针对X射线的能谱分布、量子解释以及模体材料对X射线的衰减特性, 提出了基于射线强度衰减的连续能谱投影仿真算法。该算法首先将连续X射线谱离散成若干个相邻的窄束能谱, 同时为了更逼真地反映连续X射线谱, 采用分段曲线拟合的方法拟合每段窄束能谱上的能谱函数以及在该段上衰减系数关于射线能量的函数, 再根据多色射线的衰减规律进行投影仿真, 最后进行融合, 得到连续能谱X-CT的投影数据。对该算法得到的投影进行CT重建, 显示了预期的射束硬化效果, 逼真地仿真了实际CT系统的投影过程。

In the view of the distribution of X-ray spectrum, the explanation of quantum and the characteristic of material attenuation for X-ray, the arithmetic which simulates the projection of the consecutive spectrum was proposed based on the attenuation of X-ray intensity. First in this arithmetic the consecutive spectrum of X-ray was divided into several discrete and narrow spectrums. At the same time in order to realistically reflect the consecutive spectrum of X-ray, the method of subsection curve fitting was used to fit the function of spectrum on the every narrow spectrum and the function of attenuation coefficient with the X-ray energy changing. Then the projection was simulated according to the attenuation rule of the polychromatic ray. At last, the projection of X-ray which had the consecutive spectrums characteristic was derived by fusing projection. CT reconstruction by using the projection derived from this arithmetic showed the anticipated beam hardening effects. At the same time, this arithmetic realistically simulates the projection process of practical system of CT.