基于时域后向投影的光声谱成像系统研究

A Photoacoustic Tomography System Based on Time-Domain Back Projection Method

光声谱成像是一种新的生物组织成像方法,它结合光学成像和超声成像的特点,可提供高分辨率和对比度的图像。采用波长532nm、重复频率10Hz的脉冲激光作为激励源,宽带PVDF非聚焦超声探测器频率响应范围为200kHz～15MHz,探测器以圆周扫描的方式采集样品的时域光声信号,并采用时域后向投影算法重建样品内部的二维光学吸收分布图像。实验表明,系统成像的空间分辨率小于1mm,重建的图像与原始样品完全吻合。

Photoacoustic （PA） imaging is a new method to generate tomography pictures inside biological tissues. It combines the advantages of pure optical imaging with traditional ultrasonic imaging and can provide high resolution and contrast images. A 532nm laser pulse with the repetition rate of 10Hz was used as the pumping source. A wide band PVDF unfocused ultrasonic transducer with the frequency response range of 200kHz - 15MHz was used to collect time-domain PA signal by circular scan. The 2D optical absorption image inside tissue was reconstructed by time-domain back projection algorithm. In experiment, the spatial resolution of the system was less than 1 mm, the reconstructed image agreed well with the original phantom.