title: Intra-tumour 18F-FDG uptake heterogeneity decreases the reliability on target volume definition with positron emission tomography/computed tomography imaging.
abstract: BACKGROUND
  This study aims to explore whether the intra-tumour (18) F-fluorodeoxyglucose (FDG) uptake heterogeneity affects the reliability of target volume definition with FDG positron emission tomography/computed tomography (PET/CT) imaging for nonsmall cell lung cancer (NSCLC) and squamous cell oesophageal cancer (SCEC).
  
  
  METHODS
  Patients with NSCLC (n = 50) or SCEC (n = 50) who received (18)F-FDG PET/CT scanning before treatments were included in this retrospective study. Intra-tumour FDG uptake heterogeneity was assessed by visual scoring, the coefficient of variation (COV) of the standardised uptake value (SUV) and the image texture feature (entropy). Tumour volumes (gross tumour volume (GTV)) were delineated on the CT images (GTV(CT)), the fused PET/CT images (GTV(PET-CT)) and the PET images, using a threshold at 40% SUV(max) (GTV(PET40%)) or the SUV cut-off value of 2.5 (GTV(PET2.5)). The correlation between the FDG uptake heterogeneity parameters and the differences in tumour volumes among GTV(CT), GTV(PET-CT), GTV(PET40%) and GTV(PET2.5) was analysed.
  
  
  RESULTS
  For both NSCLC and SCEC, obvious correlations were found between uptake heterogeneity, SUV or tumour volumes. Three types of heterogeneity parameters were consistent and closely related to each other. Substantial differences between the four methods of GTV definition were found. The differences between the GTV correlated significantly with PET heterogeneity defined with the visual score, the COV or the textural feature-entropy for NSCLC and SCEC.
  
  
  CONCLUSIONS
  In tumours with a high FDG uptake heterogeneity, a larger GTV delineation difference was found. Advance image segmentation algorithms dealing with tracer uptake heterogeneity should be incorporated into the treatment planning system.
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong University, Jinan, Shandong, China.
authors.forename: Xinzhe
authors.initials: X
authors.lastname: Dong
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong University, Jinan, Shandong, China.
authors.forename: Peipei
authors.initials: P
authors.lastname: Wu
authors.affiliation: Department of Radiology, Shandong Cancer Hospital and Institute, Jinan, Shandong, China.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Radiology, Shandong Cancer Hospital and Institute, Jinan, Shandong, China.
authors.forename: Wenwu
authors.initials: W
authors.lastname: Li
authors.affiliation: College of Physics and Electronic Science, Shandong Normal University, Jinan, Shandong, China.
authors.forename: Honglin
authors.initials: H
authors.lastname: Wan
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong University, Jinan, Shandong, China.
authors.forename: Jinming
authors.initials: J
authors.lastname: Yu
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Shandong University, Jinan, Shandong, China.
authors.forename: Ligang
authors.initials: L
authors.lastname: Xing
mesh_terms: D000328:Adult; D000368:Aged; D016477:Artifacts; D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis* / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000378:metabolism; D004938:Esophageal Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods; D047368:Tumor Burden
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: fluorodeoxyglucose (FDG) uptake heterogeneity; nonsmall cell lung cancer (NSCLC); positron emission tomography (PET); squamous cell oesophageal carcinoma (SCEC); target volume