Quantifying Radiation Effects of Iodinated Contrast Media in Pediatric CT Using DNA Damage Biomarkers

This prospective single-center study investigated the impact of iodinated contrast agents (Ultravist/iopromide and Visipaque/iodixanol) on DNA double-strand breaks during pediatric chest computed tomography (CT). Twenty-six children underwent medically indicated chest CT between March 2022 and November 2024: unenhanced (n = 7), Ultravist-enhanced (n = 10), and Visipaque-enhanced (n = 9). Blood samples were collected before and 30 min post-CT. DNA damage was quantified by analyzing γ-H2AX and 53BP1 foci formation in peripheral lymphocytes using immunofluorescence microscopy. All groups showed significant increases in DNA damage following CT. The absolute increases were 0.915 ± 0.250 foci/cell (unenhanced), 0.972 ± 0.279 (Ultravist), and 1.261 ± 0.251 (Visipaque), representing 6.2% and 37.8% higher values in contrast groups. However, these differences between groups were not statistically significant (p = 0.579, Kruskal-Wallis test), with small effect sizes (Cohen's d < 0.5 for all comparisons). Contrast-enhanced protocols employed higher radiation doses than unenhanced scans (CTDIvol: 4.04-4.57 mGy vs. 2.66 mGy). When DNA damage was normalized for CTDIvol, no significant differences were observed between groups (p = 0.659). DNA damage showed no significant correlation with dosimetric parameters. When accounting for radiation dose differences, iodinated contrast agents do not enhance radiation-induced DNA double-strand breaks in pediatric chest CT, confirming the safety of contrast-enhanced CT.