Abstract

Purpose

To study the differences between continuous and short-pulse mode microwave ablation (MWA).

Methods

We built a computational model for MWA including a 200 mm long and 14 G antenna from Amica-Gen and solved an electromagnetic-thermal coupled problem using COMSOL Multiphysics. We compared the coagulation zone (CZ) sizes created with pulsed and continuous modes under ex vivo and in vivo conditions. The model was used to compare long vs. short pulses, and 1000 W high-powered short pulses. Ex vivo experiments were conducted to validate the model.

Results

The computational models predicted the axial diameter of the CZ with an error of 2–3% and overestimated the transverse diameter by 9–11%. For short pulses, the ex vivo computer modeling results showed a trend toward larger CZ when duty cycles decreases. In general, short pulsed mode yielded higher CZ diameters and volumes than continuous mode, but the differences were not significant (<5%), as in terms of CZ sphericity. The same trends were observed in the simulations mimicking in vivo conditions. Both CZ diameter and sphericity were similar with short and long pulses. Short 1000 W pulses produced smaller sphericity and similar CZ sizes under in vivo and ex vivo conditions.

Conclusions

The characteristics of the CZ created by continuous and pulsed MWA show no significant differences from ex vivo experiments and computer simulations. The proposed idea of enlarging coagulation zones and improving their sphericity in pulsed mode was not evident in this study.

中文翻译：

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短脉冲微波消融：计算机建模和离体实验

摘要

目的

研究连续和短脉冲模式微波消融（MWA）之间的区别。

方法

我们为MWA建立了一个计算模型，其中包括200米长的Amica-Gen天线和14 G天线，并使用COMSOL Multiphysics解决了电磁热耦合问题。我们比较了离体和体内条件下以脉冲和连续模式产生的凝结区（CZ）大小。该模型用于比较长脉冲和短脉冲以及1000 W高功率短脉冲。进行离体实验以验证模型。

结果

计算模型预测了CZ的轴向直径，误差为2-3％，而横向直径则高估了9-11％。对于短脉冲，离体计算机建模结果显示，当占空比降低时，CZ趋向更大。通常，短脉冲模式比连续模式产生更高的CZ直径和体积，但就CZ球形度而言，差异并不显着（<5％）。在模拟体内条件的模拟中观察到了相同的趋势。短脉冲和长脉冲的CZ直径和球形度相似。在体内和离体条件下，短的1000 W脉冲产生较小的球形度和相似的CZ尺寸。

结论

由连续和脉冲MWA产生的CZ的特性与离体实验和计算机模拟没有显着差异。在脉冲波模式下扩大凝结区并改善其球形度的提议思想在本研究中并不明显。