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January 7th, 2010
12:19 PM ET

Could airport scanners give too much radiation?

As a feature of CNNhealth.com, our team of expert doctors will answer readers' questions. Here's a question for Dr. Gupta.

From Annette in Washington D.C.:

“I would like to know if the full body screening proposed for all our airports presents any health hazards – more specifically harmful radiation that could lead to long term problems, especially for frequent fliers.”

Answer:

Annette, you are not alone in your concern about these new scanners. We’ve received many e-mails like yours. So we talked with a radiologist and a physicist whose job it is to make sure people are safe when they’re getting treated with radiation. Those experts say these scans are completely safe.

I should point out that the TSA is using two types of screening machines. One, the millimeter wave imaging machine, uses radio frequency energy to image the body. According to the TSA these deliver 10,000 times less energy than your cell phone. The other type of machine, backscatter X-ray, is what has people talking because these units rely on X-ray technology.

These X-rays are very low level, they bounce radiation off the skin and back to the machine. This is how authorities can scan for dangerous items under someone’s clothes. But this also means the radiation is at very low levels. It's bouncing off the skin, not penetrating it or your organs. This is unlike a medical X-ray which is a higher level radiation penetrating the skin to see bones and other tissue.

Medical professionals working around these levels of radiation are required to wear a badge that measures radiation. Dr. Wayne Olan, director of neuroradiology and MRI at Suburban Hospital Johns Hopkins Medicine sent us a picture of such a badge explaining that he and his co-workers are required to submit their badges every month to ensure they have not been overexposed. He tells us the max whole-body dose of radiation is 5,000 millirem per year. To put these scans in perspective, it would take you 125 thousand trips through these scanners to max out.

In fact, passing through this backscatter X-ray scanner actually exposes you to a hundred times less radiation than a flight from say Boston to Los Angeles. When you fly you are exposed to cosmic rays so the backround radiation is higher at higher altitudes. This is is the same reason people in Denver are exposed to more radiation per year than, say, folks living in Miami, because Denver is at higher altitude.

The American Cancer Society told us that because the radiation levels being reported are low, its experts don’t see this being a serious issue for infrequent travelers.

The bottom line: Every expert we talked to said these were safe even if you're a frequent flier. The radiation just won't add up but the TSA says you do have the option of a pat-down if you're concerned.


soundoff (40 Responses)
  1. Brian

    When you fly, it's not being closer to the sun that increases radiation exposure, it's having less atmospheric shielding of cosmic radiation that is the culprit.

    January 7, 2010 at 14:28 | Report abuse | Reply
  2. L.A. CNN Viewer

    The proviso on these X-ray scanners is - *if properly calibrated*. As you no doubt know, there has been wide concern over the recent discover of miscalibrated CAT X-ray scanners in major L.A. hospitals and elsewhere, resulting in massive overdoses of radiation to affected patients - enough to cause skin burns and hair loss - and perhaps other more serious effects down the line.

    Conventional (baggage) X-ray scanners vary widely in calibration and upkeep - some delivering many times the X-ray dose of other units.

    How will passengers (and airport workers) know that the X-ray scanners being used for whole body scanning are properly calibrated at any given time and not exceeding official radiation standards?

    This is apart from the issues of such scanners being ineffective against materials placed in body cavities and the like - as was the case with the recent assassination attempt against a Saudi Prince.

    January 7, 2010 at 14:31 | Report abuse | Reply
  3. Doc

    The radiation just won't add up? All radiation exposure is cumulative. You should know that...

    January 7, 2010 at 15:04 | Report abuse | Reply
  4. Sheilah

    If the x-ray bounces radiation off the skin, what are the risks of skin cancer...and especially those who already have certain cancers of the skin?

    January 7, 2010 at 16:51 | Report abuse | Reply
  5. Peter Rez

    Dr Gupta's comments are incorrect. The X-ray scanning machines use the same 100kV X-ray generator as a CT machine or other hospital X-ray machines. To say that in one case the X-rays bounce off the clothing while in the other case they penetrate the body is physical nonsense. The dose is lower than a CT machine because the beam is tightly collimated. My calculations indicate that it is still much higher than the manufacturers claim, somewhere between 5 times greater to 50 times greater depending on image quality. Another issue is that these machines are not very useful for their intended purpose, they would have difficulty detecting even large amounts of some explosives such as TATP.

    Physics Professor

    January 7, 2010 at 17:10 | Report abuse | Reply
  6. Amina

    Hi Dr. Gubta,
    I want to know if it is safe for a pregnant woman to go through these scanners?

    January 7, 2010 at 17:12 | Report abuse | Reply
  7. Rob

    First it was cigarettes, then cellular phones and now it's X-Ray scanners. And we have idiots like Dr.Olan telling us that x-rays are low dose radiation, how much did they pay you to throw that ball of sh*% mr. olan? Wonder why cancer in the US is sky rocketing, oh I know, physics is no longer mandatory in high schools and lying has become the standard for all new products with health hazards. Believe half of what you read, and none of what you hear on tv !

    January 7, 2010 at 17:44 | Report abuse | Reply
  8. DFL

    I was wondering how long it would be before someone put two and two together and asked this very serious question...

    January 7, 2010 at 18:53 | Report abuse | Reply
  9. Mark Spears

    Very nicely done and accurate. As a proffesional in the nuclear industry with 35 years experience in radiation protection, it is gratifying to see the subject explained in a cogent, understandable manner.

    January 7, 2010 at 19:04 | Report abuse | Reply
  10. Michael Sherman

    If the TSA's X-ray machines are really so safe, will the TSA agree to give any passenger required to be X-rayed a badge that measures radiation which the passenger can keep? Then, the passenger can tell if the X-ray machine was really safe, or if it malfunctioned and gave the passenger a much larger dose of radiation than advertised. X-rays in CAT scans are already responsible for 40,000 cases of cancer in the US per year, resulting in 20,000 deaths per year. We should have a right to know the radiation levels we really get from the TSA's X-ray machines.

    January 7, 2010 at 21:08 | Report abuse | Reply
  11. Frank

    Hospitals used to say that cigarettes paused no threats... Dentists used to say that lead and mercury fillings were harmless... Health officials said that fluoride in water was not dangerous... and that asbestos was ok... Others say: "Oh, just a little dose of radiation" but, a little does with x-rays, scanners, irradiated food, the sun, TV, cell phones, the 1000+ world wide nuclear tests fall outs, etc., all adds up. Every 18 cigarettes mutates a gene: what if it and scanners mutates the wrong one? Cost / benefit they say. No thanks I say. The article would be more balanced if there was ANY mention of ill effects, as there sure are.

    January 7, 2010 at 22:27 | Report abuse | Reply
    • Darcy

      Thank you Frank for your comments about full body scans at airport. How quickly we forget We are willing to accept info with out the facts and the health risk we face.

      December 20, 2010 at 16:54 | Report abuse |
  12. Well

    In any event, I am guesing this backscatter machine doesn't use the same massive power requirements as a hospital x-ray machine. That would be extremely, extremely wasteful if it did. My main question remains" Is a primary beam of ionizing radiation being focused on the traveler or is it a secondary beam? If it is, indeed, a primary beam that is 1/1000th less powerful than a standard medical x-ray machine, perhaps this implies the power source is much less powerful, too. But, I just don't know.

    January 8, 2010 at 05:54 | Report abuse | Reply
  13. Well

    Also, by way of the "Compton effect", some of the radiation is "bouncing off the skin" as Dr. Gupta says. That is true. However, Dr. Gupta fails to qualify this with the fact that the majority of the x-ray waves are being absorbed at the skin's surface. Only a minority of the x-ray waves are "bouncing off the skin." Also, by looking at the pictures, it appears almost none of the radiation is passing though the patient, which happens in a typical medical x-ray. This would show up as dark or black areas, especially in the lung areas. This is a very good thing that it isn't, of course. Also, both Dr. Gupta and the TSA's own website both refer to the x-rays as low level. I assume by this, they mean low energy X-rays. If so, I wish they would just say low-energy x-rays. This woul help explain the machine better.

    January 8, 2010 at 06:55 | Report abuse | Reply
  14. A

    The fact that these scans are safe does not take away from the fact that these machines DO NOT DETECT EXPLOSIVES and that no government employee should get the right to look under my clothes so that I can go on an airplane.

    January 8, 2010 at 07:19 | Report abuse | Reply
  15. Steve851

    Scientifically informative, but irrelevant. The scanners are a total waste of time and money.

    January 8, 2010 at 08:30 | Report abuse | Reply
  16. GardenSERF

    A very clear article which I hope answers the question for most people. Now let's start using them for security.

    January 8, 2010 at 13:59 | Report abuse | Reply
  17. The Jetspert

    Annette and Amina essentially ask the same question ... and both get the wrong answer.

    You wouldn't go up to a lion you starved for 6 months and ask if it's hungry.

    With the best misplaced intention in the world Dr Gupta and others in the medical professions are mistaken. They have to support the position X-rays are safe, it's woven into the fabric of the medical industry.

    The late Dr John Gofman an expert on radiation (having worked on both sides of the fence) is on record as proving and saying that "there is no safe dose of radiation below which the risk of malignancy is nil". Gofman was excommunicated by the US govt and the nuclear industry because of his stance and went into academia.

    The sad answer to the question is that it does hold more risk to health especially in this climate where we are technology driven and ionizing radiation from technology continues to encroach on our health.

    The solution is to boost your immunity and eliminate deficiencies within your body which encourage radiation to be absorbed.

    January 8, 2010 at 16:16 | Report abuse | Reply
  18. Aafke

    The Millimeter wave immageing uses teraherz radiation. The evidence that terahertz radiation damages biological systems is mixed. “Some studies reported significant genetic damage while others, although similar, showed none,” say Boian Alexandrov at the Center for Nonlinear Studies at Los Alamos National Laboratory in New Mexico and a few buddies. Alexandrov and co have created a model to investigate how THz fields interact with double-stranded DNA and what they’ve found is remarkable. They say that although the forces generated are tiny, resonant effects allow THz waves to unzip double-stranded DNA, creating bubbles in the double strand that could significantly interfere with processes such as gene expression and DNA replication.
    As a fairly frequent flyer I am deeply concerned at these studies, Especially as I presume that the ones which show no damaging effects may be the ones sponsored by the industries who expect to make a profit by marketing these scanners.

    I do not only consider the use of these machines a breach of my privacy and bodily integrety, I also am very seriously worried about the longterm effects of frequent bombardment with teraherz radiation.
    I see no alternative but to stop flying.

    January 9, 2010 at 15:12 | Report abuse | Reply
  19. HalfGay

    This is just bad period. The worst part of this is that it would not have stopped the so called underwear bomber, so why are we being placed through this exercise of an invasion of privacy? I seriously hope this makes its way through the legal system.

    January 9, 2010 at 15:27 | Report abuse | Reply
  20. Cancer Survivor

    The opinions of truly independent experts have been overlooked about the risk. This is from an American Academy of Radiology article:

    http://preview.tinyurl.com/y9s8ybw
    "Mayo Clinic neuroradiologist Peter Kalina, M.D., FACR questions the use of even small doses of ionizing radiation in nonmedical applications. “The amount of radiation may be extremely small and safe, but parents have to grasp that their four-year-old child is being subjected to radiation. Some parents will be concerned,” he says.

    Columbia University professor of radiation oncology and public health David J. Brenner, Ph.D., is uncomfortable with the mandatory scanning of untold thousands of pregnant women and children at airports every year. Brenner, an expert in low-dose radiation risk, embraces the ALARA principle that advocates use of radiation “As Low as Realistically Achievable.” Brenner notes that about 5 percent of the general population is radiosensitive, among them women who carry the BRCA1 and BRCA2 breast cancer genes, and individuals prone to ataxia telangiectasia, an inherited neurodegenerative disease that causes severe disability.

    Kalina is concerned about a potential scenario in which a less-developed nation might adopt backscatter scanning technology, but fail to keep its scanners calibrated. “As a traveler,” he says, “I don’t know who’s checked that machine or equipment. Can I be sure there won’t be a larger dose of radiation coming from it?”"

    The risk of poor calibration Dr. Kalina brings up is very valid even in this country. We have had problems with medical imaging here so why will TSA equipment be any better calibrated?

    http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/ucm185898.htm

    I will avoid flying and if I must, then I will be stripped the old fashioned way.

    January 9, 2010 at 17:10 | Report abuse | Reply
  21. ssfb

    My question too is in regards to pregnant – or could be pregnant women.

    January 9, 2010 at 18:58 | Report abuse | Reply
  22. Mike Licht

    Body scanners have been around for a long time.

    See:

    http://notionscapital.wordpress.com/2010/01/05/full-body-scanners-old-technology/

    January 9, 2010 at 18:59 | Report abuse | Reply
  23. Markvid

    @Rob @DFL I am more concerned with the use of cell phones and what is radiating from computers!

    January 10, 2010 at 09:42 | Report abuse | Reply
  24. Eric

    The repeating themes in these comments is essentially: "These experts can't possibly understand or assess the risks as well as *I* do", "Low risk is not zero risk, so they must be understating it or outright lying" "Don't trust anyone... what if, what if, what if..."

    What if the rubber your car's brake lines degraded to the point of failure while you drove down the highway. That rubber is rated safe for many years of use, but the folks who certify that might be in cahoots with the auto industry. Those factory workers who made the brake lines could have ignored their quality controls for months without being caught. Did you check your brake lines personally today? It was a really hot dry summer this year and a well below normal cold morning... w

    Here's a tip: low risk is never no risk. Bad things can happen in all kinds of low-risk situations you do and rightly should take for granted. Getting scanned at the airport by these devices is yet another one.

    January 15, 2010 at 20:19 | Report abuse | Reply
  25. jenny

    thank you

    January 16, 2010 at 16:19 | Report abuse | Reply
  26. Pete

    The real issue here is not the safety of the scanners, but the fact that this is just "security theatre".

    These scanners may detect someone who forgot their pocket knife, of someone carrying drugs, but those are *not* safety threats to other passengers or the aircraft.

    The actual threat to passengers and aircraft is terrorists, and these terrorists have doctors in their ranks. A terrorist doctor could readily implant a substantial amount of explosives inside a would be bomber, along with a detonator mechanism containing a minimal amount of metal.

    They could readily fake x-rays and documentation for a hit replacement or similar to cover for the metal detector going off, and *none* of the current screening technology would detect this threat. The only possibly current technique to detect this threat would be profiling / behavioral analysis and those techniques are pretty weak.

    Ultimately we have to stop being "politically correct" and start focusing on the only techniques that may actually work, and stop wasting money and time on this "security theatre".

    January 28, 2010 at 10:39 | Report abuse | Reply
  27. Clare M.

    I think the suggestion that all flyers be given their own radiation card is an excellent one. Since none of the experts can agree on the safety of this new technology, I believe we should be equipped to make our own decisions on the matter. My significant other travels via airplane twice a week, and I could not fathom losing him to cancer.

    January 28, 2010 at 13:41 | Report abuse | Reply
  28. Laura

    I have a hard time believing these machines are safe. It just doesn't make sense. And I'm an engineer.

    As for the intended purpose, I also have a hard time believing these machines will prevent even a single terrorist attack. They are so widely advertised that any terrorist can simply work around.

    It would be more effective and cheaper if the agency would just follow the laws, policies, and regulations already on the books.

    January 28, 2010 at 17:13 | Report abuse | Reply
  29. john hutchison

    i have to agree to these comments a terrorist could have a doctor implant c4 in the body all the terrorist would have to do is pinch or hit his body where a detonator would be thanks

    January 29, 2010 at 04:06 | Report abuse | Reply
  30. Susan Bennett

    Upon return to the US from Mexico I was required to step into one of the new airport scanners. Immediately following I began to experience itching. I thought I was being bit by a bug but it spread out all over my body and was more like a hive or patchy. I now have red bruise like patches under my skin that do not itch as well as the itchy patches. I want to know the effects of radiation on the skin. How can I tell if the patches have been caused by the scanner and what can I do about it? Also what are the long term effects of this exposure?

    May 18, 2010 at 09:58 | Report abuse | Reply
  31. Kim

    I would like to know what kind of training the TSA agents are getting before they use the airport scanners on the passengers? As a Radiologic Technologist, I know the effects of too much radiation and want to make sure the person irradiating me knows what they are doing.

    June 15, 2010 at 16:34 | Report abuse | Reply
    • Jeff Buske

      Kim, Zero training. TSA years ago was issued dosimeter badges but, a few years back stopped. Part of Don't look don't tell. The poor people that work around this x-ray equip. day in and day out are a great risk as are crew and frequent fliers. That is perhaps why TSA personnel (as of 11sep10) are not scanned before entering secured areas, it would quickly put them over OSHA/FDA limits. We have sold our radiation absorbing garments to TSA personnel. Jeff

      November 20, 2010 at 22:32 | Report abuse |
  32. lugnut

    These devices does more then "bounce off the skin. They show internal organs. Now how much radiation does it take to do that and how many people have been tested? I want research. Not guesses. This wouldn't be the first time doctors have been wrong. How harmful are these devices to children or pregnant women? Where is the research? I remember doctors saying agent orange and anthrax vaccinations were harmless. Only if i could ask my friend.

    November 16, 2010 at 15:06 | Report abuse | Reply
    • Jeff Buske

      Lugnut, regarding x-ray's "bounce off" at the 80-120Kvp or 60,000V average energy only about 1.6% bounces off the other 98% passes through the body. About 50% of the 98% exits a 10" (25cm) thick person hardly bouncing off. We have designed garments to provide privacy (radio Opaque at x-ray energy used by backscatter ) but, more importantly protect sensitive tissues and organs under the shields. We recommend all avoid the backscatter particularly children and expecting mothers. Have a Great day.

      November 20, 2010 at 22:24 | Report abuse |
  33. omega5081

    If you work in a courthouse you are doomed. They walk through similar scanners daily.

    November 20, 2010 at 14:05 | Report abuse | Reply
  34. Angry

    This article is materially false and inaccurate. Most cosmic radiation is stopped by the hull of the plane OR goes right through you without any absorption.

    TSA irradiation specifically focuses on soft tissue frequencies that cause high collision rates with skin and tissue a bit below. This ionizes molecules and unzips DNA. Xrays that pass through you and only hit bone actually are safer than xrays that have high impact rates with soft tissue.

    Please find some new experts that aren't TSA stooges CNN.

    January 4, 2011 at 17:20 | Report abuse | Reply
    • Jeff Rockyflatsgear

      You are quite correct the comparisons of the focused collimated x-rays with random background, cell phones, banana and cosmic rays is misleading. The skin does is 15-50x greater (depending on resolution) than the "effective" dose. Expecting mothers, young children, fathers to be and people with the BRCA gene should avoid exposure. Learn More:
      http://www.rockyflatsgear.com/Airport-scanner-medical-experiment-without-consent.html
      http://www.rockyflatsgear.com/How-penetrating-are-airport-back-scatter-x-rays.html

      September 21, 2011 at 23:58 | Report abuse |
  35. Angry Citizen

    Someone mentioned asking questions as they do in Israel. This makes sense.

    For those that defend the scanners, here is an interesting tidbit.

    On February 9th, 2010, the Muslim Fiqh Council has issued a Fatwa, or religious ruling on the scanners, highly suggesting (forbidding) that Muslims do not enter the scanners. It is against the Qu'ran where it states that you should not let another person other than your spouse view you naked.

    So if the Muslims aren't using the scanners...and the War on Terror is highly focused on us being frightened of Muslims, then who is actually punished through the use of cancer promoting, full nude body scanners.

    May 22, 2011 at 20:27 | Report abuse | Reply
  36. KASALI DAVID

    kindly send to me your quotation for about 20pcs of safety radiation badges for the whole body and tag

    May 24, 2012 at 13:58 | Report abuse | Reply

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