The effect of abdominal contrast

As abdominal computed tomography (CT) radiation dose can be higher compared with other organ systems, monitoring the radiation exposure from this exam type is especially important. To evaluate the effect of abdominal contrast-enhanced CT (CE-CT) on levels of DNA double-strand breaks (DSBs) in peripheral blood lymphocytes. This study was performed in two parts: (i) an in vitro study: venous blood samples from 12 volunteers were divided into four groups. Samples in group A did not undergo radiation exposure, while groups B, C, and D received one CT scan with 1–3 times the radiation dose equivalent to abdominal CE-CT scan, respectively; and (ii) an in vivo study: blood was taken before CT and 5 min after CT in 30 patients. Lymphocytes were isolated and stained by immunofluorescence of γ-H2AX protein. DSB levels were compared by variance analysis or paired t-test. The relationship between radiation dose and γ-H2AX focus increase was analyzed using Pearson correlation analysis. In the in vitro study, DSBs levels in groups B, C, and D were 49.4%, 96.6%, and 149.4% higher than those in Group A, respectively (all P？<？0.001). Radiation dose in the four subgroups had a linear correlation to DSB levels (P？<？0.001). In the in vivo study, the DSB level was 43.5% higher after CT (P？<？0.001). Abdominal CE-CT significantly increased DSB levels in both in vitro and in vivo experiments. A positive linear correlation of CT radiation dose with intracellular DSBs levels was observed in the in vitro study