Photoacoustic microscopy (PAM) is a hybrid in vivo imaging technique that acoustically detects optical contrast via the photoacoustic effect. Unlike pure optical microscopic techniques, PAM takes advantage of the weak acoustic scattering in tissue and thus breaks through the optical diffusion limit (∼1 mm in soft tissue). With its excellent scalability, PAM can provide high‐resolution images at desired maximum imaging depths up to a few millimeters. Compared with backscattering‐based confocal microscopy and optical coherence tomography, PAM provides absorption contrast instead of scattering contrast. Furthermore, PAM can image more molecules, endogenous or exogenous, at their absorbing wavelengths than fluorescence‐based methods, such as wide‐field, confocal, and multi‐photon microscopy. Most importantly, PAM can simultaneously image anatomical, functional, molecular, flow dynamic and metabolic contrasts in vivo. Focusing on state‐of‐the‐art developments in PAM, this Review discusses the key features of PAM implementations and their applications in biomedical studies.

中文翻译：

---

光声显微镜。


光声显微镜 (PAM) 是一种混合体内成像技术，可通过光声效应以声学方式检测光学对比度。与纯光学显微技术不同，PAM 利用组织中微弱的声学散射，从而突破了光学扩散极限（软组织中约 1 mm）。凭借其出色的可扩展性，PAM 可以在所需的最大成像深度达几毫米的情况下提供高分辨率图像。与基于背散射的共焦显微镜和光学相干断层扫描相比，PAM 提供吸收对比度而不是散射对比度。此外，与基于荧光的方法（例如宽视场、共焦和多光子显微镜）相比，PAM 可以在吸收波长下对更多的内源或外源分子进行成像。最重要的是，PAM 可以同时对体内的解剖、功能、分子、血流动力学和代谢对比进行成像。本综述重点关注 PAM 的最新发展，讨论了 PAM 实现的关键特征及其在生物医学研究中的应用。