Sequential 18F-PSMA-1007 and 18F-FDG PET/CT Imaging

To reduce the mutual interference of the two radiotracers, imaging was carried out at different days. The median 6.5 (range 1.0–34.0) days passed from 18F-PSMA-1007 to 18F-FDG. Patients fasted for at least 6 h prior to injection of the 18F-FDG and blood sugar level is lower than 15 mg/L. The injected activity of 18F-FDG were mean 388 ± 55 MBq (range 281–503 MBq) and scanning was performed 60 min after injection, while the injected activity of 18F-PSMA-1007 were 348 ± 52 MBq (range 266–458 MBq), and according to Giesel et al. (5 (link)) imaging began 180 min after injection. All scans were obtained on a Biograph mCT-64 PET/CT scanner (Siemens). Non-enhanced low-dose (1.3–1.5 mSv) CT scan was performed with CT parameters (140 keV, 42 mA) section width of 8 mm, pitch of 0.8, and CT datas were used for attenuation correction. The PET-scan, PET was acquired in 3-D FlowMotion with an acquisition time of 2 min per bed position. Both scans was performed from vertex to the mid-thigh. Images were reconstructed with an ordered-subset expectation-maximization iterative reconstruction algorithm (three iterations, 21 subsets).