1. From the Departments of Radiology (S.J.B., J.C., Y.Q., K.H., G.P.C., F.Z., C.T.B., G.A.J.), Radiation Oncology (Y.M.M., A.M.B., D.G.K.), and Pathology (J.I.E.), Duke University Medical Center, Center for In Vivo Microscopy, Bryan Research Building, 311 Research Dr, Durham, NC 27710.