Establishment of diagnostic reference levels based on administered radiopharmaceutical activity for adult and pediatric nuclear medicine procedures in Taif city, Saudi Arabia

Nuclear medicine procedures are widely used in diagnostic imaging due to their ability to provide functional information about organs and tissues. However, these procedures involve exposure to ionizing radiation, which raises concerns about patient safety, particularly for vulnerable populations like children. Optimizing radiation doses has become essential to minimize unnecessary exposure while maintaining image quality. This study aims to assess patient radiation doses (administered activities), propose local diagnostic reference level (DRLs) to both adult and paediatric patients in Taif, Saudi Arabia and estimate effective radiation doses (ED), associated with commonly performed nuclear medicine procedures. Data were collected from 277 adult and 60 pediatric patients who underwent nuclear medicine procedures at three NM centers in Taif City. Patient demographics (age, gender, weight, and height when available) and procedure-specific information were obtained from electronic medical records (EMR) and radiological information system (RIS). Administered radiopharmaceutical activities were the primary dose metric for DRL establishment which then converted to effective doses (mSv) using standard conversion factors from ICRP Publication 128. Descriptive analysis was conducted to calculate mean and median doses and propose local DRLs. The study found that adult procedures such as bone (HDP and MDP) and thyroid scans had mean effective doses of 3.54 mSv, 3.71 mSv, and 3.46 mSv, respectively, all within international standards. Paediatric renal MAG3 procedures showed wider variation depending on age, ranging from 0.35 mSv (1-year-old) to 2.5 mSv (10-year-old), while the DRL for aforementioned procedure was 740.770 and 185 MBq respectively, for adult and for paediatric renal MAG3 showed 40–185 MBq depending on age . Conclusion : Most procedures were within global safety benchmarks. However, elevated paediatric doses highlight the need for local DRLs and ongoing dose optimization. Implementing region-specific DRLs will improve protocol consistency, enhance safety, and support better-quality nuclear medicine services.