射束硬化对 CT系统平面内空间分辨率的影响

摘要

To investigate the effect of beam hardening on measurement of the CT system ’ s in-plane spatial reso-lution, on two same specification body 16 slices helical CT machines , performing beam hardening calibration or not, MTF curve is calculated by a small needle image obtained by the corresponding CT respectively , and then tool 0%, 2%, 10%and 50%of the value of MTF curve to comparatively further analyze the impact of beam hardening on the CT system ’ s in-plane spatial resolution .In the case of using different thickness and different convolution kernel to reconstruct the image , whether or not performing beam hardening calibration have a impact on measure-ment results .Conclusion:beam hardening has certain influence on the CT system ’ s in-plane spatial resolution , but in the different modalities of reconstruction image , the impact trend is varying .%探讨射束硬化对于测量CT系统平面内空间分辨率的影响，在两台相同型号规格的全身16排螺旋CT机上，进行射束硬化校正和不进行射束硬化校正两种情况下，分别计算由被测CT扫描所得小针图像的MTF曲线，然后取MTF曲线幅值的0％，2％，10％以及50％处所对应的空间分辨率线对数进行对比，进而分析射束硬化对与测量扫描系统的平面内空间分辨率的影响。结果表明，在不同层厚以及不同卷积核重建小针图像情况下，是否对图像进行射束硬化校正对于测量平面内空间分辨率的影响存在差异性不同的重建图像场景，射束硬化带来的影响趋势不同。