Role of clip markers placed by endoscopic ultrasonography in contouring gross tumor volume for thoracic esophageal squamous cell carcinoma: one prospective study

Yong Guan, Jing Wang, Fuliang Cao, Xi Chen, Yuwen Wang, Shengpeng Jiang, Daguang Zhang, Wencheng Zhang, Zhoubo Guo, Ping Wang, Qingsong Pang