1. Center for Molecular
Imaging, Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109-2200, United States
2. Jiangsu Key Laboratory of New Drug Research
and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu 221004, China
3. Department of Molecular Pharmacology, Physiology & Biotechnology, Brown University, Providence, Rhode Island 02912, United States
4. Department
of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States