Assessment of image quality of a standard and two dose-reducing protocols in paediatric pelvic CT.
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.


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.
Ratcliffe
John
J
Department of Radiology, The Royal Children's Hospital, Brisbane, Queensland, Australia. ratcliffejohn@hotmail.com
Swanson
Cheryl E
CE
Hafiz
Niru
N
Frawley
Kieran
K
Coakley
Kerry
K
Cloake
John
J
D000367:Age Factors; D000704:Analysis of Variance; D002648:Child; D002675:Child, Preschool; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D007223:Infant; D016014:Linear Models; D008297:Male; D010384:Pelvic Bones / Q000002:abnormalities / Q000000981:diagnostic imaging*; D011336:Probability; D011446:Prospective Studies; D011786:Quality Control; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control*; D011856:Radiographic Image Enhancement; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000592:standards*