Low-Cost Optoacoustic Tomography System with Programmable Acoustic Delay-Line

Photoacoustic tomography (PAT) is an emerging technology for biomedical imaging that combines the superiorities of high optical contrast and acoustic penetration. In the PAT system, more photoacoustic (PA) signals are preferred to be detected from full field of view to reconstruct PA images with higher fidelity. However, the requirement for more PA signals detection leads to more time consumption for single-channel scanning based PAT system, or higher cost of data acquisition (DAQ) module for an array-based PAT system. To address this issue, we proposed a programmable acoustic delay line module to reduce DAQ cost and accelerate imaging speed for PAT system. The module is based on bidirectional conversion between acoustic signals and electrical signals, including ultrasound transmission in between to provide sufficient time delay. The acoustic delay line module achieves tens or hundreds of microseconds delay for each channel, and is controlled by a programmable control unit. In this work, it achieves to merge four inputs of PA signals into one output signal, which can be recovered into original four PA signals in the digital domain after DAQ. The imaging experiments of pencil leads embedded in agar phantom is conducted by the PAT system equipped with the proposed programmable acoustic delay-line module, which demonstrated its feasibility in biomedical imaging system.