Barman C, Rath P, Bhattacharya A
Heat Transfer Laboratory, School of Mechanical Sciences, Indian Institute of Technology, Bhubaneswar, Odisha, India, 752050.
Heat Transfer Laboratory, School of Mechanical Sciences, Indian Institute of Technology, Bhubaneswar, Odisha, India, 752050.
Comput Methods Programs Biomed. 2021 Mar;200:105857. doi: 10.1016/j.cmpb.2020.105857. Epub 2020 Nov 20.
Incorporation of non-Fourier heat conduction while studying heat transfer phenomena in biological materials has emerged has an important approach as it predicts better and more realistic results than Fourier based models. In this article we have proposed a non-Fourier computational model and applied the same to simulate cryosurgery of lung tumor and attempted minimization of freezing damage of healthy lung tissue using pulsed laser irradiation.
A non-Fourier bioheat transfer model for phase change in biological tissues is solved via a Fourier heat conduction based solution approach. A unified model is proposed combining all variants of bioheat models: Fourier's heat conduction based Pennes' bioheat model, hyperbolic heat conduction model and dual phase lag model. The proposed model takes into account the different thermophysical properties of frozen and unfrozen regions. In order to mimic the actual biotransport process, the blood perfusion and metabolic heat generation are switched off in the frozen region. Implicit source based enthalpy method is used to model phase change process. A new iterative enthalpy update equation is developed for capturing evolution of freezing front implicitly. Finite Volume based numerical discretization technique is used to discretize the governing PDE. The resulting discrete algebraic equation set is solved implicitly by Tri-diagonal Matrix Algorithm. The proposed model is verified with existing results from the literature.
For Fourier heat conduction, freezing time of 99.99% of tumor is 1247s, which increases to 1267s for τ= 5s (τ= 0s) and again reduces to 1255s for τ= 5s and τ= 3s. τ and τ are phase lag parameters for non-Fourier heat conduction. For τ= 5s and τ= 0.05s, the freezing damage of healthy tissue decreases by 23.76% when pulsed laser irradiation (I = 10 W/m) is used to warm the neighboring healthy tissue.
So non-Fourier bioheat transport models are better and more accurate in predicting temperature history, freezing time and freezing front propagation as compared to Fourier based models. Pulsed laser irradiation can prove to be a very efficient technique in minimizing collateral damage during cryosurgery.
在研究生物材料中的热传递现象时，纳入非傅里叶热传导已成为一种重要方法，因为它比基于傅里叶的模型能预测出更好、更现实的结果。在本文中，我们提出了一种非傅里叶计算模型，并将其应用于模拟肺肿瘤冷冻手术，尝试通过脉冲激光照射将健康肺组织的冷冻损伤降至最低。
通过基于傅里叶热传导的求解方法求解生物组织中相变的非傅里叶生物热传递模型。提出了一个统一模型，结合了生物热模型的所有变体：基于傅里叶热传导的彭尼斯生物热模型、双曲热传导模型和双相滞后模型。所提出的模型考虑了冷冻区和未冷冻区不同的热物理性质。为了模拟实际的生物传输过程，在冷冻区关闭血液灌注和代谢热生成。基于隐式源项的焓方法用于模拟相变过程。开发了一个新的迭代焓更新方程，用于隐式捕获冻结前沿的演变。基于有限体积的数值离散技术用于离散控制偏微分方程。所得离散代数方程组通过三对角矩阵算法隐式求解。所提出的模型与文献中的现有结果进行了验证。
对于傅里叶热传导，99.99%的肿瘤冷冻时间为1247秒，对于τ=5秒（τ=0秒）增加到1267秒，对于τ=5秒和τ=3秒又降至1255秒。τ和τ是非傅里叶热传导的相滞后参数。对于τ=5秒和τ=0.05秒，当使用脉冲激光照射（I = 10 W/m²）加热相邻健康组织时，健康组织的冷冻损伤降低了23.76%。
因此，与基于傅里叶的模型相比，非傅里叶生物热传输模型在预测温度历史、冷冻时间和冷冻前沿传播方面更好、更准确。脉冲激光照射在冷冻手术中可被证明是一种非常有效的减少附带损伤的技术。
