Abstract
Computed tomography (CT) is fundamental to modern medicine, yet ionizing radiation (IR) exposure causes DNA damage. Although often underestimated, at current doses, CT may account for ~5% of new cancer diagnoses. Complementary radioprotective approaches beyond dose reduction are needed. We conducted a prospective observational study to characterize IR-induced oxidative stress (OS)-mediated DNA damage in modern CT to explore potential antioxidant-based radioprotective strategies. In volunteers not exposed to IR (A(NONE)) and in patients with two-phase abdominal-pelvis CT (B(EXPOSURE)), blood samples were collected at T(BASE)-min 0 and T(POST)-min 60 to measure biomarkers of OS (oxidative damage and antioxidant capacity) and DNA damage. Thirty-five subjects (n = 17 A(NONE)/18 B(EXPOSURE)) were studied. Body mass index and DNA damage in T(BASE) were comparable between groups. In A(NONE), biomarkers of OS and DNA damage did not change between T(BASE) and T(POST) (p > 0.05 for all). In B(EXPOSURE), DNA damage was significantly increased [15% (-15-60); p < 0.001], which was associated with consistent increased antioxidant enzyme activity [p < 0.05 for all antioxidant enzymes]. In modern CT with relatively low effective dose (ED) levels, a significant increase in DNA damage was observed along with increased antioxidant enzyme activity as defensive response and marker of OS-mediated damage-mediating mechanisms. These findings warrant interventional studies to evaluate antioxidant-based radioprotective strategies.