Simulation Tools for Dynamic CT

描述(由申请人提供)：模拟是描述、评估和优化医学成像系统以及图像处理和重建方法的有力工具。模拟的两个主要组成部分是：(1)人体解剖和生理功能的真实模型，以及(2)生成包括成像过程影响的准确图像数据的能力。如果没有这一点，模拟的结果可能不能指示实际患者会发生什么，因此，实际价值将是有限的。目前基于四维(4D)NURBS的心脏躯干(NCAT)模型是为了提供逼真和灵活的人体解剖和生理模型而开发的，并被广泛应用于核医学成像研究中。由于其设计，该体模的优势在于它的器官形状可以改变，以积极地模拟不同的解剖变化和患者的运动。尽管NCAT模型能够更逼真，但它是为低分辨率核医学成像研究而设计的，缺乏适用于高分辨率CT的解剖细节。同时，目前在CT中使用的模体在描述真实人体器官的复杂形状方面缺乏足够的真实感，并且缺乏对解剖变化和正常生理运动进行建模的灵活性，这些不足随着这些成像技术的快速进步和新应用的开发而变得越来越重要。我们试图通过在现有的4D NCAT体模和我们实验室开发的其他模拟工具的基础上进行构建来填补这一空白。我们假设，在这项工作中开发的工具将提供模拟的CT图像数据，准确地模拟从处于不同发育阶段(成人和儿童)的实际患者(男性和女性)获得的数据。随着X射线CT发展到许多新的应用领域并得到更广泛的应用，本工作开发的模拟工具将在开发图像采集策略、图像处理和重建方法以及图像可视化和解释技术等广泛的成像研究中得到应用。此外，这些工具还为优化临床CT应用提供了必要的基础，从而以对患者可能的最小辐射剂量获得尽可能高的图像质量。由于对辐射的担忧，以特定于临床需求的方式来优化现代CT系统中可用于人类患者的大量成像参数是不切实际的。同样不切实际的是，在物理测试对象中执行优化，而这些对象无法实际复制在体内看到的条件。这样的任务只能使用尚未开发的准确和现实的计算机模拟方法来实际和有效地执行。我们的研究人员和顾问团队在开发数字模型、医学成像过程的精确模型以及3D图像重建技术和方法方面拥有广泛的专业知识，这些技术和方法非常适合该项目。

DESCRIPTION (provided by applicant): Simulation is a powerful tool for characterizing, evaluating, and optimizing medical imaging systems and mage processing and reconstruction methods. The two major components of simulation are: (1) a realistic model of the human anatomy and physiological functions, and (2) ability to generate accurate image data that include effects of the imaging process. Without such, the results of the simulation may not be indicative of what would occur in actual patients and would, therefore, have limited practical value. The current four- dimensional (4D) NURBS-based cardiac-torso (NCAT) phantom was developed to provide a realistic and flexible model of the human anatomy and physiology and is widely used in nuclear medicine imaging research. The phantom has the advantage, due to its design, that its organ shapes can be changed to ealistically model different anatomical variations and patient motion. Although capable of being far more realistic, the NCAT phantom was designed for low-resolution nuclear medicine imaging research, and lacks the anatomical detail to be applicable to high-resolution CT. At the same time, current phantoms used in CT lack sufficient realism in depicting the complex shapes of real human organs and the flexibility to model anatomical variations and normal physiologic motion, deficiencies that are becoming increasingly important with rapid advancements in these imaging technologies and in the development of new applications. We seek to fill this void by building upon the existing 4D NCAT phantom and other simulation tools developed in our laboratory. We hypothesize that the tools developed in this work will provide simulated CT image data that accurately mimic that obtained from actual patients (male and female) at different stages of development (adult and pediatric). As x-ray CT evolves into many new applications and gains wider use, the simulation tools developed in this work will have applications in a broad range of imaging research in developing image acquisition strategies, image processing and reconstruction methods, and image visualization and interpretation techniques. Also, the tools provide the necessary foundation to optimize clinical CT applications so as to obtain the highest possible image quality with the minimum possible radiation dose to the patient. Due to radiation concerns it is impractical to optimize the large number of imaging parameters available in modern CT systems in human patients in ways that are specific to clinical demands. It is equally impractical to perform optimizations in physical test objects that cannot realistically duplicate the conditions seen in vivo. Such a task can only be practically and efficiently performed using accurate and realistic computer simulation methods, which have not yet been developed. Our team of investigators and consultants has extensive expertise in developing digital phantoms, accurate models of the medical imaging process, and 3D image reconstruction techniques and methods that are well suited for this project.