Radiation dose from multidetector CT studies in children: results from the first Italian nationwide survey.

ABSTRACT

BACKGROUND: Multidetector CT (MDCT) scanners have contributed to the widespread use of CT in paediatric imaging. However, concerns are raised for the associated radiation exposure. Very few surveys on radiation exposure from MDCT studies in children are available. OBJECTIVE: The aim of this study was to outline the status of radiation exposure in children from MDCT practice in Italy. MATERIALS AND METHODS: In this retrospective multicentre study we asked Italian radiology units with an MDCT scanner with at least 16 slices to provide dosimetric and acquisition parameters of CT examinations in three age groups (1-5, 6-10, 11-15 years) for studies of head, chest and abdomen. The dosimetric results were reported in terms of third-quartile volumetric CT dose index (CTDIvol) (mGy), size-specific dose estimate (SSDE) (mGy), dose length product (DLP) (mGy cm), and total DLP for multiphase studies. These results were compared with paediatric European and adult Italian published data. A multivariate analysis assessed the association of CTDIvol with patient characteristics and scanning modalities. RESULTS: We collected data from 993 MDCT examinations performed at 25 centres. For age groups 1-5 years, 6-10 years and 11-15 years, the CTDIvol, DLP and total DLP values were statistically significantly below the values observed in our analogous national survey in adults, although the difference decreased with increasing age. CTDIvol variability among centres was statistically significant (variance = 0.07; 95% confidence interval = 0.03-0.16; P < 0.001). CONCLUSIONS: This study reviewed practice in Italian centres performing paediatric imaging with MDCT scanners. The variability of doses among centres suggests that the use of standardised CT protocols should be encouraged.