Chen Maomao, Duan Xiaoyu, Lan Bangxin, Vu Tri, Zhu Xiaoyi, Rong Qiangzhou, Yang Wei, Hoffmann Ulrike, Zou Jun, Yao Junjie
Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.
Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA.
Photoacoustics. 2021 Oct 2;24:100309. doi: 10.1016/j.pacs.2021.100309. eCollection 2021 Dec.
Optical-resolution photoacoustic microscopy (OR-PAM) can provide functional, anatomical, and molecular images at micrometer level resolution with an imaging depth of less than 1 mm in tissue. However, the imaging speed of traditional OR-PAM is often low due to the point-by-point mechanical scanning and cannot capture time-sensitive dynamic information. In this work, we demonstrate a recent effort in improving the imaging speed of OR-PAM, using a newly developed water-immersible two-axis scanner. Driven by water-compatible electromagnetic actuation force, the new scanning mirror employs a novel torsion-bending mechanism to achieve fast 2D scanning. The torsion scanning along the fast-axis works in the resonant model, and the bending scanning along the slow-axis operate at the quasi-static mode. The scanning speed and scanning range along the two axes can be independently adjusted. Steered by the two-axis torsion-bending scanning mirror immersed in water, the focused excitation light and the generated acoustic wave can be confocally aligned over the entire imaging area. Thus, a high imaging speed can be achieved without sacrificing the detection sensitivity. Equipped with the torsion-bending scanner, the high-speed OR-PAM system has achieved a cross-sectional frame rate of 400 Hz, and a volumetric imaging speed of 1 Hz over a field of view of 1.5 × 2.5 mm. We have also demonstrated high-speed OR-PAM of the hemodynamic changes in response to pharmaceutical and physiological challenges in small animal models in vivo. We expect the torsion-bending scanner based OR-PAM will find matched biomedical studies of tissue dynamics.
光学分辨率光声显微镜（OR-PAM）能够在微米级分辨率下提供功能、解剖和分子图像，其在组织中的成像深度小于1毫米。然而，传统OR-PAM的成像速度往往较低，这是由于逐点机械扫描所致，无法捕捉对时间敏感的动态信息。在这项工作中，我们展示了近期在提高OR-PAM成像速度方面所做的努力，采用了新开发的水浸式双轴扫描仪。由与水兼容的电磁驱动力驱动，新型扫描镜采用了一种新颖的扭转弯曲机制来实现快速二维扫描。沿快轴的扭转扫描工作在共振模式，沿慢轴的弯曲扫描工作在准静态模式。两个轴向上的扫描速度和扫描范围可独立调节。在浸入水中的双轴扭转弯曲扫描镜的引导下，聚焦激发光和产生的声波能够在整个成像区域共焦对准。因此，在不牺牲检测灵敏度的情况下可实现高成像速度。配备了扭转弯曲扫描仪的高速OR-PAM系统在1.5×2.5毫米的视野范围内实现了400赫兹的横截面帧率和1赫兹的体积成像速度。我们还展示了在体内小动物模型中对药物和生理刺激做出响应的血流动力学变化的高速OR-PAM。我们期望基于扭转弯曲扫描仪的OR-PAM将找到与之匹配的组织动力学生物医学研究。
