<title>Opto-acoustic imaging system for early breast cancer diagnostics: experimental and numerical studies</title>

Abstract

Optoacoustic (OA) imaging is based on the generation of thermoelastic stress waves by heating an object in an optically heterogeneous medium with a short laser pulse. The stress waves contain information on the distribution of structures with enhanced optical absorption that can be used for early cancer diagnostics. This technique has already been applied in-vivo for breast cancer diagnostics and yielded higher contrast of obtained images than that of X-ray or ultrasonic images. The resolution was comparable with that yielded by ultrasonic imaging. Therefore, OA imaging is a very promising technique and it is being rapidly developed. Research in the area is now mostly targeted to the development of OA wave detection systems and image reconstruction algorithms. In this work a new design of receiving array transducer, that allows to enhance image resolution is proposed. The array consists of 64 focused piezo-elements made of PVDF slabs imposed on a spherical surface. Resolution yielded by the array in different directions is determined. Several tissue irradiation geometries and laser wavelengths are considered for optimization of the OA image contrast. Obtained results are used for maximum imaging depth studies. All the investigations include both numerical modelling and experiment.