【摘要】 提出了一种锥束X射线CT(计算机断层扫描)投影的蒙特卡罗计算方法,对X光子逐次抽样并以随机步长跟踪,将探测器区域内的沉积能量转化为投影信号,使用蒙特卡罗计算工具EGSnrc执行后台批处理计算,得到符合成像物理学的仿真投影.经过合理加速和参数优化,计算量较通用默认设置降低了2个数量级.对生成的锥束投影进行重建,结果显示出预期的射束硬化和散射伪影.该方法易于进行二次开发,贴近真实设备,是锥束X射线CT原型机散射校正的基础.将仿真投影与真实的物理设备测量数据进行比较,平均误差为1.18%.更多还原

【Abstract】 A Monte Carlo simulation method of cone-beam X-ray computer tomography(X-CT) projection is presented.X-ray photons are sampled in series and traced with random discrete steps.Projection signals are obtained from deposited energy in the detector zone.Simulations in accordance with imaging physics are generated by adopting the Monte Carlo toolkit EGSnrc,which is batch-programmed for background calculation.In contrast with the commonly used default settings,acceleration investigation and parameters optimization lead to a decreasing in simulation time around 100 times.As expected,beam-hardening and scattering artifacts are revealed in the images reconstructed from the simulated projection.The method is convenient for further developing and can be the basis of researches in the scatter correction upon conebeam X-CT prototype.Compared with the data measured from real machines,this method is validated with 1.18% error.更多还原