儿童肘关节CT检查中优化体位减少辐射剂量的研究

Research of reducing radiation dose by optimizing position in CT examination of elbow joint of children

目的:探索检查体位优化技术对减少肘关节外伤儿童CT检查辐射剂量的应用价值。方法:选取医院收治的90例单侧肘关节外伤患儿CT扫描图像,根据肘关节摆放体位的不同分为观察组和对照组,每组45例,观察组采用患侧肘关节上举的优化体位;对照组采用传统肘关节放置身体侧面体位。对两组CT扫描的容积CT剂量指数(CTDI_(vol))、剂量-长度乘积(DLP)、有效辐射剂量(ED)以及图像质量进行比较评估。结果:观察组和对照组的CTDI_(vol)分别为(4.48±1.28)mGy和(7.00±1.75)mGy;DLP分别为(100.81±26.00)mGy·cm和(150.57±45.85)mGy·cm;ED分别为(1.55±0.41)mSv和(2.30±0.61)mSv;观察组图像的CTDI_(vol)、DLP和ED均明显低于对照组,两组间比较差异均有统计学意义(F=22.12,F=14.21,F=20.61;P<0.01)。图像质量的主观评价按5分制评分进行,观察组和对照组图像质量优良率分别为97.8%和95.5%,差异无统计学意义(Z=-1.34,P>0.05);结论:肘关节患儿CT检查中,采用将患侧关节上举的优化体位可以在不影响图像质量的情况下,明显减少辐射剂量。

Objective:To explore the application value of optimizing technique of examination position for reducing radiation dose of computed tomography(CT)examination of children with trauma on elbow joint.Methods:The CT scan images of 90 children with trauma on unilateral elbow joint in hospital were selected and were divided into observation group and control group according to the position of affected elbow joint,with 45 cases in each group.The observation group adopted the optimized position of lifting the elbow joint on affected side,and the control group adopted the traditional body position of placing elbow joint on the side of the body.And then,the CT dose index volume(CTDI_(vol)),dose-length product(DLP),effective dose(ED)and image quality of CT scan between two were(4.48±1.28 vs 7.00±1.75)mGy,(100.81±26.00 vs 150.57±45.85)mGy·cm and(1.55±0.41 vs 2.30±0.61)mSv,respectively.The CTDI_(vol),DLP and ED of the images of observation group were significantly lower than those of control group,and the differences of them between the two groups were statistically significant(F=22.12,F=14.21,F=20.61,P<0.01).The subjective evaluation of image quality was conducted on a 5-point scale.The excellent rate of image quality of observation group and control group were 97.8%and 95.5%,respectively.And the differences of that between the two groups were not statistically significant(Z=-1.34,P>0.05).Conclusion:In the CT examination of elbow joint of children,the optimized position of lifting the elbow joint on affected side can significantly reduce the radiation dose without affecting the image quality.