Department of Radiology, University of Wisconsin, Madison, Wisconsin 53705, USA.
Med Phys. 2010 Jun;37(6):2967-73. doi: 10.1118/1.3432569.
To compare ablation zones created with equal amounts of 2.45 GHz microwave and 480 kHz radiofrequency (RF) energy in ex vivo liver and lung.
A total of 38 ablations were performed in ex vivo liver and lung for 10 min each. Nineteen RF ablations (nine liver, ten lung) were performed with a 480 kHz system (200 W max, impedance-based pulsing) and cooled electrode while measuring the average RF power applied. Nineteen microwave ablations (nine liver, ten lung) were then created using a cooled triaxial antenna to deliver 2.45 GHz at the same power level as in RF experiments. Ablation zones were then sectioned and measured for minimum, maximum and mean diameters, and circularity. Measurements were compared using t-tests, with P < 0.05 indicating statistical significance.
Mean diameters of microwave ablations were greater than RF ablations in both liver and lung (4.4 +/- 0.3 vs 3.3 +/- 0.2 cm in liver; 2.45 +/- 0.3 vs 1.6 +/- 0.5 cm in lungs; P < 0.0005 all comparisons). There was no significant difference in the mean power applied during microwave or RF ablations in either organ (54.44 +/- 1.71 W vs 56.4 +/- 6.7 W in liver, P > 0.05; 40 +/- 0.95 W vs 44.9 +/- 7.1 W in lung, P > 0.05).
Using a single cooled applicator, microwave energy at 2.45 GHz produces larger ablations than an equivalent amount of 480 kHz RF energy in normal liver and lung. This was more apparent in lung, likely due to the high baseline impedance which limits RF, but not microwave power delivery.
比较 2.45GHz 微波和 480kHz 射频（RF）能量在离体肝脏和肺中产生的消融区域。
在离体肝脏和肺中进行了总共 38 次消融，每次 10 分钟。19 次 RF 消融（肝脏 9 次，肺 10 次）在 480kHz 系统（200W 最大功率，基于阻抗的脉冲）下进行，并使用冷却电极同时测量施加的平均 RF 功率。然后使用冷却三轴天线进行 19 次微波消融，以在 RF 实验中提供相同功率水平的 2.45GHz。然后将消融区域切片并测量最小、最大和平均直径以及圆度。使用 t 检验比较测量值，P<0.05 表示具有统计学意义。
在肝脏和肺中，微波消融的平均直径均大于 RF 消融（肝脏 4.4±0.3 与 3.3±0.2cm；肺 2.45±0.3 与 1.6±0.5cm；P<0.0005 所有比较）。在两种器官中，微波或 RF 消融期间施加的平均功率没有显著差异（肝脏 54.44±1.71W 与 56.4±6.7W；P>0.05；肺 40±0.95W 与 44.9±7.1W；P>0.05）。
在正常肝脏和肺中，使用单个冷却探头，2.45GHz 的微波能量产生的消融区域大于等效数量的 480kHz RF 能量。在肺中更为明显，这可能是由于高基线阻抗限制了 RF，但不限制微波功率输送。
