1. Department of Advanced Nuclear Medicine Sciences, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
2. SHI Accelerator Service, Ltd., 1-17-6 Osaki, Shinagawa-ku, Tokyo 141-0032, Japan
3. School of Biomedical Engineering and Imaging Sciences, King's College London, 4th Floor Lambeth Wing, St Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, UK