FDA Scholar Program: Blood-Mimicking Phantoms for Assessing Oximetry Performance of Photoacoustic Imaging Systems

FDA 学者计划：用于评估光声成像系统血氧饱和度性能的模拟血液模型

• 批准号: 2149602
• 负责人: Jesse Jokerst
• 金额: $ 10万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-01 至 2024-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2149602&HistoricalAwards=false
• 关键词: FDA; Scholar; Program; Blood; Mimicking

NON-TECHNICAL SUMMARYUltrasound is a powerful tool to image diseases including cancer, orthopedic disorders, and heart function. One limitation of ultrasound is that it suffers from low contrast (contrast is the difference in signal intensity between the region of interest and the background tissue). Therefore, there is a large body of research into a special kind of ultrasound known as photoacoustic imaging. Photoacoustic imaging uses light to generate sound only in the area of interest—this increases the contrast. Unfortunately, photoacoustic ultrasound is not yet approved for widespread use in people. This might be partially due to a lack of devices and methods to validate and standardize the novel imaging equipment needed for photoacoustic imaging. Therefore, this work will create specialized plastic objects with optical and acoustic properties that mimic human tissue with different amounts of tissue oxygenation. These objects can be used to calibrate and standardize photoacoustic imaging equipment. This proposal combines expertise from academia and the Food and Drug Administration to identify materials that have similar optical and acoustic properties as human tissue. We will then add dyes that have absorption spectra similar to hemoglobin. The resulting test objects will improve knowledge of how to best create photoacoustic imaging instrumentation that measures tissue oxygenation and might also streamline regulatory approval of this equipment. In turn, this will increase patient access to this important imaging technique to ultimately advance the health and quality of life of US taxpayers. TECHNICAL SUMMARYPhotoacoustic imaging provides deep tissue imaging similar to ultrasound but with enhanced optical contrast and additional functional and molecular imaging capabilities. However, no standardized performance test methods or phantoms exist for photoacoustic imaging system evaluation unlike mature techniques such as computed tomography. The fundamental limitation—and scientific problem to be studied here—is a lack of materials to simultaneously simulate tissue properties over a broad range of optical wavelengths and acoustic frequencies. This leaves investigators, instrument manufacturers, and regulatory agencies without clear strategies to evaluate device safety and effectiveness. Our prior work with the Food and Drug Administration (FDA) built stable, biologically relevant imaging phantoms with well-characterized optical absorption/scattering coefficients, acoustic impedance, etc. that broadly simulate tissue over a wide range of optical wavelengths and acoustic frequencies. We will now integrate chromophores to simulate tissue oxygenation (SO2) over a range of oxygen saturation/perfusion values. Objective 1 of this research will develop phantoms that simulate blood oxygen-dependent photoacoustic spectra. Combinations of dyes will be selected to develop tunable formulations that reproduce blood-like multispectral photoacoustic signals at sets of discrete optical wavelengths commonly used for photoacoustic oximetry. Photoacoustic-derived SO2 measurements will be compared against ground truth values as well as against photoacoustic measurements in bovine blood with variable SO2. Ground truth SO2 of bovine blood will be measured by oximetry. Objective 2 will use the phantoms to establish quantitative oximetry test methods. These methods will be performed on three different photoacoustic systems located at UCSD and FDA. Phantoms with different background optical properties and containing blood-mimicking inclusions at different depths and mimicked SO2 levels will be used for parametric study of photoacoustic device oximetry performance. Improvements in the SO2 measurement accuracy of our three photoacoustic systems using various fluence correction algorithms will be quantified to determine device sensitivity to tissue properties and morphology.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术总结超声是一种强大的工具，用于成像疾病，包括癌症，骨科疾病和心脏功能。超声波的一个局限性是它具有低对比度（对比度是感兴趣区域和背景组织之间的信号强度差异）。因此，有大量的研究进入一种特殊的超声称为光声成像。光声成像利用光只在感兴趣的区域产生声音，这增加了对比度。不幸的是，光声超声尚未被批准在人类中广泛使用。这可能部分是由于缺乏设备和方法来验证和标准化光声成像所需的新型成像设备。因此，这项工作将创造出具有光学和声学特性的专用塑料物体，模拟具有不同组织氧合量的人体组织。这些物体可用于校准和标准化光声成像设备。该提案结合了学术界和食品和药物管理局的专业知识，以确定具有与人体组织相似的光学和声学特性的材料。然后，我们将添加具有与血红蛋白相似的吸收光谱的染料。由此产生的测试对象将提高如何最好地创建测量组织氧合的光声成像仪器的知识，并且还可以简化该设备的监管批准。反过来，这将增加患者获得这种重要成像技术的机会，最终提高美国纳税人的健康和生活质量。技术概述光声成像提供与超声类似的深层组织成像，但具有增强的光学对比度和附加的功能和分子成像能力。然而，不像成熟的技术，如计算机断层扫描，没有标准化的性能测试方法或幻影存在的光声成像系统的评价。基本的限制和科学问题要研究在这里是缺乏材料，同时模拟组织的特性，在很宽的范围内的光波长和声频。这使得研究者、仪器制造商和监管机构没有明确的策略来评估器械的安全性和有效性。我们之前与美国食品药品监督管理局（FDA）的合作建立了稳定的、生物相关的成像体模，其具有良好表征的光学吸收/散射系数、声阻抗等，其在宽范围的光学波长和声学频率上广泛地模拟组织。我们现在将整合发色团，以模拟氧饱和度/灌注值范围内的组织氧合（SO2）。本研究的目的一是研制模拟血氧依赖性光声光谱的体模。将选择染料的组合来开发可调制剂，其在通常用于光声血氧测定的离散光学波长的集合处再现血液样多光谱光声信号。将光声衍生的SO2测量值与地面实况值以及具有可变SO2的牛血中的光声测量值进行比较。将通过血氧测定法测量牛血的真实SO2。目的二是利用体模建立定量血氧检测方法。这些方法将在位于UCSD和FDA的三个不同的光声系统上进行。将使用具有不同背景光学特性并在不同深度含有血液模拟内含物和模拟SO2水平的样品进行光声装置血氧测定性能的参数研究。我们的三个光声系统使用各种通量校正算法的SO2测量精度的改进将被量化，以确定设备对组织特性和形态的灵敏度。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

3D-Bioprinted Phantom with Human Skin Phototypes for Biomedical Optics.

用于生物医学光学的具有人体皮肤光型的 3D 生物打印模型。

• DOI: 10.1002/adma.202206385
• 发表时间: 2023
• 期刊: Advanced materials (Deerfield Beach, Fla.)
• 作者: Yim,Wonjun;Zhou,Jiajing;Sasi,Lekshmi;Zhao,Jiayu;Yeung,Justin;Cheng,Yong;Jin,Zhicheng;Johnson,Wade;Xu,Ming;Palma-Chavez,Jorge;Fu,Lei;Qi,Baiyan;Retout,Maurice;Shah,NisargJ;Bae,Jinhye;Jokerst,JesseV
• 通讯作者: Jokerst,JesseV