Low dose X-radiation induced DNA damage and its association with Glandular dose in women undergoing mammography

Mammography is a widespread X-ray-based tool used for screening as well as early diagnosis of certain diseases related to breast tissue. However, the use of X-rays in mammography raised concern as a series of low-dose radiation exposures received during this procedure might increase health risks similar to high doses of acute exposure. To understand the effects of low-dose X-irradiation, blood samples were drawn from healthy volunteers (n = 5), X-irradiated in vitro with a dose similar to that obtained during mammography (2.5-3 mGy/plane), and also from women undergoing digital breast tomosynthesis imaging (before and after 1-2 h) (n = 18) were used as models. The level of induced DNA damage was determined using γ-H2AX foci and micronucleus (MN) formation in blood lymphocytes. In the in vitro irradiated samples, the mean γ-H2AX foci frequency in unirradiated control was 0.12 ± 0.03, and in irradiated samples was 0.25 ± 0.02 (p < 0.0001). A similar increase in mean γ-H2AX foci frequency of 0.13 ± 0.01 and 0.21 ± 0.05 was observed before and after mammography imaging respectively (p < 0.0001). A similar trend was observed for in vitro MN where the frequency was 0.0008 ± 0.0008 in unirradiated control and 0.0046 ± 0.0018 in irradiated samples (p < 0.01). Whereas, a heterogeneous increase in MN frequency was observed in women who underwent mammography (p < 0.001). Pearson correlation revealed a strong correlation between Average Glandular Dose (AGD) and γ-H2AX frequency (r²=0.7820) and a weak correlation between AGD and MN frequency (r²=0.0008). The present study suggests that the low doses of radiation from mammography imaging have the potential to induce early DNA damage and residual DNA damage observed until 72 h post-exposure; it might result in an increased risk for stochastic health effects during their lifetime.