RFA Using Gradual RF Energy Delivery Mode With Octopus Electrodes

The investigators intend to perform RFA therapy on HCC less than 4 cm in size using octopus electrode, double alternating unipolar high-frequency transmission mode and gradual high-frequency energy loading mode, and to find out the therapeutic results. The primary evaluation variable is the ideal technical success rate for securing a safety margin of 5 mm or more around the tumor on the CT obtained immediately after the procedure, and the secondary evaluation variable is the volume of the cauterization lesion per unit time measured on the CT obtained immediately after the procedure, The local tumor recurrence rate, survival rate and disease-free survival rate of 12 months after the procedure, the presence or absence of multiple recurrences within the same segment, the actual procedure time, and the incidence of complications associated with the procedure are examined. The performance of RFA therapy of HCC using the Octopus electrode and gradual high-frequency energy transfer mode is compared with that of the existing Octopus electrode and RFA therapy using the basic maximum high-frequency energy transfer mode using historic cohort.