Photoacoustic Imaging in Optically Diffusive Media Using Structured Illumination

使用结构照明的光扩散介质中的光声成像

• 批准号: 1810314
• 负责人: Todd Murray
• 金额: $ 36.5万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-15 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1810314&HistoricalAwards=false
• 关键词: Photoacoustic; Imaging; Optically; Diffusive; Media

Part 1:Optical imaging of objects inside or behind turbid media is exceptionally challenging. Multiple scattering scrambles the object information and hides features from view. This project aims to develop and characterize a technique for imaging deep inside of optically scattering media with unprecedented spatial resolution. The approach combines photoacoustic imaging, an emerging modality that uses light and ultrasound to image absorbing structures within tissue, with structured illumination microscopy, an established means of improving imaging resolution by spatially patterning the illumination. Mathematical and experimental techniques are proposed that exploit the optical speckle field that naturally emerges as light propagates through scattering media to enhance the resolution of photoacoustic imaging such that it approaches optical resolution, even deep within scattering media. The proposed research aims to transform biomedical imaging, allowing physicians to see through biological tissue to detect and diagnose disease states or conditions with exceptional resolution. It also enables nondestructive testing applications such as detecting structural defects in highly scattering polymer matrix composites and ceramic samples. The interdisciplinary research effort will support graduate students in applied mathematics and mechanical engineering and provide training in engineering, applied mathematics, and biology. Undergraduate researchers will also be supported for the duration of the project. An outreach program to a local high school is proposed and the research results will be incorporated into new and existing undergraduate classes.Part 2:The objective of this proposal is to develop an experimental technique and associated mathematical framework to image inside of and through multiply scattering media using random speckle illumination and photoacoustic detection. The goal is to achieve optical resolution imaging in the multiple scattering regime. The speckle patterns that naturally emerge as light propagates through diffuse media provide structured illumination to an object placed behind a scattering wall. The photoacoustic signal produced by such illumination is detected using a focused ultrasound transducer. Blind structured illumination photoacoustic microscopy (BSIPAM) offers a fundamentally new approach to imaging in turbid media, where image resolution is enhanced by making use of speckle patterns that are a result of the scattering process itself. BSIPAM exploits the fact that the photoacoustic signal generated by an absorbing object subjected to pulsed laser illumination is proportional to the product of the object optical absorption distribution and the illumination pattern. In the case of non-uniform illumination by a random speckle pattern, frequency mixing between the illumination and object encodes the high spatial frequencies of the object in a low spatial frequency photoacoustic response that can be detected with an ultrasound transducer. Furthermore, if the photoacoustic response generated by multiple random speckle patterns is recorded then there is sufficient information to reconstruct an image of the object with a spatial resolution approaching the speckle size. This project develops experimental techniques and reconstruction algorithms that allow for optical resolution imaging at unprecedented depths within static and dynamic diffusive media using the BSIPAM concept. The fundamental resolution enhancement that can be achieved using BSIPAM is explored and the performance of image reconstruction algorithms as a function of speckle size, imaging geometry, number of speckle patterns, imaging depth, and signal to noise ratio are determined.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.

第 1 部分：对浑浊介质内部或后面的物体进行光学成像极具挑战性。多重散射会扰乱物体信息并隐藏视图中的特征。该项目旨在开发并表征一种以前所未有的空间分辨率对光学散射介质内部深处进行成像的技术。该方法将光声成像（一种使用光和超声波对组织内吸收结构进行成像的新兴模式）与结构照明显微镜（一种通过空间图案化照明来提高成像分辨率的既定方法）相结合。提出了数学和实验技术，利用光通过散射介质传播时自然出现的光学散斑场来增强光声成像的分辨率，使其接近光学分辨率，甚至在散射介质深处也是如此。拟议的研究旨在改变生物医学成像，使医生能够透视生物组织，以卓越的分辨率检测和诊断疾病状态或状况。它还支持无损检测应用，例如检测高散射聚合物基复合材料和陶瓷样品中的结构缺陷。跨学科研究工作将支持应用数学和机械工程的研究生，并提供工程、应用数学和生物学方面的培训。本科研究人员也将在项目期间得到支持。提出了对当地高中的推广计划，研究结果将纳入新的和现有的本科课程。第 2 部分：本提案的目标是开发一种实验技术和相关的数学框架，使用随机散斑照明和光声检测在多重散射介质内部和通过多重散射介质进行成像。目标是在多重散射范围内实现光学分辨率成像。当光通过漫射介质传播时自然出现的散斑图案为放置在散射墙后面的物体提供结构化照明。使用聚焦超声换能器检测由这种照明产生的光声信号。盲结构照明光声显微镜（BSIPAM）提供了一种在浑浊介质中成像的全新方法，其中通过利用散射过程本身产生的散斑图案来增强图像分辨率。 BSIPAM 利用了这样一个事实：吸收物体在脉冲激光照射下产生的光声信号与物体光吸收分布和照射图案的乘积成正比。在随机散斑图案的非均匀照明的情况下，照明和物体之间的频率混合将物体的高空间频率编码为可以用超声换能器检测到的低空间频率光声响应。此外，如果记录由多个随机散斑图案生成的光声响应，则有足够的信息以接近散斑尺寸的空间分辨率重建物体的图像。该项目开发实验技术和重建算法，允许使用 BSIPAM 概念在静态和动态扩散介质中以前所未有的深度进行光学分辨率成像。探索了使用 BSIPAM 可以实现的基本分辨率增强，并确定了图像重建算法的性能作为散斑尺寸、成像几何、散斑图案数量、成像深度和信噪比的函数。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力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

Superresolution Photoacoustic Tomography Using Random Speckle Illumination and Second Order Moments

使用随机散斑照明和二阶矩的超分辨率光声断层扫描

• DOI: 10.1109/waspaa52581.2021.9632758
• 发表时间: 2021
• 期刊: 2021 IEEE Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA
• 作者: Malik, Osman Asif;Narumanchi, Venkatalakshmi Vyjayanthi;Becker, Stephen;Murray, Todd W.
• 通讯作者: Murray, Todd W.

Sub-acoustic resolution optical focusing through scattering using photoacoustic fluctuation guided wavefront shaping

• DOI: 10.1364/oe.385320
• 发表时间: 2020-03-30
• 期刊: OPTICS EXPRESS
• 影响因子: 3.8
• 作者: Inzunza-Ibarra, Marco A.;Premillieu, Evolene;Murray, Todd W.
• 通讯作者: Murray, Todd W.