*3.1. Assessment of SUVmax, MTV, and TLG on 18F-FDG Uptake*

In all 85 patients, the median values of SUVmax, MTV, and TLG on 18F-FDG and TB were 6.0 (range, 3.1–21.0), 17.8 cm3 (range, 1.1–379 cm3), 75.4 gcm3/mL (range, 3.9–2550 g·cm3/mL), and 65 cm (range, 6.6–230.6 cm), respectively. According to histological types, the median values of SUVmax, MTV, and TLG on 18F-FDG and TB in adenocarcinoma were 6.7 (range, 3.1–21.3), 11.3 cm3 (range, 1.1–276 cm3), 58.3 g·cm3/mL (range, 3.9–1398 g·cm3/mL), and 53 cm (range, 6.6–230.6 cm), respectively, and those in non-adenocarcinoma displayed 8.4 (range, 3.2–20.4) 24.8 cm3 (range, 1.1–379 cm3), 105.6 g·cm3/mL (range, 4.0–2550 g·cm3/mL), and 75 cm (range, 18.2–228.3 cm), respectively. The difference of each parameter for SUVmax, MTV, and TLG on 18F-FDG and TB was not significant between adenocarcinoma and non- adenocarcinoma. The SUVmax correlated significantly with MTV (*r* = 0.49, *p* < 0.01), TLG (*r* = 0.56, *p* < 0.01), and TB (*r* = 0.33, *p* < 0.01). Figure 1 is a representative PET image showing the assessment of SUVmax, MTV, and TLG on 18F-FDG.

The discriminative value of various SUVmax, MTV, and TLG cutoffs for 18F-FDG uptake were explored in the context of OS and PFS (Figure 2) [13]. For prognosis in OS and PFS analyses, the most discriminative cutoffs based on log-rank test for SUVmax, MTV, and TLG were 6.0, 5.0, and 20, respectively. The TLG cutoff of 20 was significant in the OS analysis, but not in the PFS analysis, although it was the most favorable TLG cutoff. The SUVmax cutoff of 6 was not significant in either OS or PFS analysis, but still seemed better considering the results of the log-rank test. The 12 cm cutoff for TB was based on a previous study [13].

**Figure 1.** Imaging from a positron emission tomography (PET) scan of non-small cell lung cancer (NSCLC), indicating the measurement of SUVmax, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) on 2-deoxy-2-[18F]fluoro-d-glucose (18F-FDG).
