Quantitative Biophotonics for Tissue Characterization and Function

用于组织表征和功能的定量生物光子学

• 批准号: 7968482
• 负责人: Amir H Gandjbakhche
• 金额: $ 83.32万
• 依托单位: EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7968482
• 关键词: Accounting; Acquired Immunodeficiency Syndrome; Address; Animals; Antibodies; Back; Bioenergetics; Biological; Biological Phenomena; Biophotonics; Biophysics; Blood Vessels; Blood Volume; Cells; Cervix Uteri; Characteristics; Clinical Trials; Code; Collaborations; Community Clinical Oncology Program; Complex Regional Pain Syndromes; Computer Simulation; Contralateral; Contrast Media; Country; Data; Data Collection; Data Set; Detection; Diagnostic Procedure; Diffuse; Disease; Disease Progression; Drug Kinetics; Dyes; Electrons; Elements; Environment; Fiber Optics; Fluorescence; Frequencies; Functional Imaging; Goals; Hemoglobin; Human; Image; Image Analysis; Imaging Techniques; Investigational Therapies; Kaposi Sarcoma; Knowledge; Label; Laser Microscopy; Lasers; Lesion; Light; Lighting; Lipids; Location; Malignant - descriptor; Malignant Neoplasms; Maps; Measurement; Metabolic; Methodology; Methods; Microscope; Microscopy; Modality; Modeling; Monitor; Morbidity - disease rate; Mus; National Heart, Lung, and Blood Institute; National Institute of Child Health and Human Development; Nature; Neoplasms in Vascular Tissue; Noise; Normal tissue morphology; Nutrient; Optical Coherence Tomography; Optics; Oxygen; Patient Monitoring; Patients; Pattern; Performance; Pharmaceutical Preparations; Photons; Physiological; Positioning Attribute; Property; Protocols documentation; Radiation Oncology; Research; Research Personnel; Resolution; Sampling; Scanning; Scientist; Site; Skin; Skin Kaposi' s Sarcoma; Source; Specimen; Spectrum Analysis; Structure; Surface; System; Techniques; Technology; Temperature; Testing; Texture; Therapeutic Agents; Thermography; Time; Tissue Embedding; Tissues; Tooth structure; Transillumination; Treatment Protocols; Treatment outcome; Tumor Markers; United States National Institutes of Health; Walking; Water; Work; absorption; angiogenesis; base; bioimaging; chromophore; comparative; density; design; detector; diffuse optical tomography; flexibility; fluorescence imaging; fluorophore; imaging modality; in vivo; instrumentation; interest; malignant breast neoplasm; migration; nanoparticle; nanoscale; neoplastic cell; novel; novel diagnostics; optical imaging; polarized light; receptor; reconstruction; research study; response; simulation; submicron; theories; time resolved data; time use; tool; tumor; two-photon; user-friendly

Transition from normal tissue function to diseased tissue can be detected by quantifying irregular patterns. The degree of statistical similarities in a region of interest can carry valuable comparative information about the structural features of the tissue and can help to characterize tissue, i.e., analyze disease localization and progression. To visualize subsurface structural features of biological tissues, we have developed a user-friendly polarization imaging system that simultaneously images cross- and co-polarized light. We have developed a quantitative statistical tool, based on Pearson correlation coefficient analysis to enhance the image quality and reveal regions of high statistical similarities within the noisy tissue images. We have shown that under certain conditions, such maps of the correlation coefficient are determined by the textural character of tissues and not the choice of the reference image region, providing information on tissue structure. As an example, the subsurface texture of a demineralized tooth sample was enhanced from a noisy polarized light image. We have recently adapted the polarized camera to be used in a colposcopeto study tissue structures in the cervix. Fluorophore lifetime imaging is a promising tool for studying tissue environment such as tumors. The lifetime (time for an electron to return from excited state to initial state) of a fluorophore can vary in response to changes in the immediate environment such as temperature, pH, tissue oxygen content, nutrient supply, and bioenergetic status. Mapping the lifetime and location of a fluorophore in tissue at different depths can be used to monitor such parameters. Toward this goal, we have developed a time-resolved lifetime imaging system for in vivo small animal studies that maps fluorophores lifetimes. The system consists of a single source-multiple detector array that scans the surface of the tissue. Using several source-detector separations, one is able to probe different depths of the medium. We have used a pH sensitive dye in the near-infrared region in order to study the tumor environment below the skin. We have demonstrated that by using simplified back projections we are able to map near surface fluorescent lifetime in vivo. Combining this with the pre-calibrated lifetime response to pH, we have shown that biologically plausible, non-invasive, quantification of pH in mouse tumors can be determined. In collaboration with Dr. Capala in the Radiation Oncology Branch project of NCI who has developed probe for in vivo monitoring of HER2-positive cancer (for example breast cancer) non invasively and HER2 specific delivery of therapeutic agents. We have been able to quantify the bio-distribution of the probe and, HER2 receptors on tumor cells, showing the potentila of this method for monitoring non-invasively and quantitatively the teatment response. To further this work to include deeper tissue imaging we have examined the use of novel data-types for reconstructing location and lifetime of fluorophores embedded deeper in a turbid medium. We have developed a set of local data-types which provide enhanced noise tolerance over the standard global data-types for imaging purposes. Analysis of deeply embedded tissue abnormalities, using time-resolved fluorescence, should take into account highly scattering nature of biological tissues. To address corresponding complications we investigated the limitations of previously developed analytical model of photon migration for localized fluorophores. It was shown that to better describe experimental results the model should incorporate more realistic distribution of fluorescence lifetimes thus providing more flexibility to the inverse model to converge. This analytic model has been used as a forward model to reconstruct the lifetime and location of a point source fluorophore. Other advances have been made in studying the noise sensitivity of different data-types in time-resolved fluorescence imaging, we suggested a new local set of data-types that is likely toprovide more stability to noise than classical statistical (global) data-types used in diffuse optical tomography. We have pursued also another approach to quantification of fluorescence lifetimes of deeply embedded fluorophores that can work when intrinsic lifetime of the fluorophore is comparable to photon migration time in the medium, using general scaling relations to correct observed time-resolved intensity distributions from fluorescent targets at a given depth z inside turbid medium to an expected surface distribution (from the same fluorophore), revealing the intrinsic fluorescence lifetime without the need for full-scale reconstruction. Similar corrections could be applied when comparing the time-resolved data obtained from the same deeply embedded fluorophore by several detectors, positioned at different distances from the source (excitation photon entry point into the medium). . We experimentally verified these relations, usingtissue-like phantoms. Developed random walk model of time-resolved fluorescence imaging substantiates these scaling relations. Another optical imaging modality of interest to the group is Two-Photon Microscopy. Colleagues at NHLBI have recently developed a new system for Two-Photon imaging based on the Total Emission Detection (TED) principle. Here instead of using a standard TED system where only transmitted or reflected light is collected the TED Two Photon system captures all light emitted from the sample. Researchers in this group were contacted to model Two Photon emission and evaluate the systems performance. Using our Monte- Carlo simulation code we were able to evaluate different aspects of Two-Photon Imaging and the related field of Fluorescence Correlation Spectroscopy in collaboration with Section on Cell Biophysics at NICHD. The oncology community is testing a number of novel targeted approaches for use against a variety of cancers. With regard to monitoring vasculature, it is desirable to develop and assess noninvasive and quantitative techniques that can not only monitor structural changes, but can also assess the functional characteristics or the metabolic status of the tumor. We are testing three potential noninvasive imaging techniques to monitor patients undergoing an experimental therapy: infrared thermal imaging (thermography), laser Doppler imaging (LDI) and multi-spectral imaging. These imaging techniques are being tested on subjects with Kaposi s sarcoma (KS), a highly vascular tumor that occurs frequently among people infected with acquired immunodeficiency syndrome (AIDS). Cutaneous KS lesions are easily accessible for noninvasive techniques that involve imaging of tumor vasculature, and they thus represent a tumor model in which to assess certain parameters of angiogenesis. The KS studies are ongoing clinical trials under four different NCI protocols. We have shown that our multi-modality techniques can non-invasively monitor the functional properties of the tumor and surrounding tissues and has the potential to predict treatment outcomes. To better quantify the blood volume and oxygenation we have developed a frequency domain Optical Coherence Tomography system to better correlate the strctural information with functional activities of the tumor. Integration of this technique is underway. High-resolution confocal laser microscopy is an intensively active field in modern bioimaging technologies because this technique provides sharp, high-magnification, three dimensional imaging with submicron resolution by non-invasive optical sectioning and rejection of out-of-focus information. We have developed a simple fiber-optic confocal microscope with nanoscale depth resolution beyond the diffraction barrier. We are extensively working to increase the acquisition time for data collection in 3D.

从正常组织功能到病变组织的转变可以通过量化不规则模式来检测。感兴趣区域的统计相似性程度可以携带有关组织结构特征的有价值的比较信息，并有助于表征组织，即分析疾病的定位和进展。为了可视化生物组织的地下结构特征，我们开发了一种用户友好的偏振成像系统，可以同时成像交叉和共偏振光。我们开发了一种基于Pearson相关系数分析的定量统计工具，以提高图像质量并揭示噪声组织图像中高统计相似性的区域。我们已经证明，在某些条件下，这种相关系数的图是由组织的纹理特征决定的，而不是参考图像区域的选择，提供了组织结构的信息。作为一个例子，从噪声偏振光图像中增强脱矿牙齿样品的亚表面纹理。我们最近将偏光相机用于阴道镜来研究宫颈的组织结构。荧光团寿命成像是研究肿瘤等组织环境的一种很有前途的工具。荧光团的寿命（电子从激发态返回到初始态的时间）可以随着直接环境的变化而变化，如温度、pH值、组织氧含量、营养供应和生物能量状态。绘制荧光团在不同深度组织中的寿命和位置可用于监测这些参数。为了实现这一目标，我们开发了一种时间分辨寿命成像系统，用于体内小动物研究，绘制荧光团的寿命。该系统由一个单源多探测器阵列组成，扫描组织表面。使用几个源探测器分离，人们能够探测介质的不同深度。为了研究皮肤下的肿瘤环境，我们在近红外区域使用了pH敏感染料。我们已经证明，通过使用简化的反向投影，我们能够在体内绘制近表面荧光寿命。结合预先校准的生命周期对pH值的反应，我们已经证明了生物学上合理的，非侵入性的，小鼠肿瘤pH值的定量可以确定。在NCI放射肿瘤学分支项目中与Capala博士合作，他开发了用于HER2阳性癌症（例如乳腺癌）非侵入性和HER2特异性治疗药物递送的体内监测探针。我们已经能够量化探针和HER2受体在肿瘤细胞上的生物分布，显示出这种方法在非侵入性和定量监测治疗反应方面的潜力。为了进一步将这项工作包括更深的组织成像，我们研究了使用新的数据类型来重建在浑浊介质中嵌入更深的荧光团的位置和寿命。我们开发了一套本地数据类型，为成像目的提供了比标准全局数据类型更强的噪声容忍度。使用时间分辨荧光分析深埋组织异常，应考虑到生物组织的高度散射性质。为了解决相应的并发症，我们研究了先前开发的局部荧光团光子迁移分析模型的局限性。结果表明，为了更好地描述实验结果，模型应该包含更真实的荧光寿命分布，从而为逆模型收敛提供更大的灵活性。该解析模型已被用作重建点光源荧光团的寿命和位置的正演模型。在研究时间分辨荧光成像中不同数据类型的噪声敏感性方面也取得了其他进展，我们提出了一种新的局部数据类型集，它可能比漫射光学断层扫描中使用的经典统计（全局）数据类型提供更多的噪声稳定性。我们还采用了另一种方法来定量深嵌荧光团的荧光寿命，当荧光团的固有寿命与介质中的光子迁移时间相当时，可以使用一般缩放关系将观察到的时间分辨强度分布从浊介质内给定深度z的荧光靶到预期的表面分布（来自相同的荧光团）。揭示固有的荧光寿命，而不需要全尺寸重建。当比较几个探测器从同一深嵌荧光团获得的时间分辨数据时，可以应用类似的修正，这些探测器位于距离源（激发光子进入介质的入口点）不同的距离。我们用组织样的幻影实验验证了这些关系。建立的时间分辨荧光成像随机游走模型证实了这些尺度关系。