Research On Basis Material Decomposition Algorithm For Energy Spectrum CT

Computed Tomography plays an important role in medical diagnosis and Dual Energy CT imaging technology is the further development of traditional CT.The traditional CT which can only get the morphological structure of image scanning organization utilizes the X-ray attenuation information and ignores spectral information.The Dual Energy CT has fully considered the information of X-ray attenuation and spectrum at the same time.We can compute the morphological image and chemical composition image,and we can carry on the analysis of chemical composition.Therefore,Dual Energy CT imaging technology has important applications in clinical practice.The mainstream model of Dual Energy CT projection decomposition algorithm is the basis material decomposition model.The key point of the algorithm is to calculate the projection value of the base material decomposition coefficients.Through the CT reconstruction algorithms such as the traditional FBP filter back projection,we can calculate the single energy image reconstruction to remove the image artifacts.At the same time,the linear attenuation coefficient curve,the electron density image,and the atomic number of the specific area material can be computed.In this study,through the MATLAB programming tool and GATE simulation software to produce Dual Energy CT projection data,we test the classical algorithm which is Projection Decomposition Algorithm of X-Ray Dual-Energy Computed Tomography Based on Projection Matching.Based on the classical decomposition algorithm,the computational efficiency and accuracy are improved and the improved algorithms are proposed.At the same time,this paper also puts forward a new idea for the decomposition of the base material,and gives a new algorithm which is the Dual energy projection decomposition algorithm based on genetic algorithm and Material Decomposition Algorithm of Dual Energy CT base on Gradient Descent.The experimental results show that the classical algorithm can get a good decomposition effect and the efficiency of the improved algorithm is better than that of the classical algorithm.The gradient descent algorithm is superior to the classical algorithm in terms of efficiency and accuracy.The Genetic algorithm is inefficiency but it can get a better decomposition results.Due to the existence of ring artifacts in the reconstructed image based on the projection matching decomposition algorithm,the TV algorithm is used to reduce the noise.Dual Energy CT decomposition algorithm can also be extended to the multi energy CT decomposition and the multi energy CT data of projections can be reconstructed.