迭代重建对日常CT检查平均辐射剂量的影响

Influence of iterative reconstruction on average radiation dose of daily CT examination

目的:对比3台不同CT设备的常规检查辐射剂量,探讨迭代重建(ASIR)技术对常规检查辐射剂量的影响效果。方法:3台CT扫描仪为A、B、C,其中C设备应用迭代重建技术。A和B扫描仪使用原来常用的每台设备记录一周内成人不同部位扫描的实际辐射剂量,包括容积CT剂量指数(CTDI vol)和剂量长度乘积(DLP)。每台设备每个部位记录数据各40例。对所有数据进行统计学处理,P<0.05为差异有统计学意义。选取不同部位相同层面兴趣区,测量噪声值(SD)并进行统计学分析。结果:3台CT设备不同部位常规扫描辐射剂量差异有统计学意义(P<0.05)。其中头部辐射剂量比较,B组比A组下降7%(2.84/45.5),C组比A组下降5%(2.12/45.5);胸部辐射剂量比较,C组比A组下降55%(8.1/14.87),C组比B组下降了62%(10.78/17.55);冠脉CTA辐射剂量比较,C组较A组下降了10%(5.57/53.63),C组较B组下降了25%(16.46/64.52);腹部辐射剂量比较B组较A组下降了12%(269.83/2297.21),C组较A组下降了7%(171.95/2297.21)。结论:三台不同CT设备的日常检查辐射剂量有区别,C设备应用迭代重建技术后辐射剂量低于另外两台CT设备,尤其是在胸部和冠脉CTA检查中更加明显。

Objective：To explore the influence of CT iterative technique on routine examination radiation dose by comparing the radiation dose of routine examination on three different CT scanners. Methods：Among three CT scanners （A,B, C） ,the scanner C was used with iterative reconstruction technique. The adult scanning radiation dose CTDIvol （volume CT dose index） and DLP （dose length product） of different parts in a week were recorded. Each set of data included forty cases. For statistics processing of all data, P（0.05 difference had statistical significance. Regions of interest at the same level in different parts were selected, the noise value （SD） was measured and the statistical analysis was made. Results.. The radiation dose difference at different parts of the body shown in the three CT scanners routine scan had statistical significance. In comparing the radiation dose of the head,radiation dose in group B was lower by 70% than that in group A;that in group C was lower by 5% than in group A;in the chest examination,the radiation dose in group C was lower by 55% than that in group A;that in group C was lower by 62% than that in group B;in the coronary CTA examination,the radiation dose in group C was lower by 10% than that in group A,that in group C was lower by 25% than that in group B. In the abdominal examination,the radiation dose in group B was lower by 12% than that in group A,and that in group C was lower by 7% than that in group A. Conclusion.. The radiation dose of daily examination using these different CT scanners is different. The radiation dose of the scanner C using iterative reconstruction technique is lower than other two scanners using FBP technique,and it is more obviou in the chest and coronary CTA examination especially.