1 Department of Biomedical Engineering, College of Future Technology, National Biomedical Imaging Center, Peking University, Beijing, China.
2 Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, USA.
3 Department of Biomedical Engineering, College of Future Technology, National Biomedical Imaging Center, Peking University, Beijing, China. zhifei.dai@pku.edu.cn.