Department of Radiology, Shiraz University of Medical Sciences, Shiraz, Iran
Department of Radiology, Shiraz University of Medical Sciences, Shiraz
Medical Imaging Research Center, Shiraz University of Medical Sciences
Computed Tomography (CT) is one of the most
important diagnostic methods for craniosynostosis evaluation to assess the skull sutures of pediatric patients. Since the risk of radiation dose is especially very serious in pediatric, the aim of this study is to evaluate the possibility of radiation dose reduction in CT scanning of skull for craniosynostosis, with respect to image quality.
A cadaver skull bone was scanned, by 8-MDCT GE Health care, with standard dose (100 kVp, 9mAs) and with 20% reduced dose (80 kVp, 9mAs). Reconstructed 3D images (with 1.25mm slice thickness) were evaluated by two experienced radiologists, subjectively blinded to the exposure parameters. Image quality were reported to be acceptable in both standard and reduced dose cases. Therefore, dose reduction protocol was used to scan 57 pediatric patients, 1 to 36 months old, suspicious of craniosynostosis. Radiation dose indices including volume CT dose index (CTDIvol in mGy) and Dose Length Product (DLP in mGy.cm) for standard (41 patients) and dose reduction protocol were recorded from PACS system. Conversion factor k (in mSv/mGy. cm) was used to calculate effective dose (ED) in mSv.
Statistical analysis shows that the mean and standard deviation of CTDIvol, DLP and ED are 12.86±2.2 mGy, 199±48 mGy.cm, 1.94 mSv for standard dose and 5.35±0.2 mGy, 84.26±7.4, 0.77±0.17 mSv for
dose reduction protocol respectively with p<0.001 for all pair parameters.Conclusion:
Dose reduction protocol for scanning skull of pediatric patients, to evaluate craniosynostosis is able to reduce CTDIvol, DLP and ED values by 58%, 57.5% and 70% respectively relative to standard one, while the diagnostic image quality is acceptable. Therefore, standard dose protocol can be replaced by dose reduction one, as is established in this study.
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