[1
]Molecular
Imaging Chemistry Laboratory, Wolfson Brain Imaging Centre, University of
Cambridge, Cambridge CB2 1TN, U.K.
[2
]Division
of Nuclear Medicine, Department of Radiology, The University of Michigan
Medical School, Ann Arbor, Michigan 48109, United States
[3
]Laboratory
for Molecular Imaging, Wolfson Brain Imaging Centre, University of Cambridge,
Cambridge CB2 1TN, U.K.
[4
]The
Interdepartmental Program in Medicinal Chemistry, The University of Michigan,
Ann
Arbor, Michigan 48109, United States