Background,Motivation and Objective Integrating the optoacoustic(OA) and pulse-echo(PE) ultrasound images is essential to characterize the optical and acoustic properties of the tissue and lesion.The coupling is optimum when the transducer design accommodates the laser beam inherently,such as annular array.Yet,this synergistic approach suffers from the low depth resolution,relatively high level of side lobe,off axis contributions and phase distortion(S.Park et al.2008).Indeed,it is challenging to tackle all of these elements simultaneously.A weighted dynamic focusing based reconstruction technique namely,weighted synthetic aperture(WSA),has been developed to address the aforementioned defects.In this work,we probe the efficiency of WSA method in 3D reconstruction of simulated phantom.