Molecular Imaging Program at Stanford (MIPS) and Bio-X Program, Department of Radiology, Stanford University School of Medicine, 1201 Welch Road, Stanford, California 94305, Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, California 94305, and Department of Bioengineering, Stanford University School of Medicine, Stanford, California 94305(2006-03-11時点)