Lee Jeong Min, Rhim Hyunchul, Han Joon Koo, Youn Byung Jai, Kim Se Hyung, Choi Byung Ihn
Department of Radiology, Seoul National University College of Medicine.
Invest Radiol. 2004 Feb;39(2):89-96. doi: 10.1097/01.rli.0000105041.12347.4b.
To determine whether alternative radiofrequency (RF) application with dual probes has advantages over sequential or simultaneous RF application for creating larger coagulation necrosis.
Using 2 17-gauge internally cooled electrodes and a 200-watt generator (CC-3 model, Radionics), RF energy was applied sequentially (group A, n = 20), simultaneously (group B, n = 20), or alternately (group C, n = 20) to explanted bovine liver. After preliminary experiments with a probe distance of 2-5 cm, a distance of 2 cm and 3 cm were chosen for main experiments. Total duration of the RF application was 10 minutes. In the alternative mode, the energy was applied alternately to both RF electrodes in 2-second intervals. Changes occurring in tissue impedance, current, power output, and temperature at the midpoint between the 2 electrodes were measured. The technical parameters, temperatures, and dimension of the ablated area were compared in the 3 groups using analysis of variance or Kruskal-Wallis test.
In the groups B and C, the impedance was gradually decreased during RF application and the mean current flow of both groups was 1550 +/- 130 mA and 1375 +/- 175 mA, respectively. However, in the group A, the impedance was markedly increased during RF application, and the mean current was 940 +/- 484 mA (P < 0.05, between groups A and B, and groups A and C). With 3-cm spacing, the alternative RF application created oval-shaped ablation zones with larger shortest axis diameter at the midpoint than either the sequential or simultaneous RF application: 12.0 +/- 7.1 mm in group A; 27.0 +/- 3.1 mm in group B; 34.9 +/- 3.4 mm in group C (P < 0.05). With 2 cm spacing, the corresponding figures were 25.3 +/- 7.8 mm in group A; 34.9 +/- 7.8 mm in group B; 41.5 +/- 1.8 mm in group C (P < 0.05): the differences between groups A and B, and between groups A and C were statistically significant (P < 0.05). With 3-cm spacing, the temperature at the midpoint between the 2 probes was higher in group C (102 degrees C) than in either the group A (62 degrees C) or the group B (78 degrees C; P < 0.05). With 2-cm spacing, groups B and C showed higher temperature than group A (P < 0.05), but the difference between groups B and C was not significant (P > 0.05).
The alternative RF application creates larger, more regular ablation zones than either the sequential or simultaneous RF application. This result suggests that use of an alternating RF power application will improve the results of RF ablation for the treatment of larger tumors.
确定使用双探头交替射频（RF）应用在产生更大的凝固性坏死方面是否优于顺序或同时RF应用。
使用2根17号内部冷却电极和一台200瓦发生器（CC - 3型，Radionics公司），对离体牛肝依次（A组，n = 20）、同时（B组，n = 20）或交替（C组，n = 20）施加RF能量。在探头距离为2 - 5 cm的初步实验后，主实验选择2 cm和3 cm的距离。RF应用的总持续时间为10分钟。在交替模式下，能量以2秒的间隔交替施加到两个RF电极上。测量两个电极中点处组织阻抗、电流、功率输出和温度的变化。使用方差分析或Kruskal - Wallis检验比较三组的技术参数、温度和消融区域的尺寸。
在B组和C组中，RF应用期间阻抗逐渐降低，两组的平均电流分别为1550±130 mA和1375±175 mA。然而，在A组中，RF应用期间阻抗显著增加，平均电流为940±484 mA（A组与B组以及A组与C组之间，P < 0.05）。间距为3 cm时，交替RF应用产生的椭圆形消融区在中点处的最短轴直径比顺序或同时RF应用的更大：A组为12.0±7.1 mm；B组为27.0±3.1 mm；C组为34.9±3.4 mm（P < 0.05）。间距为2 cm时，相应的数据分别为：A组25.3±7.8 mm；B组34.9±7.8 mm；C组41.5±1.8 mm（P < 0.05）：A组与B组以及A组与C组之间的差异具有统计学意义（P < 0.05）。间距为3 cm时，C组两个探头中点处的温度（102℃）高于A组（62℃）或B组（78℃；P < 0.05）。间距为2 cm时，B组和C组的温度高于A组（P < 0.05），但B组和C组之间的差异不显著（P > 0.05）。
交替RF应用比顺序或同时RF应用产生更大、更规则的消融区。该结果表明，使用交替RF功率应用将改善RF消融治疗较大肿瘤的效果。
