1. Laboratory
of Molecular Imaging and Nanomedicine (LOMIN), National Institute
of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, Maryland 20892, United States
2. School
of Engineering, China Pharmaceutical University, Nanjing 210009, P. R. China
3. Molecular
Imaging Center, Department of Radiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, United States
4. The White Oak Group, Washington, D.C. 20006, United States