目的 评价多层螺旋CT低剂量扫 描条件对小儿支气管异物图像质量的影 响。方法 将60例误吸异物的患儿随机分 成三组行低剂量CT扫描，CT扫描参数：管 电压分别为80/100/120kV，管电流均为 30mAs，准直器1.5mm，螺距1.15，重建轴 位、斜冠状位及VR图像。用方差分析对3 组患儿的年龄及扫描参数中各组剂量长度 乘积(DLP)进行比较分析，图像质量评价 数据用构成比χ2 检验。结果 三组患儿年 龄无统计学差异，三组患儿CT扫描剂量长 度乘积有显著性差异，三组患儿CT图像质 量评分无统计学差异。结论 在低管电流 条件下，降低CT扫描管电压(80kV)，可以 进一步降低辐射剂量，而不影响图像质 量。

Objective To evaluate the effect of low dose MSCT scanning conditions on image quality for children's airway foreign bodies. Methods 60 patients with inhalation history of airway foreign bodies were randomly divided into 3 groups, and performed low-dose spiral CT scanning with the following parameters: 80/100/120kV, 30mAs, collimator of 1.5mm, pitch 1.15, and reconstructed the axial image, oblique coronal image and VR. The variance analysis was used to compare the age and dose length product (DLP) of the 3 groups of children and chi square test was used to analyze the data of image quality evaluation. Results There was no significant difference in age and the Image quality between the three groups, and there was significant difference between the three groups in CT scan dose length product. Conclusion Under the condition of low tube current, reducing the tube voltage(80kV) can reduce the radiation dose further and not affect the image quality.