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Electrical circuit modeling and analysis of microwave acoustic interaction with biological tissues
Author(s) -
Gao Fei,
Zheng Qian,
Zheng Yuanjin
Publication year - 2014
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4871783
Subject(s) - finite difference time domain method , acoustics , microwave , equivalent circuit , electrical element , spice , electronic engineering , electronic circuit simulation , transmission line , rlc circuit , computer science , capacitor , physics , voltage , optics , engineering , electrical engineering , electronic circuit , telecommunications
Purpose: Numerical study of microwave imaging and microwave‐induced thermoacoustic imaging utilizes finite difference time domain (FDTD) analysis for simulation of microwave and acoustic interaction with biological tissues, which is time consuming due to complex grid‐segmentation and numerous calculations, not straightforward due to no analytical solution and physical explanation, and incompatible with hardware development requiring circuit simulator such as SPICE. In this paper, instead of conventional FDTD numerical simulation, an equivalent electrical circuit model is proposed to model the microwave acoustic interaction with biological tissues for fast simulation and quantitative analysis in both one and two dimensions (2D).Methods: The equivalent circuit of ideal point‐like tissue for microwave‐acoustic interaction is proposed including transmission line, voltage‐controlled current source, envelop detector, and resistor‐inductor‐capacitor (RLC) network, to model the microwave scattering, thermal expansion, and acoustic generation. Based on which, two‐port network of the point‐like tissue is built and characterized using pseudo S‐parameters and transducer gain. Two dimensional circuit network including acoustic scatterer and acoustic channel is also constructed to model the 2D spatial information and acoustic scattering effect in heterogeneous medium.Results: Both FDTD simulation, circuit simulation, and experimental measurement are performed to compare the results in terms of time domain, frequency domain, and pseudo S‐parameters characterization. 2D circuit network simulation is also performed under different scenarios including different sizes of tumors and the effect of acoustic scatterer.Conclusions: The proposed circuit model of microwave acoustic interaction with biological tissue could give good agreement with FDTD simulated and experimental measured results. The pseudo S‐parameters and characteristic gain could globally evaluate the performance of tumor detection. The 2D circuit network enables the potential to combine the quasi‐numerical simulation and circuit simulation in a uniform simulator for codesign and simulation of a microwave acoustic imaging system, bridging bioeffect study and hardware development seamlessly.