An iterative reconstruction method for photoacoustic tomography in heterogeneous media based on point source response

In photoacoustic tomography (PAT), image reconstruction refers to the formation process from photoacoustic signals to target images, which has an important influence on the image quality. At present, most reconstruction algorithms assume that the medium is homogeneous, which may cause distortion and artifacts in the reconstructed images. Therefore, considering the heterogeneity of the medium is important for accurate image reconstruction in PAT. The iterative reconstruction (IR) algorithm can incorporate the information of imaging system and media, and thus can provide high-quality image reconstruction. In this work, we investigate the IR algorithm in PAT with heterogeneous media based on point source response. We obtain the system matrix by calculating the photoacoustic signal of each point source in heterogeneous media based on the k-space pseudospectral method. The target image is reconstructed iteratively with the media information-coupled system matrix and the total variation (TV) regularization. We take a set of simulations to verify the effectiveness of the IR algorithm in heterogeneous media. The results demonstrate the validity and rationality of the proposed method. The work provides a new method for accurate reconstruction of photoacoustic images.