Flexible Ribbon Guide - In-Vivo & Hand-Held THz Imaging

柔性色带指南 - In-Vivo

• 批准号: 6801700
• 负责人: PETER H SIEGEL
• 金额: $ 20.11万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6801700
• 关键词: bioengineering /biomedical engineering; bioimaging /biomedical imaging; biomedical equipment development; electromagnetic radiation; endoscopy; fiber optics; physical property; portable biomedical equipment; radiowave radiation

DESCRIPTION (provided by applicant): Flexible Ribbon Guide for In-Vivo and Hand-Held THz Imaging: Recent interest in terahertz frequency imaging for medical applications (wavelength range from 1 mm to 100 microns) has stimulated a flurry of new instrument proposals using both time domain and high resolution frequency domain spectral techniques. However, the field is very new, and definitive contrast mechanisms other than strong liquid absorption, have not yet been established. Terahertz studies on basal cell carcinoma, both in-vivo and ex-vivo, are very promising but the instrumentation employed is limited to fixed-position skin surface scans only. The problem lies with the fact that there exists no methodology for flexibly transporting terahertz signals from place-to-place with low loss, other than rigid-path free-space quasi-optical beam propagation. This means no terahertz instrument can be used in a hand-scanning mode or an in-vivo endoscopic application, with its greatly enhanced range of surveyable tissue and contrast. This research will change the modality and capability of all terahertz imaging instruments providing contrast that cannot be obtained today. In order to take advantage of techniques common at optical wavelengths, including in-vivo and portable hand-held sensor/receiver systems, the equivalent of signal-confining optical fiber links must be developed for the terahertz bands. Commonly employed transparent materials in the visible are all extremely lousy at longer wavelengths due to strong vibrational mode absorption. Dielectric substances with low absorption coefficient and high index do exist at terahertz frequencies, but they tend to be crystalline and therefore have poor mechanical properties when it comes to forming flexible guiding structures. Metallic waveguide (hollow or coaxial), although somewhat flexible, has untenable high resistive wall loss. A few plastics have very low dispersion and absorption but have a low refractive index that makes it difficult to confine single mode terahertz energy as it propagates around bends or through joints. Work by our collaborators has shown that high index materials formed into ultra-thin ribbons can form very low loss guiding media at millimeter-wave frequencies (30-300 GHz). Extrapolating this concept into the terahertz bands, and taking advantage of modern thin film fabrication techniques, we believe it is possible to use a combination of electro-deposited high-dielectric-constant crystalline materials in conjunction with low-loss, low index plastics to produce the equivalent of flexible terahertz optical fiber, i.e., "terahertz ribbon guide." The work to be performed will offer a solution to a major stumbling block in terahertz imaging and will significantly enhance the range of applications for all terahertz imagers, making it possible to scan fixed samples directly, or transport terahertz signals into the body where additional modalities, such as localized thermography, may be explored.

描述（由申请人提供）： 用于体内和手持太赫兹成像的灵活色带导轨：最近对医疗应用太赫兹频率成像（波长范围从 1 毫米到 100 微米）的兴趣激发了一系列使用时域和高分辨率频域的新仪器提案光谱技术。然而，这个领域非常新，除了强液体吸收之外，尚未建立明确的对比机制。对基底细胞癌的体内和离体太赫兹研究非常有前景，但所使用的仪器仅限于固定位置皮肤表面扫描。问题在于，除了刚性路径自由空间准光束传播之外，不存在以低损耗灵活地将太赫兹信号从一个地方传输到另一个地方的方法。这意味着太赫兹仪器无法用于手动扫描模式或体内内窥镜应用，其可测量组织和对比度的范围大大增强。这项研究将改变所有太赫兹成像仪器的模式和功能，提供当今无法获得的对比度。为了利用光波长下常见的技术，包括体内和便携式手持式传感器/接收器系统，必须为太赫兹频段开发等效的信号限制光纤链路。由于强烈的振动模式吸收，可见光中常用的透明材料在较长波长下都非常糟糕。太赫兹频率下确实存在具有低吸收系数和高折射率的介电物质，但它们往往是结晶的，因此在形成柔性引导结构时机械性能较差。金属波导（空心或同轴）虽然有些柔性，但具有难以维持的高电阻壁损耗。一些塑料具有非常低的色散和吸收，但折射率较低，这使得当单模太赫兹能量在弯曲处或通过接头传播时很难限制它。我们合作者的工作表明，形成超薄带的高折射率材料可以在毫米波频率 (30-300 GHz) 下形成非常低损耗的引导介质。将这一概念推广到太赫兹频段，并利用现代薄膜制造技术，我们相信可以将电镀高介电常数晶体材料与低损耗、低折射率塑料相结合来生产相当于柔性太赫兹光纤，即“太赫兹带状波导”。即将开展的工作将为太赫兹成像中的一个主要障碍提供解决方案，并将显着增强所有太赫兹成像仪的应用范围，从而可以直接扫描固定样本，或将太赫兹信号传输到需要额外模式的体内，可以探索诸如局部热成像技术。