Evidence for the lack of an increase in DNA damage in occupational healthcare workers exposed to ionizing radiation: An indication of radiation safety

Understanding the health concerns linked to long-term low-dose ionizing radiation exposure is essential to creating safety protocols and protective gear for healthcare workers. Despite reports on the biological effects of low-dose chronic or protracted exposure to ionizing radiation, its association with long-term health effects remains unclear. To examine this, the authors obtained and tested peripheral blood samples from control participants (Healthcare workers not involved in radiation-based work (<i>n</i> = 21) and healthcare professionals (<i>n</i> = 25) receiving low-dose radiation over time as part of their occupation. Change in case with alignment to control, for early and delayed DNA damage was measured using the formation of gamma H2AX (γ-H2AX), micronucleus (MN), and <i>Ferrodoxin reductase</i> (<i>FDXR</i>) expression changes. These biomarkers were compared to cumulative registered doses, as determined by the individuals' personal dosimetry records using thermoluminescent dosimeters (TLDs). The mean γ-H2AX foci frequency estimated in blood lymphocytes among the control group was 0.05 ± 0.01, and in healthcare workers was 0.04 ± 0.01 (<i>p</i> > 0.05). The mean of MN aberration frequency <i>±</i> standard error (SE) in control was 0.001 ± 0.001 and in healthcare workers was 0.005 ± 0.002 (<i>p</i> < 0.0001). Similarly, <i>FDXR</i> expression in healthcare workers increased by 7% when compared to the control group. The cumulative registered dose in the healthcare workers' monitoring device varied between 0 and 21 mSv with an average of 3.65 mSv. A weak correlation was observed between the registered TLD dose and biomarker- γ-H2AX (R²=0.0123), MN (R²= 0.0011), and <i>FDXR</i> expression (R²= 0.0006). The study results suggest a lack of dose-dependent increase in DNA damage as evaluated by γ-H2AX, MN formation, and <i>FDXR</i> expression change among healthcare workers exposed to chronic low-dose radiation. Moreover, the observed range of these biomarkers was not significantly different from the baseline data established from apparently healthy non-radiation workers of the same population. Assay sensitivity and healthcare worker adherence to safety procedures to decrease exposures are two probable factors for the lack of correlation between the registered dose and that of DNA damage.