title: [Comparison of microwave coagulation using a new type electrode with radiofrequency ablation in the liver of living animals].
abstract: In the present study, we compared microwave coagulation using a new type of electrode, a teflon-coated electrode that was developed in order to increase the area of coagulation, with radiofrequency ablation using a Radionics Cool-tip electrode inserted into the pig liver. Two Landrace male pig were put under general anesthesia. A microwave electrode (insulated area: 6 mm, teflon-coated electrode 16 G) and a radiofreqency (RF) electrode (Cool-tip RF single electrode 17 G) were passed through the surface of the livers of the pig. A thermometer was placed 1 cm from the tip of the electrode in order to measure the changes in the temperature of the area surrounding the electrode. In this study, the microwave setting was 80 W, and the RF pulse was set automatically. The coagulated and ablated areas of the liver were measured after 2.5, 5, and 10 minutes of energy delivery (n = 4). The diameter of the coagulated area of the liver following 2.5, 5 and 10 minutes of microwave exposure was 23.5 +/- 4.8 mm, 29.5 +/- 5.2 mm and 32.5 +/- 6.4 mm, respectively. On the other hand, the diameter of the ablated area of the liver following 2.5, 5 and 10 minutes of RF exposure was 18.5 +/- 4.1 mm, 24 +/- 7.8 mm and 28 +/- 4.9 mm, respectively. The mean temperature of the liver 1 cm from the microwave and RF electrodes (measured time: 2 minutes) was 69.6 degrees C and 56.3 degrees C. respectively (n = 12). Thus, the temperature of the area surrounding the microwave electrode was significantly higher than the temperature of the area surrounding the RF electrode (p = 0.0065). The teflon-coated microwave electrode achieved superior results to the Radionics Cool-tip electrode with respect to the diameter of the coagulated area and the temperature of the area in which the electrode was inserted, at the specified times.
authors.affiliation: Dept. of Surgery, Toyonaka Municipal Hospital.
authors.forename: T
authors.initials: T
authors.lastname: Shibata
authors.forename: T
authors.initials: T
authors.lastname: Morita
authors.forename: M
authors.initials: M
authors.lastname: Okuyama
authors.forename: M
authors.initials: M
authors.lastname: Kitada
authors.forename: Y
authors.initials: Y
authors.lastname: Tsukahara
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: R
authors.initials: R
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Shimano
authors.forename: T
authors.initials: T
authors.lastname: Ishida
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D004564:Electrocoagulation / Q000379:methods*; D004566:Electrodes; D008099:Liver / Q000601:surgery*; D008872:Microwaves / Q000627:therapeutic use*; D013552:Swine