1. School of Mechanical, Electrical and Information Engineering, Shandong University, Weihai 264209, China
2. Department of Radiation Oncology and Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan 250117, China
3. Laboratory of Image Science and Technology, School of Computer Science and Engineering, Southeast University, Nanjing 210096, China
4. Department of Oncology, Binzhou People’s Hospital, Binzhou 256610, China
5. Third Clinical Medical College, Xinjiang Medical University, Urumqi 830011, China