Cai Jiangze, Duan Xiaoman, Qi Hongliang, Chen Yusi, Ma Jianhui, Zhou Linghong, Xu Yuan
School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, P.R.China.
Guangzhou Huaduan Technology Limited Company, Guangzhou 510700, P.R.China.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2021 Oct 25;38(5):951-959. doi: 10.7507/1001-5515.202101066.
In order to suppress the geometrical artifacts caused by random jitter in ray source scanning, and to achieve flexible ray source scanning trajectory and meet the requirements of task-driven scanning imaging, a method of free trajectory cone-beam computed tomography (CBCT) reconstruction is proposed in this paper. This method proposed a geometric calibration method of two-dimensional plane. Based on this method, the geometric calibration phantom and the imaging object could be simultaneously imaged. Then, the geometric parameters could be obtained by online calibration method, and then combined with the geometric parameters, the alternating direction multiplier method (ADMM) was used for image iterative reconstruction. Experimental results showed that this method obtained high quality reconstruction image with high contrast and clear feature edge. The root mean square errors (RMSE) of the simulation results were rather small, and the structural similarity (SSIM) values were all above 0.99. The experimental results showed that it had lower image information entropy (IE) and higher contrast noise ratio (CNR). This method provides some practical value for CBCT to realize trajectory freedom and obtain high quality reconstructed image.
为了抑制射线源扫描中随机抖动引起的几何伪影，实现灵活的射线源扫描轨迹并满足任务驱动扫描成像的要求，本文提出了一种自由轨迹锥束计算机断层扫描（CBCT）重建方法。该方法提出了一种二维平面的几何校准方法。基于此方法，几何校准体模和成像对象可以同时成像。然后，通过在线校准方法获得几何参数，再结合几何参数，使用交替方向乘子法（ADMM）进行图像迭代重建。实验结果表明，该方法获得了高质量的重建图像，具有高对比度和清晰的特征边缘。模拟结果的均方根误差（RMSE）相当小，结构相似性（SSIM）值均高于0.99。实验结果表明，它具有较低的图像信息熵（IE）和较高的对比噪声比（CNR）。该方法为CBCT实现轨迹自由和获得高质量重建图像提供了一定的实用价值。
