1 Medical Physics & Informatics Laboratory of Electronics Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 80778, Taiwan ; Graduate Institute of Clinical Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
2 Department of Radiation Oncology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 83305, Taiwan.
3 Department of Radiation Oncology, City of Hope National Medical Center, Duarte, CA 91010, USA.
4 Department of Radiation Oncology, The Ohio State University, Columbus, OH 43210, USA.