Lack of association between occupational radiation exposure and thyroid nodules in healthcare personnel

Objectives: To investigate whether healthcare workers routinely exposed to low-level ionizing radiation have a higher prevalence of thyroid nodularity. Methods: Presence of thyroid nodularity, as assessed by 10-MHz neck ultrasonography, was compared with accumulated radiation doses of 579 exposed university hospital workers (M:F 350:229) obliged to wear a personal dosimeter. Results: Nodules were detected in 141/579 (24.3%) subjects. Mean accumulated dose was not different among subjects with and without nodules (14.19+/-28.00 mSv vs 17.71+/-32.89 mSv; P=0.12). Duration of occupational exposure (<10 years vs 10-19 years vs >or=20 years) did not affect prevalence of nodularity. At multivariate analysis, only female gender and age were significant risk factors. Conclusions: Mildly exposed health workers do not appear to incur any excess risk of thyroid nodularity.