- Ammonia Perfusion PET: The participant will be scheduled for the tumor ablation procedure as part of the participant's routine care. If the participant decided to take part in this research study, then the participant will have one or two ammonia perfusion PET scans during the ablation procedure to see if the ablation was successful or not as compared to standard CT scanning. The ammonia perfusion PET scans are the research part of the participant's procedure. The rest of the participant's procedure is not research. The participant will receive one or two doses of the radioactive tracer called N-13 ammonia. This tracer is administered through the same IV (thin tube placed in a vein) used by the Anesthesiologist to give the participant routine medications that relax the participant, prevent pain, and allow the participant to sleep during the procedure. This tracer does not treat the participant's tumor in any way. Instead, the tracer may allow the radiologist to better see how much of the participant's tumor was destroyed.