Radiation doses in diagnostic imaging for suspected physical abuse.

OBJECTIVE

To measure the actual radiation dose delivered by imaging techniques commonly used in the radiography of suspected physical abuse and to make this information available to health professionals and families.

METHODS

Data were collected retrospectively on children under 3 years referred for skeletal surveys for suspected physical abuse, non-contrast CT head scan or radionuclide imaging of the bones in Starship Children's Hospital, Auckland, New Zealand from January to December 2015. Patient size-specific conversion coefficients were derived from International Commission on Radiologic Protection tissue weighting factors and used to calculate effective dose.

RESULTS

Seventy-one patients underwent an initial skeletal survey, receiving a mean effective dose of 0.20 mSv (95% CI 0.18 to 0.22). Sixteen patients had a follow-up survey with a mean effective dose of 0.10 mSv (95% CI 0.08 to 0.11). Eighty patients underwent CT head which delivered a mean effective dose of 2.49 mSv (95% CI 2.37 to 2.60). Thirty-nine patients underwent radionuclide bone imaging which delivered a mean effective dose of 2.27 mSv (95% CI 2.11 to 2.43).

CONCLUSIONS

In a paediatric centre, skeletal surveys deliver a relatively low effective radiation dose, equivalent to approximately 1 month of background radiation. Non-contrast CT head scan and radionuclide bone imaging deliver similar doses, equivalent to approximately 1 year of background radiation. This information should be considered when gaining informed consent and incorporated in patient education handouts.