RESUMO
BACKGROUND: Concerns exist regarding the effect of radiation dose from paediatric pelvic CT scans and the potential later risk of radiation-induced neoplasm and teratogenic outcomes in these patients. OBJECTIVE: To assess the diagnostic quality of CT images of the paediatric pelvis using either reduced mAs or increased pitch compared with standard settings. MATERIALS AND METHODS: A prospective study of pelvic CT scans of 105 paediatric patients was performed using one of three protocols: (1) 31 at a standard protocol of 200 mA with rotation time of 0.75 s at 120 kVp and a pitch factor approximating 1.4; (2) 31 at increased pitch factor approaching 2 and 200 mA; and (3) 43 at a reduced setting of 100 mA and a pitch factor of 1.4. All other settings remained the same in all three groups. Image quality was assessed by radiologists blinded to the protocol used in each scan. RESULTS: No significant difference was found between the quality of images acquired at standard settings and those acquired at half the standard mAs. The use of increased pitch factor resulted in a higher proportion of poor images. CONCLUSIONS: Images acquired at 120 kVp using 75 mAs are equivalent in diagnostic quality to those acquired at 150 mAs. Reduced settings can provide useful imaging of the paediatric pelvis and should be considered as a standard protocol in these situations.
