Effect of contrast enhancement in delineating GTV and constructing IGTV of thoracic oesophageal cancer based on 4D-CT scans

Contrast-enhanced 4D-CT scans can reduce the error of target volume delineation and be used to construct a more accurate internal target volume in patients with middle thoracic oesophageal cancer, however, whether GTV delineation or IGTV construction for patients with upper or lower thoracic oesophageal cancer, no significant benefit was found from contrast-enhanced 4D-CT scan.