一种锥束CT散射场检测优化方法

Optimized method of scatter field detection for cone beam CT

针对采用射束衰减网格的散射校正方法需额外增加较大扫描量的问题,提出了基于局部极值点扫描的检测优化方法,首先采集少量用于计算散射图像的辅助投影图像,然后采用三次样条插值由少量不同扫描角度的散射图像计算出完整的圆周扫描散射图像集,最后通过与原方法获取的散射图像及散射校正切片图像的对比分析,评估该方法的可行性与可靠性。实验结果表明,该方法仅需获取原方法1/20的散射图像即可完成锥束CT的散射校正,使扫描效率提高了47.6%,同时将散射校正切片误差控制在1%之内。

Aiming at reducing scanning amount in scatter field detection approach based on beam attenuation grid method,this paper proposes an optimized method.First,a small amount of assistant projections are acquired,which are used to calculate scatter images.And then,cubic spline interpolation is used to calculate complete circular scatter images from a few of scatter images in different scanning angles.Finally,the feasibility and reliability of the method is evaluated through comparing the obtained images with the scatter images acquired using beam attenuation grid method and the scatter correction slice images.Experiment results indicate that our method only needs 1/20 scatter images of original method to complete scatter correction,and increases the scanning efficiency by 47.6%;and the slice scatter correction error is 1%.