[18F]FAZA images in Caki-1 tumor mice in the absence (left) and presence (right) of sunitinib. The insets show the respective transaxial slides of both mice. Time-activity curves for the radioactivity uptake into Caki-1 tumor in the absence and presence of sunitinib in vivo (bottom left). Image data are shown as maximum intensity projection (MIP) at 3 h post injection and TAC data as SUV and mean ± SEM from four tumors grown in two mice. Kinetic constants k1 to k4 were calculated based on a two-compartment model (bottom right). Changes were significant for k2 and k4 (*p < 0.05).