1. From the Department of Medical Imaging (Y.S.H., W.C.K., Y.C.C.) and Statistical Consulting Unit (Y.H.C., C.H.C.), National Taiwan University Hospital, No. 7 Chung-Shan S. Rd, Taipei 100, Taiwan; Department of Radiology, National Taiwan University College of Medicine, Taipei, Taiwan (Y.S.H., J.L.Y.C., Y.C.C.); and Department of Radiation Oncology, National Taiwan University Cancer Center, Taipei, Taiwan (J.L.Y.C.).