Hospital workers exposed regularly to 鈥渟afe鈥� levels of X-rays have experienced changes at the cellular level that might prove beneficial.
Gian Luigi Russo and colleagues at Italy鈥檚 National Research Council took blood samples from 10 cardiologists who are exposed to 4 millisieverts of radiation per year from X-ray-guided surgery. Those levels are slightly above average natural levels but well within the US Code of Federal Regulation鈥檚 safe limit of 50 millisieverts per year.
Russo鈥檚 team found that the blood contained levels of hydrogen peroxide 鈥� a marker of cell damage 鈥� three times higher than expected. White blood cells in the samples also showed a marker that suggested they were more susceptible to death. On the flip side, the blood also contained twice the normal level of glutathione, an antioxidant that protects cells.
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Friend or foe?
Russo says the results provide the first evidence that 鈥渟afe鈥� radiation levels can induce profound biochemical and cellular changes 鈥� but it is unclear whether those changes are damaging or beneficial.
鈥淭he risk associated with low doses of radiation is very controversial,鈥� says at the University of Oxford, who was not involved in the study. Cells that are more susceptible to death will be easier for the body to remove if they become dangerously damaged, which might lower the risk that they will trigger conditions such as cancer. 鈥淗owever, people have also argued that the removal of cells will stimulate other cells to divide, which may act to promote cancer.鈥�
Tommaso Gori, a cardiologist at the University Medical Center Mainz in Germany, points out that boosted antioxidant levels are known to offer a degree of protection against heart attack in some individuals. 鈥淲hat doesn鈥檛 kill you makes you stronger,鈥� he says. 鈥淭hat might be the case with low-dose radiation.鈥�
Journal reference: , DOI: 10.1093/eurheartj/ehr263
