Li Changhui, Ku Geng, Wang Lihong V
Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Aug;78(2 Pt 1):021901. doi: 10.1103/PhysRevE.78.021901. Epub 2008 Aug 6.
Although a small point ultrasound transducer has a wide acceptance angle, its small active area leads to a high thermal-noise-induced electric voltage in the transducer, thus the sensitivity is low. By contrast, a finite-size flat transducer has high sensitivity, but the acceptance angle is small, which limits its application in reconstruction-based photoacoustic tomography (PAT). Here, we propose a negative lens concept to increase the acceptance angle of a flat transducer without losing sensitivity. Phantom experiments demonstrate that use of this concept greatly increases the detection region for PAT with high sensitivity.
尽管小型点超声换能器具有较宽的接受角，但其较小的有效面积会导致换能器中由热噪声引起的电压较高，因此灵敏度较低。相比之下，有限尺寸的平面换能器具有高灵敏度，但接受角较小，这限制了其在基于重建的光声断层扫描（PAT）中的应用。在此，我们提出一种负透镜概念，以在不损失灵敏度的情况下增加平面换能器的接受角。体模实验表明，使用这一概念可极大地增加高灵敏度PAT的检测区域。
