Grkovski M, et al. - In this study serial dynamic ¹⁸F-fluoromisonidazole (¹⁸F-FMISO) PET is performed to examine changes in tumor biomarkers of perfusion and hypoxia after cediranib treatment. The outcome suggests that the ¹⁸F-FMISO kinetic modeling uncovers a more detailed response to antiangiogenic treatment than a single static image is able to reveal. The decreased mean K₁ reflects a reduction in tumor vascular perfusion, whereas the increased k₃ reflects a rise in hypoxia-mediated entrapment of the radiotracer. However, if only late static images are examined, the observed reduction in ¹⁸F-FMISO uptake after treatment with cediranib may be mistakenly interpreted as a global decrease, rather than an increase, in tumor hypoxia. These outcomes support the utilization of ¹⁸F-FMISO kinetic modeling to more accurately characterize the response to treatments that have a direct affect on tumor vascularization and perfusion.