Discovery d600

Participants were asked to fast overnight before PET/CT scan. Blood glucose levels at the time of injection of ¹⁸F-FDG were lower than 160 mg/dl. PET/CT scans were performed on Discovery D600 (for 57 subjects) or Discovery STE scanners (for 6 subjects) (GE Medical Systems, Waukesha, WI, USA) with a tracer uptake time of 60 min. ¹⁸F-FDG was injected based on weight (0.1 mCi/kg on the D600 scanner, 10-13 mCi on the STE scanner). No intravenous contrast agent was given. For the Discovery D600 scanner, slice thickness was 3.75 mm, current was 40–120 mAs, and energy was 120 kVp. For the Discovery STE scanner, slice thickness was 3.3 mm, current was 40–200 mAs, and energy was 140 kVp. Following CT acquisition, a PET emission scan was acquired with an acquisition time of 2.5–3 min per bed in 3D mode from the proximal thigh to the skull base. CT data were used for attenuation correction. The images were reconstructed using a conventional iterative algorithm (OSEM). Using dedicated software (Advanced Workstation, GE Healthcare, Milwaukee, WI, USA), CT, PET, and fused PET/CT images were reviewed.

All patients fasted for at least 6 h before the PET/CT scans were taken. Serum glucose levels (preferably < 150 mg/dL) were measured followed by intravenous administration of 5.5 MBq/kg ¹⁸F-FDG (with a maximum of 400 MBq). PET and combined low-dose CT scans were performed with commercial PET/CT scanners (Discovery STE, Discovery D600, Discovery D710 [GE Healthcare, Chicago, IL, USA], or Biograph TruePoint40 [Siemens Healthineers, Erlangen, Germany]) after 1 h. The PET scan was performed with an acquisition time of 2 min per bed position in the 3-dimensional mode. PET data were reconstructed iteratively using an ordered subset expectation maximization algorithm with the low-dose CT datasets for attenuation correction.