1. Cyclotron Research Center, Iwate Medical University, 348-58 Tomegamori, Takizawa, Iwate 020-0603, Japan
2. Takizawa Laboratory, Japan Radioisotope Association, 348-1 Tomegamori, Takizawa, Iwate 020-0603, Japan
3. Graduate School of Health Sciences, Gunma University, 3-39-22 Showa-machi, Mabashi, Gunma 371-8514, Japan