1. Key Laboratory of Particle & Radiation Imaging, Ministry of Education, Department of Engineering Physics, Tsinghua University, Beijing 100084, P. R. China
2. Department of Engineering Mechanics, Tsinghua University, Beijing 100084, P. R. China
3. Medicament Department, Union Jiangbei Hospital, Huazhong University of Science and Technology, Wuhan Caidian People’s Hospital, Wuhan 43000, P. R. China