1. Key Laboratory of Protein and Peptide PharmaceuticalsCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences Beijing 100101 P. R. China
2. University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Medical and Health Analysis CenterPeking University Beijing 100191 P. R. China
4. Medical Isotopes Research Center and Department of Radiation MedicineSchool of Basic Medical SciencesPeking University Beijing 100191 P. R. China
5. Department of UltrasoundPeking University Third Hospital Beijing 100191 P. R. China