Microwave-induced Thermo-acoustic Tomo- Graphy System Using Trm-pstd Technique

Time reversal imaging method based on full wave numerical technique for likely breast tumors biological tissue in the Microwave-Induced Thermo-Acoustic Tomography (MITAT) system is discussed. In this paper, the mechanism of microwave-induced thermo-acoustic is strictly described based on thermodynamics and thermo-diffusion principles; the equivalent relationship between the absorbed microwave energy distribution of the biological tissue and the induced thermo-acoustic source distribution is used as the basis of the imaging algorithm. Due to its unique noise suppression feature and the stability of the algorithm, the Time Reversal Method (TRM) based on the Pseudospectral Time-Domain (PSTD) technique is applied to image heterogeneous phantom tissues from low Signal-to-Noise-Ratio (SNR) thermo-acoustic signals. Thereafter, an integrated MITAT prototype system is presented to obtain the thermo-acoustic signals from some biologic tissue with millimeter scale. The proposed TRM method is based on PSTD technique produced two-dimensional images, presented to study the performances of the MITAT in terms of contrast and resolution. These images prove predominant advantages in both contrast and resolution compared with conventional microwave and ultrasound imaging systems for malignant tumor detection. Based on the current results, our TRM-PSTD MITAT system provides evidence to predict breast tumor in an early stage and millimeter scale. Received 15 November 2012, Accepted 10 January 2013, Scheduled 19 January 2013 * Corresponding author: Guoping Chen ([email protected]). 44 Chen, Wang, and Liu