CELL PHONES MYTHS Since the massive increase of cell phone use in recent years, health concerns have been raised, in particular whether they cause brain tumors. This has resulted in extensive research on both animals and people. Cell phones use electromagnetic waves in the microwave range. Some of these waves can be absorbed into the human head. Microwaves are known to produce dielectric heating, in which living tissue is heated. With cell phone use, this results in the temperature of the head increasing slightly. Some experts suggest that cell phone use may lead to brain tumors, although others say that the brain easily disposes of excess heat by regulating its blood circulation. It is also thought that the levels of radiation emitted by cell phones damage the blood-brain barrier, which prevents harmful substances from entering the brain. Some studies have shown that the radiation causes the cells in blood vessels to shrink, allowing molecules to pass into the brain tiss
