What do brain surgeons know about cellphone safety that the rest of us don't? Last week, three prominent neurosurgeons told the CNN interviewer Larry King that they did not hold cellphones next to their ears. I think the safe practice," said Dr. Keith Black, a surgeon at Cedars-Sinai Medical Center in Los Angeles, "is to use an earpiece so you keep the microwave antenna away from your brain." Dr. Vini Khurana, an associate professor of neurosurgery at the Australian National University who is an outspoken critic of cellphones, said: "I use it on the speaker-phone mode. I do not hold it to my ear." And CNN's chief medical correspondent, Dr. Sanjay Gupta, a neurosurgeon at Emory University Hospital, said that like Dr. Black he used an earpiece. In recent studies that suggest a risk, ... tumors tend to occur on the same side of the head where the patient typically holds the phone. The most important of these studies is called Interphone, a vast research effort in 13 countries, including Canada, Israel and several in Europe. Some of the research suggests a link between cellphone use and three types of tumors: glioma; cancer of the parotid, a salivary gland near the ear; and acoustic neuroma, a tumor that essentially occurs where the ear meets the brain. Last year, The American Journal of Epidemiology published data from Israel finding a 58 percent higher risk of parotid gland tumors among heavy cellphone users. Also last year, a Swedish analysis of 16 studies in the journal Occupational and Environmental Medicine showed a doubling of risk for acoustic neuroma and glioma after 10 years of heavy cellphone use.