Hypoxia is a known factor for resistance to radiotherapy in tumors. Response to transarterial radioembolization is known to be variable between different patients even if the same dose of radiation was delivered. In this study the investigators aim to quantify the hypoxia in the primary and secondary tumors of liver with 18F-FMISO PET before radioembolization and to prove any effect of the hypoxia, if present, on the dose that should be delivered to tumor to ensure treatment response.

Inclusion Criteria:

• Diagnosed with colorectal carcinoma with liver metastasis or hepatocellular carcinoma.
• Is not eligible for surgery
• Above 18 years old
• The patients who are referred for transarterial radioembolization treatment to Ankara University School of Medicine Department of Nuclear Medicine.

Exclusion Criteria:

• Patients with ECOG performance score >1
• Claustrophobia
• Life expectancy shorter than 3 months
• Pregnant or breast-feeding patients

The patients with hepatocellular carcinoma or colorectal carcinoma with liver metastasis who are referred for transarterial radioembolization to Ankara University School of Medicine Department of Nuclear Medicine will be enrolled for the trial.