Small Animal Tomography System for Green Fluorescent Protein Imaging

用于绿色荧光蛋白成像的小动物断层扫描系统

• 批准号: 7319424
• 负责人: ANDREAS H HIELSCHER
• 金额: $ 23.98万
• 依托单位: COLUMBIA UNIV NEW YORK MORNINGSIDE
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-20 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7319424
• 关键词: Accounting; Affect; Algorithms; Animal Model; Animals; Area; Autopsy; Behavior; Biology; Bioluminescence; Brain; Cell Line; Cells; Characteristics; Chimeric Proteins; Code; Data; Data Set; Development; Devices; Diffusion; Disease; Disease Progression; Equation; Equipment; Fluorescence; Fluorescent Probes; Frequencies; Gene Proteins; Goals; Green Fluorescent Proteins; Growth; Herpesvirus 1; Histocompatibility Testing; Image; Imaging Techniques; In Vitro; Knowledge; Lead; Light; Liver; Location; Lung; Magnetic Resonance Imaging; Malignant Neoplasms; Measurement; Measures; Methods; Microscopic; Modeling; Molds; Molecular; Mus; Neoplasm Metastasis; Noise; Optical Methods; Optical Tomography; Optics; Organ; Organelles; Pathway interactions; Performance; Personal Satisfaction; Phase; Positioning Attribute; Positron-Emission Tomography; Process; Property; Proteins; Radiolabeled; Reading; Reporter; Reporter Genes; Research; Research Personnel; Resolution; Scheme; Signal Transduction; Signaling Molecule; Simulate; Solutions; Source; Spatial Distribution; Staging; Surface; System; Techniques; Testing; Thymidine Kinase; Time; Tissues; Work; Xenograft procedure; absorption; anticancer research; base; design; detector; experience; fluorescence imaging; fluorophore; human disease; image reconstruction; improved; in vivo; innovation; insight; instrumentation; interest; intracellular protein transport; light scattering; mouse model; novel; optical imaging; protein transport; radiotracer; reconstruction; response; single molecule; size; theories; tomography; treatment effect; tumor; tumor progression; tumorigenesis

DESCRIPTION (provided by applicant): The overall goal of this proposal is to develop image reconstruction schemes and instrumentation for tomographic imaging of green fluorescent proteins (GFP) in small animals. Small animal imaging has gained considerable importance in recent years as more and more animal models for human diseases have become available. Imaging of disease progression and effects of treatments in animals has many scientific and economical advantages, as sacrificing animals at various disease stages and performing necropsy and histopathological studies can be sharply reduced. Optical techniques have proven to be very valuable when applied to small animal imaging because of an abundance of optical markers that can target and visualize various disease related processes on the cellular and molecular level. However, to date most optical imaging studies have only explored whole animal surface imaging without tomographic reconstruction. Only a few groups including our team have presented first tomographic results that reveal three-dimensional fluorescent probe distribution in small animals. In these cases the image reconstructions were exclusively based on the diffusion model of light propagation in tissue, which is an approximation to the more generally applicable transport model. This has limited the application of such codes to studies involving fluorophores that emit in the near-infrared, where tissue absorption is smaller than in the visible spectrum. Furthermore, only steady-state instrumentation or frequency-domain devices with modulation frequencies smaller than 150 MHz were employed. While promising, these systems still suffer from cross-talk between absorption and scattering effects, limited spatial resolution, and limited accuracy in fluorescence absorption and lifetime determination. It is highly desirable to extend optical tomographic methods to shorter wavelengths, which would provide a means to image green fluorescence proteins that emit light in the visible spectrum. Using GFP and its derivatives, it is now possible to visualize nearly any protein of interest in any cell, tissue, or species. Researchers working at all levels of biology, such as single-molecule dynamics, protein trafficking within cells, organelle dynamics, and cell and tissue behaviors during development, cancer progression, and other diseases, are nowadays making use of GFP mostly in vitro studies. The availability of an optical tomography system for in vivo GFP imaging would have a significant impact on this large area of research. Themain hypothesis of this proposal is that limitations related to existing instrumentation for optical tomography can be overcome by an imaging system that uses a frequency-domain light propagation model that is based on the equation of radiative transfer (also called "transport equation"). Combined with instrumentation that allows for modulation frequencies higher than the currently available 150MHz, this will lead to better spatial resolution and reduced cross-talk between scattering and absorption effects. Furthermore, using a multi-wavelength and multi-frequency imaging system offers unique opportunities to reduce undesirable background signal due to autofluorescence. The overall goal of this proposal is to develop novel optical methods for volumetric imaging of small animals that are used in research to better understand and treat numerous diseases. For example, the imaging system could help visualize tumor location and growth. If successfully implemented the new imaging system will provide new insights into how various diseases, such as cancer, spread and affect the body.

描述（由申请人提供）：该提案的总体目标是开发用于小动物绿色荧光蛋白（GFP）断层成像的图像重建方案和仪器。近年来，随着越来越多的人类疾病动物模型的出现，小动物成像变得相当重要。对动物疾病进展和治疗效果进行成像具有许多科学和经济优势，因为可以大幅减少在不同疾病阶段处死动物以及进行尸检和组织病理学研究。光学技术已被证明在应用于小动物成像时非常有价值，因为大量的光学标记可以在细胞和分子水平上瞄准和可视化各种疾病相关过程。然而，迄今为止，大多数光学成像研究仅探索了整个动物表面成像，而没有进行断层扫描重建。只有包括我们团队在内的少数几个小组首次提出了揭示小动物体内三维荧光探针分布的断层扫描结果。在这些情况下，图像重建完全基于组织中光传播的扩散模型，这是更普遍适用的传输模型的近似。这限制了此类代码在涉及在近红外发射的荧光团的研究中的应用，其中组织吸收小于可见光谱。此外，仅采用调制频率小于 150 MHz 的稳态仪器或频域设备。尽管前景广阔，但这些系统仍然受到吸收和散射效应之间的串扰、有限的空间分辨率以及荧光吸收和寿命测定的准确性有限的影响。人们非常希望将光学断层扫描方法扩展到更短的波长，这将提供一种对在可见光谱中发射光的绿色荧光蛋白进行成像的方法。使用 GFP 及其衍生物，现在可以可视化任何细胞、组织或物种中几乎任何感兴趣的蛋白质。如今，从事单分子动力学、细胞内蛋白质运输、细胞器动力学以及发育、癌症进展和其他疾病期间的细胞和组织行为等生物学各个层面的研究人员大多在体外研究中使用 GFP。用于体内 GFP 成像的光学断层扫描系统的可用性将对这一大领域的研究产生重大影响。该提案的主要假设是，与现有光学断层扫描仪器相关的限制可以通过使用基于辐射传输方程（也称为“传输方程”）的频域光传播模型的成像系统来克服。与允许调制频率高于当前可用的 150MHz 的仪器相结合，这将带来更好的空间分辨率并减少散射和吸收效应之间的串扰。此外，使用多波长和多频率成像系统提供了独特的机会来减少由于自发荧光而产生的不良背景信号。该提案的总体目标是开发用于小动物体积成像的新型光学方法，用于更好地了解和治疗多种疾病的研究。例如，成像系统可以帮助可视化肿瘤的位置和生长。如果成功实施，新的成像系统将为了解癌症等各种疾病如何传播和影响身体提供新的见解。