The Study of Low - dose CT Scanning Technical Parameters in Neonate Brain

Objective To investigate the optimal technical parameters of low-dose CT scanning in neonate brain so that to reduce the radiation dose.Methods 150 neonates undergone CT scanning of head were randomly divided into five groups averagely.The technical parameters included:tube voltage 120 kV,slice thickness and gap 6 mm,tube current 250,200,150,100 and 50 mAs respectively for scanning the whole brain.The CT value of ROI and standard deviation(SD) were measured in the region of left basal nucleus.The weighted CT dose index(CTDIw),dose length product(DLP),noise and imaging quality were blindly evaluated in five different dose groups.Results (1)With the scanning dose reduced,CTDIw and DLP were evidently reduced,the 50 mAs group was only 20% of the conventional dose group;(2) The imaging quality in 50 mAs group was better and general in majority,in 100 mAs and above groups was good and better in majority.The imaging quality decreased with mAs reduced;(3)The imaging noise in 50 mAs group was heavy,but it could still demonstrate intracranial normal structure and lesion.The imaging quality could be improved through adjusting the window width and window level,and it did not influence the diagnosis on the whole.Conclusion The imaging quality using 50 mAs during CT scanning of head in neonate is certainly decreased, but do not influence the diagnosis and can protect newborns effectively undergone high radiation dose.