Simulation Tools for 3D and 4D CT and Dosimetry

描述(由申请人提供)：随着计算机断层扫描(CT)的使用日益广泛和人们对辐射风险的认识不断提高，研究的重要领域包括：(1)优化CT临床应用以最大限度地减少辐射剂量；(2)开发准确评估检查辐射风险的方法。由于患者对辐射的担忧，以及不能反映患者解剖变化的物理模体数量有限，此类研究只能使用目前尚不存在的现实计算模体群体来进行。目前CT中使用的模特儿仅限于少数几个模特，大多数是成年人。在上一个项目中，我们开发了新的4D xCAT计算模型，用于3D和4D CT研究。基于高分辨率成像数据，我们为成年男性和女性xCAT创建了详细的全身模型，包括心脏和呼吸运动，包含9000多个解剖结构。在这次更新的第一部分，我们将通过利用计算解剖学中的创新方法将xCAT扩展到这些成人模型之外，这些方法长期以来一直被用于表征种群的解剖变异，以有效地创建一个史无前例的库，其中包含数百个高度详细的4D xCAT幻影。这些模特将真实地代表公众的全部范围，包括性别，以及从婴儿期到成年期的不同年龄、身高和体重。对解剖变异进行建模的能力是CT成像优化的关键。为了更接近地模仿临床研究或试验，需要一个包括一系列代表公众的解剖变异的幻影群体。这样一个解剖不同的模型库也提供了唯一实用的技术，可以用来估计患者特定的CT剂量和相关的辐射风险。在这个项目的第二部分，该文库将与本工作开发和验证的准确的蒙特卡罗剂量估计程序相结合，以研究CT中基于患者和基于人群的剂量相关性。这一发现将被用于建立针对患者的回顾性和前瞻性CT剂量报告系统。这样的系统将有助于妥善记录辐射风险，合理使用CT检查，并在图像质量和辐射剂量方面优化临床CT应用，特别是在脆弱人群中。它还支持目前的任务，即对医学成像造成的累积辐射剂量进行核算。分布到研究界的剂量学方法和模型库将为定量评估和改进3D和4D CT成像设备和技术提供重要工具。 公共卫生相关性：在这次更新中，我们将创建一个史无前例的库，包含数百个详细的4D计算模型，真实地代表包括性别、不同年龄、身高和体重(10%到90%)的广泛受试者，涵盖从儿科到成年患者的所有范围。在这项工作中开发的体模系列将提供一个重要的工具，用于在图像质量和辐射剂量方面优化临床CT应用，并准确估计患者特定的CT剂量(有效剂量和器官剂量)和相关的辐射风险。

DESCRIPTION (provided by applicant): With the growing use of computed tomography (CT) and the increasing awareness of radiation risk, important areas of research concern (1) optimizing CT clinical applications to minimize radiation dose and (2) developing methods to accurately assess radiation risk from examinations. Due to radiation concerns in patients and the limited number of physical phantoms that do not reflect the variability of patient anatomy, such research can only be performed using a population of realistic computational phantoms, which currently does not exist. Current phantoms used in CT are limited to only a handful of models, most being adults. In the previous project, we developed the new 4D XCAT computational phantom for use in 3D and 4D CT research. Based on high-resolution imaging data, we created detailed whole-body models for the male and female XCAT adult, including the cardiac and respiratory motions, containing over 9000 anatomical structures. In part one of this renewal, we will extend the XCAT beyond these adult models by utilizing innovative methods in computational anatomy, that have long been used to characterize anatomical variations in populations, to efficiently create an unprecedented library of hundreds of highly detailed 4D XCAT phantoms. The models will realistically represent the full spectrum of the public at large including both genders, and varying ages, heights, and weights from infancy to adulthood. The ability to model anatomical variations is essential to CT imaging optimization. A population of phantoms that includes a range of anatomical variations representative of the public at large is needed to more closely mimic a clinical study or trial. Such a library of anatomically diverse phantoms also offers the only practical technique with which to estimate patient-specific CT dose and associated radiation risk. In the second part of this project, the library will be combined with an accurate Monte Carlo dose estimation program, developed and validated in this work, to investigate patient-based and population-based dose correlations in CT. The findings will be used to establish a patient-specific retrospective and prospective CT dose reporting system. Such a system will be instrumental in proper documentation of radiation risk, justifiable use of CT examination, and optimization of clinical CT applications in terms of image quality and radiation dose, particularly in vulnerable populations. It further supports the current mandate to account for cumulative radiation dose exposure from medical imaging. Distributed to the research community, the dosimetry methods and the phantom library will provide vital tools to quantitatively evaluate and improve 3D and 4D CT imaging devices and techniques. PUBLIC HEALTH RELEVANCE: In this renewal, we will create an unprecedented library of hundreds of detailed 4D computational models realistically representing a wide population of subjects including both genders, and varying ages, heights and weights (10th to 90th percentile) encompassing the full range from pediatric to adult patients. The phantom series developed in this work will provide a vital tool with which to optimize clinical CT applications in terms of image quality and radiation dose and to accurately estimate patient-specific CT dose (both effective dose and organ dose) and associated radiation risk.