1. Dental Clinic for the Disabled, Tohoku University Hospital Dental Center, 4-1, Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
2. Department of Quantum Science and Energy Engineering, Tohoku University, Aramaki-Aza-Aoba 6-6-01-2, Aoba-ku, Sendai 980-8579, Japan
3. Cyclotron and Radioisotope Center, Tohoku University, Aramaki-Aza-Aoba 6-3, Aoba-Ku, Sendai 980-8578, Japan