为了实现单元探测器高质量的快速光声图像重建, 提出了不同旋转扫描次数对光声层析成像的影响方案。实验采用的光源为YAG激光器, 波长为1 064 nm, 重复频率为20 Hz, 脉宽为7 ns, 探测器为针状的PVDF膜水听器, 接收直径为1 mm, 得到了26个字母、12根头发丝、树叶骨架和模拟血管的光声重建图像。由仿真和实验结果表明, 在不牺牲光声重建图像质量的前提下, 单元探测器环形扫描一圈, 均匀采集100个位置的信号, 图像重建时间为5.903 s。该研究结果对于单元探测器的快速旋转扫描成像和环形阵列探测器阵元数的设计具有一定的指导意义。

In order to perform photoacoustic imaging with high-contrast and fast speed, we studied the influence on the reconstructed images of the number of detection positions by a single-element transducer circularly scanning targets. A Q-switched Nd: YAG laser, operating at 1 064 nm, was used as the illuminating source. The laser has a 7 ns pulse width and a repetition frequency of 20 Hz. A needle polyvinylidene fluoride(PVDF) hydrophone with 1 mm diameter was used to detect photoacoustic signals. We reconstructed the photoacoustic images of 26 letters, 12 hairs, leaf skeleton and simulated blood vessels. Both simulation and experimental results show that an optimized strategy in both imaging quality and speed can be achieved by evenly detecting 100 times around the circle, and the image reconstruction time is 5.903 s. The results of this study would help the performance and design for both scanning single-element transducer and ring array systems.