Interpretation and examination of18F-FDG-PET/CT scans
All patients fasted for ≥6 h. 18F‐FDG was purchased from Tianjin Atom High Science Isotopes Medicine Co., Ltd. According to the manufacturer’s test, the radiochemical purity of18F‐FDG is 98%. The dose of 18F-FDG was adjusted according to the body weight of the patient. Sixty minutes after intravenous injection, the whole-body PET/CT examination was performed using a Biograph mCT 64 system (Siemens Healthineers, Erlangen, Germany) in the supine position. Whole-body CT images were obtained for attenuation mapping and lesion localization (94–140 mAs, 120 kVp, 5‐mm-wide section). We reconstructed a 3.0-mm-thick section for attenuation correction and then performed subsequent image fusion. PET images of the same area were acquired following CT scans in a 3‐dimensional mode, with 6–7 bed positions. We used an iterative algorithm to reconstruct the image, transferred the image to a dedicated workstation (syngoMMWP VE40A; Siemens Healthineers), and used the syngo TrueD software program (TRUED_ SYSLATEST_VE10A40; Siemens Healthineers) for analysis. Main outcome measures included the location, quantity, and size of abnormal 18F-FDG uptake. During quantitative analysis, the maximum standardized uptake value (SUVmax) and the maximum standardized uptake value of the posterior wall of tonsil or nasopharynx (SUVmaxTon) were measured or calculated using TrueD software.