Hypoxic Changes in Hepatocellular Carcinoma (HCC) Following Trans Arterial Chemo Embolization and Stereotactic Radiation: Fluorine18 (18F) Fluoromisonidazole (FMISO) Imaging

Inclusion Criteria: * Adult (\> 18 years of age) patients with documented HCC tumor mass \>3cm, who are scheduled to undergo TACE with additional selective internal radiation therapy (SIRT) * The appropriate criteria for inclusion for this patient population are: * Biopsy or radiological diagnosis of HCC (defined as Organ Procurement and Transplantation Network (OPTN\*) Category 5 lesion either on CT or MRI) * Scheduled for TACE (using doxorubicin-eluting beads) + SBRT * Willingness to undergo PET/CT * Able to lie on the imaging table for up to 1 hour. * Able to provide signed informed consent. * Women with childbearing potential must have a negative urine Beta-Human Chorionic Gonadotropin (β-hCG) test day of procedure Exclusion Criteria: * Estimated life expectancy \<12 months or serious medical co-morbidities that would preclude definitive local therapy * Unable to lie on the imaging table * Age less than 18 years. * Pregnancy or lactation * Inability or unwillingness to provide informed consent. * Weight \>500 lbs (the weight limit of the tomograph gantry table)