Figure 1From: Designed-seamless irradiation technique for extended whole mediastinal proton-beam irradiation for esophageal cancerDefinition of PTV. CTV included the primary tumor plus a 30-mm cranial-caudal margin, and included the metastatic lymph nodes plus a 10-mm margin. PTV encompassed the CTV with a 5- to 10-mm margin in all directions. PTV was divided into two sections covered by a single PBT field: cranial PTV and caudal PTV.Back to article page