Rejesh Nadaparambil Aravindakshan, Pullagurla Harish, Pramanik Manojit
J Opt Soc Am A Opt Image Sci Vis. 2013 Oct 1;30(10):1994-2001. doi: 10.1364/JOSAA.30.001994.
Photoacoustic/thermoacoustic tomography is an emerging hybrid imaging modality combining optical/microwave imaging with ultrasound imaging. Here, a k-wave MATLAB toolbox was used to simulate various configurations of excitation pulse shape, width, transducer types, and target object sizes to see their effect on the photoacoustic/thermoacoustic signals. A numerical blood vessel phantom was also used to demonstrate the effect of various excitation pulse waveforms and pulse widths on the reconstructed images. Reconstructed images were blurred due to the broadening of the pressure waves by the excitation pulse width as well as by the limited transducer bandwidth. The blurring increases with increase in pulse width. A deconvolution approach is presented here with Tikhonov regularization to correct the photoacoustic/thermoacoustic signals, which resulted in improved reconstructed images by reducing the blurring effect. It is observed that the reconstructed images remain unaffected by change in pulse widths or pulse shapes, as well as by the limited bandwidth of the ultrasound detectors after the use of the deconvolution technique.
光声/热声断层扫描是一种新兴的混合成像模式，它将光学/微波成像与超声成像相结合。在此，使用了一个k波MATLAB工具箱来模拟激发脉冲形状、宽度、换能器类型和目标物体尺寸的各种配置，以观察它们对光声/热声信号的影响。还使用了一个数值血管模型来展示各种激发脉冲波形和脉冲宽度对重建图像的影响。由于激发脉冲宽度以及有限的换能器带宽导致压力波展宽，重建图像出现模糊。模糊程度随着脉冲宽度的增加而增大。本文提出了一种采用蒂霍诺夫正则化的去卷积方法来校正光声/热声信号，通过减少模糊效应得到了改进的重建图像。观察到在使用去卷积技术后，重建图像不受脉冲宽度或脉冲形状变化以及超声探测器有限带宽的影响。
