Paediatric Dose AssessmentToward Establishment of National Diagnostic Reference Levels for Digital Radiography Examinations in Iran

Introduction: Paediatric patients deserve special attention because of the higher radiation risks compared with adults. The main purpose of this study is to determine patient dose and diagnostic reference level for Paediatric through Entrance Surface Dose (ESD) calculations in common X-ray examination and to establish Paediatric national DRLs in digital radiography in Iran. Materials and Methods: The study was performed on 5260 patients in 53 X-ray room. They are classified into four age groups, 0>1 year, 1>5 years, 5>10 years and 10>15 years old. Skull (PA), Skull (Lat), Chest (PA), Chest (Lat), Pelvis(AP), Abdomen (AP) digital X-ray examination is done for them. The dosimetry protocol in this study was indirect method to measure Entrance Surface Air Kerma (ESAK). The X-ray tube output for each equipment is measured using RTI solid state detector (Model Barracuda). Finally, the third quarter determined diagnostic reference level. Results: Based on the results of this study, national diagnostic reference levels were established: for example, for age group 0 to 1-year-old: 0.51 mGy for Skull(AP/PA), 0.46 mGy for Skull(Lat), 0.11 mGy for Cervical spine(AP), 0.11 mGy for Cervical spine(Lat), 0.06mGy for Chest(PA), 0.08 mGy Chest(Lat), 0.15 mGy for Thoracic spine(AP), 0.26 mGy for Thoracic spine (Lat), 0.48 mGy for Lumbar spine (AP), 0.74 mGy for Lumbar spine(Lat), 0.47 mGy for Pelvis (AP) and 0.47 mGy for Abdomen (AP). Conclusion: This article has determined wide variations in radiation dose of x-ray examinations among hospitals in Iran. Application of a diagnostic reference levels (DRL) could be a optimization procedure for reducing patients dose. The survey reveals significant variations in the radiological practices.