不同成像参数对胸部CT图像质量及辐射剂量的影响

Effects of Different Imaging Parameters on Image Quality and Radiation Dose of Chest CT

目的探讨不同成像参数在胸部电子计算机断层扫描(CT)图像质量及有效辐射剂量(ED)中的应用价值。方法选取我院行胸部CT筛查的108例患者作为研究对象,在不同管电压(80、100、120 kV)与管电流(15、30、100 mAs)进行分次成像,对图像质量行主观与客观评价,对比不同管电压与不同管电流图像噪声比(CNR)、信噪比(SNR)、不同管电流与管电压对应ED、管电压与管电流对CT值影响及图像质量与ED关系。结果管电压与管电流逐渐升高,图像质量亦随之提升(P<0.05);随着管电流、管电压水平不断降低,ED明显降低(P<0.05);管电流固定100 mAs时,椎体CT值随管电压增高而降低(P<0.05),双肺CT值随管电压增高变化不显著(P>0.05);经pearson分析,图像质量与ED呈正相关(r=0.847,P<0.001)。结论图像质量可伴随管电流及管电压水平增加逐渐升高,ED随管电压及与管电流水平上升逐渐增加,若适当降低管电压,增加管电流可有效降低ED。

Objective To explore the application value of different imaging parameters in image quality and radiation dose of chest computed tomography(CT)imaging.Methods 108 patients with chest CT screening in our hospital were selected as subjects,Separate imaging of different tube voltages(80,100,120 kV)with tube currents(15,30,100 mAs),Subjective and objective evaluation of image quality,The noise ratio(CNR),signal-to-noise ratio(signal-to-noise ratio(SNR)),radiation dose corresponding to different tube current and tube voltage,the effect of tube voltage and tube current on CT value and the relationship between image quality and radiation dose were compared.Asaresult The tube voltage and current gradually increased,Image quality also improved(P<0.05);As the current and voltage levels of the tube decrease,A significant decrease in radiation dose(P<0.05);If the current is 100 mAs,Vertebral body CT decreased with increased tube voltage(P<0.05),Double lung CT increased with tube voltage,Changes were not significant(P>0.05);After pearson analysis,Image quality was positively correlated with radiation dose(r=0.847,P<0.001).Conclusion Image quality can increase gradually with the increase of tube current and voltage level,The radiation dose increases gradually with the increase of tube voltage and current level,If the tube voltage is reduced properly,Increasing the tube current can effectively reduce the radiation dose.