1. Department of Ultrasound, Peking University Third Hospital, Beijing 100191, China
2. National Engineering Research Center of Flame Retardant Materials, School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China
3. Medical Isotopes Research Center and Department of Radiation Medicine, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
4. Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore 138673, Singapore