1. Department of Quantum Science and Energy Engineering, Tohoku University, Sendai 980-8579, Japan
2. Cyclotron Radioisotope Center, Tohoku University, Sendai 980-8578, Japan
3. Department of Pharmacology, Tohoku University, Sendai 980-8575, Japan
4. Department of Pharmacology, Iwaki Meisei University, Iwaki 970-8551, Japan