Chen Keyu, Swanson Stephanie, Bizheva Kostadinka
Department of Physics and Astronomy, University of Waterloo, Waterloo N2 L 3G1, ON, Canada.
School of Optometry and Vision Sciences, University of Waterloo, Waterloo, ON, Canada.
Biomed Opt Express. 2024 Jun 7;15(7):4162-4175. doi: 10.1364/BOE.527797. eCollection 2024 Jul 1.
Dynamic optical coherence tomography (dOCT) utilizes time-dependent signal intensity fluctuations to enhance contrast in OCT images and indirectly probe physiological processes in cells. Majority of the dOCT studies published so far are based on acquisition of 2D images (B-scans or C-scans) by utilizing point-scanning Fourier domain (spectral or swept-source) OCT or full-field OCT respectively, primarily due to limitations in the image acquisition rate. Here we introduce a novel, high-speed spectral domain line-field dOCT (SD-LF-dOCT) system and image acquisition protocols designed for fast, volumetric dOCT imaging of biological tissues. The imaging probe is based on an exchangeable afocal lens pair that enables selection of combinations of transverse resolution (from 1.1 µm to 6.4 µm) and FOV (from 250 × 250 µm to 1.4 × 1.4 mm), suitable for different biomedical applications. The system offers axial resolution of ∼ 1.9 µm in biological tissue, assuming an average refractive index of 1.38. Maximum sensitivity of 90.5 dB is achieved for 3.5 mW optical imaging power at the tissue surface and maximum camera acquisition rate of 2,000 fps. Volumetric dOCT images acquired with the SD-LF-dOCT system from plant tissue (cucumber), animal tissue (mouse liver) and human prostate carcinoma spheroids allow for volumetric visualization of the tissues' cellular and sub-cellular structures and assessment of cellular motility.
动态光学相干断层扫描（dOCT）利用随时间变化的信号强度波动来增强OCT图像的对比度，并间接探测细胞中的生理过程。迄今为止发表的大多数dOCT研究分别基于利用点扫描傅里叶域（光谱或扫频光源）OCT或全场OCT获取二维图像（B扫描或C扫描），这主要是由于图像采集速率的限制。在此，我们介绍一种新型的高速光谱域线场dOCT（SD-LF-dOCT）系统以及为生物组织的快速体积dOCT成像设计的图像采集协议。成像探头基于一对可互换的无焦透镜，能够选择横向分辨率（从1.1 µm到6.4 µm）和视野（从250×250 µm到1.4×1.4 mm）的组合，适用于不同的生物医学应用。假设平均折射率为1.38，该系统在生物组织中的轴向分辨率约为1.9 µm。在组织表面光学成像功率为3.5 mW时，实现了90.5 dB的最大灵敏度，相机的最大采集速率为2000 fps。使用SD-LF-dOCT系统从植物组织（黄瓜）、动物组织（小鼠肝脏）和人前列腺癌球体获取的体积dOCT图像能够对组织的细胞和亚细胞结构进行体积可视化，并评估细胞运动性。
