Pramanik Manojit, Ku Geng, Wang Lihong V
Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, Campus Box 1097, One Brookings Drive, St. Louis, Missouri 63130, USA.
J Biomed Opt. 2009 Mar-Apr;14(2):024028. doi: 10.1117/1.3103778.
We developed a novel concept of using a negative acoustic lens to increase the acceptance angle of an unfocused large-area ultrasonic transducer (detector), leading to more than twofold improvement of the tangential resolution in both thermoacoustic and photoacoustic tomography. In both thermoacoustic and photoacoustic tomography, for a given transducer bandwidth, the aperture size of the detector affects the tangential resolution greatly when the object of interest is near the detector surface. We were able to overcome such tangential resolution deterioration by attaching an acoustic concave lens, made of acrylic in front of the flat detector surface. We then quantified the tangential resolution improvement using phantom images. We also showed that the use of the negative lens preserves the shape of an object after the image is reconstructed.
我们提出了一种新颖的概念，即使用负声透镜来增加未聚焦大面积超声换能器（探测器）的接收角，从而使热声和光声断层扫描中的切向分辨率提高两倍以上。在热声和光声断层扫描中，对于给定的换能器带宽，当感兴趣的物体靠近探测器表面时，探测器的孔径大小对切向分辨率有很大影响。通过在平面探测器表面前方安装一个由丙烯酸制成的声学凹透镜，我们能够克服这种切向分辨率的下降。然后，我们使用体模图像对切向分辨率的提高进行了量化。我们还表明，使用负透镜在重建图像后能保持物体的形状。
