Multi-Spectral CT Reconstruction Algorithm Based On Photon Count Detector And Its Application

In recent years,with the rapid development of energy resolution X-ray photon counting detector technology based on X-ray energy spectrum technology has become a hot research issue in CT imaging,including reconstruction algorithm,energy,material identification etc..Compared with the traditional CT,the ray multi energy spectrum can be used to obtain the projection image of the object in different spectral channels in a single scan,which is helpful to distinguish the material and improve the contrast to noise ratio(CNR).In this paper,based on the photon counting detector multi-spectral CT reconstruction algorithm and its application,the main research contents are as follows:(1)multi-spectral CT reconstruction,and the characteristics of X-ray energy spectral CT projection data and image reconstruction algorithm are studied.The multi-pectral CT can provide the attenuation map of the detected object in different spectral dimensions.Because of the narrow band of the CT spectral,the noise in each channel can be increased.In order to effectively reduce the noise in the channel,this paper uses Split-Bregman algorithm based on TV to reconstruct the X-ray energy spectrum CT.Firstly,according to the prior information of the reconstruction module,the energy spectral channel is divided.Then,the Split-Bregman algorithm is used to reconstruct the noise and sparse angle of the spectral projection data.The simulation results show that the energy spectrum CT reconstruction method based on the Split-Bregman algorithm can effectively remove the noise in the spectral channel,and meet the needs of the material distinction.(2)Material discrimination and recognition,ray multi spectrum can provide a wealth of information about the material.First of all,the principal component analysis method is usedto analyze the multi spectral data of X-ray energy spectrum,and the energy spectrum information of X ray can be extracted and quantified.Secondly,the K edge characteristics of different materials were studied by means of different absorption characteristics of X ray of different materials.