CHARLOTTE, N.C. ( TheStreet) -- Pilots could be endangered by repeated radiation exposure from airport body imaging scanners, according to the president of the US Airways ( LCC) pilots union. Increasingly, the Transportation Security Administration is using the scanners, which employ "advanced imaging technology" and are now used at 65 U.S. airports. Some critics charge the scanners offer intrusive looks at the subject's bodies. But Mike Cleary, president of the U.S. Airline Pilots Association, objects because they emit radiation. "Based on currently available medical information, USAPA has determined that frequent exposure to TSA-operated scanner devices may subject pilots to significant health risks," Cleary wrote in a letter to members. "Pilots should not submit to AIT screening," Cleary noted. "As pilots, we are (already) exposed to more radiation as a function of our normal duties than nearly every other category of worker in the United States. Currently, the alternative to only a full-body scan is a pat down which, under guidelines implemented on Oct. 29, requires TSA officers to use open hands and fingers, rather than the backs of their hands, to search a passenger's body. Cleary said that too is unacceptable. In the short-term, he recommends that pilots seek out checkpoints where the new machines are not in use. Longer term, he said, the union will pursue remedies including potentially approaching Congress. Dave Bates, president of the Allied Pilots Association, which represents pilots at American ( AMR), has a similar view. In a message to union members last week, Bates objected to both the radiation associated with the body scanners and the humiliation associated with enhanced pat downs. "Airline pilots in the United States already receive higher doses of radiation in their on-the-job environment than nearly every other category of worker in the United States, including nuclear power plant employees," Bates said, because of exposure to the sun at high altitudes. At the same time, "there is absolutely no denying that the enhanced pat-down is a demeaning experience," he said. Pilots are "keenly aware that we may serve as the last line of defense against another terrorist attack on commercial aviation," Bates said. "Rather than being viewed as potential threats, we should be treated commensurate with the authority and responsibility that we are vested with as professional pilots."