DENVER -- This holiday week millions of people will be flying across the country, and they will notice different kinds of machines at different security check points.
They are all considered safe by the TSA, but some doctors say one kind of machine may put you more at risk than the other.
Backscatter X- ray machines are used in dozens of airports to screen passengers for weapons or explosives hidden under their clothing.
Some people want to avoid them because of privacy concerns, others because of exposure to radiation, no matter how small.
The TSA says the technology is safe and many doctors agree.
But last year the European Union voted to prohibit the use of X-ray scans in order to protect the health and safety of residents.
Dr. David Brenner, the director of radiological research at Columbia University Medical Center in New York City, says he wishes the US would make the same decision.
“Homeland Security are making choices to use this type of machine, where in truth we don’t really know what the risks are,” Dr. Brenner said.
He says it’s all a numbers game. If the risk of getting cancer from the machines is one in 10,000,000, that seems pretty safe.
But what if hundreds of millions of people go through the machines each year? “Even though your risk is very, very small, somebody will end up potentially getting cancer from these X-rays and you'll never know who it is,” he said.
The TSA maintains the machines are safe.
In a statement the TSA said, “Each backscatter scan is equivalent to naturally occurring radiation a passenger receives during about 2 minutes of airplane flight at altitude. All independent scientific studies have concluded that backscatter is well within national safety standards set by the American National Standards Institute.”
TSA points out an Office of the Inspector General Report says to reach radiation limits a passenger would have to receive about 17,000 screenings in a year.
Anyone who is concerned can opt for a pat down instead.
Still, people like Dr. Brenner wish the US would use a different option.
At Denver International Airport passengers go through millimeter wave scanners. They are the ones that look like big glass phone booths, and they don’t use any ionizing radiation.
The machines use low energy radio waves. Right now the TSA uses both technologies. Thirty-three airports use backscatter X-ray scans including Phoenix, Washington Dulles, and San Diego. 167 airports use millimeter wave scanners, including Denver.
While some frequent fliers feel fine about the X-ray machines, other passengers believe there is a clear choice to be made. The TSA says they use a variety of machines hoping to encourage competition which would result in improved technology and lower prices.
In October the TSA announced it was pulling the large X-ray machines out of seven high traffic airports, and replacing them with the smaller millimeter wave scanners.
The decision had nothing to do with safety. It was based on speed. Since then those backscatter machines have been warehoused, because of software issues.