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Photoacoustic computed tomography in biological tissues: Algorithms and breast imaging.

机译：生物组织中的光声计算机断层扫描：算法和乳房成像。

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摘要

Photoacoustic computed tomography (PAT) has great potential for application in the biomedical field. It best combines the high contrast of electromagnetic absorption and the high resolution of ultrasonic waves in biological tissues.;In Chapter II, we present time-domain reconstruction algorithms for PAT. First, a formal reconstruction formula for arbitrary measurement geometry is presented. Then, we derive a universal and exact back-projection formula for three commonly used measurement geometries, including spherical, planar and cylindrical surfaces. We also find this back-projection formula can be extended to arbitrary measurement surfaces under certain conditions. A method to implement the back-projection algorithm is also given. Finally, numerical simulations are performed to demonstrate the performance of the back-projection formula.;In Chapter III, we present a theoretical analysis of the spatial resolution of PAT for the first time. The three common geometries as well as other general cases are investigated. The point-spread functions (PSF's) related to the bandwidth and the sensing aperture of the detector are derived. Both the full-width-at-half-maximum of the PSF and the Rayleigh criterion are used to define the spatial resolution.;In Chapter IV, we first present a theoretical analysis of spatial sampling in the PA measurement for three common geometries. Then, based on the sampling theorem, we propose an optimal sampling strategy for the PA measurement. Optimal spatial sampling periods for different geometries are derived. The aliasing effects on the PAT images are also discussed. Finally, we conduct numerical simulations to test the proposed optimal sampling strategy and also to demonstrate how the aliasing related to spatially discrete sampling affects the PAT image.;In Chapter V, we first describe a prototype of the RF-induced PAT imaging system that we have built. Then, we present experiments of phantom samples as well as a preliminary study of breast imaging for cancer detection.
机译：光声计算机断层扫描（PAT）在生物医学领域具有巨大的应用潜力。它最好地结合了电磁吸收的高对比度和生物组织中的超声波的高分辨率。在第二章中，我们提出了PAT的时域重构算法。首先，给出了用于任意测量几何的形式化重构公式。然后，我们针对三个常用的测量几何体（包括球面，平面和圆柱面）推导了通用且精确的反投影公式。我们还发现该反投影公式可以在某些条件下扩展到任意测量表面。还给出了一种实现反投影算法的方法。最后，进行了数值模拟，以证明反投影公式的性能。在第三章中，我们首次对PAT的空间分辨率进行了理论分析。研究了三种常见的几何形状以及其他一般情况。得出与检测器的带宽和检测孔径有关的点扩展函数（PSF）。 PSF的半峰全宽和瑞利准则均用于定义空间分辨率。在第四章​​中，我们首先对三种常见几何形状的PA测量中的空间采样进行了理论分析。然后，基于采样定理，我们提出了一种用于功率放大器测量的最佳采样策略。得出了不同几何形状的最佳空间采样周期。还讨论了混叠效应对PAT图像的影响。最后，我们进行数值模拟，以测试提出的最佳采样策略，并演示与空间离散采样相关的混叠如何影响PAT图像。在第五章中，我们首先描述了RF诱导的PAT成像系统的原型，已经建成。然后，我们介绍了幻像样品的实验以及对乳腺癌成像进行癌症检测的初步研究。

著录项

  • 作者

    Xu, Minghua.;

  • 作者单位

    Texas A&M University.;

  • 授予单位 Texas A&M University.;
  • 学科 Engineering Biomedical.;Health Sciences Oncology.;Health Sciences Radiology.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 136 p.
  • 总页数 136
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生物医学工程;预防医学、卫生学;肿瘤学;
  • 关键词

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