Unipolar Back-Projection Algorithm for Photoacoustic Tomography

Among different transducer configurations of a photoacoustic (PA) imaging system, limited-view configurations (e.g., planar and limited-view circular configurations) have more clinical applications. On the other hand, the generated PA wave is bipolar. Therefore, qualifying physiological parameters would be challenging, especially in a limited-view configuration. To tackle this issue, in this paper a unipolar back-projection reconstruction algorithm is presented. The proposed method uses the initial PA signals and derivatives to reconstruct a unipolar image. The numerical results showed that by using the proposed method, the quality of the reconstructed image by using only a half-view circular transducer array would be close to that of the full-view circular array. Quantitatively speaking, the generalized contrast-to-noise ratio (gCNR) value in the half-view configuration reaches 0.96. Moreover, the proposed method improves the resolution/contrast and gCNR values by ∼50 %/15 dB and ∼ 50%, respectively, compared to the conventional method.