Ahn Joongho, Choi Hyoseok, Lim Seongjun, Kim Jin Young, Park Jeongwoo
Departments of Electrical Engineering and Convergence IT Engineering, Medical Device Innovation Center, Pohang University of Science and Technology, Pohang 37673, Republic of Korea.
Opticho Inc., Pohang 37673, Republic of Korea.
Biosensors (Basel). 2025 Mar 21;15(4):200. doi: 10.3390/bios15040200.
Photoacoustic (PA) imaging combines optical contrast with ultrasound (US) detection, enabling high-resolution imaging of biological tissues with greater penetration depth than conventional optical techniques. Among its various implementations, photoacoustic microscopy (PAM) achieves micrometer-scale resolution by focusing laser excitation and detecting ultrasonic signals, allowing for the detailed visualization of microvascular structures and fine tissue morphology. Over the last decade, PAM imaging speed has significantly increased by adopting PA scanners that steer optical and acoustic waves. However, these scanners must be placed after focusing optics to co-align the waves on a spot, which creates bent focal lines along the scanning direction and limits the scanning range. To achieve wide-field imaging, various image mosaic algorithms have been applied, but these methods require multiple manual operations, which take more time than the imaging itself. In this study, we developed a wide-field, high-speed scanning acoustic/photoacoustic microscopy (SA/PAM) system equipped with a transparent ultrasound transducer and a moving magnet linear stage, which eliminates the need for complex mosaic algorithms. This system enables wide-field imaging up to 50 × 50 mm while maintaining high lateral resolution, achieving an imaging speed of 50 Hz in a B-scan image. Through in vivo mouse US/PA imaging, the system demonstrated its capability to visualize blood vessels and organs across the whole body of small animals. These findings suggest that the SA/PAM system is a practical tool for biomedical research, allowing for efficient visualization of vascular networks and anatomical structures in various preclinical studies.
光声（PA）成像将光学对比度与超声（US）检测相结合，能够对生物组织进行高分辨率成像，其穿透深度比传统光学技术更大。在其各种实现方式中，光声显微镜（PAM）通过聚焦激光激发并检测超声信号实现微米级分辨率，从而能够详细可视化微血管结构和精细组织形态。在过去十年中，通过采用能够操控光波和声波的PA扫描仪，PAM成像速度有了显著提高。然而，这些扫描仪必须放置在聚焦光学器件之后，以便在一个点上使波共对准，这会在扫描方向上产生弯曲的焦线并限制扫描范围。为了实现宽场成像，已经应用了各种图像拼接算法，但这些方法需要多次手动操作，花费的时间比成像本身还多。在本研究中，我们开发了一种配备透明超声换能器和移动磁体线性平台的宽场、高速扫描声/光声显微镜（SA/PAM）系统，该系统无需复杂的拼接算法。该系统能够实现高达50×50毫米的宽场成像，同时保持高横向分辨率，在B扫描图像中实现50赫兹的成像速度。通过对小鼠进行体内超声/光声成像，该系统展示了其在小动物全身可视化血管和器官的能力。这些发现表明，SA/PAM系统是生物医学研究的一种实用工具，可在各种临床前研究中高效可视化血管网络和解剖结构。
