Investigation of a large-area phased array for focused ultrasound surgery through the skull
Investigation of a large-area phased array for focused ultrasound surgery through the skull
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DOI：
10.1088/0031-9155/45/4/319
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发表时间：
2000-04-01
影响因子：
3.5
通讯作者：
Hynynen, K
中科院分区：
文献类型：
--
作者：
Clement, GT;White, J;Hynynen, K
使用超声波的脑部疾病的非侵入性治疗将需要能够将超声波传播通过颅骨并且仍然在脑内的特定位置处产生足够的声压的换能器。此外，阵列不得在颅骨附近或大脑的其他区域引起过度加热。提出了一种半球形换能器，其将超声波分散在颅骨的大区域上。覆盖的大表面积允许最大的超声增益，同时最大限度地减少不必要的加热。为了测试换能器的可行性，通过叠加来自11个单元和40个单元的球面凹面静止阵列的多个测量值来模拟两个虚拟阵列。每个阵列通过离体人类颅骨聚焦在颅骨表面周围的四个单独位置。所得到的超声波场计算相结合的测量与聚偏二氟乙烯针水听器提供的领域从44元和160元的虚拟阵列覆盖88%和33%的半球分别。在调整每个阵列元件的相位以使换能器的几何焦点处的相长干涉最大化之后重复测量。机械和电子束转向通过颅骨的调查也与160元件的虚拟阵列，定相，使传感器的焦点位于14毫米的几何中心。结果表明，通过颅骨使用在一个大的表面积上分布的阵列的聚焦和波束转向的可行性。此外，它表明，通过头骨的波束转向是合理的。
Non-invasive treatment of brain disorders using ultrasound would require a transducer ru ray that can propagate ultrasound through the skull and still produce sufficient acoustic pressure at a specific location within the brain. Additionally, the array must not cause excessive heating near the skull or in other regions of the brain. A hemisphere-shaped transducer is proposed which disperses the ultrasound over a large region of the skull. The large surface area covered allows maximum ultrasound gain while minimizing undesired heating. To test the feasibility of the transducer two virtual arrays are simulated by superposition of multiple measurements from an 11-element and a 40-element spherically concave rest array. Each array is focused through an ex vivo human skull at four separate locations around the skull surface. The resultant ultrasound field is calculated by combining measurements taken with a polyvinylidene difluoride needle hydrophone providing the fields from a 44-element and a 160-element virtual array covering 88% and 33% of a hemisphere respectively. Measurements are repeated after the phase of each array element is adjusted to maximize the constructive interference at the transducer's geometric focus. An investigation of mechanical and electronic beam steering through the skull is also performed with the 160-element virtual array, phasing it such that the focus of the transducer is located 14 mm from the geometric centre. Results indicate the feasibility of focusing and beam steering through the skull using an array spread over a large surface area. Further, it is demonstrated that beam steering through the skull is plausible.