Fast Adapted Delay and Sum Reconstruction Algorithm in Circular Photoacoustic Tomography

Circular photoacoustic tomography (C-PAT) arrangements are widely used in PAT systems. Many algorithms are proposed for PAT to reconstruct images such as delay and sum (DAS), universal back-projection (UBP), etc., all suffering from their own disadvantages. In this paper, to overcome these limitations, we proposed a fast uniform adapted delay and sum (ADAS) and filtered adapted delay and sum (F-ADAS) for detectors with finite and infinite bandwidth, respectively. Moreover, the edge uniformity index (EUI) metric was proposed for quantitative evaluation. Two cases 1) infinite bandwidth and 25 dB SNR level and 2) 2.25 MHz, 80% bandwidth with the same SNR level were considered for numerical study. The simulation results indicate that by using ADAS and F-ADAS, EUI improves 17.3-39% for infinite bandwidth scenario and EUI value can reach the value of 1 in finite bandwidth scenario. Therefore, highly uniform reconstructed images can be thus obtained with our proposed algorithm.