Photoacoustic tomography of micro-blood vessels in tissue mimicking phantom

In order to get the photoacoustic(PA) image of micro-blood vessel deep inside tissue-mimicking phantom. A 532nm pulse laser with repetition rate of 10Hz was used as the pumping source. A wide band unfocused needle ultrasound transducer was used to collect time-domain PA signal of micro-blood vessels inside tissue-mimicking phantom by circular scan. The spatial resolution was measured by full width at half maximum(FWHM) of line-spread-function(LSF). The 2D optical absorption image was reconstructed by time-domain spherical back projection algorithm. The experimental results demonstrated that the spatial resolution was 0.1mm and the PA image of the micro-vascular network agreed well with the tissue-mimicking phantom. The method demonstrated the potential feasibility of photoacoustic tomography in micro-vascular network imaging inside soft tissue.