Fusion imaging of US and MRI is very helpful for interventional procedure such as radiofrequency ablation in liver. However, manual registration of US and magnetic resonance (MR) imaging is somewhat time-consuming and difficult for less-experienced physicians. Recently, automatic registration function was developed to help the fusion of US and CT/MRI imaging. The purpose of this trial is to compare the registration time and accuracy of manual registration system and automatic registration system.

1. Patients will be randomized and assigned.
2. For automatic registration group, automatic image fusion will be done by RS80A US unit and RF ablation will be performed. Image fusion time will be measured.
3. For manual registration group, manual image fusion will be done by LOGIQ-E9 US unit and RF ablation will be performed. Image fusion time will be measured.

3) After radiofrequency (RF) ablation, immediate, contrast enhanced CT will be performed to evaluate technical success and complications 4) Accuracy of registration will be measured by home-made software using 3D techniques.

5) After one month, technical effectiveness will be evaluated by contrast enhanced CT 6) F/U of CT images will be obtained until one year after RF ablation with a interval of 1-3 months.

Inclusion Criteria:

• More than 40-years old
• Patients with hepatic malignancy who will underwent radiofrequency ablation

Exclusion Criteria:

• Not using fusion imaging (CT guidance or fluoroscopic guidance)