Direct numerical simulations of micro-bubble expansion in gas embolotherapy.
Direct numerical simulations of micro-bubble expansion in gas embolotherapy.
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DOI：
10.1115/1.1824131
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发表时间：
2004-12
期刊：
影响因子：
--
通讯作者：
T. Ye;J. Bull
中科院分区：
文献类型：
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作者：
T. Ye;J. Bull
我们目前正在开发一种新的气体栓塞治疗技术，该技术涉及选择性的，声学汽化的液体全氟化碳液滴在肿瘤或附近作为一种可能的治疗癌症。所产生的气泡，然后可以坚持在肿瘤血管闭塞血流和“饿死”的肿瘤。液滴汽化过程中的高应力的潜在发展是一个主要的关注安全实施这项技术。没有先前的研究，无论是实验还是理论，解决这个重要的问题。在这项工作中，声汽化治疗过程中的直接数值模拟研究。非线性，多相，计算模型是由一个理想的气泡包围的液体内的长管。对流和非定常惯性，粘度和表面张力影响气泡的动力学，并包括在这个模型中，这是一个新的固定网格，尖锐的界面，移动边界的方法来解决。我们通过改变无量纲参数--雷诺数、韦伯数和斯特罗哈尔数、惯性能和初始液滴尺寸，评估了在一系列操作条件下汽化过程中流动诱导的壁应力破裂血管或损伤内皮的可能性。结果发现，壁面压力通常是最高的气泡膨胀开始时，但最大壁面剪应力发生在稍后的时间。相对于血管直径，较小的初始气泡直径导致较低的壁应力。
We are currently developing a novel gas embolotherapy technique that involves the selective, acoustic vaporization of liquid perfluorocarbon droplets in or near a tumor as a possible treatment for cancer The resulting bubbles can then stick within the tumor vasculature to occlude blood flow and "starve" the tumor The potential development of high stresses during droplet vaporization is a major concern for safe implementation of this technique. No prior study, either experimentally or theoretically, addresses this important issue. In this work, the acoustic vaporization procedure of the therapy is investigated by direct numerical simulations. The nonlinear, multiphase, computational model is comprised of an ideal gas bubble surrounded by liquid inside a long tube. Convective and unsteady inertia, viscosity, and surface tension affect the bubble dynamics and are included in this model, which is solved by a novel fixed-grid, sharp-interface, moving boundary method. We assess the potential for flow-induced wall stresses to rupture the vessel or damage the endothelium during vaporization under a range of operating conditions by varying dimensionless parameters--Reynolds, Weber, and Strouhal numbers, inertial energy and initial droplet size. It is found that the wall pressure is typically highest at the start of the bubble expansion, but the maximum wall shear stress occurs at a later time. Smaller initial bubble diameters, relative to the vessel diameter, result in lower wall stresses.