In diffuse optical tomography (DOT) and spectroscopy (DOS) using handheld probes, tissue curvature can cause bad fiber-to-tissue contact. Understanding and minimizing image artifacts caused by these coupling errors would significantly improve DOT and DOS image quality. In this work, we utilized Monte Carlo simulations and experiments with gelatin-Intralipid phantoms to systematically study the influence of source or detector (optode) coupling errors. Optode coupling errors can increase the amplitude and decrease the phase of the measured diffuse reflectance, creating artifacts in the reconstructed absorption maps, such as hot spots on the edges. We propose an outlier removal algorithm that can correct these image artifacts, and we demonstrate its performance using simulations, phantom experiments, and breast patient data acquired with bad probe contact due to a dense or small breast. Further, we designed and implemented a new resistance-type thin-film force sensor array that provides real-time optode coupling feedback and guides the outlier removal to minimize optode coupling errors. Our approaches and study results have significant implications for reducing image artifacts arising from handheld probes, which are commonly used with mobile and wearable DOT and DOS devices.

中文翻译：

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使用漫射光学断层扫描对乳腺成像中光极耦合误差的影响和校正

在使用手持探头的漫射光学断层扫描 (DOT) 和光谱学 (DOS) 中，组织弯曲会导致纤维与组织的接触不良。了解并尽量减少由这些耦合错误引起的图像伪影将显着提高 DOT 和 DOS 图像质量。在这项工作中，我们利用 Monte Carlo 模拟和明胶-Intralipid 体模实验来系统地研究源或检测器（光极）耦合误差的影响。光极耦合误差会增加测量的漫反射的幅度并降低相位，从而在重建的吸收图中产生伪影，例如边缘上的热点。我们提出了一种可以纠正这些图像伪影的异常值去除算法，并且我们使用模拟、幻像实验证明了其性能，由于乳房密集或小，探头接触不良而获得的乳房患者数据。此外，我们设计并实现了一种新的电阻型薄膜力传感器阵列，可提供实时光极耦合反馈并指导异常值去除以最大限度地减少光极耦合误差。我们的方法和研究结果对于减少手持探针产生的图像伪影具有重要意义，手持探针通常与移动和可穿戴 DOT 和 DOS 设备一起使用。