As newer cancer treatments are cytostatic rather than cytotoxic, functional changes are expected to precede the morphologic ones and therefore [18F]FDG PET/CT has the potential to improve the diagnostic accuracy and prediction of tumor course [46] Moreover, [18F]FDG reflects glucose metabolism, which is controlled by the PI3K/AKT pathways, also known as the protein kinase B. As lenvatinib inhibits this pathway upstream, its therapeutic effects can be detected as [18F]FDG uptake decreases on PET/CT [47,48]. Here, AKT1 is linked to cancer.