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The Transportation Security Administration (TSA) is looking to monitor the levels of radiation that its employees are exposed to from X-ray technology, including airport body scanners, a document from the agency says.
In the document, the TSA said it plans to start performing radiation measurements using "personal dosimeters," which are devices worn on the body that measure a person's exposure to radiation, at certain airports. Such devices are used by people who work near sources of radiation such as hospital and nuclear power plant employees.
"The measurements will assist the TSA in determining if the Transportation Security Officers (TSO) at selected federalized airports are exposed to ionizing radiation above minimum detectable levels, and whether any measured radiation doses approach or exceed the threshold where personnel dosimetry monitoring is required by [Department of Homeland Security]/TSA policy," according to the document, which was posted on a government website.
The purpose of the document, called "request for information," is to identify and collect information on vendors that could supply personal dosimeters to the TSA.
Personal dosimeters measure exactly how much radiation a person receives, so the levels can be compared with the limits set by the government.
Experts today expressed surprise that such devices, which are required by law for anyone who works with radiation, were not already used by airport screeners.
"I wouldn’t dream of them not having that already," said Dr. Nagy Elsayyad, a radiation oncologist at the University of Miami Miller School of Medicine. "They really should have some form of monitoring device," Elsayyad said.
"By any possible definition, they are radiation workers," said David Brenner, director of the Center for Radiological Research at Columbia University Medical Center in New York.
Airport screening and radiation
Some of the airport body scanners, known as backscatter scanners, emit X-rays which bounce off the body to create an image. There are about 250 such scanners in use in the United States.
Michael McCarthy, a spokesman for TSA, said personal dosimeters are not currently used by TSA employees because the level of radiation they are exposed to "is well below the minimum threshold where personal dosimeters would be required."
McCarthy said all studies done to date on airport scanners suggest the amount of radiation they emit is well within national safety standards. The scanners are also tested at least once a year to check radiation emissions.
Even though the radiation doses are likely to be very low, Elsayyad said the doses should still be confirmed using dosimeters. Because dosimeters are fairly inexpensive (equating a few dollars per month per person), the TSA has nothing to lose, and a lot to gain, from providing its employees with dosimeters, Elsayyad said.
By not already measuring the radiation airport screeners receive, the TSA is indicating it considers its employees to have about the same exposure to radiation as the general public, "which I don’t think is true," Elsayyad said. While a passenger will likely go through the scanners just once in a day, "these guys are sitting there all the time," Elsayyad said.
The actual levels of radiation exposure to airport security workers should be investigated, he said. Elsayyad said the plan to start using personal dosimeters should be commended.
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6 Comments
Add CommentRe: Wikipedia
Reply | Report Abuse | Link to thisBackscatter x-ray imaging, similar to CT imaging, employs a pencil beam of x-rays to scan the subject. With CT imaging, the transmitted component of the x-ray beam is detected. With backscatter imaging the back scattered (Compton scattered) component of the x-rays are detected by a large detector. The radiation density levels within the pencil beam striking the subject can be very high but appear low when mathematically averaged over a large area. It is important to know the radiation flux density within the pencil beam to asses the safety issue.
TSA Officers are NOT radiation workers. Radiation workers are clearly defined by OSHA and NRC regulations, and the TSA Officers do not meet the criteria for radiation workers, or come anywhere close. As stated in the document the authors cite, the TSA has adopted a dose limit of 100 mrem per year, which is the PUBLIC dose limit. The dose threshold for declaring an employee to be a "radiation worker" is at least five times higher.
Reply | Report Abuse | Link to thisThese systems have been heavily scrutinized for radiation safety. The dose per scan is actually over 5 times lower than that cited in the article and is consistent with the UK measurements on these identical systems:
[Source: http://bit.ly/xPhmeF] "The effective dose from one scan from an x-ray backscatter unit (single or double scan) is 0.02 micro Sv or less (worst case scenario). Effective dose is a quantity that integrates radiation dose across the whole body. This dose is a small fraction of the annual background radiation. ... Natural radiation sources include cosmic rays, for which the radiation exposure increases with altitude; the typical dose rate during a commercial flight is approximately 5 micro Sv/h. In comparison, the dose rate from terrestrial and cosmic radiation sources at ground level is approximately 0.08 – 0.12 micro Sv/h." [Note the "per hour" rate.]
It would truly be nice if the authors would have stepped outside the medical profession and academia and interviewed persons actively engaged in occupational radiation safety (i.e., actual practicing health physicists: www.hps.org) who know what the governing regulations contain and WHY the TSA is undertaking this initiative.
This RFI merely outlines actions the TSA has taken and CONTINUES to take that demonstrates the exceedingly low dose any TSA Officer will receive in operating this equipment. Not only have the employee exposures been monitored, but the screening systems themselves have been and continued to be closely monitored at each airport where they have been deployed.
If the authors had thoroughly reviewed the document they are reporting on, they could inform their readers that this would be the THIRD study to be performed regarding radiation exposures to the TSA work force.
I think by all standards, the TSA is being extremely thorough in their efforts to assess the conditions of their work environments, and should be applauded for going above and beyond what any regulations might otherwise require.
See comment by @GilZw.
Reply | Report Abuse | Link to thisAlso, the TSA was supposed to go to the FDA to get those machines approved in the first place, instead they basically claimed that it would be putting national security at risk to wait the few months it would have taken for the FDA to perform an independent test to confirm the machine's safety for public use.
Those systems are not regulated by FDA. However, the FDA worked with other national organizations to produce the ANSI standard to which those systems are designed, and the FDA continues to work closely with TSA in the monitoring and use of these systems.
Reply | Report Abuse | Link to thisThese machines are completely safe. If you're concerned about the radiation you receive from these machines, I recommend that you not fly at all, or live in the mountains.
Mike,
Reply | Report Abuse | Link to thisExcellent posts. There is so much misinformation out there concerning these machines. It is especially unfortunate that the original report that contained so much misinformation written by folks who lacked a background in radiation safety, is still cited even after their colleagues from the schools department of radiology debunked it. From what I have seen the residual risk presented by whole body scanners to TSOs is about the same as the cabinet designated machines for scanning bags as long as appropriate mitigations are applied.
racer79 - don't eat any bananas. I would hate for you to be exposed to that hazards anti-matter.
Whoa whoa whoa, no where did I state that these machines are hazardous, or that I even have concerns about their safety, or even that the TSA isn't working with FDA to make sure these things are safe. All I said is that (according to an article I previously read on this site) the TSA totally pulled the national security card in order to avoid the same tests that every other radiation emitting machine that is intended for use on humans has to go through.
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