Cytotoxic Heat Transfer and Thrombotic Risk in Microwave Tumor Ablation

描述(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肿瘤的主要选择。目前，最流行的消融方法是射频消融，其原理与电灼术相同。然而，较大的肿瘤由于其自身的局限性，很难用射频治疗。 加热机制和对附近血管系统降温效应的敏感性。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。但更好的消融边缘带来的额外好处是以潜在的血管损伤和血栓为代价的。这项研究的目的是模拟微波能量对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联系起来。我们将使用数值模拟分析对加热的血管进行参数研究，隔离可能导致细胞毒性热传递的血管直径、血流速度和距离消融区的生理相关范围(目标1)。然后，我们将使用包含临床组件(如真实血液和微波敷贴器)的体模血管模型来验证模拟结果(AIM 2)。最后，我们将使用体内模型进行血管附近的消融，使我们能够分析复杂的、与临床相关的环境中的细胞毒性热传递(目标3)。该项目的完成将使我们更好地了解电磁分析与热流耦合、高温环境下血液粘度的变化以及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风险函数。这一功能将使医生能够安全地指导微波消融器的放置，将血栓事件的风险降至最低。我们将主要使用肝脏作为我们感兴趣的器官，但我们的数据 编制的计划将在临床上用于任何实体肿瘤的消融。与我们过去的许多研究一样，拟议的工作旨在直接影响世界范围内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.