Nonlinear Interferometric Vibrational Imaging of Cancer

描述(申请人提供)：生物医学成像的趋势是在疾病最有可能治愈的最早时间点发现并可视化癌症等疾病。为了这个目的，分子成像技术正在几乎所有的成像方式中得到发展。光学分子成像不仅提供了高成像分辨率的可能性，而且提供了获得分子灵敏度的多种方法。我们开发了一种名为非线性干涉振动成像(NIVI)的光学分子成像技术。这项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，我们利用光学相干层析成像(OCT)中的许多原理，使用外差干涉检测来执行深度分辨相干选通。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。我们将通过剔除生物环境中水中常见的、对背景噪声有显著贡献的非共振信号来提高检测灵敏度，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极限，以及根据分子组成和分类区分大鼠乳腺肿瘤模型中的肿瘤和正常组织，来演示NIVI的生物学应用。通过展示NiVI在生物分子诊断中的潜在用途，我们将在R33阶段将这项技术推向活体成像。为了实现这一目标，我们将建造一台超宽带NIVI仪器，利用飞秒脉冲整形技术快速激发特定分子的多重振动共振。我们将确定这项技术的灵敏度下限，并量化可以区分类似分子振动的分辨率。最后，为了展示我们系统的实时分子成像能力，我们将使用一个具有良好特性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。在整个致癌过程中，肿瘤将被活体成像，以表征它们不断变化的分子组成，并量化DMA的浓度和空间分布。这项研究将使NIVI成为一种独特的体内非线性光学分子成像技术，用于区分和空间绘制与癌症相关的分子的分布。

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.