1. Gordon Center for Medical Imaging, Massachusetts General Hospital and Harvard Medical School, 125 Nashua Street, Suite 660, Boston, Massachusetts 02114, USA
2. School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou 450001, China
3. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, 149 Thirteenth Street, Suite 2301, Charlestown, Massachusetts 02129, USA