Positron Emission Tomography (PET) with 2-deoxy-2-(18F)fluoro-D-glucose ([18F]FDG) is an integral part of the diagnostic workup in patients with suspected or confirmed cancer. The ability of the (18F)FDG-PET study to characterize and detect malignancies can be increased by dual-phase acquisition; this is due to the different kinetics of the radiotracer in the tumor tissue and in the background. We present two cases of (18F)FDG-PET/CT scans acquired in patients previously treated for malignant neoplasms who had suspected pelvic recurrences, in which the delayed acquisition was critical in accurately characterizing abnormalities.