Xiao Jiaying, Luo Xiaofei, Peng Kuan, Wang Bo
Appl Opt. 2017 Nov 10;56(32):8983-8990. doi: 10.1364/AO.56.008983.
While photoacoustic computed tomography (PACT) is generally built with planar transducers of finite size, most current reconstruction algorithms assume the transducer to be an ideal point, which leads to a spinning blur in the consequently obtained PACT images due to the model mismatch. In this work, we put forward an improved back-projection method that factors in the geometry of the transducers to improve the tangential resolution for the reconstruction of 2D circular-scanning-based photoacoustic tomography. Extensive simulations and experiments were carried out to study the adaptability and stability of the proposed method. Results show that this method can effectively restore the tangential distortion of the PACT image for both simulated and experimental data. Results indicated that the improvement of the tangential resolution is more obvious for transducers with larger size. We also demonstrated the application of this method to transducers other than planar, and results show that the reconstructed image quality can be significantly affected by the shape and position of the transducers used. This study may help to guide the selection of transducer and design of scanning strategy in PACT.
虽然光声计算机断层扫描（PACT）通常是用有限尺寸的平面换能器构建的，但目前大多数重建算法都假定换能器是一个理想点，由于模型不匹配，这会导致在随后获得的PACT图像中出现旋转模糊。在这项工作中，我们提出了一种改进的反投影方法，该方法考虑了换能器的几何形状，以提高基于二维圆形扫描的光声断层扫描重建的切向分辨率。进行了大量的模拟和实验来研究该方法的适应性和稳定性。结果表明，该方法能够有效地恢复模拟数据和实验数据的PACT图像的切向畸变。结果表明，对于尺寸较大的换能器，切向分辨率的提高更为明显。我们还展示了该方法在非平面换能器上的应用，结果表明，所使用的换能器的形状和位置会显著影响重建图像的质量。这项研究可能有助于指导PACT中换能器的选择和扫描策略的设计。
