A method for estimating sinogram of energy spectrum ct base material

Abstract

The invention provides a method for estimating energy spectrum CT-based material sinograms, and relates to the technical field of computed tomography reconstruction methods. Utilizing the concave characteristics of the forward projection physical model function of the energy spectrum CT scan, each X-ray corresponds to the high-energy projection data, low-energy projection data, high-energy projection estimated value vector current value, low-energy projection estimated value vector current value, and sinogram matrix. The current value of A and the current value of the sinogram matrix B determine the new value of the sinogram matrix A and the new value of the sinogram matrix B corresponding to the X-ray. According to the high-energy projection data, the number of low-energy projections, and the estimated value of the forward high-energy projection The size of the estimation error obtained from the forward low-energy projection estimate determines whether the new value of the sinogram matrix is ​​qualified. The method provided by the invention has strong applicability. For different energy spectrum CT scanning systems or different matrix material pairs, there is no need to adjust coefficients or re-establish lookup tables; it can increase calculation speed and reduce calculation time while ensuring accuracy.

Description

Technical field: [0001] The invention relates to the technical field of computerized tomography (CT) reconstruction methods, in particular to a method for estimating sinograms of energy spectrum CT-based materials. Background technique: [0002] Computed tomography (CT) scans the detected object under different viewing angles through X-rays to obtain a set of projected sinograms. Using the sinograms to reconstruct the internal structure of the detected object, the contrast of each part in the reconstructed image is determined by its attenuation coefficient for X-rays. It is determined that the attenuation coefficient of different substances to X-rays varies with the energy level of X-rays used for scanning. In traditional CT reconstruction, it is assumed that X-rays used for scanning are of a single energy level, but the actual X-rays used for scanning contain multiple energy levels. The approximation of the energy levels of X-rays by traditional CT can easily lead to metal ...

AI Technical Summary

Problems solved by technology

The accuracy of the base substance sinogram obtained by the lookup table method is related to the precision of the established lookup table. The higher the precision of the lookup table, the higher the accuracy of the obtained base substance sinogram. Larger, and the longer it takes to find

In addition, although the lookup table method does not need to create different lookup tables for different spectral CT scanning systems, when the selected base material changes, the lookup table needs to be recreated

In short, the polynomial fitting method and the lookup table method are both slow and time-consuming, and for different energy spectrum CT scanning systems or different base substances, it is necessary to recalculate the correlation coefficient or establish a lookup table, which is not very applicable

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