Physicians regularly exposed to small doses of X-rays are experiencing changes that may be beneficial for them, says New Scientist.
The Italian team, led by Gian Luigi Russo, collected blood samples from 10 cardiologists exposed to a radiation dose of four millisieverts per year (they were involved in operations where the inside of the patient’s body was imaged using X-ray machines). This dose is slightly higher than the typical background radiation, but does not exceed the limit of 50 millisieverts allowed at this stand.
It turned out that in the blood of doctors there was three times more hydrogen peroxide (H2O2) than expected. High levels of this substance indicate cell damage. Moreover, white blood cells showed the presence of a marker typical of their death. On the other hand, blood contained twice as much of the cell-protective antioxidant glutathione.
According to Russo, this is the first evidence that safe levels of radiation can cause profound biochemical and cellular changes – although it is unclear whether these changes are ultimately beneficial or harmful.
The risks associated with low radiation doses are controversial. As Mark Hill of the University of Oxford comments, abnormal, less viable cells can die under the influence of ionizing radiation, which prevents them from becoming a problem like cancer. On the other hand, however, other cells can be stimulated to divide, which promotes cancer. Cardiologist Tommaso Gori of the University Medical Center in Mainz, Germany, points out that elevated levels of antioxidants may protect some people from heart attacks.