Liver cancer, especially colorectal cancer, is a significant health concern. In the United States, half of the 157,000 new cases of colorectal cancer will lead to metastases in the liver, which will lead to over 17,000 deaths. And while not as significant a health risk as colorectal metastasis, hepatocellular carcinoma is being diagnosed with increasing frequency. The current standard of practice for treating liver cancer is surgical resection, but only 10% of patients are eligible for this procedure. Thermal ablation using radiofrequency is a promising alternative therapy, but it can only treat small tumors. The applicants propose to continue development of a saline-enhanced radiofrequency ablation system for treating large liver tumors. The system uses radiofrequency energy to heat tissue, but this would be complimented with simultaneous injection of warm saline through the electrode and into the tissue The injected saline flows through the extracellular space and convects the thermal energy deep into the tissue. Consequently, it would be possible to treat significantly larger tumor volumes than previously possible. The technique has been reported to created thermal lesions whose volumes are 90 times as large as those created with conventional radiofrequency electrodes. The method would therefor enable percutaneous thermal ablation therapy to be used on larger tumors, greatly increasing the number of patients eligible for therapy