γ-H2AX foci are increased in lymphocytes in vivo in young children 1 h after very low-dose X-irradiation: a pilot study
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- Halm, B.M., Franke, A.A., Lai, J.F. et al. Pediatr Radiol (2014) 44: 1310. doi:10.1007/s00247-014-2983-3
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Computed tomography (CT) is an imaging modality involving ionizing radiation. The presence of γ-H2AX foci after low to moderate ionizing radiation exposure has been demonstrated; however it is unknown whether very low ionizing radiation exposure doses from CT exams can induce γ-H2AX formation in vivo in young children.
To test whether very low ionizing radiation doses from CT exams can induce lymphocytic γ-H2AX foci (phosphorylated histones used as a marker of DNA damage) formation in vivo in young children.
Materials and methods
Parents of participating children signed a consent form. Blood samples from three children (ages 3–21 months) undergoing CT exams involving very low blood ionizing radiation exposure doses (blood doses of 0.22–1.22 mGy) were collected immediately before and 1 h post CT exams. Isolated lymphocytes were quantified for γ-H2AX foci by a technician blinded to the radiation status and dose of the patients. Paired t-tests and regression analyses were performed with significance levels set at P < 0.05.
We observed a dose-dependent increase in γ-H2AX foci post-CT exams (P = 0.046) among the three children. Ionizing radiation exposure doses led to a linear increase of foci per cell in post-CT samples (102% between lowest and highest dose).
We found a significant induction of γ-H2AX foci in lymphocytes from post-CT samples of three very young children. When possible, CT exams should be limited or avoided by possibly applying non-ionizing radiation exposure techniques such as US or MRI.