PET/CT-Assessment of Liver Tumor Ablation

In this research study, the investigators are evaluating whether ammonia PET scans or FDG PET perfusion scans are more useful in helping radiologists determine whether liver tumors were successfully destroyed by the heating or freezing procedures (ablations) than other scans currently available to radiologists, such as CT scans and MRI scans. The currently available scan (usually a CT scan with contrast dye) is not always effective in showing how completely the tumor has been destroyed. The ammonia PET scan is a different way of looking at how much tumor has been destroyed. This study will compare the standard scan (CT scan) with the ammonia PET scan.