Iodine Dose of Administered Contrast Media Affects the Level of Radiation-Induced DNA Damage During Cardiac CT Scans.
AJR Am J Roentgenol. 2019 Aug;213(2):404-409. doi: 10.2214/AJR.18.20950. Epub 2019 Apr 23.
Van Cauteren T, Honoria Da Silva E, Van Gompel G, Kersemans V, Sermon K, de Mey J, Buls N.
OBJECTIVE. The purpose of this study is to investigate the contributing effect of contrast media (CM) iodine dose on radiation-induced DNA damage in blood lymphocytes during a cardiac CT scan.
MATERIALS AND METHODS. The minipigs were exposed 12 times in total to a fixed cardiac CT scan protocol. An unenhanced and two CM injection protocols were considered, the latter with 50% saline diluted (160 mg I/mL) and standard iodixanol. Blood samples were collected before and after CT, and radiation-induced DNA double-strand breaks were assessed using γ-H2AX (H2A histone family member X) immunofluorescent staining of the blood lymphocytes. Significant differences in foci numbers were investigated with an independent sample t test. In addition, a numeric dosimetry model was applied that simulates the cardiac CT scan, with the heart represented by a blood volume containing a mixture of six iodine concentrations (0, 10, 20, 30, 40, and 50 mg I/mL).
RESULTS. Compared with the unenhanced (0 mg I/mL) protocol, the number of γ-H2AX foci per cell increased significantly (p < 0.038), by 56.1% for the reduced iodine dose (160 mg I/mL) and by 141.1% for the standard iodine dose (320 mg I/mL) protocols. These in vivo results are confirmed by the dosimetry simulation model, in which 78.8% and 133.7% increases in locally absorbed blood dose in the left ventricle were observed for the reduced and standard iodine dose protocols, respectively.
CONCLUSION. Administration of CM during a cardiac CT examination significantly increases radiation-induced DNA damage in blood lymphocytes. Moreover, a lower CM iodine dose results in a reduced level of DNA damage, at constant radiation exposure.
Read Full Article Here: https://doi.org/10.2214/AJR.18.20950