4MettlerFA,WisetPW,LockenjA,et al.CT,scanning,pattemsofuse and dose[J].JRa- diolProt,2000,20:353-359.
5United Nations Scinetific Ccomm ittee on the Effects of A tom ic Radiation. 2000 report to the General Assembly,AnnexD:medicalrad iadiation exposures[R].. New York,NY:United Nations ,2000.
6BrennerD,Elliston C,HallE,Berdon W.Estimated risks of radiation-induced fatal cancer from pediatric CT [J].AJR AmJR oentgenol,2001,176:299-296.
