1. Key Laboratory for Organic Electronics & Information Displays and Institute of Advanced Materials; Nanjing University of Posts & Telecommunications; Nanjing 210046 China
2. Molecular Imaging Program at Stanford (MIPS), Canary Center at Stanford for Cancer Early Detection, Department of Radiology and Bio-X Program, School of Medicine; Stanford University; Stanford California 94305-5484 USA
3. Department of Radiology; First Hospital of Shanxi Medical University; Taiyuan 030001 China
4. Key Laboratory of Nuclear Medicine Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine; Jiangsu Institute of Nuclear Medicine; Wuxi 214063 China
5. Department of Neurosurgery, School of Medicine; Stanford University; Stanford California 94305 USA