目的： 探讨生理盐水隔离液在激光、射频及微波三种甲状腺消融术中的安全性。方法： 实验用猪分为激光、射频及微波消融3组,每组5头。麻醉后注射10 mL无菌生理盐水,使甲状腺腺体与周围组织分离,形成宽度>5 mm的液体隔离带。将3根测温针中2根分别置于距消融针能量发射端约5、10 mm的组织内,另1根测温针在消融针能量发射端另侧约5 mm的生理盐水中。在超声引导下分别给予激光、射频及微波消融猪甲状腺,形成横切长约10 mm的热消融灶。超声扫描实时观察消融过程,并记录二维消融超声检查变化,密切观察记录测温针的温度变化。结果： 激光、射频、微波术后灰阶超声检查消融灶体积、术后造影灌注检查体积缺损,组间差异均无统计学意义（P>0.05）。激光、射频及微波消融方式距离中心点5 mm的温度证明消融治疗有效。在拟定安全区域生理盐水隔离带中,微波消融组有3头猪温度超过60.0 ℃,其中1头最高达80.7 ℃。结论： 生理盐水作为甲状腺热消融液体隔离带应用于激光和射频消融相对安全,不宜用生理盐水作为微波消融隔离带。建议用介电性能与周围生物组织差异较大的非极性物质作为隔离带,可提高微波热消融的安全性。

Objective To investigate the safety of normal saline isolation zone in laser, radiofrequency and microwave thyroid ablation. Methods Fifteen pigs were divided into laser, radiofrequency and microwave three groups. Ten mL sterile normal saline were injected postanesthesialy to separate thyroid from surrounding tissues and form a liquid isolation zone with the width >5 mm. Two of 3 temperature measurement needles were placed in the tissues beneath 5 mm, 10 mm from ablation needle, and one needle in normal saline isolation zone 5 mm from ablation needle other side. Porcine thyroid was ablated using ultrasound-guided laser, radiofrequency or microwave respectively and a thermal ablated lesion in thyroid was formed with inner diameter about 10 mm. Two-dimensional ablation process was observed and recorded by ultrasound in real time and the change in temperature of ablation was carefully observed and recorded by temperature measurement needle. Results There were no significant differences statistically in the volume of ablation lesion and the volume of defect measured by perfusion after thermal ablation among laser, radiofrequency or microwave (P>0.05). Ablation process was proved effective by laser, radiofrequency or microwave ablation with the temperature at 5 mm from center point. The temperature in normal saline isolation zone of three pigs with microwave ablation exceeded 60.0 ℃, and up to 80.7 ℃ in one pig. Conclusions Normal saline may provide safe isolation zone in thyroid thermal ablation for laser or radiofrequency ablation, but not appropriate for microwave ablation. We recommended to use non-polar substances with great difference in dielectric properties from surrounding biological tissues as isolation zone, which can improve safety for microwave thermal ablation.