Abstract：
Magnetic hyperthermia regulates the therapeutic temperature within a specific range to damage malignant cells after exposing the magnetic nanoparticles inside tumor tissue to an alternating magnetic field. The therapeutic temperature of living tissues can be generally predicted using Pennes\' bio-heat equation after ignoring both the inhomogeneity of biological structure and the microstructural responses. Although various of the bio-heat transfer models proposed in literature fix these shortages, there is still a lack of a comprehensive report on investigating the discrepancy for different models when applied in the magnetic hyperthermia context. This study compares four different bio-heat equations in terms of the therapeutic temperature distribution and the heat-induced damage situation for a proposed geometric model, which is established based on computed tomography images of a tumor bearing mouse. The therapeutic temperature is also used as an index to evaluate the effect of two key relaxation times for the phase lag behavior on bio-heat transfer. Moreover, this work evaluates the effects of two blood perfusion rates on both the treatment temperature and the cumulative equivalent heating minutes at 43 °C. Numerical analysis results reveal that relaxation times for phase-lag behavior as well as the porosity for living tissues directly affect the therapeutic temperature variation and ultimately the thermal damage for the malignant tissue during magnetic hyperthermia. The dual-phase-lag equation can be converted into Pennes\' equation and simple-phase-lag equation when relaxation times meet specific conditions during the process of heat transfer. In addition, different blood perfusion rates can result in an amplitude discrepancy for treatment temperature, but this parameter does not change the characteristics of thermal propagation during therapy.
摘要：
在将肿瘤组织内的磁性纳米颗粒暴露于交变磁场之后,磁性热疗将治疗温度调节在特定范围内以损伤恶性细胞。在忽略生物结构的不均匀性和微观结构响应之后，通常可以使用Pennes\'生物热方程来预测活组织的治疗温度。尽管文献中提出的各种生物传热模型解决了这些不足，目前仍然缺乏一份全面的报告，调查不同模型在磁热治疗背景下的差异。这项研究比较了四个不同的生物热方程在治疗温度分布和热诱导损伤情况下提出的几何模型，这是基于荷瘤小鼠的计算机断层扫描图像建立的。治疗温度也用作评估相位滞后行为的两个关键弛豫时间对生物传热的影响的指标。此外，这项工作评估了两种血液灌注速率对治疗温度和43°C下累积等效加热分钟的影响。数值分析结果表明，相位滞后行为的弛豫时间以及活组织的孔隙率直接影响治疗温度的变化，并最终影响磁性热疗过程中恶性组织的热损伤。在传热过程中，当弛豫时间满足特定条件时，可以将双相滞后方程转换为Pennes\'方程和简单相滞方程。此外,不同的血液灌注率可能导致治疗温度的振幅差异，但该参数不会改变治疗过程中热传播的特性。
