Limited-View Photoacoustic Tomography Based on Transient Radiative Transfer Equation

As a research hotspot in the biomedical field, photoacoustic (PA) tomography combines the advantages of higher resolution of optical tomography and deeper imaging depth in ultrasonic imaging, making excellent imaging contrast possible. Full view imaging mode is limited in practical clinical applications. In addition, the forward model based on the diffusion approximation equation cannot accurately presents the absorption characteristics inside medium. Therefore, the detected model of limited view is adopted for PA tomography based on the complete transient radiative transfer equation (RTE). For the non-uniform PA signal under the limited-view, to obtain a higher precision image, the transient RTE is solved by discrete ordinate method, and the initial sound pressure signal generated by the laser pulse is obtained. The imaging model adopts array detection elements to collect PA signals, and finally inverts the optical absorption distribution image based on conjugate gradient algorithm. The results show that the proposed limited-view PA tomography model based on RTE can accurately reconstructed the internal absorption characteristics of non-uniform translucent media, and has ideal computational speed as well as robustness.