Recently, diffusion-weighted (DW) MR imaging has widened its application on various oncologic applications. Especially, it is expected the DW MRI could provide valuable information about early response evaluation after treatment using rapid apparent diffusion coefficient (ADC) value change. It has demonstrated potential usefulness in response evaluation in the liver tumors after treatments such as transarterial chemoembolization (TACE) and radiation therapy (RT). Furthermore, it is a functional imaging technique that does not require a contrast agent, it can be safely used in patients with renal insufficiency or other medical contraindications for contrast agents.

The optimal assessment of early response of RT could provide one of the most important information to prescribe patient and cancer specific RT dose. It might be also important in palliative RT of HCC bone metastasis which is related with painful aggressive mass formation.

This study is performed to evaluate the usefulness of DW MRI in early response evaluation after RT for HCC bone metastasis.

Inclusion Criteria:

• Hepatocellular carcinoma
• Spine metastasis
• Eastern Cooperative Oncology Group (ECOG) performance status 0 to 3
• 20 or older age
• informed consent
• consent to birth control during 6 months after treatment

Exclusion Criteria:

• less than 12 weeks of expected survival
• indication of emergency operation
• uncontrolled ascites or encephalopathy
• previous RT field lesion (within in 1 month)