Longitudinal occupational radiation exposure trends in nuclear medicine personnel: a five-year retrospective dosimetry study in Saudi Arabia

Vollständiger Abstract

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Occupational radiation monitoring is essential for protecting nuclear medicine personnel who routinely handle unsealed radionuclides. This retrospective longitudinal study evaluated occupational radiation exposure among nuclear medicine staff at a tertiary care hospital in Najran, southwestern Saudi Arabia, using routine thermoluminescent dosimetry records. Whole-body dosimetry records covered March 2021 to October 2025, while extremity dosimetry records obtained using ring dosimeters covered April 2021 to November 2024. Whole-body exposure was assessed using Hp(10) and Hp(0.07), and extremity exposure using ring Hp(0.07). Temporal trends were analysed using generalized estimating equations. A total of 107 cleaned whole-body records and 145 ring dosimetry records were analysed. Occupational radiation doses remained well below internationally recommended limits throughout the study period. Significant declining temporal trends were observed for Hp(10), Hp(0.07), and extremity Hp(0.07). Radiography technologists accumulated the highest extremity doses, whereas nurses showed the highest mean whole-body doses, although differences between professional categories were not statistically significant. Although annual whole-body and extremity doses showed a moderate positive correlation, the bootstrap confidence interval included zero, indicating uncertainty in the strength of the association because of the limited number of paired worker-years. These results nevertheless support the continued use of dedicated ring dosimeters, as whole-body dosimetry cannot reliably substitute for direct extremity monitoring. Routine occupational radiation exposure among nuclear medicine personnel remained low throughout the study period. Longitudinal analysis of routine dosimetry records provides valuable evidence for evaluating temporal trends and supporting optimization of occupational radiation protection programmes.