锥束微型CT图像重建中射线源位置的修正

基金项目:

国家自然科学基金(90508003)

国家科技攻关计划(2005BA711A04)

详细信息

Adjusting of Cone-beam X-ray Source of Micro CT

The Key Laboratory of Biomedical Photonics of Ministry of Education-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China

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FAXITRONMR₂0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。
- 锥束CT /
- 射线源 /
- 滤波逆投影
Abstract: Accurate coordinate of X-ray source is one of the key parameters in design of micro CT based on cone-beam X-ray system. The method of calculating the coordinate of X-ray 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-ray source are represented. Model test are performed to show the effect after corrected for the shift of X-ray source.
- cone-beam CT /
- X-ray source /
- FDK