FDG-PET Imaging Protocol for Head and Neck LGSCC

For PET, all patients fasted for 6 hours prior to imaging. After intravenous administration of FDG (4.0 MBq/kg), patients were allowed to rest for 60 minutes before imaging. The images were analyzed by a certified PET nuclear medicine physician with clinical experience in head and neck imaging using the analysis software workstation syngo via (Multimodality Workplace, Siemens Healthcare GmbH, Erlangen, Germany). SUVmax (Bq/mL) and SUVpeak (Bq/mL) were calculated as the imaging parameters of the SUV (Bq/mL). SUVmax is the maximum value of 1 pixel in a region of interest (ROI). Abnormal accumulation in LGSCC was manually set as the 3-dimensional volume of interest (VOI). The mean value of the SUV at a 1 cm³ voxel was measured in the VOI and the mean value, SUVpeak, was calculated. In addition, MTV and TLG were analyzed as 2 imaging parameters for FDG accumulation in the whole tumor. The metabolic tumor volume above the SUV value of 2.5 Bq/kg threshold was measured as MTV (cm³).^{[20 ,21 (link)]} TLG was calculated as the MTV multiplied by the mean value of the SUV (SUVmean), which reflects both glucose metabolic activity and tumor volume.^{[4 (link)–8 ]}