论文部分内容阅读
Objective: To evaluate a new PET image parameter, FDG uptake heterogeneity, and its effect on various approaches of target volume delineation.Methods: Twenty-five patients with newly diagnosed and pathologically proven esophageal squamous cell carcinoma were included in this study.All patients were treated with definitive chemo-radiotherapy and received whole body FDG PET/CT scanning before treatment.Intra-tumor FDG uptake heterogeneity was accessed by visual scoring, coefficient of variation (COV) of SUVs, and image texture features(entropy and energy).Tumor volumes were delineated on the CT (GTVCT).PET/CT images (GTVPET-CT) and PET images were fused using a fixed threshold at 40％ of the SUVmax (GTVPET40％) or at absolute SUV cut-off value of 2.5 (GTVPET2.5).The correlations among the uptake heterogeneity parameters and the differences in GTVPET-CT,GTVPET40％, and GTVPET2.5 were analyzed.