1 From the Department of Chemistry, Hunter College, City University of New York (B.M.Z.), the Department of Radiology (B.M.Z., J.S.L.) and the Program in Molecular Pharmacology (J.S.L.), Memorial Sloan Kettering Cancer Center, and the Department of Radiology, Weill Cornell Medicine (B.M.Z., J.S.L.) - all in New York.