Non-invasive transcranial ultrasound therapy based on a 3D CT scan: protocol validation and in vitro results
Non-invasive transcranial ultrasound therapy based on a 3D CT scan: protocol validation and in vitro results
复制标题
DOI：
10.1088/0031-9155/54/9/001
复制
发表时间：
2009-05-07
影响因子：
3.5
通讯作者：
Fink, M.
中科院分区：
文献类型：
--
作者：
Marquet, F.;Pernot, M.;Fink, M.
研究了一种无创的超声经颅脑组织消融方案，并在体外进行了验证。颅骨在相位和振幅上都引起强烈的像差，导致波束形状的严重退化。使用颅骨结构的先前3D计算断层摄影扫描采集（CT）来执行对由颅骨引起的失真的自适应校正。这些CT扫描数据被用作全波传播方程的FDTD（时域有限差分）模拟中的入口参数。数值计算用于推导与目标位置和超声治疗阵列相关的脉冲响应，从而提供虚拟时间反转镜。该脉冲响应然后被时间反转，并通过与CT扫描采集期间使用的参考系完全相同的参考系中定位的治疗阵列进行实验性传输。使用在1MHz的中心频率下工作的300个发射元件的阵列在猴和人头骨标本上进行体外实验。这些实验表明，一个精确的重新聚焦的超声波束在目标位置的定位误差低于0.7毫米。这种经颅自适应聚焦程序的完整验证铺平了道路，在体内动物和人类经颅HIFU调查。
A non-invasive protocol for transcranial brain tissue ablation with ultrasound is studied and validated in vitro. The skull induces strong aberrations both in phase and in amplitude, resulting in a severe degradation of the beam shape. Adaptive corrections of the distortions induced by the skull bone are performed using a previous 3D computational tomography scan acquisition (CT) of the skull bone structure. These CT scan data are used as entry parameters in a FDTD (finite differences time domain) simulation of the full wave propagation equation. A numerical computation is used to deduce the impulse response relating the targeted location and the ultrasound therapeutic array, thus providing a virtual time-reversal mirror. This impulse response is then time-reversed and transmitted experimentally by a therapeutic array positioned exactly in the same referential frame as the one used during CT scan acquisitions. In vitro experiments are conducted on monkey and human skull specimens using an array of 300 transmit elements working at a central frequency of 1 MHz. These experiments show a precise refocusing of the ultrasonic beam at the targeted location with a positioning error lower than 0.7 mm. The complete validation of this transcranial adaptive focusing procedure paves the way to in vivo animal and human transcranial HIFU investigations.