Proposed Diagnostic Reference Levels for Frequently Performed Paediatric Radiographic Examinations

Paediatric diagnostic reference levels (DRLs) are dose levels for typical medical imaging examinations for broadly defined types of equipment with weight-stratification preferred by the International Commission on Radiological Protection. Australia has never published paediatric DRLs for general radiography. The aim of this study was to collect radiation dose metrics for commonly performed radiographic projections in children in Australia and propose weight-based DRLs.

Ethics approval was granted to collect data, along with a waiver of consent. Radiographs were acquired in accordance with local protocols using direct digital X-ray equipment for children who presented for routine radiographic imaging. A spreadsheet was provided to each centre to record the patient's age and weight, as well as tube voltage and current-time product, source-to-image distance, use of a grid, additional filtration, automatic exposure control chamber selection and the displayed air kerma area product (KAP). Facility reference levels (FRLs) were calculated as the median for each X-ray unit based on data submitted for a minimum of three patients. The 75th percentiles of the FRLs across nine X-ray units from five centres were calculated as the proposed Local DRLs (LDRLs).

The most commonly radiographed body parts in children were the chest, wrist, abdomen, elbow and foot. The proposed LDRLs range from 4 mGy•cm² (oblique hand in 5-15 kg) to 884 mGy•cm² (antero-posterior pelvis in 50-80 kg).

The estimation of LDRLs for radiographs from a weight-based patient study offers Australian reference values for guidance in the optimisation process.