摘要
目的:针对利用锥束光X射线机构建的微型CT系统,对射线源的微小偏差进行校准。方法:以FAXITRONMR_20型cone-beam数字X射线机为实验对象,利用金属球模型的二维投影图像计算出射线源垂直投影位于探测板平面相对坐标。对常用的锥束CT滤波逆投影算法,给出了在非标准位置扫描时的锥束CT的修正公式。结果:通过投影测量法发现所使用仪器的射线源和探测器中心存在1.056mm的偏差,并进行了修正;以模型实验显示了修正前后的结果。结论:该方法可以精确测量射线源的相对位置,通过软件修正,重建清晰的CT图像。
Accurate coordinate of X-ray source is one ofthe key parameters in design of micro CT based on cone-beam X-my system. The method of calculating the coordinate of X-my source through a metallic ball model＇s 2-D projections is represented. It is based on micro source system which the source is counted as a particle under a certain amplification. Coordinate of the source could be calculated through projective lines. Avoiding the micro CT system is fixed, cone-beam reconstruction formulas with a nonstationary shift of X-my source are represented. Model test are performed to show the effect after corrected for the shift of X-my source.
出处
《CT理论与应用研究（中英文）》
2006年第2期69-73,共5页
Computerized Tomography Theory and Applications
基金
国家自然科学基金(90508003)
国家科技攻关计划(2005BA711A04)
