Optimization of scanning parameters in children CT examination / 中华放射医学与防护杂志

ABSTRACT

Objective To reduce the radiation dose to children from CT scanning through proper adjustment to milliamps (mAs) and scan lengths with a view to learning the relationship between scanning condition and radiation dose.Methods To compare the differences in main scanning parameters used for head,chest and abdomen at multi-detector CT examination of paediatric patients (＜ 1 year old,1-5 years old,6-10 years old,11-15 years old) at seven hospitals in Jiangsu province.CT dose index (CTDI) and dose-length-product (DLP) were gained by using standard children dose model (diameter 16 cm) under the same scanning conditions.Effective doses (E) at different parts of the body from children CT scanning were estimated after modification by empirical weighting factor.Statistical analyses of mAs,scan lengths and DLP were performed with SPSS 16.0 software.The differences in radiation dose due to the choice of condition of scanning were compared between two typical hospitals.Results The mean values of effective doses to paediatric patients during head,chest and abdomen CT scanning were 2.46,5.69,11.86 mSv,respectively.DLP was correlated positively with mAs and scan length (head,chest and abdomen examination,r =0.81,0.81,0.92,P ＜0.05).Due to higher mAs used,the effective dose from chest and abdomen CT examination among all age groups was higher than that in Germany Galanski research.Due to larger scanning length in abdominal examination among all age groups,effective doses in hospital were the highest.Conclusions Reasonablely reducing the scan length and mAs during CT scanning could lower children's CT radiation risk,while clinical diagnosis is not affected.