锥束计算机断层成像(Come-Beam computed tomography,CBCT)中,由于X射线具有较宽的能谱范围,导致在重建图像中产生严重的射束硬化伪影,对实验结果造成严重干扰.因此,对射束硬化伪影的校正是十分有必要的.目前各类校正方法中,基于重投影的射束硬化伪影校正方法因其无需材料先验信息的特点得到了广泛应用.本文针对现有基于重投影的校正方法在校正过程中易受外界因素影响,导致校正效果下降的问题,从数据预处理、数据筛选以及校正模型求解三方面对其进行改进,以此提升校正效果.实验结果表明,本文所提方法能够更有效的实现对射束硬化伪影的校正,对比度信噪比(Contrast to Noise Ratio,CNR)、杯状伪影指数(Tcup)以及平均梯度(Average Gradient,AG)均具有不同程度的提升.
Abstract
In Come-Beam computed tomography(CBCT),due to the wide energy spectrum of X-rays,serious beam hardening artifacts could exist in reconstructed images,which seriously interferes with exper-imental results.Therefore,it is necessary to correct the beam hardening artifacts.Among all kinds of cor-rection methods,the beam hardening artifact correction method based on reprojection has been widely used because it does not need the prior information of materials.In order to improve the correction effect,this paper improves the existing correction method based on reprojection from three aspects:data prepro-cessing,data screening and correction model solving,which is susceptible to external factors in the cor-rection process.Practical experimental results show that the proposed method can more effectively correct beam hardening artifacts,and the Contrast to Noise Ratio(CNR),cupping artifact index(Tcup)and Average Gradient(AG)are all improved to varying degrees.
维普
万方数据