不同CT设备肺结节扫描参数优化的体模对照研究  

Optimization of scanning parameters for pulmonary nodules using different CT scanner:a comparativephantom study

作　　者：刘俊七 程勇 陈澜菁 沈倩 兰永树 LIU Jun-qi;CHENG Yong;CHEN Lan-jing(Department of Radiology,The Affiliated Hospital of Southwest Medical University,Sichuan 646000,China)

机构地区：[1]西南医科大学附属医院放射科,四川泸州646000

出　　处：《放射学实践》2021年第12期1577-1581,共5页Radiologic Practice

摘　　要：目的:探讨不同CT设备不同肺结节扫描参数对图像质量及辐射剂量的影响,旨在进一步优化肺结节CT筛查方案。方法:在一仿真人体胸部模型中植入3种直径(3、5和8 mm)和3种密度(100、-630和-800 HU)共9个肺结节,在固定管电压(120 kVp)及不同曝光量(10、15、20、30、50、100和200 mAs)条件下对体模进行CT扫描。根据CT扫描设备分为A组(联影uCT 550)、B组(Philips iCT 256)和C组(GE Optima CT 540)。记录每次扫描的CT容积剂量指数(CTDIvol)和剂量长度乘积(DLP),计算结节检出率,对图像质量进行主观和客观评价。分析CT扫描设备及扫描参数与辐射剂量、图像质量的相关性。采用单因素方差分析和Kruskal-Wallis H检验比较3组之间图像质量的差异。结果:辐射剂量、图像质量随曝光量的减少而降低,不同CT设备的最优曝光量有所不同;A、B、C组在相同曝光量条件下的图像对比噪声比(CNR)及信号噪声比(SNR)差异均具有统计学差异(P<0.05);A、B、C组在曝光量为100、50、30和20 mAs时,肺结节主观评分差异具有统计学意义(P<0.05);A、B、C组在曝光量为50 mAs以上,肺结节检出率均为100%。曝光量为30、20、15和10 mAs时A组肺结节检出率分别为100%、100%、88.9%、77.8%,B组分别为79.6%、77.8%、77.8%、68.5%,C组分别为100%、94.5%、79.6%、66.7%,A组明显优于B组和C组。综合评判,A、B、C组最优化曝光量分别为20、50和30 mAs,CTDIvol分别为1.75、3.38和3.45 mGy。结论:在图像质量合格的前提下,联影uCT 550 CT机具有最优化的扫描参数,辐射剂量最低,建议作为常规肺结节CT筛查的优化方案。Objective:To investigate the effect of different lung nodule scanning parameters on image quality and radiation dose with the settings of different CT equipments,and to optimize the lung nodule CT screening protocol.Methods:A total of 9 pulmonary nodule model with three different dia-meters(3,5 and 8mm)and three different densities(100,-630 and-800HU)were implanted into the simulated human chest model.The images were scanned under the fixed tube voltage(120kVp)and different CT exposure(10,15,20,30,50,100 and 200mAs).The scanning parameters were recorded as group A(United imaging uCT 550),B(Philips iCT 256)and C(GE optima CT 540)according to the CT scanner.The CT volume dose index(CTDIvol)and dose length product(DLP)were recorded.The nodule detection rate and image quality(subjective evaluation and objective evaluation)were evaluated.The correlation between any two CT scanners and scanning parameters on radiation dose and image quality was analyzed.One-way ANOVA and Kruskal Wallis H test were used to analyze the difference of image quality among the three groups.Results:The CT exposure and image quality decreased as the CT exposure decreased,but the optimal CT exposure was different for different CT equipment.The differences of CNR and SNR among group A,B and C in the same CT exposure parameters were all statistically significant(P<0.05).The difference of subjective score of lung nodules among the three group was statistically significant when the tube current was 100,50,30 and 20mAs(P<0.05).The detection rate of pulmonary nodules was 100%when the exposure was more than 50mAs in group A,B and C.The detection rate of lung nodules were 100%,100%,88.9%and 77.8%when CT exposure was 30,20,15 and 10mAs in group A,and those were 79.6%,77.8%,77.8%and 68.5%in group B;100%,94.5%,79.6%and 66.7%in group C correspondingly.There were significantly better in group A than in groups B and C.For comprehensive evaluation,the optimal CT exposure for qualified image quality of group A,B and C were 20,50 and 30mAs respectively,the CTDI

关 键 词：肺结节 体模 扫描参数 图像质量 辐射量 体层摄影术 X线计算机 

分 类 号：R814.42[医药卫生—影像医学与核医学] R734.2[医药卫生—放射医学]