Brace Christopher L, Hinshaw J Louis, Laeseke Paul F, Sampson Lisa A, Lee Fred T
Department of Radiology, University of Wisconsin, Clinical Sciences Center, E1/322, 600 Highland Ave, Madison, WI 53792-3252, USA.
Radiology. 2009 Jun;251(3):705-11. doi: 10.1148/radiol.2513081564. Epub 2009 Mar 31.
To compare the performance of equivalently sized radiofrequency and microwave ablation applicators in a normal porcine lung model.
All experiments were approved by an institutional animal care and use committee. A total of 18 ablations were performed in vivo in normal porcine lungs. By using computed tomographic (CT) fluoroscopic guidance, a 17-gauge cooled triaxial microwave antenna (n = 9) and a 17-gauge cooled radiofrequency (RF) electrode (n = 9) were placed percutaneously. Ablations were performed for 10 minutes by using either 125 W of microwave power or 200 W of RF power delivered with an impedance-based pulsing algorithm. CT images were acquired every minute during ablation to monitor growth. Animals were sacrificed after the procedure. Ablation zones were then excised and sectioned transverse to the applicator in 5-mm increments. Minimum and maximum diameter, cross-sectional area, length, and circularity were measured from gross specimens and CT images. Comparisons of each measurement were performed by using a mixed-effects model; P < .05 was considered to indicate a significant difference.
Mean diameter (3.32 cm +/- 0.19 [standard deviation] vs 2.70 cm +/- 0.23, P < .001) was 25% larger with microwave ablation and mean cross-sectional area (8.25 cm(2) +/- 0.92 vs 5.45 cm(2) +/- 1.14, P < .001) was 50% larger with microwave ablation, compared with RF ablation. With microwave ablation, the zones of ablation were also significantly more circular in cross section (mean circularity, 0.90 +/- 0.06 vs 0.82 +/- 0.09; P < .05). One small pneumothorax was noted during RF ablation but stabilized without intervention.
Microwave ablation with a 17-gauge high-power triaxial antenna creates larger and more circular zones of ablation than does a similarly sized RF applicator in a preclinical animal model. Microwave ablation may be a more effective treatment of lung tumors.
在正常猪肺模型中比较同等大小的射频和微波消融器的性能。
所有实验均经机构动物护理和使用委员会批准。在正常猪肺中进行了共18次体内消融。使用计算机断层扫描（CT）透视引导，经皮放置一根17号冷却三轴微波天线（n = 9）和一根17号冷却射频（RF）电极（n = 9）。使用基于阻抗的脉冲算法，以125 W的微波功率或200 W的射频功率进行10分钟的消融。消融过程中每分钟采集CT图像以监测消融范围的扩大情况。术后处死动物。然后切除消融区，并以5毫米的增量垂直于消融器进行切片。从大体标本和CT图像测量最小和最大直径、横截面积、长度和圆形度。使用混合效应模型对每项测量进行比较；P < 0.05被认为表示有显著差异。
与射频消融相比，微波消融的平均直径（3.32 cm ± 0.19 [标准差] 对 2.70 cm ± 0.23，P < 0.ooo1）大25%，平均横截面积（8.25 cm² ± 0.92 对 5.45 cm² ± 1.14，P < 0.001）大50%。微波消融时，消融区的横截面也明显更接近圆形（平均圆形度，0.90 ± 0.06 对 0.82 ± 0.09；P < 0.05）。射频消融过程中发现一个小气胸，但未干预自行稳定。
在临床前动物模型中，使用17号高功率三轴天线进行微波消融比同等大小的射频消融器产生更大且更接近圆形的消融区。微波消融可能是治疗肺肿瘤更有效的方法。
