Wang Yi, Xing Da, Zeng Yaguang, Chen Qun
Institute of Laser Life Science, South China Normal University, Guangzhou 510631, People's Republic of China.
Phys Med Biol. 2004 Jul 21;49(14):3117-24. doi: 10.1088/0031-9155/49/14/006.
The impulse response of the ultrasonic transducer used for detection is crucial for photoacoustic imaging with high resolution. We demonstrate a reconstruction method that allows the optical absorption distribution of a sample to be reconstructed without knowing the impulse response of the ultrasonic transducer. A convolution relationship between photoacoustic signals measured by an ultrasound transducer and optical absorption distribution is developed. Based on this theory, the projection of the optical absorption distribution of a sample can be obtained directly by deconvolving the recorded PA signal originating from a point source out of that from the sample. And a modified filtered back projection algorithm is used to reconstruct the optical absorption distribution. We constructed a photoacoustic imaging system to validate the reconstruction method and the experimental results demonstrated that the reconstructed images agreed well with the original phantom samples. The spatial resolution of the system reaches 0.3 mm.
用于检测的超声换能器的脉冲响应对于高分辨率光声成像至关重要。我们展示了一种重建方法，该方法能够在不知道超声换能器脉冲响应的情况下重建样品的光吸收分布。建立了超声换能器测量的光声信号与光吸收分布之间的卷积关系。基于该理论，通过将记录的源自点源的光声信号与源自样品的光声信号进行去卷积，可以直接获得样品光吸收分布的投影。并使用改进的滤波反投影算法重建光吸收分布。我们构建了一个光声成像系统来验证该重建方法，实验结果表明重建图像与原始体模样品吻合良好。该系统的空间分辨率达到0.3毫米。
