Thermal lesions induced by 480 KHz localized current field in guinea pig and pig liver

We evaluated the type, dimension and histopathological evolution of thermal lesions induced in guinea pig and pig liver by radiofrequency electrode needles at various temperatures for different exposure times. The greatest useful necrosis volume was induced by a needle of 1.1 mm diameter and exposed Up 10 mm long at 90 degrees C and 120 seconds exposure time. It was an ellipsoid with the biggest diameter of about 14 mm diameter and length of about 18 mm. It seems possible that liver tumors of not more than 20 mm diameter in patients without surgical prospects could be destroyed, ultrasonography guiding the needle into the tumor and using the temperature and exposure time mentioned above.