1. Departments of Radiology and Medical Physics University of Wisconsin–Madison Madison WI 53705 USA
2. Department of Nuclear Medicine Union Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430073 China
3. State Key Laboratory of High Performance Ceramics and Superfine Microstructures Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China
4. Medical Isotopes Research Center and Department of Radiation Medicine School of Basic Medical Sciences Peking University Health Science Center Beijing 100191 China
5. University of Wisconsin Carbone Cancer Center Madison WI 53705 USA