1. Molecular Imaging Program and
2. Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-1088
3. Nuclear Medicine Department, Warren Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892
4. Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan