Cao Rui, Luo Yilin, Xu Jinhua, Luo Xiaofei, Geng Ku, Aborahama Yousuf, Cui Manxiu, Davis Samuel, Na Shuai, Tong Xin, Liu Cindy, Sastry Karteek, Maslov Konstantin, Hu Peng, Zhang Yide, Lin Li, Zhang Yang, Wang Lihong V
Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, California Institute of Technology, Pasadena, CA, USA.
Caltech Optical Imaging Laboratory, Department of Electrical Engineering, California Institute of Technology, Pasadena, CA, USA.
ArXiv. 2023 Jun 26:arXiv:2306.14471v1.
Photoacoustic computed tomography (PACT) is emerging as a new technique for functional brain imaging, primarily due to its capabilities in label-free hemodynamic imaging. Despite its potential, the transcranial application of PACT has encountered hurdles, such as acoustic attenuations and distortions by the skull and limited light penetration through the skull. To overcome these challenges, we have engineered a PACT system that features a densely packed hemispherical ultrasonic transducer array with 3072 channels, operating at a central frequency of 1 MHz. This system allows for single-shot 3D imaging at a rate equal to the laser repetition rate, such as 20 Hz. We have achieved a single-shot light penetration depth of approximately 9 cm in chicken breast tissue utilizing a 750 nm laser (withstanding 3295-fold light attenuation and still retaining an SNR of 74) and successfully performed transcranial imaging through an human skull using a 1064 nm laser. Moreover, we have proven the capacity of our system to perform single-shot 3D PACT imaging in both tissue phantoms and human subjects. These results suggest that our PACT system is poised to unlock potential for real-time, transcranial functional imaging in humans.
光声计算机断层扫描（PACT）正在成为一种用于功能性脑成像的新技术，主要是因为它在无标记血流动力学成像方面的能力。尽管具有潜力，但PACT的经颅应用遇到了障碍，例如颅骨的声学衰减和畸变以及光透过颅骨的穿透有限。为了克服这些挑战，我们设计了一种PACT系统，该系统具有一个密集排列的半球形超声换能器阵列，有3072个通道，工作中心频率为1MHz。该系统允许以等于激光重复频率（如20Hz）的速率进行单次三维成像。我们利用750nm激光在鸡胸组织中实现了约9cm的单次光穿透深度（经受3295倍的光衰减且仍保持74的信噪比），并使用1064nm激光成功地通过人类颅骨进行了经颅成像。此外，我们已经证明了我们的系统在组织模型和人类受试者中进行单次三维PACT成像的能力。这些结果表明，我们的PACT系统有望为人类实时经颅功能成像开启潜力。
