A Radiographic Diagnostic Reference Level Survey Using Patient and Phantom Data

A diagnostic reference level (DRL) survey was conducted for seven common radiographic projections across an integrated health region, covering 27 hospitals and clinics. The projections surveyed were Chest Posterior-Anterior (PA) and Lateral, Abdomen Supine and Upright, L-spine Anterior-Posterior (AP) and Lateral, and Pelvis. Dose area product (DAP) values were collected from patient examinations in 43 digital radiography (DR) rooms and in 18 conventional rooms which use computed radiography (CR). In each room, data were collected for between 10 and 20 patient exposures for each surveyed projection. In addition, for each projection and room, a DAP value was measured for the exposure of a uniform acrylic phantom of standardized thickness. DAP values in DR rooms were found to be significantly lower than in CR rooms (p < 0.05). Therefore, DR and CR rooms were analyzed separately. Based on the survey results, separate DRLs are presented for DR and CR rooms, for both patient and phantom DAP values. DRLs have been set at the 75th percentile values; 25th percentile and median values are also presented to characterize the range of observed values. When identifying which rooms were above the DRLs, the patient and phantom data identified a partially different set of rooms. Possible reasons for these differences, including uncertainties in the patient data, are discussed.