Radiation exposure during paediatric emergency CT: time we took notice?

Concerns exist about radiation exposure during medical imaging. Comprehensive computerised tomography (CT) dose standards exist for adults, but are incomplete for children. We investigated paediatric CT radiation doses at a NHS Trust in order to define the extent of the risk.

CT dose indicators (CTDI) were recorded for all scans on paediatric patients from January - December 2011 and benchmarked against American College of Radiologists reference levels (75 mGy for adult head, 25 mGy for adult abdomen, and 20 mGy for paediatric (5-year-old) abdomen). Size-specific dose estimates (SSDE) were calculated based on effective patient diameter as recommended by the American Association of Physicists in Medicine. Student t-test was used to compare CTDI and SSDE values for each anatomical region.

Of 53,648 paediatric emergency presentations, CT was requested in 211 (0.39%). One hundred fifty-four patients underwent 169 scans, with the rest being cancelled for clinical improvement or senior overrule. Indication for CT was trauma in 130/154 (90%), of which 55% were after falls, 19% following road traffic collisions, 12% after sporting injury, and 12% after alleged assault. CTDI values were available for 96/169 (57%) scans, with the rest lacking sufficient data. There was no significant difference between CTDI and derived SSDE values. 3% of head scans exceeded the adult head reference level.

There is wide variation in radiation exposure during paediatric trauma CT, with some scans delivering doses in excess of recommended adult values. There is an urgent need to define standards for radiation dose in paediatric CT for all ages and anatomical regions.