A reconstruction algorithm for thermoacoustic tomography with compensation for acoustic speed heterogeneity.

An inverse reconstruction algorithm for thermoacoustic tomography (TAT) is proposed with the compensation for the acoustic speed heterogeneity. Not requiring the prior knowledge of the acoustic speed distribution like most other algorithms, this algorithm utilizes the correlation information between thermoacoustic signals to compensate for the acoustic heterogeneity. The absorbed energy density is reconstructed on the basis of a corrected time-domain formula. Computer simulations are carried out to validate the algorithm. It is shown that the algorithm has a good precision within the acoustic speed variation of 10%, strong robustness to random data noises and good computational efficiency compared to other model-based methods. Therefore, the algorithm may be used in TAT of biological soft tissues, in which the acoustic speed variation is normally within 10%.