Reconstruction of Microwave Absorption Properties in Heterogeneous Tissue for Microwave-Induced Thermo-Acoustic Tomography

Wang, Jinguo; Zhao, Zhiqin; Song, Jian; Zhu, Xiaozhang; Nie, Zaiping; Liu, Qing

doi:10.2528/pier12062704

Cited by 18 publications

(16 citation statements)

References 35 publications

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“…An improved method based on the time reversal mirror (TRM) technique is adopted to reconstruct the TA image [39]. The method used in this paper calculates the acoustic speed distribution of the background instead of the assumption that the background is homogenous for traditional TRM.…”

Section: B Numerical Imaging Resultsmentioning

confidence: 99%

Evaluation of Contrast Enhancement by Carbon Nanotubes for Microwave-Induced Thermoacoustic Tomography

Song

Zhao

Wang

et al. 2015

IEEE Trans. Biomed. Eng.

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Microwave-induced thermoacoustic tomography (MITAT) is a hybrid method which constructs images with ultrasound spatial resolution while exploiting dielectric contrast at microwave frequency. It has great potential in biomedical imaging especially in early breast cancer detection. The detection of early stage breast tumor in MITAT is challenged by the moderate endogenous dielectric contrast between malignant and healthy glandular tissues. In order to overcome this limitation, the performance of using carbon nanotubes (CNTs) as an imaging contrast enhancement agent is evaluated. First, the influences in dielectric and acoustic properties caused by CNTs are measured. Second, based on the measurements and the published data, numerical breast phantom is created and then used to explore the contrast enhancing effect of CNTs for MITAT, by an integrated simulation approach in both electromagnetic and acoustic field. With an experimental MITAT system, the thermoacoustic responses of tissue mimicking materials with different CNTs concentrations are also quantitatively investigated. Finally, the effectiveness of the contrast agent is also validated experimentally by using a MITAT system. The results show that the using of the dielectric contrast agent can effectively enhance the contrast of the MITAT image.

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Section: B Numerical Imaging Resultsmentioning

confidence: 99%

Evaluation of Contrast Enhancement by Carbon Nanotubes for Microwave-Induced Thermoacoustic Tomography

Song

Zhao

Wang

et al. 2015

IEEE Trans. Biomed. Eng.

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“…FMM is a narrow band level set method, and has widely applied in path planning and tumor cell detection acoustic imaging [4] etc. In generally, it is used as a numerical solution method for Eikonal equation [3] .…”

Section: Theory Of Fmmmentioning

confidence: 99%

Time Reversal and Fast Marching Method Applied in Wireless Indoor Positioning

Chen

Wang

2013

2013 International Conference on Computer Sciences and Applications

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Multipath effect is the main factor for a precise channel model in an indoor environment. Time reversed (TR) wireless indoor positioning method has been validated to effectively reduce signals fading or time delay affected by multipath effect. However, without a prior known channel model, the accuracy of TR method will be seriously deteriorated. To solve the shortcoming of a general TR method in an unknown channel model application, we present a combining Time Reversal and Fast Marching Method (TR-FMM) positioning method. This method locates a target with two stages. In stage one, the precise channel model of an indoor environment is estimated by FMM and simultaneous algebraic reconstruction technique (SART). In this stage, the Time of Flight (TOF) information generated by some fixed spatial position anchors are used to fulfill the indoor channel model estimation, then the needed channel impulse response (CIR) for TR method will be obtained based on the estimated channel model. In stage two, with the obtained CIR, any new joint mobile target will be accurately located by a general TR wireless indoor positioning method. Simulative results depict the positioning deviation is less than 6cm for a newly joined mobile target with 1cm scale in a moderate complex indoor configure, and the accuracy of the positioning is improved 14 times comparing to a general TR method. The positioning time in stage 2 is less than 12 minutes in a PC with 1.6 GHz dual CPUs and 2G Bytes memory. The proposed method has great advantage in high accuracy and low complexity for wireless indoor positioning system.

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“…To solve Equation (1), many methods in terms of some special measurement configuration are developed [10][11][12][13]. Based on priori information of the heterogeneous medium parameters or the homogenous hypotheses, the phase information of the measured data can be used to reconstruct the initial value f , such as filtered back project or eigen function expansions etc.…”

Section: Physical Principle Of Mitat and Imaging Inverse Problemmentioning

confidence: 99%

Tr Adjoint Imaging Method for Mitat

Chen¹,

Wang²,

Wang³

et al. 2013

PIER B

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Abstract-Most of the current imaging methods in microwave induced thermoacoustic tomography (MITAT) system assume that the heterogeneous sound velocity (SV) and density distribution are given or subject to Gaussian distribution. These situations generally are not satisfied. To improve multi-targets thermoacoustic sources imaging quality in a heterogeneous tissue, an iterative TR adjoint imaging method is proposed. The proposed iterative TR adjoint method can reconstruct thermoacoustic sources from the measured data even if the prior heterogeneous information of the tissue is unknown. This method estimates misfit between synthesized and observed measured signals, and iteratively updates supposed model parameters which give the heterogeneous tissue structure. In this iterative procedure, error kernels of SV, density and the approximate point source position information can be obtained independently. After the time of flight (TOF) convergence criterion is reached, a regular time reversal (TR) method with updated model will give out the final imaging result. The proposed TR adjoint imaging method is based on strictly theoretical derivation, and some simulations are presented to validate the method.

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Reconstruction of Microwave Absorption Properties in Heterogeneous Tissue for Microwave-Induced Thermo-Acoustic Tomography

Cited by 18 publications

References 35 publications

Evaluation of Contrast Enhancement by Carbon Nanotubes for Microwave-Induced Thermoacoustic Tomography

Evaluation of Contrast Enhancement by Carbon Nanotubes for Microwave-Induced Thermoacoustic Tomography

Time Reversal and Fast Marching Method Applied in Wireless Indoor Positioning

Tr Adjoint Imaging Method for Mitat

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