1. Cyclotron Research Center, Iwate Medical University, 348-58 Tomegamori, Takizawa, Iwate 020-0173, Japan
2. Nishina Memorial Cyclotron Center, Japan Radioisotope Association, 348-58 Tomegamori, Takizawa, Iwate 020-0173, Japan
3. First Department of Oral Anatomy, Iwate Medical University, 3-27 Chuodori 1-chome, Morioka 020-8505, Japan