Background: Despite major diagnostic and industrial progresses in the technology and use of Ionizing radiations, they have been found to be harmful to the health of the radiology and nuclear medicine staffs. Since Ionizing radiations have the potential to produce free radicals, therefore, it is likely that the total plasma level of anti-oxidant in medical and nuclear medicine staffs could be reduced.

Methods: In this case-control study the relationship of total anti oxidant level of plasma and the function of immune cells such as lymphocyte proliferating response using MTT method, Neutrophil chemotaxi, Intensity of respiratory burst (NBT) and evaluation of IL-2 and IL-4 (ELISA) were investigated. 101 samples were collected for this study and they were assigned as two groups: 61 samples cases from radiology and nuclear medicine staffs of Tehran University Of Medical Science hospitals (Shariaty, Imam Khomeyni, Ghalb-e-Tehran) were assigned as the exposed group, whereas, 40 samples from Pediatric, Orthopedic, Infirmary and Emergencies wards were assigned as control group. Using heparinized syringes, 8 to 10 ml of blood samples were collected from each person with age between 25 to 50, averaging 36.4±7.2, and several assays including Anii Oxidant Capacity of Total Plasma (FRAP Method), T cell proliferative response to PHA mitogen (MTT Method), Chemotaxi of neutrophils and Magnitude of respiratory burst were carried out on these samples. The results were analyzed using spirman correlation analysis.

Results: The results showed that exposure to ionizing radiation chronically with low dosed had no effect on chemotaxis of neutorophils and intensity of respiratory burst, but could have effect on lymphocyte function specially in cytokines secretion like IL-2 which are essential in the immune responses.

Conclusion: This study indicates that long term low dose ionizing radiation may have effect in some parts of the immune function.