1. Cyclotron Research Center, Iwate Medical University, 348-58 Tomegamori, Takizawa, Iwate 020-0603, Japan
2. Takizawa Laboratory, Japan Radioisotope Association, 348-58 Tomegamori, Takizawa, Iwate 020-0603, Japan
3. General Research Center, 1220-69 Oaza Tomioka, Nasu-chou, Nasu-gun, Tochigi 329-3212, Japan