2003-2004. Resident in Department of Radiation Oncology, Gunma University Hospital, Gunma, Japan. 2004-2005. Resident in Department of Radiology, Takasaki National Hospital, Gunma, Japan. 2005-2006. Resident in Department of Radiation Oncology, Gunma University Hospital. Gunma, Japan. 2006-2009. Resident for Department of Radiation Oncology, Gunma Prefectural Cancer Center. Gunma, Japan. 2009-2011. Postdoctoral researcher in Department of Radiation Oncology, Arthur G. James Comprehensive Cancer Center, The Ohio State University Medical School, Columbus, Ohio, United States. 2011-2013. Assistant professor in Department of Radiation Oncology, Gunma University Hospital, Gunma, Japan. 2013-2017. Associate professor, Department of Radiation Oncology, Gunma University Hospital, Gunma, Japan. 2017-2020. Professor in Department of Radiology, Saitama Medical Center, Jichi Medical University, Saitama, Japan. 2020-Present. Professor in Department of Radiation Oncology, Jichi Medical University Hospital, Tochigi, Japan.