Generation of Temperature Maps of Heated Materials using 3D Ultrasound Imaging

背景：超声成像是一种廉价的技术，在人体成像和无损检测中容易获得并广泛使用，具有结构的实时成像、使用多普勒技术测量流体的速度以及使用各种方法的材料弹性等功能。正在进行重要的研究，以扩展US成像的能力，以允许生成材料的其他方面的信息。 在过去的20年里，我们的实验室专注于探索和开发基于3DUS(我们是这项技术的世界先驱之一)、机器人技术和先进的图像处理技术(如3D可视化、分割和配准)的US引导治疗系统。在治疗指导方面，我们使用了各种组织热消融技术，如射频、微波和激光，并通过磁共振成像来绘制组织温度。在这项提案中，我们建议利用我们正在进行的研究，探索用于3D温度映射的US成像能力。 目的：我们的目标是从根本上研究三维超声在测量材料和组织中温度变化方面的应用。具体地说，在五年的时间里，我们将实现以下目标：(1)探索可以优化3DUS的条件，以在受热的均匀材料中生成3D温度图；(2)在动物组织中使用3DUS生成3D温度图；(3)将金标准温度测量和基于3DUS的温度图与计算模型相关联；以及(4)开发在基于3DUS的温度图期间校正材料运动的方法。 方法：美国的温度监测技术主要基于两种现象：量化材料热膨胀引起的声信号漂移和声速的局部变化。因此，使用在两个不同温度下获得的两个单独图像中相同位置的斑块的回波去相关，已经表明去相关度量可以被校准以提供关于温差的信息。然而，由于材料的运动以及所开发的技术使用2D图像的事实，这种方法的开发一直受到阻碍，但由于温度变化导致的材料变化发生在3D中。因此，我们的研究计划将研究如何利用我们实验室的3DUS成像和运动补偿技术来测量3D温度变化。 新颖性和预期意义：我们的研究计划将产生关于美国测量的基本物理以及3DUS信号如何随着温度变化而变化的新知识。我们认为，通过将3DUS信号检测与运动补偿相结合，有可能克服其他人在开发基于美国的温度测量方面所面临的障碍，并在各种应用中为US成像提供扩展能力。

BACKGROUND: Ultrasound (US) imaging is an inexpensive technique that is readily available and used extensively in human imaging and non-destructive testing, with capabilities such as real-time imaging of structure, velocity measurements of fluids using Doppler techniques, and material elasticity using a variety of approaches. Significant research is ongoing to extend the capability of US imaging to allow generation of information of other aspects of materials. For the past 2 decades our lab has focused on exploring and developing systems used for US-guided therapy based on 3DUS (we are among the world pioneers of this technology), robotics and advanced image processing techniques such as 3D visualization, segmentation, and registration. For therapy guidance we used various techniques for thermal ablation of tissues, such as RF, microwave and lasers, with magnetic resonance imaging to map temperature of tissue. In this proposal, we propose to leverage our ongoing research and explore the capability of US imaging for 3D temperature mapping. OBJECTIVE: Our aim is to fundamentally investigate the use of 3DUS to measure changes in temperature in materials and tissues. Specifically, over 5 years, we will pursue our aim following these objectives: (1) explore the conditions whereby 3DUS may be optimized to generate 3D temperature maps in homogenous materials as they are heated; (2) generate 3D temperature maps using 3DUS in animal tissues; (3) correlate gold standard temperature measurements and 3DUS-based temperature maps with computational models; and (4) develop methods to correct for motion of materials during 3DUS-based temperature mapping. APPROACH: US-based temperature monitoring techniques are primarily based on two phenomena: quantification of acoustic signal shifts due to thermal expansion of the material and local changes of the speed of sound. Thus, using echo decorrelation of patches of the same location in two separate images obtained at two different temperatures, it has been shown that the decorrelation metric can be calibrated to provide information on the temperature difference. However, exploiting this approach has been hampered by motion of the material and the fact that techniques developed used 2D images, yet changes in the material due to temperature changes occurs in 3D. Thus, our research program will investigate how to leverage 3DUS imaging and motion compensation developments in our lab to be able to measure temperature changes in 3D. NOVELTY AND EXPECTED SIGNIFICANCE: Our research program will generate new knowledge of the fundamental physics of US measurements and how 3DUS signals change with changes in temperature. We think that by combining 3DUS signal detection with motion compensation has the potential to overcome the obstacles others have faced in developing US-based thermometry and provide extended capability for US imaging in a variety of applications.