PURPOSE: To investigate the correlations in target volumes based on @entity419 PET/CT and four-dimensional CT (4DCT) to detect the feasibility of implementing PET in determining gross target volumes (GTV) for @entity5 motion for primary @entity418 (EC). METHODS: Thirty-three @entity1 with EC sequentially underwent contrast-enhanced 3DCT, 4DCT, and @entity419 PET-CT thoracic simulation. The internal gross target volume (IGTV)10 was obtained by combining the GTV from ten phases of 4DCT. The GTVs based on PET/CT images were defined by setting of different standardized uptake value thresholds and visual contouring. The difference in volume ratio, conformity index (CI), and @entity2803 ( @entity2803 ) between IGTV10 and GTVPET was compared. RESULTS: The images from 20 @entity1 were suitable for further analysis. The optimal volume ratio of 0.95  0.32, 1.06  0.50, 1.07  0.49 was at standardized uptake value (SUV)2.5, SUV20%, or manual contouring. The mean CIs were from 0.33 to 0.54. The best CIs were at SUV2.0 (0.51  0.11), SUV2.5 (0.53  0.13), SUV20% (0.53  0.12), and manual contouring (0.54  0.14). The mean DIs of GTVPET in IGTV10 were from 0.60 to 0.90, and the mean DIs of IGTV10 in GTVPET ranged from 0.35 to 0.78. A negative correlation was found between the mean CI and different SUV (P=0.000). CONCLUSION: None of the PET-based contours had both close spatial and volumetric approximation to the 4DCT IGTV10. Further evaluation and optimization of PET as a tool for target identification are required.

A comparative study of target volumes based on XXXX PET-CT and ten phases of 4DCT for primary @entity418 .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity2803 :: ('MESH:D003586', 'Disease') :: ['degree of inclusion', 'DI'] @entity419 :: ('MESH:D019788', 'Chemical') :: ['(18)F-FDG'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor'] @entity418 :: ('MESH:D004938', 'Disease') :: ['thoracic esophageal cancer']
@entity419 :: (MESH:D019788,Chemical) :: ['(18)F-FDG']
