BACKGROUND: Extensive-stage small cell lung cancer (ES-SCLC) comprises most SCLC cases, with up to 40% of patients failing to achieve an objective response (OR) to first-line treatment. The prognostic value of conventional fluorine-18 fluorodeoxyglucose ( METHODS: This prospective pilot cohort study enrolled 15 patients with SCLC who planned to undergo dynamic PET imaging (November 2022 to January 2024). All participants underwent dynamic PET imaging before receiving first-line treatment. Tumor regions of interest (ROIs) were delineated on the PET images to facilitate the calculation of TAC. From these curves, 6 dynamic features were derived. The Mann-Whitney U test was applied to evaluate the significance of variations in continuous variables, encompassing both TAC features and conventional metabolic parameters. Statistically significant features were used to distinguish between the OR group and the non-objective response (non-OR) group and the area under the receiver operating characteristic curve (AUC) was calculated. RESULTS: A total of 10 patients were included for analysis. Clinical characteristics such as age, gender, smoking history, and treatment regimens were similar between the OR and non-OR groups. Analyses of conventional metabolic features [SUXmax, minimum standardized uptake value (SUVmin), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG)] did not reveal significant differences between the groups (all P>
0.05), with MTV showing a trend towards significance (P=0.095). Among the TAC features, the slope of the TAC between 10 to 30 minutes ( CONCLUSIONS: The TAC feature (