Holograms to Focus Arbitrary Ultrasonic Fields through the Skull
Holograms to Focus Arbitrary Ultrasonic Fields through the Skull
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DOI：
10.1103/physrevapplied.12.014016
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发表时间：
2019-07-10
影响因子：
4.6
通讯作者：
Camarena, Francisco
中科院分区：
文献类型：
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作者：
Jimenez-Gambin, Sergio;Jimenez, Noe;Camarena, Francisco
我们报告三维（3D）打印的声学全息透镜，用于形成颅骨内复杂空间分布的超声场。使用全息透镜，我们实验，数值和理论产生的声束的空间分布相匹配的中枢神经系统的目标结构。特别是，我们产生三种类型的目标越来越复杂。首先，在人体右、左右腰的中心选择一组点。使用颅骨模型和3D打印的声学全息透镜的实验表明，相应的双焦点透镜同时将声能聚焦在目标焦点处，理论和模拟之间具有良好的一致性。第二，在颅骨模型内设置任意曲线作为目标。使用时间反转方法，全息光束以与自由空间中的自弯曲光束类似的方式沿着目标路径弯曲。最后，选择右侧人类海马作为目标体积。相应的全息透镜的焦点与目标体积重叠，在自由介质中的理论与包括颅骨模型的实验和模拟之间具有极好的一致性。聚焦超声进入中枢神经系统的精确控制主要是由于颅骨的折射和衰减产生的强相位像差而受到限制。使用本方法，超声波束不仅可以聚焦在单个点处，而且可以使用低成本的3D打印声学全息透镜同时重叠一个或多个目标结构。这些结果为传播生物医学超声应用开辟了替代途径，包括血脑屏障开放或神经调节。
We report three-dimensional (3D)-printed acoustic holographic lenses for the formation of ultrasonic fields of complex spatial distribution inside the skull. Using holographic lenses, we experimentally, numerically, and theoretically produce acoustic beams whose spatial distribution matches target structures of the central nervous system. In particular, we produce three types of targets of increasing complexity. First, a set of points are selected at the center of both right and left human hippocampi. Experiments using a skull phantom and 3D-printed acoustic holographic lenses show that the corresponding bifocal lens simultaneously focuses acoustic energy at the target foci, with good agreement between theory and simulations. Second, an arbitrary curve is set as the target inside the skull phantom. Using time-reversal methods, the holographic beam bends following the target path, in a similar way as self-bending beams do in free space. Finally, the right human hippocampus is selected as a target volume. The focus of the corresponding holographic lens overlaps with the target volume in excellent agreement between theory in free media, and experiments and simulations including the skull phantom. The precise control of focused ultrasound into the central nervous system is mainly limited due to the strong phase aberrations produced by refraction and attenuation of the skull. Using the present method, the ultrasonic beam can be focused not only at a single point but overlapping one or various target structures simultaneously using low-cost 3D-printed acoustic holographic lens. The results open alternative paths to spread incoming biomedical ultrasound applications, including blood-brain-barrier opening or neuromodulation.