Do Body Scanners Pose Cancer Risk?


Using X-ray scanners for airport security is raising concerns about cancer risks. According to a recent New York Times report, some say the use of these scanners will result in additional cancer deaths.

The risk for an individual from these machines, known as backscatter scanners, is negligible, since they deliver an ionizing radiation dose equivalent to 1 percent or less of that in a dental X-ray. But according to The New York Times, some experts think the use of the machines will “incrementally increase the risk of fatal cancers among the thousands or millions of travelers who will be exposed.”

In a 2002 report on the safety of backscatter scanners, the National Council on Radiation Protection and Measurements said it “cannot exclude the possibility of a fatal cancer attributable to radiation in a very large population of people exposed to very low doses of radiation.” An author of the report, David J. Brenner, a professor of radiation biophysics at Columbia and director of the university’s Center for Radiological Research, told The New York Times that risks might increase as airports begin using backscatter scanners as a first-line screening system.

Nuclear physicist, Arjun Makhijani, told the Times that if a billion passengers were screened with the dose assumed by the radiation protection council, that would mean 10 more cancer deaths a year, a number that represents only a small increase in the cancer death rate.

However, others disagree that the cancer rate would increase. Robert Barish, a radiation consultant in New York and the author of a 1996 book, “The Invisible Passenger,” told the Times that the doses delivered by the scanners were tiny by any standard, and passengers would get the same dose in a few minutes in a high-altitude jet.

The Transportation Security Administration (TSA) says the radiation from the scanner is approximately the same as someone receives from natural background sources in four minutes on the ground. Kristin Lee, spokesperson for the agency, told the Times that even for pregnant women, children and people whose genetic makeup made them more susceptible to X-ray damage, each person would need 1,000 screenings per year to exceed radiation levels.

Other machines, called millimeter wave scanners, emit a lower dose of radiation.  The less powerful, non-ionizing radiation does not pose the same risk, but the scanner images are not as sharp as those produced by backscatter scanners, says the Times.

According to the Times, the TSA has already tried out a handful of the machines, and they could acquire another 450 by the end of September. The agency’s current contract would allow them to buy as many as 900 machines.