With the help of FDG-PET, researchers at the U.S. National Institutes of Health (NIH) found that a 50-minute mobile phone call, which emits weaker radiofrequency (RF)-modulated electromagnetic fields than a constantly operating smart meter, was associated with increased brain glucose metabolism in the region closest to the phone antenna.
The study also emphasizes that the clinical relevance of the findings are unknown.
The randomized study of 47 subjects was conducted between January 1 and December 31, 2009, with mobile phones that were placed on the left and right ears. FDG-PET was performed on the subjects to measure brain glucose metabolism twice, once with the right cell phone activated for 50 minutes and once with both cell phones deactivated.
The researchers found that whole-brain metabolism did not differ between the on and off conditions. However, there were significant regional effects. Metabolism in the brain region closest to the antenna (orbitofrontal cortex and temporal pole) was 7% greater when the cell phone was on compared to when power was off.
"The increases were significantly correlated with the estimated electromagnetic field amplitudes both for absolute metabolism and normalized metabolism," the authors noted. "This indicates that the regions expected to have the greater absorption of radiofrequency-modulated electromagnetic fields (RF-EMFs) from the cell phone exposure were the ones that showed the larger increases in glucose metabolism."
The results provide evidence that the human brain is sensitive to the effects of RF-EMFs from acute cell phone exposures, according to the study. The authors added that additional studies are needed to determine if these effects could have potential long-term, harmful consequences.
