Nonlinear Interferometric Vibrational Imaging of Cancer

描述（由申请人提供）：生物医学成像的趋势是在最早的时间点检测和可视化疾病，如癌症，当疾病最有可能被治愈时。为此目的，正在开发几乎所有成像方式的分子成像技术。光学分子成像不仅提供了高成像分辨率的潜力，而且提供了多种获得分子灵敏度的方法。我们开发了一种称为非线性干涉振动成像（NIVI）的光学分子成像技术。该技术根据分子的振动共振频率对分子的三维空间分布进行成像。利用相干反斯托克斯拉曼散射（CARS）产生的非线性光信号检测分子的振动共振。利用CARS的相干特性，我们使用外差干涉检测进行深度分辨相干门控，利用光学相干断层扫描（OCT）中的许多原理。在这个项目的R21阶段，我们将把NIVI的成像能力扩展到与癌症相关的生物分子。我们将通过拒绝生物环境中水通常产生的非共振信号来提高检测灵敏度，这些信号对背景噪声有很大贡献，并将实施谱域检测，同时检测多个拉曼频率。在进入R33阶段之前，我们将通过建立生物大分子的灵敏度检测限，以及基于分子组成和分类将肿瘤组织与正常组织与大鼠乳腺肿瘤模型区分开来，来展示NIVI的生物学应用。通过展示NIVI在生物分子诊断中的潜在应用，我们将在R33阶段推进这项技术的体内成像。为了实现这一目标，我们将构建一个超宽带NIVI仪器，该仪器利用飞秒脉冲整形技术快速刺激特定分子中的多个振动共振。我们将建立这种技术的低灵敏度限制，并量化分辨类似分子振动的分辨率。最后，为了证明我们系统的实时分子成像能力，我们将使用一种具有良好特征的致癌物诱导的大鼠乳腺肿瘤模型进行细胞、组织和体内动物研究。在整个癌变过程中，肿瘤将在体内成像，以表征其分子组成的变化，并量化DMA的浓度和空间分布。本研究将确立NIVI作为一种独特的体内非线性光学分子成像技术，用于区分和空间定位与癌症相关的分子分布。

DESCRIPTION (provided by applicant): The trend in biomedical imaging is to detect and visualize diseases such as cancer at their earliest time-points, when the disease is most likely to be cured. Molecular imaging techniques are being developed across virtually all imaging modalities for this purpose. Optical molecular imaging offers the potential for not only high imaging resolution, but also multiple approaches for obtaining molecular sensitivity. We have developed an optical molecular imaging technique called Nonlinear Interferometric Vibrational Imaging (NIVI). This technique images the three-dimensional spatial distribution of molecules based on their vibrational resonance frequencies. Molecular vibrational resonances are detected by the nonlinear optical signals from Coherent Anti-Stokes Raman Scattering (CARS). Taking advantage of the coherent nature of CARS, we perform depth-resolved coherence-gating using heterodyne interferometric detection, leveraging many of the principles found in optical coherence tomography (OCT). For the R21 phase of this project, we will extend the imaging capabilities of NIVI to biological molecules associated with cancer. We will improve the sensitivity of detection by rejecting nonresonant signals that are commonly generated from water in biological environments and significantly contribute to background noise, and will implement spectral-domain detection to detect multiple Raman frequencies simultaneously. Before advancing to the R33 phase, we will demonstrate the biological application of NIVI by establishing sensitivity detection limits for biological macromolecules, and by differentiating neoplastic from normal tissue from a rat mammary tumor model based on molecular composition and classification. By demonstrating the potential use of NIVI for biomolecular diagnostics, we will advance this technology toward in vivo imaging in the R33 phase. To accomplish this, we will construct an ultra-broadband NIVI instrument that utilizes femtosecond pulse-shaping techniques to rapidly stimulate multiple vibrational resonances in specific molecules. We will establish the lower sensitivity limits of this technique as well as quantify the resolution at which similar molecular vibrations can be differentiated. Finally to demonstrate the real-time molecular imaging capabilities of our system, we will perform cell, tissue, and in vivo animal studies using a well-characterized carcinogen-induced rat mammary tumor model. Throughout carcinogenesis, tumors will be imaged in vivo to characterize their changing molecular composition and quantify the concentration and spatial distribution of DMA. This research will establish NIVI as a unique in vivo nonlinear optical molecular imaging technique for distinguishing and spatially mapping the distribution of molecules associated with cancer.