【摘要】 平板探测器是锥束CT的关键组成部件，像元间的信号串扰是造成平板探测器投影图像空间分辨率低于极限值的主要因素，校正平板探测器信号串扰对提高锥束CT检测精度具有重要意义。本文基于点扩散函数矩阵反卷积投影图像去串扰校正思路，研究了点扩散函数矩阵的准确性对投影图像串扰校正的影响、点扩散函数和线扩散函数的关系及其与X射线成像的相似性，提出一种结合刀口法测量线扩散函数与平行束CT扫描重建的平板探测器点扩散函数矩阵测算方法。DR/CT扫描成像实验中，应用本文方法校正信号串扰后，DR成像空间分辨率由约10 lp/mm提升至优于25 lp/mm,高能CT成像空间分辨率由不到4 lp/mm提升至优于5 lp/mm,实验证明，应用本文方法能有效校正平板探测器信号串扰，提升锥束CT图像的空间分辨率和对比度。更多还原

【Abstract】 The flat panel detector is a key component of cone-beam CT, and the signal crosstalk between pixels is the main factor that causes the spatial resolution of the projection image to be lower than the possible highest resolution of the flat panel detector. It is essential to correct the signal crosstalk of the flat panel detector for improving the detection accuracy of cone-beam CT. In this article, the crosstalk correction effect of the point spread function matrices with different accuracy, the relationship between the point spread function and line spread function, and the similarity between the relationship and X-ray imaging are studied, based on the signal crosstalk correction idea of the point spread function matrix deconvoluting projection image. In addition, a new method for calculating the point spread function matrix of a flat panel detector is proposed, which combines the knife edge method for measuring line spread function with parallel-beam CT scanning reconstruction. In DR/CT scanning experiments, the spatial resolution of DR projection image is improved from about 10 lp/mm to better than 25 lp/mm and the spatial resolution of high-energy CT image is improved from less than 4 lp/mm to better than 5 lp/mm after correcting signal crosstalk by the proposed method. Experimental results show that the proposed method can effectively correct the signal crosstalk of flat panel detector and improve the spatial resolution and contrast of cone-beam CT images.更多还原