| It is very important to investigate interaction between electromagnetic field and biological tissues using numerical methods in Biomedical Engineering. The investigation is helpful for the application of the electromagnetic field in the medical works, and it can also provide useful data and information to avoid unnecessary hurt and accident. In this paper, two new diagnosis methods are presented and analyzed using two different numerical methods respectively.A new low-frequency 3D electromagnetic imaging method excited by a coil is discussed. And the forward problem is solved using Finite Element Method (FEM). A designed example is given, and results show that this method is effective for solving the forward problem. This is very helpful and useful for the design of the imaging system.In another diagnosis method, microwave reflection characteristics of a microstrip antenna applicator contacted with layered biological tissues are analyzed by using FDTD method. Three-layer tissues model, which is consisted of thin skin, fat and the semi-infinite muscle, is adopted. A spherical tumor with the different permittivity from the surrounding normal muscle tissue is assumed to exist inside the muscle tissue. Simulation results show that the difference of the permittivity between the tumor and the normal muscle tissue can be detected through microwave reflection measurement. The relationship between the reflection characteristics of the antenna and sizes of tumors is also discussed. Numerical results show that the position of the tumor can be determined by measuring the reflection of the antenna. This technique can be applied to general examination and early diagnosis of thesubcutaneous tumor. In the analysis process, some special method such as setting the excitation source and a new perfectly matched layer is applied.All the results above are useful for the further research in the electromagnetic diagnosis methods in the Biomedical Engineering. |
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