Near-infrared diffuse correlation spectroscopy/tomography (DCS/DCT) has recently emerged as a noninvasive measurement/imaging technology for tissue blood flow. In DCT studies, the high-dense collection of light temporal autocorrelation curves (g₂(τ)) via fiber array are critical for image reconstruction of blood flow. Previously, the camera-based fiber array limits the field of view (FOV), precluding its applications on large-size human tissues. The line-shape fiber probe based on lens combination, which is predominantly used in current DCT studies, requires rotated-scanning over the surface of target tissue, substantially prolonging the measurement time and increasing the system instability. In this study, we design a noncontact optical probe for DCT based on collimating micro-lens fiber array, termed as FA-nc-DCT system. For each source/detector fiber, a single optical path was collimated by coupling with one micro-lens in the fiber array that is integrated in a square-shape base. Additionally, an 8×8 optical switch is used to share the hardware laser and detectors without spatial scanning. The FA-nc approach for the precise collection of g₂(τ) curves was validated through a speed-varied phantom experiment and the human experiments of cuff occlusion, from which the expected value of the blood flow index (BFI) was obtained. Furthermore, the flow anomaly in the phantom and the ischemic muscle in human were accurately reconstructed from the FA-nc-DCT system, which is combined with the imaging framework based on the Nth-order linear algorithm that we recently created. Those outcomes demonstrated the great potential of FA-nc-DCT technology for fast and robust imaging of various diseases such as human breast cancers.

中文翻译：

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用于非接触式近红外漫射相关层析成像的准直微透镜光纤阵列

近红外漫相关光谱/断层扫描/断层扫描（DCS / DCT）作为一种非侵入性的组织血流测量/成像技术最近已经出现。在DCT研究中，光时间自相关曲线（g ₂（τ））通过光纤阵列对血流图像重建至关重要。以前，基于摄像头的光纤阵列限制了视场（FOV），排除了其在大型人体组织上的应用。基于透镜组合的线形光纤探头主要用于当前的DCT研究中，需要对目标组织的表面进行旋转扫描，从而大大延长了测量时间并增加了系统的不稳定性。在这项研究中，我们设计了一种基于准直微透镜光纤阵列的DCT非接触式光学探头，称为FA-nc-DCT系统。对于每个源/检测器光纤，通过与集成在方形底座中的光纤阵列中的一个微透镜耦合来准直单个光路。此外，一个8×8的光开关用于共享硬件激光器和检测器，而无需进行空间扫描。FA-nc方法可精确收集g ₂（τ）曲线通过变速幻象实验和袖带阻塞的人体实验得到验证，从而获得了预期的血流指数（BFI）。此外，从FA-nc-DCT系统准确地重建了人体的幻影和局部缺血肌肉中的血流异常，并将其与基于我们最近创建的N阶线性算法的成像框架相结合。这些结果证明了FA-nc-DCT技术在对各种疾病（例如人类乳腺癌）进行快速而强大的成像方面的巨大潜力。