Transcranial Ultrasonic Therapy Based on Time Reversal of Acoustically Induced Cavitation Bubble Signature
Transcranial Ultrasonic Therapy Based on Time Reversal of Acoustically Induced Cavitation Bubble Signature
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DOI：
10.1109/tbme.2009.2031816
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发表时间：
2010-01-01
影响因子：
4.6
通讯作者：
Fink, Mathias
中科院分区：
文献类型：
--
作者：
Gatcau, Jerome;Marsac, Laurent;Fink, Mathias
通过多通道阵列和时间反转等自适应聚焦技术，可以通过高强度聚焦超声通过颅骨进行脑部治疗。该方法需要参考信号由嵌入脑组织中的真实源发出，或者使用从计算机断层扫描图像导出的头骨的声学特性从虚拟源计算。这种非侵入性计算方法可以精确聚焦，但存在建模和重新定位误差，与使用植入水听器的完全实验性时间反转相比，这些误差降低了焦点处可达到的声压。在本文中，这种基于模拟的瞄准已在实验中用作通过离体人类头骨聚焦在单个位置的第一步。它能够在焦点处产生空化气泡，该空化气泡自发地发射阵列接收到的超声波。该主动源信号允许在几何焦点处恢复 97 +/- 1.1% 的参考压力（基于水听器）。为了以最佳压力水平瞄准焦点周围的点，从初始焦点开始的传统电子转向与气泡生成相结合。由于逐步产生气泡，阵列通过头骨的电子转向能力得到了提高。
Brain treatment through the skull with high-intensity focused ultrasound can be achieved with multichannel arrays and adaptive focusing techniques such as time reversal. This method requires a reference signal to be either emitted by a real source embedded in brain tissues or computed from a virtual source, using the acoustic properties of the skull derived from computed tomography images. This noninvasive computational method focuses with precision, but suffers from modeling and repositioning errors that reduce the accessible acoustic pressure at the focus in comparison with fully experimental time reversal using an implanted hydrophone. In this paper, this simulation-based targeting has been used experimentally as a first step for focusing through an ex vivo human skull at a single location. It has enabled the creation of a cavitation bubble at focus that spontaneously emitted an ultrasonic wave received by the array. This active source signal has allowed 97 +/- 1.1% of the reference pressure (hydrophone-based) to be restored at the geometrical focus. To target points around the focus with an optimal pressure level, conventional electronic steering from the initial focus has been combined with bubble generation. Thanks to step-by-step bubble generation, the electronic steering capabilities of the array through the skull were improved.