Research on Applied Current Thermoacoustic Imaging Based on Synthetic Receive Aperture

Applied current thermoacoustic imaging (ACTAI) is a promising biomedical imaging modality, which combines the advantages of high resolution from ultrasound imaging and of high contrast from electrical impedance imaging. Acoustic source reconstruction is one of the main research topics of ACTAI which provides preliminary conductivity distribution information and lay a foundation for further quantitative conductivity reconstruction. Now days the acoustic source is usually reconstructed from the first derivative of the received acoustic signal through back projection. The result is seriously affected by electromagnetic interference that is amplified by the derivative operation. In this paper, a synthetic receive aperture (SRA) method is applied to reconstruct the acoustic source in ACTAI, where multiple traces of acoustic signal are delayed and summed directly. Numerical simulation and phantom experiment are carried out to verify the feasibility of this method. The results show that the reconstructed acoustic source using SRA can provide 1 mm spatial resolution. “TA” and “S” phantom experiment shows the robustness of the proposed method. Successful tumor detection in an in vivo mouse model demonstrates the application promise of ACTAI with SRA to cancer detection in the future.