1. Institute of Chemistry, Chinese Academy of Sciences, Bei Yi Jie 2, Zhong Guan Cun, Beijing 100190, China
2. Institute for Biochemistry, Westfälische Wilhelms-Universität, Wilhelm Klemm Straße 2, 48149 Münster, Germany
3. Molecular Imaging Laboratory, Department of Radiology, West China Hospital, Sichuan University, Chengdu 610041, China