Department of Mathematics and Statistics, Indian Institute of Technology Tirupati, Andhra Pradesh, India.
PLoS One. 2023 Jul 28;18(7):e0289262. doi: 10.1371/journal.pone.0289262. eCollection 2023.
Microwave ablation (MWA) is a cancer thermal ablation treatment that uses electromagnetic waves to generate heat within the tissue. The goal of this treatment is to eliminate tumor cells while leaving healthy cells unharmed. During MWA, excess heat generation can kill healthy cells. Hence, mathematical models and numerical techniques are required to analyze the heat distribution in the tissue before the treatment. The aim of this research is to explain the implementation of the 3D vector finite element method in a wave propagation model that simulates the specific absorption rate in the liver. The 3D Nedelec elements from H(curl; Ω) space are used to discretize the wave propagation model, and this implementation is helpful in solving many real-world problems that involve electromagnetic propagation with perfect conducting and absorbing boundary conditions. One of the difficulties in ablation treatment is creating a large ablation zone for a large tumor (diameter greater than 3 cm) in a short period of time with minimum damage to the surrounding tissue. This article addresses the aforementioned issue by introducing four antennas into the different places of the tumor sequentially and producing heat uniformly over the tumor. The results demonstrated that 95.5% of the tumor cells were killed with minimal damage to the healthy cells when the heating time was increased to 4 minutes at each position. Subsequently, we studied the temperature distribution and localised tissue contraction in the tissue using the three-dimensional bio-heat equation and temperature-time dependent model, respectively. The local tissue contraction is measured at arbitrary points in the domain and is more noticeable at temperatures higher than 102°C. The thermal damage in the liver during MWA treatment is investigated using the three-state cell death model. The system of partial differential equations is solved numerically due to the complex geometry of the domain, and the results are compared with experimental data to validate the models and parameters.
微波消融(MWA)是一种癌症热消融治疗方法,利用电磁波在组织内产生热量。这种治疗的目的是消除肿瘤细胞,同时不伤害健康细胞。在 MWA 过程中,过多的热量会杀死健康细胞。因此,在治疗前需要使用数学模型和数值技术来分析组织内的热量分布。本研究旨在解释在肝脏中模拟比吸收率的波传播模型中实施 3D 向量有限元方法。使用 H(curl; Ω)空间中的 3D Nedelec 元素离散化波传播模型,这种实现有助于解决许多涉及具有理想导电和吸收边界条件的电磁传播的实际问题。消融治疗的困难之一是在短时间内用最小的周围组织损伤为大肿瘤(直径大于 3 厘米)创建大的消融区。本文通过在肿瘤的不同位置依次引入四个天线并均匀加热肿瘤来解决上述问题。结果表明,当每个位置的加热时间增加到 4 分钟时,95.5%的肿瘤细胞被杀死,而健康细胞的损伤最小。随后,我们使用三维生物传热方程和温度时间相关模型分别研究了组织中的温度分布和局部组织收缩。在域中的任意点测量局部组织收缩,并且在高于 102°C 的温度下更为明显。使用三状态细胞死亡模型研究 MWA 治疗过程中肝脏的热损伤。由于域的复杂几何形状,系统的偏微分方程通过数值求解,并将结果与实验数据进行比较以验证模型和参数。