How to enlarge the radiofrequency ablation area in the lung: experimental study

射频消融术是近年来应用于肺部恶性肿瘤治疗的一种新的临床技术。扩大肺内射频消融面积是提高临床疗效的重要手段。扩大消融面积的一种可能方法是在肺内注射生理盐水以改善射频感应。另一种方法是在消融区人工阻塞肺动脉，减少血流，冷却消融区。我们的研究目的是通过动物实验来证实这两种干预措施的有效性。本实验采用家猪和直径2cm的leven射频电极和射频2000或3000发生器系统（放射治疗）。在相同的消融算法下，用注射和不注射3m1生理盐水的射频消融活猪的肺，然后将猪切开。宏观和显微镜检查显示，注射生理盐水后消融区域的体积几乎是未注射生理盐水时的两倍，注射生理盐水后消融更加均匀。在接下来的实验中，用可降解淀粉微球（DSM）暂时阻塞血管，在肺动脉栓塞和不栓塞的情况下对猪肺进行消融。宏镜检查显示，栓塞后的消融面积几乎是未栓塞时的两倍，且肺组织未因栓塞而受损。本研究揭示了当我们尝试用射频扩大肺部消融面积时，注射生理盐水和暂时阻塞肺动脉的安全性和有效性。

Radiofrequency (RF) ablation is a new clinical procedure which has been applied for the treatment of lung malignancies for recent years.To improve clinical results, it is very important to enlarge the RF ablation area in the lung. One possible way to enlarge the ablation area is an injection of saline in the lung to improve RF induction. The other way is an artificial obstruction of the pulmonary artery in the ablation area to reduce the blood flow which cools the ablation area. The purpose of our study was to confirm the usefulness of these two interventions by animal experiment.Domestic pigs and LeVeen RF electrode with 2cm in diameter and RF 2000 or 3000 Generator system (Radiotherapeutics) were used in this experiment. Living pig's lung was ablated by RF with and without 3m1 of saline injection under the same ablation algorism then the pig was scarified. Macro-and microscopic examinations showed that the volume of the ablated area with saline injection was almost twice as much as that without saline injection and more homogenous ablation was observed with saline injection.In the next experiment, pig's lung was ablated with and without pulmonary arterial embolization with degradable starch micro-spheres (DSM) which could temporarily occlude vessels. Macro-and microscopic examinations showed that the volume of the ablated area with embolization was almost twice as much as that without embolization and the lung tissue was not injured by embolization.This study revealed the safety and usefulness of saline injection and temporary occlusion of the pulmonary artery when we try to enlarge the ablation area in the lung by RF.