An Adaptive Focusing Reconstruction Method for Endoscopic Photoacoustic Tomography in Scattering Tissues

In endoscopic photoacoustic tomography (EPAT), the propagation of photoacoustic (PA) waves in tissues is generally distorted caused by the acoustic scattering, which subsequently leads to serious artifacts in the reconstructed images. Herein, an adaptive focusing method based on time reversal (TR) is presented to improve the quality of EPAT reconstructions. The distribution of the acoustic scatterers in the imaged tubular object is assumed to be known in priori. Then, the scattered PA waves is converged to the acoustic sources according to the TR invariance of the acoustic waves. Finally, the images of the initial acoustic pressure distribution on the cross-sections of the imaged object are reconstructed. Results of computer-simulation experiments indicate that the reconstruction quality is obviously improved compared with the case that the acoustic scattering is ignored in the standard TR reconstruction. A conclusion can be drawn that the image artifacts caused by the acoustic scattering can be significantly reduced with the proposed method.