Comparisons of filtered back-projection and time reversal algorithms in photoacoustic tomography

In photoacoustic tomography (PAT), image reconstruction has a fundamental impact on image quality and imaging speed. Among various reconstruction algorithms, the analytical filtered back-projection (FBP) and the numerical time reversal (TR) algorithms are two commonly used image reconstruction techniques in PAT. However, so far, no comprehensive studies are reported on the comparisons of FBP and TR algorithms. In this work, we compare these two algorithms from the perspectives of computational efficiency, robustness to non-ideal detection surfaces, and applicability to heterogeneous media. The results show that: 1) In terms of computational efficiency, FBP is typically faster than TR due to its flexibility in the selection of the reconstruction region. 2) For non-ideal detection surfaces-based reconstruction, FBP can provide more accurate amplitude information for the limited-view reconstruction and can produce fewer image artifacts for the sparse-view reconstruction. 3) For acoustically heterogeneous media, the TR algorithm can incorporate acoustic properties and thus can yield high-quality images, while FBP fails in this case. This study can help researchers gain a deeper understanding of the FBP and TR algorithms and is expected to provide a guide for the reasonable selection of PAT image reconstruction algorithms.