Cytotoxic Heat Transfer and Thrombotic Risk in Microwave Tumor Ablation

描述（由申请人提供）：通过热消融的图像引导肿瘤治疗现在是治疗早期实体瘤的主要选择。目前，最流行的消融方法是射频（RF）消融，其原理与电烙术相同。然而，较大的肿瘤由于其自限性而难以用RF治疗 加热机制和对附近脉管系统的冷却效应的敏感性。我们实验室最近的研究表明，微波消融能够克服这种“热沉”效应，并提供更一致的消融区。但是更好的消融边缘的额外好处是以血管损伤和血栓形成的潜在风险为代价的。本研究的目的是模拟微波能量在血管附近的加热效应，并通过成本函数将这些血管的损伤与血栓形成的风险相关联。我们将使用数值建模分析对加热血管进行参数研究，隔离可能导致细胞毒性热传递的血管直径、血液流速和与消融区距离的生理相关范围（目标1）。然后，我们将使用体模血管模型验证模拟结果，该模型包含临床组件，例如真实的血液和微波施加器（目标2）。最后，我们将使用体内模型在血管附近进行消融，使我们能够分析复杂的临床相关环境中的细胞毒性热传递（目标3）。该项目的完成将导致更好地理解耦合电磁分析与热流、高温环境中血液粘度变化和微波消融区附近的内皮损伤。该项目的目标是使用来自三个目标的数据来创建血栓形成风险函数。该功能将允许医生安全地引导微波消融施源器的放置，以最大限度地降低血栓形成事件的风险。我们将主要使用肝脏作为我们感兴趣的器官，但我们 计划编制将是临床上有用的任何实体瘤的消融。与我们过去的许多研究一样，拟议的工作旨在直接影响全球肿瘤消融计划中的患者护理。

DESCRIPTION (provided by applicant): Image-guided tumor therapy through thermal ablation is now the predominant choice for treating early-stage solid tumors. Currently, the most popular ablation method is radiofrequency (RF) ablation, which is based on the same principle as electrocautery. However, larger tumors are difficult to treat with RF because of its self- limiting heating mechanism and susceptibility to the cooling effect of nearby vasculature. Recent studies from our lab have shown that microwave ablations are capable of overcoming this "heat-sink" effect and providing a more consistent ablation zone. But the added benefit of better ablative margins comes at the cost of the potential of vascular damage and thrombosis. The aim of this study is to model the heating effects of microwave energy near blood vessels and correlate the damage from these vessels to the risk of thrombosis through a cost function. We will use numerical modeling analysis to perform a parametric study on a heated vessel, isolating the physiologically-relevant range of vessel diameters, blood flow rates and distances from the ablation zone which can lead to cytotoxic heat transfer (Aim 1). We will then validate the simulation results with a phantom vessel model, incorporating clinical components such as real blood and microwave applicators (Aim 2). Lastly, we will perform ablations near vessels using in-vivo models, allowing us to analyze cytotoxic heat transfer in a complex, clinically-relevant environment (Aim 3). Completion of this project will lead to better understanding of coupling electromagnetic analysis with thermal flow, blood viscosity changes in a high-temperature environment and endothelial damage near microwave ablation zones. The goal of this project is to use the data from the three aims to create a thrombotic risk function. This function will allow physicians to safely guide the placement of a microwave ablation applicator to minimize the risk for a thrombotic event. We will primarily using the liver as our organ of interest, but the data we plan to compile will be clinically useful for the ablation of any solid tumor. As with many of our studies in the past, the proposed work is designed to directly influence patient care in tumor ablation programs world-wide.