Discovery pet ct 690 elite scanner

The PET/CT images were acquired on a General Electric Discovery PET/CT 690 Elite scanner (General Electric Health care, Waukesha, WI). The scanning interval between the ¹⁸F-FDG and ¹⁸F-OC scans was less than 1 month but more than one day. For the ¹⁸F-FDG scan, the patients fasted for at least 6 hours before the scan, and the serum glucose level needed to be less than 180 mg/dl. Both ¹⁸F-FDG and ¹⁸F-OC scans were performed using PET approximately 1 hour after intravenous (IV) injection of the radiotracer at a dose of 3.7 to 4.44 MBq (0.1–0.12 mCi) per kilogram of body weight. Whole-body (top of the skull to midthigh) low-dose CT scans (120 kV; automatic mAs; pitch, 1; slice thickness, 3.75 mm; matrix, 512 × 512) were performed. After a CT, the PET scan was performed on the same anatomical area immediately. Each bed position was held for 2 minutes for each patient. The PET datasets were reconstructed with a 3-dimensional ordered-subset expectation maximization (OSEM) algorithm with 2 iterations and 23 subsets.