens ExploraFDG4, Germany) were used to synthesize 18F-FDG, and the resulting radiochemical purity was >95%. All of the subjects were asked to fast at least 6 h before the exam, rested for 15 min in a dark, quiet environment, and received intravenous FDG 0.15 mCi/kg via the cubital vein. Afterward, the subjects continued to rest for 40–50 min and then underwent head PET scans for 3 min. The PET scanner used was a Siemens Biograph 64 HD PET/CT (Siemens AG, Germany), and the spatial resolution of the scanner is 4.2 mm full width at half maximum (FWHM) in axial, sagittal or coronal plane. The PET scan used the 3-dimensional (3D) mode.

¹⁸F-FDG was synthesized using a Siemens Eclipse cyclotron (Siemens Medical Solutions, Knoxville, TN 37,932, USA) and a Siemens Explora FDG4 chemical synthesis module. The patients were fasted for at least 4 h before being injected with ¹⁸F-FDG at a dose of 4.44 to 5.55 MBq/kg. Images were acquired using a PET/CT instrument (Biograph 16 and Version, Siemens Company, Germany). Two experienced nuclear medicine physicians independently reviewed PET/CT images until consensus was reached. Semiquantitative analysis was performed using the maximum standardized uptake value (SUV_max). Furthermore, 10 metabolic parameters were also recorded: SUV_Top (SUV_max of the most FDG-avid lesion), SUV_I−Lung (SUV_max of intra-pulmonary lesions), SUV_E−Lung (SUV_max of extra-pulmonary lesions), SUV_Liver (SUV_max of the liver), SUV_Spleen (SUV_max of the spleen), SUV_Marrow (SUV_max of the marrow), SUR_Liver (the most FDG-avid lesion-to-liver SUV_max ratio) and SUR_Blood (the most FDG-avid lesion-to-blood pool SUV_max ratio), metabolic lesion volume (MLV) and total lesion glycolysis (TLG). The MLV of each lesion was calculated using an automated region-growing algorithm with SUV thresholds of 2.5. The TLG was measured as MTV multiplied by the average SUV of each lesion.

¹⁸F-FES was produced using a modified Explora FDG₄ module (Siemens) in our center as previously reported [29 ]. MicroPET/CT (Inveon, Siemens) scanning was performed on days 0, 3, 14, and 21 after treatment with injection of 5.55 MBq (150 μCi) of ¹⁸F-FES into the tail vein. 10 min static PET scans and CT imaging were acquired at 60 min after the injection of ¹⁸F-FES. Isoflurane was administered 10 minutes before the scanning, and mice were maintained under anesthesia during the scanning period. The images were reconstructed using three-dimensional ordered-subset expectation maximization (OSEM3D)/maximum algorithm. For data analysis, the region of interest (ROI) was manually drawn to cover the whole tumor on fused PET/CT images. A similar ROI was drawn on the muscle of the opposite foreleg. The max of percentage-injected dose per Gram (%ID/g_max) and standardized uptake values (SUV_max) of the tumor and muscle in the ROIs were recorded. %ID/g before and after therapy was denoted as %ID/g day₀ and %ID/g day_n, respectively. Changes after therapy are denoted as Δ%ID/g = (%ID/g day_n − %ID/g day₀)/%ID/g day₀ × 100%.