Testbed for Quantitative Thermoacoustic Tomography

定量热声断层扫描试验台

• 批准号: 7798351
• 负责人: SARAH Kathryn PATCH
• 金额: $ 19.06万
• 依托单位: UNIVERSITY OF WISCONSIN MILWAUKEE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-01 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7798351
• 关键词: Acoustics; Cellular Phone; Clinical; Clinical Trials; Code; Computer software; Contrast Media; Data; Deposition; Diagnostic; Drops; Effectiveness; Electromagnetic Energy; Electromagnetic Fields; Electromagnetics; Ensure; Environment; Exploratory/Developmental Grant; Frequencies; Goals; Heat Losses; Histocompatibility Testing; Image; Imaging Techniques; Lighting; Magnetic Resonance Imaging; Malignant neoplasm of prostate; Measurement; Measures; Medical Imaging; Microbubbles; Optics; Pattern; Penetration; Physiologic pulse; Property; Relative (related person); Reporting; Research Personnel; Resources; Safety; Signal Transduction; Skin; Source; Specimen; Structure; Surface; System; Testing; Tissues; Translating; Ultrasonic Transducer; Ultrasonography; Vertebral column; Width; Work; X-Ray Computed Tomography; absorption; animal tissue; cancer imaging; design; electric field; flexibility; in vivo; microwave electromagnetic radiation; nanoparticle; pressure; public health relevance; radiofrequency; reconstruction; response; soft tissue; software development; tomography; tool

DESCRIPTION (provided by applicant): We propose to develop a testbed for quantifying thermoacoustic computerized tomography (TCT) signal strength as a function of electromagnetic (EM) illumination pulse parameters. TCT images a completely new contrast mechanism: conversion of EM to acoustic pressures via thermal expansion. TCT pressures are measured by ultrasound transducers located outside of the imaging field of view (FOV) but are generated by thermal expansion inside the FOV caused by the short burst of EM illumination propagated into the FOV. TCT pressures can be reconstructed to provide an image related to the tissue's specific absorption rate (SAR) of EM energy. SAR is a function of both applied electric field strength, |E|, and intrinsic tissue properties. The goal of quantitative TCT is to recover intrinsic tissue properties independent of |E| applied by the TCT system. The goal of this proposal is to quantify TCT signal strength as a function of |E| to ensure strong TCT signal can be generated robustly in vivo. Many encouraging photoacoustic tomography (PAT) studies show good results within 2-3 cm of the skin surface and intravascularly, but only one clinical trial of TCT with deeply penetrating radiofrequency (RF) illumination has been reported. We will use both software and hardware "testbeds" designed to generate TCT pressure signals under a controlled EM environment to achieve the following specific aims: 1. Quantify TCT acoustic signal strength in Pascals (Pa) vs. RF illumination parameters: peak power, carrier frequency, polarization and pulse width for simple test phantoms and animal tissue specimens. Analytical calculations for geometrically simple phantoms from the software testbed will be compared to measurements from the hardware testbed. 2. Quantify effect of contrast agents on TCT contrast and S/N. We will focus on microbubbles used in ultrasound and nanoparticles as used in PAT. 3. Modify the testbed to become a benchtop TCT tomography system for ex vivo imaging. This testbed will rotate and translate specimens, providing cylindrical measurement surfaces for tomographic reconstruction. PUBLIC HEALTH RELEVANCE: We will validate a completely new contrast mechanism for diagnostic medical imaging in soft tissues. Thermoacoustics may be a boon to applications for which current imaging techniques are woefully inadequate, such as prostate cancer imaging.

描述（由申请人提供）：我们建议开发一种测试台，用于量化热声计算机断层扫描（TCT）信号强度作为电磁（EM）照明脉冲参数的函数。 TCT 成像了一种全新的对比机制：通过热膨胀将电磁转换为声压。 TCT 压力由位于成像视场 (FOV) 外部的超声换能器测量，但由传播到 FOV 的电磁照明短脉冲引起的 FOV 内部热膨胀产生。可以重建 TCT 压力，以提供与组织的 EM 能量比吸收率 (SAR) 相关的图像。 SAR 是外加电场强度 |E| 和固有组织特性的函数。定量 TCT 的目标是恢复独立于 |E| 的内在组织特性。由TCT系统应用。该提案的目标是将 TCT 信号强度量化为 |E| 的函数以确保在体内能够产生强TCT信号。 许多令人鼓舞的光声断层扫描 (PAT) 研究显示，在皮肤表面 2-3 厘米范围内和血管内取得了良好的结果，但仅报道了一项采用深穿透射频 (RF) 照明的 TCT 临床试验。我们将使用设计用于在受控 EM 环境下生成 TCT 压力信号的软件和硬件“测试台”，以实现以下具体目标： 1. 量化以帕斯卡 (Pa) 为单位的 TCT 声信号强度与 RF 照明参数：峰值功率、载波简单测试体模和动物组织样本的频率、偏振和脉冲宽度。软件测试台的几何简单模型的分析计算将与硬件测试台的测量结果进行比较。 2. 量化造影剂对 TCT 对比度和信噪比的影响。我们将重点关注超声波中使用的微泡和 PAT 中使用的纳米颗粒。 3. 修改测试台，使其成为用于离体成像的台式 TCT 断层扫描系统。该测试台将旋转和平移样本，为断层扫描重建提供圆柱形测量表面。 公共健康相关性：我们将验证一种用于软组织诊断医学成像的全新对比机制。热声学对于当前成像技术严重不足的应用可能是一个福音，例如前列腺癌成像。