1Department of Medical Imaging, Chi Mei Medical Center, Tainan, Taiwan, 2Institute of Biomedical Science, National Sun Yat-Sen University, Kaohsiung, Taiwan, 3Department of Radiology, I-Shou University and Eda Hospital, Kaohsiung, Taiwan, 4Center for Functional Onco-Imaging, University of California, Irvine, CA, United States