Analysis of Temperature Distribution within the Human Body in Electromagnetic Hyperthermia

在本研究项目中，已经完成了一个算法，用于计算非常实用的模型，这是几乎相同的真实的模型组成的非均匀人体区域，水丸区域和波导多喷头系统的电磁场和功率损耗分布在人体内。在该算法中，完成了以下重要技术：1。针对波导源内部立柱的激励机制进行了适当的考虑，以适应FD-TD分析.推导了适用于人体等有耗介质中吸收边界的新的吸收边界条件，并完成了人体变化时间内温度分布的计算算法。依赖于由电磁波辐射引起的功率损耗的影响以及人体固有的和来自在身体之外。该算法采用了隐式交替方向法，并通过对各种数值结果的仔细检验，得到了一些新的结果。典型的是1。对于热疗多辐射源系统，TE（横向电）波型辐射源系统比TM（横向磁）波型辐射源系统具有上级优势，因为TE波型辐射源系统比TM波型辐射源系统在人体纵向上获得了更好的功率损耗分布集中.水团应该在靠近感兴趣的加热区域周围的有限区域中使用，因为水区域倾向于不必要地扩大热区域。

In this research project, an algorithm has been completed for calculating electromagnetic fields and power loss distributions within the human body for very practical models which are almost the same as the real models consisting of inhomogeneous human body regions, water bolus regions and waveguide multi-applicator systems. In this algorithm, the following important techniques are accomplished :1. Excitation mechanism by a post situated inside the wavequide applicator is pertinently taken into account to accommodate itself to FD-TD analyzing.2. New absorbing boundary conditions are derived which are useful for the absorbing boundaries located in lossy media such as the human body regions.Also completed in the project is the algorithm for calculating the temperature distributions within the human body changing time-dependently under the influence of the power loss induced by electromagnetic wave irradiation as well as the influence of various cooling effects inherent in the human body and coming from outside the body. An Implicit Alternating Direction method is employed in this algorithm.Moreover, several new findings have been obtained from careful examinations of various numerical results. Typical ones are1. For the hyperthermia multi-applicator system, the TE(Transverse Electric)wave type applicator system is superior over the TM(Transverse Magnetic)wave type system, because better concentration of the power loss distribution in the longitudinal direction of the body is attained by the former system than the latter.2. The water bolus should be used in the limited region near around the heated regions of interest because the water region tends to expand the hot regions unnecessarily.