CDI-Type II: Collaborative Proposal - Simulation of ultrasonic-wave propagation with application to cancer therapy

CDI-Type II：合作提案 - 超声波传播模拟及其在癌症治疗中的应用

• 批准号: 0835804
• 负责人: Ronald Roy
• 金额: $ 3.15万
• 依托单位: American Institute of Mathematics
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-10-01 至 2012-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0835804&HistoricalAwards=false
• 关键词: CDI; Type; II; Collaborative; Proposal

The project develops and implements recent "Fourier continuation alternating direction" (FC-AD) high-performance algorithms for nonlinear Partial Differential Equations (PDE), validates such solvers via comparisons with experiments and well-known approximations, and applies the resulting methodology to realistic medical configurations. A significant portion of the effort will design strategies to expand significantly the applicability of High-Intensity-Focused-Ultrasound (HIFU) (an emerging minimally invasive therapy that uses focused ultrasound beams to cause localized destruction of cancer tissue), and to enable design of optimal HIFU therapies for liver, kidney, and pancreatic cancers. In HIFU, an ultrasound source acoustically contacts the patient's skin to produce a high-amplitude ultrasonic field within the body that focuses on (and heats) a target region---thus leading to tumor destruction. The ultrasound propagates within a medium that is highly heterogeneous---most strongly so due to bone---thus affecting heating, which arises, for example, through perfusion by large blood vessels. Optimal HIFU requires a treatment-planning computational tool, which ensures treatment of the targeted zone and minimal impact on the surrounding tissue. Because previous 3D PDE solvers are more expensive, solution of such complex HIFU problems has not been possible. Using alternating directions and a rapidly convergent Fourier series for non-periodic functions, the proposed FC-AD method has provided for the first time high-order unconditionally stable numerics for general 3D domains at a cost that grows only linearly with the size of the spatial discretization; preliminary tests have demonstrated the capability of the FC-AD method to address satisfactorily the types of nonlinear acoustic problems under consideration. This approach will make possible the study of the effect of heterogeneity on field focusing, heat deposition, and ablation properties - enabling highly optimized HIFU treatment. The associated geometric/computational demands provide a powerful driving force for additional developments of our solvers, geometry modeling tools, etc. The proposed multi-disciplinary interactions will further significantly the state of the art in all three fields: computational science, nonlinear wave physics, and cancer therapy.Broader Significance of the Project: Already a well-established technique for medical imaging, ultrasound is seeing widening use in diagnostic and therapeutic applications ranging from tumor detection, to kidney stone destruction, to targeted drug delivery. Both the accuracy of ultrasound images, and the precision and reliability with which ultrasound can deliver energy or modify the structure of tissue, depend critically on the type of software that will result from this effort, providing a capability to predict the propagation properties of ultrasonic fields in biological media. The resulting methodology will be applicable across the broad spectrum of biomedical ultrasonics - enabling rapid instrument prototyping, treatment planning, and ultrasound safety assessment. Although the work plan is focused on the modeling of HIFU-based cancer treatment, the potential for effecting key advances in multiple therapeutic and diagnostic applications is very significant.

该项目开发和实现了最近的非线性偏微分方程(PDE)的“傅立叶连续交替方向”(FC-AD)高性能算法，通过与实验和众所周知的近似的比较来验证这些解算器，并将所得到的方法应用于现实的医疗配置。其中很大一部分工作将设计战略，以显著扩大高强度聚焦超声(HIFU)(一种新兴的微创疗法，使用聚焦超声束导致局部破坏癌症组织)的适用性，并使设计出适用于肝脏、肾脏和胰腺癌的最佳HIFU疗法。在HIFU中，超声源声学地接触患者的皮肤，在体内产生高幅超声场，聚焦(并加热)目标区域-从而导致肿瘤破坏。超声波在高度不均匀的介质中传播-最强烈的是由于骨骼-从而影响加热，例如，通过大血管的灌流。最佳HIFU需要一个治疗计划计算工具，确保目标区域的治疗，并将对周围组织的影响降至最低。由于以前的3D PDE解算器更昂贵，因此解决如此复杂的HIFU问题是不可能的。对于非周期函数，利用交替方向和快速收敛的傅立叶级数，FC-AD方法首次提供了一般3D区域的高阶无条件稳定的数值，而代价仅随着空间离散的大小而线性增长；初步测试表明，FC-AD方法能够令人满意地处理所考虑的类型的非线性声学问题。这种方法将使研究异质性对场聚焦、热沉积和烧蚀特性的影响成为可能，从而实现高度优化的HIFU治疗。相关的几何/计算需求为我们的解算器、几何建模工具等的其他开发提供了强大的推动力。拟议的多学科交互将显著促进所有三个领域的最新水平：计算科学、非线性波动物理和癌症治疗。该项目的广泛意义：超声已经是一项成熟的医学成像技术，在诊断和治疗应用中的应用越来越广泛，从肿瘤检测到肾结石破坏，再到靶向药物输送。超声图像的准确性，以及超声波传递能量或改变组织结构的精确度和可靠性，都关键取决于这项工作将产生的软件类型，该软件提供了预测超声场在生物介质中传播特性的能力。由此产生的方法将适用于广泛的生物医学超声--实现快速的仪器原型、治疗计划和超声安全评估。尽管该工作计划的重点是基于HIFU的癌症治疗的建模，但在多种治疗和诊断应用方面取得关键进展的潜力是非常大的。