Multimodality workplace

The data were transferred to a workstation (Multi-Modality Workplace®, Siemens, Forchheim, Germany) and processed using the Volume Perfusion Computed Tomography (VPCT) Body program. The PCT studies were post-processed and analysed by a senior chest radiologist with 14 years of experience who has received specific training in lung cancer perfusion post-processing, without knowledge of the results of the first standard computed tomography control after treatment with CCT.
First, the automatic motion and noise correction algorithms included in the VPCT Body software were applied. An arterial density-to-time curve was obtained by placing a region of interest in the thoracic aorta, where the unenhanced reference image was selected. The tumour volume was selected via manual segmentation, drawing the contours of the lesion in the axial, coronal, and sagittal planes, using a cut-off threshold of -50–150 UH, which permitted automatically excluding the normal pulmonary parenchyma, non-tumour vascular structures, and calcium, from the segmented volume.
The following perfusion parameters were calculated using a deconvolution model: BF, in mL/100 mL/min; BV, in mL/100 mL; PMB, in mL/100 mL/min, and MTT, in seconds. Each parameter was represented as a colour on parametric maps; numerical values were given as mean and standard deviation.

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 ]}