Evaluation of Pulmonary Nodules Using Low dose Spiral CT

Objective:The purpose of this study is to investigate scanning parameters of low dose spiral CT in evaluation of pulmonary nodules and to evaluate low dose helical CT in chest compared with conventional dose helical CT.Methods:Eighty-eight pulmonary nodules of seventy-five patients underwent spiral CT scan with 200mA,40mA,30mA,20mA and 10mA respectively.The diameter,CT value and the highest CT value were measured.The different signs of the nodules were analyzed.So did the excessive noise and artifact of images.The weighted CT dose index (CTDIw) and milliampere seconds (mAs) were recorded.Results:There was no significant difference between the five groups in detection,diameter,CT value and all the signs within the nodules (P0.05).Noise and artifact of images in 10mAs group were higher than other groups (P0.05).There was significant difference about the data of the CTDIw between the conventional helical CT group and the other groups (40mA,30mA,20mA,10mA)(P0.05).Conclusion:20mA is the most appropriate milliampere for lung scanning.With the lower radiation and the higher sensitivity and the better price performance ratio,low-dose spiral CT is worthy to be used widely.