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Low-Cost Photoacoustic Tomography System Based on Water-Made Acoustic Delay-Line

In this study, an acoustic delay line module is proposed to improve the imaging quality and speed of low-cost photoacoustic tomography (PAT) system. In PAT system, the PA signals are generated by the instantaneous pulse laser excitation. For image reconstruction, it needs to receive PA signals simultaneously in different angles requiring multi-channel data acquisition (DAQ) device. By applying the proposed delay line module, it can merge multichannel PA signals into one output, which reduces system cost of DAQ and the time consumption for signals sampling. The acoustic delay line module aims at sharing the DAQ’s limited channel by combining multiple PA signals into single series signal. In this paper, a PAT system with a four-in-one acoustic delay line module was developed to verify its feasibility. Delay line unit is based on ceramic piezoelectric plates to transmit and receive ultrasound, and water as the propagation medium. The four-in-one acoustic delay line module can compact four simultaneous PA signals into one output and distinguish with different time delays. Moreover, the merged output signal can be reconstructed into multiple signals in the digital domain by computer. With the contribution of the delayed signals, the image of target can be reconstructed by the low-cost PAT system.