基于声透镜的多频经颅聚焦

Multifrequency transcranial focusing based on acoustic lensing

经颅聚焦超声是一种具有发展前景的技术,具有无创、安全、穿透深度大等优点.声全息透镜作为一种低成本且便捷的经颅聚焦方法,具有较大的发展潜力.然而,基于单片声全息透镜通常只能实现单一经颅聚焦声场的重建,在实际应用场景下缺乏应用灵活性.针对该问题,本文提出了一种用于经颅聚焦的多频声全息透镜的设计方法,通过提取在不同频率下设计的聚焦到不同位置的两片声全息透镜中的有效信息,并将其整合到一片声全息透镜中来实现,生成的声全息透镜可以在不同频率的激发下聚焦到不同位置.仿真和实验结果表明,通过此方法设计的声全息透镜在不同频率的超声波激发下,可以克服颅骨对超声波的散射效应,在颅骨后方精确地形成高质量的声聚焦点.

Transcranial focused ultrasound(tFUS)possesses significant advantages such as non-invasiveness and high tissue penetration depth,making it a promising tool in the field of brain science.Acoustic holographic lenses can manipulate the sound field through phase modulation,providing a low-cost and convenient approach for realizing transcranial focusing.Acoustic holographic lenses have been successfully utilized for achieving precise transcranial focusing in living mice to open the blood-brain barrier and for performing neural modulation,which shows considerable application potential.However,existing transcranial acoustic holographic lenses can only be driven by specific ultrasound frequencies and focused at predetermined positions,which limits their flexibility in complex applications.To address this issue,this study establishes a multi-frequency transcranial focusing method based on acoustic holographic lenses to enhance its adaptability in the field of tFUS.By integrating acoustic holographic lenses designed for different focal positions at various frequencies,we generate multifrequency acoustic holographic lenses suitable for transcranial focusing and conduct experiments to evaluate their performance.In simulations,for single-focus tasks,the peak signal to noise ratio(PSNR)of the proposed method achieves 32.16 dB under 1 MHz ultrasound excitation,and 40.18 dB and 2 MHz ultrasound excitation,respectively;for multi-focus tasks,the PSNR values are 29.39 dB and 39.89 dB,respectively.In experiments,for single-focus tasks,the PSNR value of the proposed method is 27.48 dB under 1 MHz ultrasound excitation,and 32.33 dB under 2 MHz ultrasound excitation,respectively;for multi-focus tasks,the PSNR values are 23.30 dB and 32.17 dB,respectively.These results demonstrate that the multi-frequency transcranial acoustic holographic lens can effectively modulate the sound field under varying ultrasound frequencies and create high-quality focal points at different locations behind the skull,which significantly enhances the application flexibility of transcranial acoustic holographic lenses.