title: Comparison of primary tumour volumes delineated on four-dimensional computed tomography maximum intensity projection and (18) F-fluorodeoxyglucose positron emission tomography computed tomography images of non-small cell lung cancer.
abstract: BACKGROUND
  The study aims to compare the positional and volumetric differences of tumour volumes based on the maximum intensity projection (MIP) of four-dimensional CT (4DCT) and (18) F-fluorodexyglucose ((18) F-FDG) positron emission tomography CT (PET/CT) images for the primary tumour of non-small cell lung cancer (NSCLC).
  
  
  METHODS
  Ten patients with NSCLC underwent 4DCT and (18) F-FDG PET/CT scans of the thorax on the same day. Internal gross target volumes (IGTVs) of the primary tumours were contoured on the MIP images of 4DCT to generate IGTVMIP . Gross target volumes (GTVs) based on PET (GTVPET ) were determined with nine different threshold methods using the auto-contouring function. The differences in the volume, position, matching index (MI) and degree of inclusion (DI) of the GTVPET and IGTVMIP were investigated.
  
  
  RESULTS
  In volume terms, GTVPET 2.0 and GTVPET 20% approximated closely to IGTVMIP with mean volume ratio of 0.93 ± 0.45 and 1.06 ± 0.43, respectively. The best MI was between IGTVMIP and GTVPET 20% (0.45 ± 0.23). The best DI of IGTVMIP in GTVPET was IGTVMIP in GTVPET 20% (0.61 ± 0.26).
  
  
  CONCLUSIONS
  In 3D PET images, the GTVPET contoured by standardised uptake value (SUV) 2.0 or 20% of maximal SUV (SUVmax ) approximate closely to the IGTVMIP in target size, while the spatial mismatch is apparent between them. Therefore, neither of them could replace IGTVMIP in spatial position and form. The advent of 4D PET/CT may improve the accuracy of contouring the perimeter for moving targets.
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
authors.forename: Yili
authors.initials: Y
authors.lastname: Duan
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
authors.forename: Jianbin
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: PET/CT Room, Shandong Cancer Hospital and Institute, Jinan, China.
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
authors.forename: Tingyong
authors.initials: T
authors.lastname: Fan
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Shao
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.affiliation: Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan, China.
authors.forename: Yanluan
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Big Bore CT Room, Shandong Cancer Hospital and Institute, Jinan, China.
authors.forename: Dongping
authors.initials: D
authors.lastname: Shang
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D047368:Tumor Burden
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: fluorodeoxyglucose positron emission tomography; four-dimensional computed tomography; internal gross target volume; maximum intensity projection; non-small cell lung cancer