摘要
目的探讨不同管电压及不同管电流对模拟植入肺部结节的胸部CT图像质量及相应辐射剂量的影响。方法利用仿真人体模型模拟植入四种不同直径大小(3 mm、5 mm、8 mm、10 mm)及每种直径设置三种不同密度(-630 HU、-800 HU、+100 HU)共12枚结节,在不同管电压(80 kV、100 kV和120 kV)及管电流(15 mAs、20 mAs、25 mAs、30 mAs、100 mAs、200 mAs)条件下进行分次成像,对结节检出率、结节变形度及图像质量(主观评价及客观评价)进行评价,并记录分次成像辐射剂量,分析成像参数与结节检出率、结节变形度、辐射剂量及图像质量的相关性。结果在图像质量评价方面,当管电压或管电流不变时,图像质量[对比噪声比(CNR)、信噪比(SNR)]随管电压或管电流的增加而提升(P<0.05);胸部器官CT值评价:当管电流不变时,随着管电压增加,椎体CT值逐渐降低(P<0.05),肺野CT值差异无统计学意义(P>0.05)。相同管电流100 mAs,不同管电压条件下,高密度(+100 HU)肺结节CT值差异有统计学意义(F=98.35,P<0.05);磨玻璃(-630 HU)肺结节CT值差异有统计学意义(F=13.03,P<0.05);更低密度(-800 HU)肺结节CT值差异无统计学意义(F=0.587,P=0.57)。对于肺结节检出率,在100 kV及120 kV条件下,所有管电流结节检出率为100%;80 kV/15 mAs条件下,3 mm结节检出率为33%,80 kV/20 mAs条件下,3 mm结节检出率为66%。对于肺结节变形度的影响,-630 HU密度结节及直径小于5 mm结节变异度最大,其差异有统计学意义(P<0.05)。分析不同管电压下图像质量与辐射剂量的关系,并确立相关性方程:80 kV:Y=2.625X+0.038;100 kV:Y=14.66X+0.158;120 kV:Y=18.59X+0.093。结论图像质量随管电流及管电压的增加逐渐上升,辐射剂量随管电压及管电流的上升相应增加。适当降低管电压,增加管电流可降低辐射剂量。肺部磨玻璃结节随访CT检查,应遵循相同管电压成像参数,从而有效减低结节密度测量的误差,更真实地�
Objectives To investigate the influence of scanning parameters(tube voltages and tube currents) on image quality and corresponding radiation doses with simulated lung nodules in chest CT. Methods The anthropomorphic chest phantoms with 12 simulated, randomly placed nodules of different diameters and densities in the chest were scanned by different scanning parameters. The detection rate, degree of nodular deformation, image quality(with both subjective and objective evaluation) and the corresponding radiation doses were recorded and evaluated, and the correlation between nodule detection rate, degree of nodular deformation, radiation dose and image quality using different scanning parameters was analyzed. Results The image quality improved with the increase of tube voltage and tube current(P<0.05). When the tube current was constant, the CT values of the vertebral decreased gradually with the increase of tube voltages(P<0.05);however, significant difference was not detected in CT values of the lung field(P>0.05).When the tube current was 100 mAs, the lung nodules with CT values of +100 HU and-630 HU showed statistical difference when using different tube voltage(P<0.05);but there was no significant difference in nodules of-800 HU(P=0.57). When tube voltage was 100 kV and 120 kV each, it was possible to detect all lung nodules with a detection rate of100%. The detection rate was 33% and 66% in 3 mm diameter when the tube current was 80 kV/15 mA and 80 kV/20 mA,respectively. The nodules deformation in nodules with a CT value of-630 HU and diameter less than 5 mm was the most prominent(P<0.05). After analyzing the relationship between image quality and radiation doses using different tube voltages, we established a system of correlation equations: 80 kV: Y=2.625 X+0.038;100 kV: Y=14.66 X+0.158;120 kV:Y=18.59 X+0.093. Conclusions The image quality improves with the increase of tube current and tube voltage, as well as the corresponding radiation doses. By reducing the tube voltage and increasing the tube current appr
作者
彭盛坤
赵原
蒲红
PENG Shengkun;ZHAO Yuan;PU Hong(Department of Radiology,Sichuan Province of People's Hospital,Chengdu,610000,P.R.China)
出处
《中国循证医学杂志》
CSCD
北大核心
2019年第10期1158-1162,共5页
Chinese Journal of Evidence-based Medicine
基金
四川省卫计委普及项目（编号：17PJ421、16PJ465）
