Abstract

Objective: To explore various microwave (MW) time/power combinations to achieve maximum single-probe system performance in a live pig liver model.

Methods: Fifty-one microwave ablations performed in 12 female pigs using the following time/power combinations: 65 W for 10 min (65W 10MIN), ramped from 20 to 65 W (RAMPED), 95 W pulses with cooling periods (95W PULSED), 40 W for 16 min 15 s (LOW POWER), 1 min 95 W pulse then 8 min 65 W then a second 1 min 95 W pulse (BOOKEND 95W) and 65 W for 15 min (65W 15MIN). Temperatures 1.5 cm from the antenna were measured. Livers were excised, and ablations were measured and compared.

Results: At fixed overall energy, LOW POWER produced ablation zones with the smallest volume compared to 65W 10MIN, RAMPED and 95W PULSED. At a fixed time of 10-min, BOOKEND 95W protocol achieved wider and larger ablation zones than 65W 10MIN (p = 0.038, p = 0.008) and 95W PULSED (p = 0.049, p = 0.004). The 65W 15MIN combination had significantly larger diameters (p = 0.026), larger lengths (p = 0.014) and larger volumes (p = 0.005) versus 65W 10MIN. Maximum temperatures were highest with BOOKEND 95W (62.9 °C) and 65 W 15 MIN (63.0 °C) and lowest with LOW POWER (45.9 °C), p = 0.009.

Conclusions: Low power ablations, even if controlled for total energy delivery, create small ablation zones. High peak powers are associated with larger ablation zones and high margin temperatures if cooling pauses are avoided. Ramping and pulsing protocols with interleaved cooling appear to be of no benefit versus continuous 65 W for creating large ablation zones.

摘要

目的：探索各种微波（MW）时间/功率组合，以在活猪肝模型中实现最大的单探头系统性能。

方法：使用以下时间/功率组合在12只雌猪中进行五十一次微波消融：65 W持续10分钟（65W 10MIN），从20 W升高到65 W（RAMPED），95 W脉冲并具有冷却时间（95W PULSED） ，40 W持续16分钟15 s（低功率），1分钟95 W脉冲，然后8分钟65 W，然后再进行1分钟95 W脉冲（BOOKEND 95W），然后65 W持续15分钟（65W 15MIN）。测量距天线1.5厘米的温度。切除肝脏，测量并比较消融。

结果：在固定的总能量下，低功率产生的消融区体积最小，而65W 10MIN，RAMPED和95W PULSED。在10分钟的固定时间，BOOKEND 95W协议实现了比65W 10MIN（p  = 0.038，p  = 0.008）和95W PULSED（p  = 0.049，p  = 0.004）更大，更大的消融区域。 与65W 10MIN相比，65W 15MIN组合具有明显更大的直径（p  = 0.026），更大的长度（p  = 0.014）和更大的体积（p = 0.005）。BOOKEND 95W（62.9°C）和65 W 15 MIN（63.0°C）的最高温度最高，而LOW POWER（45.9°C）的最低温度最低，p  = 0.009。

结论：即使控制总能量输送，低功率消融也会产生小的消融区。如果避免冷却暂停，则较高的峰值功率会与较大的烧蚀区和较高的容限温度相关。相对于连续65 W产生较大的消融区，采用交错冷却的斜坡和脉冲方案似乎没有任何好处。