1. Medical Engineering and Technology Research Center, School of Radiology, Shandong First Medical University, Shandong Academy of Medical Sciences, Taian 271000, China
2. Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu 808-0196, Japan
3. College of Materials and Chemistry, China Jiliang University, Hangzhou 310018, P. R. China