本文關鍵詞： X射線能譜CT 光子計數(shù)探測器 能譜通道劃分 Split-Bregman 彩色CT成像 K邊緣值成像　出處：《中北大學》2017年碩士論文　論文類型：學位論文

【摘要】：近年來,隨著光子計數(shù)探測器技術的快速發(fā)展,X射線多能譜CT技術成為CT成像領域的研究熱點問題,包括重建算法,能量選擇,材料識別等。與傳統(tǒng)CT相比,X射線多能譜CT在一次掃描中能得到物體在不同能譜通道下的投影圖像,有利于區(qū)分物體的材質,提高對比噪聲比(CNR)。本文基于光子計數(shù)探測技術研究多能譜CT重建算法及應用,主要研究內容如下:(1)多能譜CT重建,多能譜CT可以提供被檢測物體在不同能譜維度的衰減圖,但由于能譜通道變窄,每個能譜通道內的噪聲增加了。為了有效降低通道內的噪聲,本文使用基于TV最小化的Split-Bregman算法對X射線多能譜CT進行重建。首先,根據(jù)重建模體的先驗信息,進行能譜通道的劃分。然后,采用Split-Bregman算法對能譜投影數(shù)據(jù)進行噪聲和稀疏角度重建。仿真實驗結果表明,基于Split-Bregman算法的能譜CT重建方法能夠有效去除能譜通道內的噪聲,滿足物體材質區(qū)分的需求。(2)材質區(qū)分與識別,X射線多能譜CT能夠提供豐富的有關物質材質的信息。首先通過主成分分析方法對X射線能譜多CT數(shù)據(jù)進行分析,提取和量化X射線的能譜信息,并融合出彩色CT圖像,可直觀區(qū)分材料的不同物質。其次利用不同物質X射線的吸收特性不同,通過實驗研究了不同材料的K邊緣特性,進一步評估了X射線多能譜CT材質的鑒別能力。
[Abstract]:In recent years, with the rapid development of photon counting detector technology, X-ray multispectral CT technology has become a hot issue in the field of CT imaging, including reconstruction algorithm, energy selection. Compared with traditional CT, X-ray multispectral CT can get projection images of objects in different energy spectrum channels in a single scan, which is helpful to distinguish the materials of objects. In this paper, the multispectral CT reconstruction algorithm and its application are studied based on photon counting detection technology. The main research contents are as follows: 1) multispectral CT reconstruction. Multi-spectral CT can provide attenuation map of the detected object in different energy spectrum dimensions, but because the energy spectrum channel becomes narrower, the noise in each energy spectrum channel increases, in order to effectively reduce the noise in the channel. In this paper, the Split-Bregman algorithm based on TV minimization is used to reconstruct X-ray multispectral CT. Firstly, the energy spectrum channels are divided according to the priori information of the remodeled volume. The Split-Bregman algorithm is used to reconstruct the noise and sparse angle of the energy spectrum projection data. The simulation results show that. The energy spectrum CT reconstruction method based on Split-Bregman algorithm can effectively remove the noise in the energy spectrum channel and meet the requirements of material differentiation. X-ray multispectral CT can provide abundant information about material material. Firstly, the multi-CT data of X-ray energy spectrum are analyzed by principal component analysis (PCA) to extract and quantify the information of X-ray energy spectrum. The color CT images can be used to distinguish different materials directly. Secondly, the characteristics of K edge of different materials are studied by using different X-ray absorption characteristics of different materials. The discrimination ability of X-ray multispectral CT materials was further evaluated.
【學位授予單位】：中北大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TP391.41

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本文編號：1471597