Due to its advantages in both contrast and resolution compared with conventional microwave or ultrasound imaging system, microwave-induced thermo-acoustic tomography (MITAT) has received more and more concerns in biologic tissue image field. In this paper, an integrated prototype of MITAT system is presented. Using this system, some basic experiments for biologic tissue objects with high water-content imbedded in fatty material have been done. In the MITAT experiments, the signals generated by two porcine muscle tissue strips with millimeter order scale in cross-section were collected. Images with both good contrast and resolution were obtained. In order to demonstrate the advantages of MITAT, some ultrasonic experiments were studied using a commercial ultrasonic linear array system. The comparisons of the results of both systems show the good performance of the MITAT prototype system for the detection of high water content targets, which is generally the same as the tumor in biologic tissue.
Microwave-induced thermo-acoustic tomography (MITAT) is a promising technique with great potential in biomedical imaging. It has both the high contrast of the microwave imaging and the high resolution of the ultrasound imaging. In this paper, the proportional relationship between the absorbed microwave energy distribution and the induced ultrasound source distribution is derived. Further, the time reversal mirror (TRM) technique based on the pseudo-spectral time domain (PSTD) method is applied to MITAT system. The simulation results show that high contrast and resolution can be achieved by the TRM technique based on PSTD method even for the received signals with very low signal-to-noise ratio (SNR) and the model parameter with random fluctuation.
