Dosimetric comparison of TomoDirect, helical tomotherapy, VMAT, and ff-IMRT for upper thoracic esophageal carcinoma.

All techniques are able to provide a homogeneous and highly conformal dose distribution. The TD technique is a good option for treating upper thoracic EC involvement. It could achieve optimal low dose to the lungs and spinal cord with acceptable PTV coverage. HT is a good option as it could achieve quality dose conformality and uniformity, while TD generated superior conformality.