基于标准剂量CT图像非局部权值先验的低剂量图像恢复

本文提出一种基于标准剂量CT图像非局部权值先验的低剂量图像恢复方法，该方法首先将先前标准剂量图像与低剂量CT图像配准，并对低剂量CT图像进行预处理以抑制部分噪声，随后利用非局部均值的思想计算配准后的先前标准剂量CT图像的权值矩阵，基于该权值矩阵对预处理后的低剂量CT图像进行加权均值滤波.仿真实验和临床脑灌注数据实验表明，本文方法在消除低剂量CT图像噪声和伪影的同时，还可提升图像分辨率，对临床脑灌注CT扫描的疾病诊断中尤为有效.

Low-Dose CT Image Restoration Using a Non-Local Weights Prior from Previous Normal-Dose Scan Image

A novel approach is proposed to improve low-dose CT image quality by a non-local weighs prior which is acquired from previous normal-dose scan.First,we align two images—the low-dose and the previous normal-dose scan image,and filter the low-dose image to suppress noise.Then,the weight matrix of the registered normal-dose image is calculated by the non-local means weighting formula,and the low-dose image is restorated using this weight matrix as a prior.Simulated phantom and perfusion data experiment results demonstrate a highly quality improvement in terms of suppressing noise-induced streak artifacts and preserving resolution of the low-dose image using the proposed method.The proposed method is especially effective for clinical short-term repeated CT scan,such as perfusion and radiation therapy.