Applications of Photon Migration to Tissue Tomography and Spectroscopy

我们继续我们的工作在理论，实验和计算方面的光组织相互作用的非侵入性定量光学成像和光谱。柏林PTB的研究人员为我们提供了两种波长（670和780 nm）的乳房图像透照几何学的飞行时间测量。我们已经应用我们的方法，称为时间依赖性对比度函数，量化的大小和光学特性的正常组织背景和肿瘤定位的标准乳房X线摄影。我们成功地找到了准确的位置，估计的大小，并检索的散射和吸收系数的肿瘤和背景。使用氧合血红蛋白和脱氧血红蛋白的吸收光谱，我们能够从670和780 nm处的吸收系数估计肿瘤和背景组织的氧饱和度和总血容量。目前正在研究边界对图像的影响。为了避免在口腔中的切开活检，已经开发了一个理论框架来非侵入性地量化口腔粘膜中的上皮层的增厚。我们已经开发了一种光谱装置，该装置使用斜角反射设置，并开始用于II期临床试验（由NCI设计），用于炎症和化学预防药物效果的非侵入性研究。与正常受试者相比，白斑病患者的结果定性地显示了理论的预测。我们正在努力筛选更多的患者，并使测量更加定量。我们正在寻求使用外源性和内源性荧光标记物，以便能够实现所研究组织异常的光谱特征的特异性。 在与特拉维夫大学的合作中，我们获得了BSF资助，继续研究我们以前开发的3D重建算法的实际实施，该算法定位荧光团质量的位置和浓度。 我们的逆算法将被用来找到填充有荧光颗粒的脂质体的位置和浓度，作为体内局部荧光质量的模型。沿着这些研究路线，我们正在测试的光子迁移的分析理论，以恢复生物分析物的寿命，通过使用幻影实验。我们正在继续与NCI的研究人员合作，研究我们的光子迁移理论在开发引导活检红外荧光成像系统中的实际应用，该系统用于使用荧光颗粒进行乳腺癌前哨淋巴结检测。

We have continued our work on theoretical, experimental, and computational aspects of light -tissue interactions for non-invasive quantitative optical imaging and spectroscopy. Researchers at PTB of Berlin provided us time of flight measurements in transillumination geometry of breast images in two wavelengths (670 and 780nm). We have applied our methodology known as time-dependent contrast functions, to quantify the size and the optical properties of the normal tissue background and those of the tumor localized by standard mammography. We were successfully able to find the exact location, estimate the size, and retrieve the scattering and the absorption coefficients of the tumor and those of the background. Using the absorption spectra of oxy- and deoxy-hemoglobin, we were able to estimate the oxygen saturation and the total blood volume of the tumor and background tissue from the absorption coefficients at 670 and 780nm. Work is underway to study the effects of boundaries on the images. In order to avoid incisional biopsy in the oral cavity, a theoretical framework has been developed to quantify the thickening of the epithelial layer in oral mucosa non-invasively. We have developed a spectroscopic device which uses an oblique angle reflectance setting and started to be used in a Phase II clinical trial (designed by NCI) for the non-invasive study of inflammation and effects of chemopreventative drugs. The results from a patient with leukoplakia compared to that obtained from a normal subject show qualitatively the prediction of the theory. Work is underway to screen more patients and make the measurement more quantitative.We are pursuing the use of exogenous and endogenous fluorescent markers to be able to achieve specificity of the spectroscopic signatures of the tissue abnormality under investigation. In collaboration with the University of Tel-Aviv, we have been awarded a BSF grant to continue our research on practical implementation of our previously developed 3D reconstruction algorithm which localizes the position and the concentration of fluorophore masses. Our inverse algorithm will be used to find the position and the concentration of liposomes filled with fluorescent particles as a model for localized fluorescent masses in vivo.. Along these line of research, we are testing an analytical theory of photon migration to retrieve the life-time of biological analytes by using phantom experiments. We are continuing a collaboration with researchers at NCI to study the practical use of our photon migration theory in the development of a guided biopsy infrared fluorescence imaging system for sentinel node detection in breast cancer using fluorescent particles.