Fast photoacoustic imaging with multi-element linear transducer array system

Noninvasive monitoring of the microvascular network and detection the angiogenesis around tumors is one of the most active areas in biomedical research. In this paper, we present a multi-element photoacoustic imaging system for fast imaging the blood vessels. In this system, a Q-switched Nd: YAG pulse laser operated at 532nm with a 6 ns pulse width is used to generate a photoacoustic signals; a 64-element linear transducer array with the central frequency of 7.5MHz is used to measure the photoacoustic waves. The limited-field filtered back projection algorithm is used to reconstruct the optical absorption distribution in tissue. The experiments of a phantom model and in vitro blood vessels were performed with this system. A clear photoacoustic image of microvascular network was obtained with high resolution. The experimental results demonstrate that our multi-element photoacoustic imaging system has the ability of imaging microvascular network and may potentially be used to monitor the angiogenesis around tumors.