6Kalra MK,Maher MM , Toth TL ,et al . St rategies for CT Radiation dose Optimization[J] . Radiology ,2004 ,230 (3) :619-628.
7Cohnen M ,Fischer H ,Hamacher J ,et al . CT of the Head by Use of Reduced Current and Kilovoltage : Relationship between Image Quality and Dose Reduction[J] . AJNR ,2000 ,21 (10) :1654-1660.
8Paterson A,Frush DP,Donnelly LF.Helical CT of the Body:Are Settings Adjusted for Pediatric Patients?[J].AJR,2001,176():97-301.