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Cell phone use and its effect on the brain has been a controversial issue over the past couple of years. Research has investigated the effects that radiofrequency energy, which cell phones emit, has on human's health, such as causing brain tumors. In the World Health Organization's May 2010 fact sheet on electromagnetic fields and health, the organization stated that “results of epidemiological studies provide no consistent evidence of a causal relationship between radiofrequency exposure and any adverse health effect.” But continuing studies are still needed, as widespread use of cell phones occurred only in the 1990s and it can take several years before cancers are detected. In a new study published in The Journal of the American Medical Association, researchers found that cell phone use does affect brain activity, but the health consequences are at this time unknown.
The study, which was conducted throughout all of 2009, was a randomized trial that included 47 participants. The “on” condition for the cell phone was being activated and muted for 50 minutes, and the “off” condition for the cell phone was being deactivated. Participants had cell phones placed next to their left and right ears: one measurement was taken with the right cell phone in the “on” condition and the second measurement was taken with both cell phones in the “off” condition. To measure the brain activity, the researchers use a positron emission tomography (PET) scan, a type of imaging that uses a radioactive substance. This study used (18F)fluorodeoxyglucose, which is injected in the veins and travels through the blood and measures brain glucose metabolism. MedlinePlus noted that the radiation used for a PET scan is low, but women who are either pregnant or breastfeeding should tell their doctors before undergoing a PET scan, as infants are more sensitive to the radiation's effects.