1. Engineering Research Center of Molecular‐imaging and Neuro‐imaging of Ministry of Education School of Life Science and Technology Xidian University Xi'an Shaanxi 710126 China
2. Laboratory of Molecular Imaging and Nanomedicine (LOMIN) National Institute of Biomedical Imaging and Bioengineering (NIBIB) National Institutes of Health (NIH) Bethesda MD 20892 USA
3. State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine School of Public Health Xiamen University Xiamen 361005 China