Figure 5: Graph shows similar mean values of loss of radiation-induced 
H2AX foci in PBMCs after chest-abdominal-pelvic CT (CAP-CT) and chest CT only (C-CT) and after in vitro exposure to 20, 100, and 500 mGy of x-ray radiation. For each treatment group, the mean numbers of foci per cell were normalized to the yield measured 5 minutes after exposure. Error bars represent standard errors of the mean at analysis of 40–360 cells in one patient who underwent chest CT only and in one patient whose blood sample was irradiated at 500 mGy and at analysis of the data for two to eight patients who underwent chest-abdominal-pelvic CT and whose blood samples were irradiated at 20 and 100 mGy.