[1] Singapore Gen Hosp, Dept Diagnost Radiol, Singapore 169608, Singapore
[2] Natl Canc Ctr, Dept Therapeut Radiol, Singapore, Singapore
[3] Univ N Carolina, Dept Radiol, Chapel Hill, NC USA
[4] Univ Texas, MD Anderson Canc Ctr, Dept Radiol, Houston, TX 77030 USA
[5] Chang Gung Mem Hosp, Dept Diagnost Radiol, Taoyuan, Taiwan
[6] Univ Hong Kong, Queen Mary Hosp, Dept Radiat Oncol, Hong Kong, Peoples R China
[7] Univ Toronto, Princess Margaret Hosp, Dept Radiat Oncol, Toronto, ON, Canada