Near-infrared (NIR) diffuse correlation spectroscopy (DCS) provides a novel tool for clinical blood flow monitoring. Although DCS has the advantages of non-invasiveness, high sensitivity and large penetration depth, increasing its acquisition speed to achieve real-time imaging is still an on-going task. In this work, we propose a multi-channel DCS system for dynamic topography of blood flow index in deep tissues, where a dynamic nature up to one frame per second is implemented by combining the concurrency of FPGA-based 10 channel hardware correlators of multi-τ -design and NIR-sensitive avalanche photodiode detectors. The flow-velocity resolution, measurement fidelity and imaging depth of the system were evaluated by phantom experiments. In vivo experiments on human arm were then performed that accurately imaged the shape and position of the blood vessels and demonstrated the ability of the proposed methodology to capture blood flow changes.
Diffuse optical tomography (DOT) is a novel functional imaging technique that has the vital clinical application. Aiming at the problems in DOT technology, we developed a three-wavelength continuous wave DOT system with high sensitivity and temporal resolution by adopting photo-multiple tube and photon counting detection, as well as lock-in technique. To assess the performance of the system, we conducted a series of cylindrical phantom experiments with optical properties that closely match those of human tissue, and obtained the reconstruction images by combining with our developed imaging scheme. The experimental results show that the position and size of the reconstructed targets are accurate, demonstrating the feasibility of the system. Additionally, the sensitivity, quantitativeness and spatial resolution of the imaging system were assessed by varying the target-to-background contrasting absorption contrast and target size. These preliminary results indicate that the system is scientifically capable of subcentimeter resolution imaging of low-contrast the lesion from the normal background.