Vishwanath Karthik, Chang Kevin, Klein Daniel, Deng Yu Feng, Chang Vivide, Phelps Janelle E, Ramanujam Nimmi
Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708.
Appl Spectrosc. 2011 Feb 1;62(2):206-215. doi: 10.1366/10-06052.
Steady-state diffuse reflection spectroscopy is a well-studied optical technique that can provide a noninvasive and quantitative method for characterizing the absorption and scattering properties of biological tissues. Here, we compare three fiber-based diffuse reflection spectroscopy systems that were assembled to create a light-weight, portable, and robust optical spectrometer that could be easily translated for repeated and reliable use in mobile settings. The three systems were built using a broadband light source and a compact, commercially available spectrograph. We tested two different light sources and two spectrographs (manufactured by two different vendors). The assembled systems were characterized by their signal-to-noise ratios, the source-intensity drifts, and detector linearity. We quantified the performance of these instruments in extracting optical properties from diffuse reflectance spectra in tissue-mimicking liquid phantoms with well-controlled optical absorption and scattering coefficients. We show that all assembled systems were able to extract the optical absorption and scattering properties with errors less than 10%, while providing greater than ten-fold decrease in footprint and cost (relative to a previously well-characterized and widely used commercial system). Finally, we demonstrate the use of these small systems to measure optical biomarkers in vivo in a small-animal model cancer therapy study. We show that optical measurements from the simple portable system provide estimates of tumor oxygen saturation similar to those detected using the commercial system in murine tumor models of head and neck cancer.
稳态漫反射光谱学是一种经过充分研究的光学技术，它能够提供一种非侵入性的定量方法来表征生物组织的吸收和散射特性。在此，我们比较了三种基于光纤的漫反射光谱系统，这些系统被组装成一个轻便、便携且坚固的光学光谱仪，该光谱仪能够轻松转化以便在移动环境中进行重复且可靠的使用。这三种系统是使用宽带光源和紧凑的商用光谱仪构建而成的。我们测试了两种不同的光源和两种光谱仪（由两家不同的供应商制造）。组装后的系统通过其信噪比、光源强度漂移和探测器线性度来表征。我们在具有良好控制的光学吸收和散射系数的组织模拟液体模型中，量化了这些仪器从漫反射光谱中提取光学特性的性能。我们表明，所有组装后的系统都能够以小于10%的误差提取光学吸收和散射特性，同时占地面积和成本降低了十倍以上（相对于之前一个经过充分表征且广泛使用的商业系统）。最后，我们展示了在小动物模型癌症治疗研究中使用这些小型系统进行体内光学生物标志物测量的情况。我们表明，来自简单便携式系统的光学测量提供的肿瘤氧饱和度估计值与在小鼠头颈癌肿瘤模型中使用商业系统检测到的估计值相似。
