Numerical simulation of low-intensity focused ultrasound in brain for neuromodulation

低强度聚焦超声(LIFU)可以有效地调制大脑中靶区的神经元。 超声焦斑，显示了超声无创性治疗神经功能障碍的潜力。 利福使用与医学超声成像相似或更低的超声强度，以便 利福不会造成组织损伤或温度升高。利福可以将超声强度定位在 所需的大脑位置为毫米范围内的焦点，分辨率为亚毫米。因此， 靶细胞可以在不影响周围神经元的情况下进行高特异性的调节。然而，它 由于复杂的原因，预测所需脑区的超声焦点位置是一项挑战 头部几何形状和结构。核磁共振成像(MRI)可以用来监测在 超声波神经调节，但MRI是昂贵的，并不总是在治疗现场可用。 此外，可能很难准确估计施加在目标上的超声波能量的量。 这是由于复杂头部结构内的超声衰减造成的。本研究项目的目的 是开发一种数值模拟工具来了解和评估力富光束的轮廓和强度 在脑内的分布，这是关键和迫切需要使这种理府神经调制 可作为认知和精神障碍研究的标准工具的技术。已开发的 模拟工具将使我们能够以亚毫米分辨率定位超声焦点，并控制 所需的超声能量精确地施加在目标大脑区域。该项目为神经科学家和 临床医生是了解和治疗严重抑郁症的新工具，可能使数百万加拿大人受益 以及全球范围内。

Low-intensity focused ultrasound (LIFU) could effectively modulate neurons at a target brain region within the ultrasound focal spot, which indicates a potential of ultrasound for therapy of neural disorder noninvasively. LIFU employs ultrasound intensity similar to or lower than that used by medical ultrasound imaging so that LIFU does not produce tissue damage or temperature increase. LIFU could localize ultrasound intensity at a desired brain location of a millimeter range of the focal spot with sub-millimetre resolution. Therefore, the target brain cells can be modulated with high specificity without affecting the surrounding neurons. However, it is challenge to predict the ultrasound focal spot location at the desired brain region because of complicated head geometry and structures. Magnetic resonance imaging (MRI) can be used to monitor the focal spot during ultrasound neuro-modulation, but MRI is expensive and may not be always available at the treatment site. Furthermore, it could be difficult to estimate accurately the amount of ultrasonic energy applied at the target region due to ultrasound attenuation within the complicated head structures. Objective of this research project is to develop a numerical simulation tool to understand and evaluate the LIFU beam profile and intensity distribution within the brain, which is crucial and urgently demanded to make this LIFU neuro-modulation technology available as a standard tool for research in cognitive and psychiatric disorders. The developed simulation tool will allow us to locate ultrasound focal spot with sub-millimetre resolution and to control the desired ultrasound energy applied at the target brain region precisely. This project provides neuroscientists and clinicians a new tool to understand and treat major depression with potential benefits for millions of Canadians and globally.