A Metallic Additively Manufactured Metamaterial for Enhanced Monitoring of Acoustic Cavitation-Based Therapeutic Ultrasound
A Metallic Additively Manufactured Metamaterial for Enhanced Monitoring of Acoustic Cavitation-Based Therapeutic Ultrasound
复制标题
用于增强声空化治疗性超声监测的金属增材制造超材料
DOI：
10.1002/adem.202100972
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发表时间：
2021
影响因子：
3.6
通讯作者：
Nie L
中科院分区：
文献类型：
--
作者：
Nie L
超声和微泡的结合可以治疗传统手术不可能或风险太大的适应症。在治疗过程中，只能从微泡中产生的亚谐和超谐成分对术中监测非常有意义。然而，与超声辐射器的基频分量相比，微泡发射的功率低几个数量级，导致用于监测的信噪比(SNR)较低。提出了一种浸入水中的三维声学超材料(AMM)来抑制不需要的超声波，从而提高了对微弱微泡发射的检测灵敏度。在数值上，虽然只有纵向超声波在水中传播，但剪切波对AMM传输特性的重要性得到了强调。在实验上，该设计是在钛材料中使用添加剂制造实现的，在基频处的衰减级为40 分贝。因此，该方法的应用有效地提高了亚谐和超谐微泡发射的信噪比，分别提高了11.8和11.9 分贝。恢复了原来被噪声淹没的次谐波分量。这是AMMS首次应用于被动声学监测，这项工作旨在改善空化介导的聚焦超声治疗的治疗结果。
The combination of ultrasound and microbubbles allows treatment of indications that would be impossible or too risk adverse with conventional surgery. During treatment, subharmonic and ultraharmonic components that can only be generated from microbubbles are of great interest for intraoperative monitoring. However, the microbubble emissions are several orders of magnitude lower in power compared to that of the fundamental frequency component from the ultrasound applicator, resulting in a low signal‐to‐noise ratio (SNR) for monitoring. A 3D acoustic metamaterial (AMM) immersed in water is proposed for suppressing unwanted ultrasound waves, which allows the improved sensitivity for detecting weak microbubble emissions. Numerically, the importance of shear waves on the AMM transfer properties is highlighted, though only longitudinal ultrasound waves are transmitted through water. Experimentally, the design is implemented in titanium using additive manufacturing, with an attenuation level of 40 dB at the fundamental frequency. Consequently, the application of the AMM efficiently improves the SNR for subharmonic and ultraharmonic microbubble emissions by 11.8 and 11.9 dB, respectively. The subharmonic components originally overwhelmed by noise are recovered. This is the first time that AMMs have been applied to passive acoustic monitoring and this work stands to improve treatment outcomes from cavitation‐mediated focused ultrasound therapy.