A Real-time Photoacoustic Imaging System with High Density Integrated Circuit

摘要

Based on an array transducer, a real-time photoacoustic imaging system with high density integrated circuit is built. The system is composed of a short pulsed laser, an ultrasonic transducer array, a data acquisition circuit and a computer. The data acquisition circuit consists of 128-channel variable gain amplifiers, 128-channel anti-aliasing filters, 128-channel analog-to-digital converters, and field programmable gate arrays. Biological tissues are irradiated by the laser to generate the thermoelastic expansion. The transducer array is used to detect the photoacoustic signals generated from the tissue thermoelastic expansion. Then the photoacoustic signals are amplified and sampled by multiple parallel data acquisition channels. Subsequently, the sampled data set is transferred to the computer through an USB interface. The final photoacoustic image is reconstructed by the computer. The traditional "delay-and-sum" bcamforming method is used as the reconstruction algorithm. An experiment with a ph antom of two hairs is made. The result shows that two hairs can be displayed clearly in the reconstructed image and the imaging rate is the same as the pulse repetition frequency of the laser.