Are Airport Scanners Safe?

The Transportation Security Administration (TSA) recently deployed new full body scanners in an effort to beef up airport security.  So far the scanners are in 70 out of 450 US airports.  There has been a lot of interest generated in the media lately about the impact of the radiation from these scanners on our bodies.  Many of my patients have expressed concern for their safety, and rightfully so.  

There are two different types of scanners used in airport security, one is a millimeter radiowave scannner (does not use x-rays), and the other is a backscatter x-ray scanner that uses low dose radiation. It is the latter of the two that has started all the buzz. Experts are lining up on both sides of this argument, some supporting the idea that the scanners do not deliver enough radiation to cause damage, while others believe that low dose radiation can in fact be harmful and that there is still not enough information about this technology to claim that it is absolutely safe.

We know that every one must go through a metal detector at an airport.  Now some may then be asked to go through the full-body x-ray scanner.  If that person decides to not go through the scanner they will be subjected to a full body search by a TSA agent of the same sex.

Experts from the Mayo clinic tell patients that the amount of radiation from one full-body airport scan is equivalent to two minutes of flying in an airplane, to sleeping next to another person for the night, and to 40 minutes of just living.  The US Dept. of Homeland Security claims that the radiation from one full-body scan is equivalent to the radiation a person is exposed to from two minutes of flying at cruising altitude. The American College of Radiology stated that a traveler would require at least 1000 full body scans a year to reach the dose of radiation equivalent to that from a standard chest X-ray.  Scientists from Johns Hopkins tested the Rapiscan brand of full-body backscatter scanner and found that if a person had 46 screenings a day, everyday for a year, the dosage will be one quarter the total amount of radiation commonly accepted as an unsafe level.  Scientists from Arizona State University disagreed with the Johns Hopkins calculations and claimed that the radiation emitted from the Rapiscan was much higher but still not enough to exceed acceptable limits. 

However a group of scientists from the University of California San Francisco wrote a letter to the White House expressing their concern about the “potential serious health risks” posed by the scanners.  The group took issue with the lack of testing of the machines, the impact they will have on the elderly, pregnant, HIV and cancer positive passengers.  They were also concerned with the impact of the scanners on breast, testicular, and other tissues directly beneath the surface of the skin.  Many scientists also do not believe that the effects of radiation are linearly related to dose and that low dose radiation may be relatively more harmful than an acute exposure at higher doses. 

There is also some concern in regards to the machines breaking down or getting stuck, and a person receiving a large dose in one area.  However opposing voices stated that someone would have to stand in the scanner for over an hour to have any injury. 

Once again, there is no definitive answer and no one really knows.  So, ask yourself are you willing to endure the potential risks the scanner poses vs. being subjected to a pat down search.  I for one, will be taking the pat down.

In any event all of this buzz has gotten me thinking about other sources of radiation we are regularly exposed to and how we can protect ourselves.  Below is a link to access dose information on different imaging studies done as medical procedures.  I have also included some studies on nutrients that could potentially give us some protection.  Any comments?

The Link:

http://www.doseinfo-radar.com/RADARDoseRiskCalc.html

Dietary antioxidants protect hematopoietic cells and improve animal survival after total-body irradiation.

Wambi C, Sanzari J, Wan XS, Nuth M, Davis J, Ko YH, Sayers CM, Baran M, Ware JH, Kennedy AR.

Department of Radiation Oncology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.

Abstract

The purpose of this study was to determine whether a dietary supplement consisting of L-selenomethionine, vitamin C, vitamin E succinate, alpha-lipoic acid and N-acetyl cysteine could improve the survival of mice after total-body irradiation. Antioxidants significantly increased the 30-day survival of mice after exposure to a potentially lethal dose of X rays when given prior to or after animal irradiation. Pretreatment of animals with antioxidants resulted in significantly higher total white blood cell and neutrophil counts in peripheral blood at 4 and 24 h after 1 Gy and 8 Gy. Antioxidants were effective in preventing peripheral lymphopenia only after low-dose irradiation. Antioxidant supplementation was also associated with increased bone marrow cell counts after irradiation. Supplementation with antioxidants was associated with increased Bcl2 and decreased Bax, caspase 9 and TGF-beta1 mRNA expression in the bone marrow after irradiation. Maintenance of the antioxidant diet was associated with improved recovery of the bone marrow after sublethal or potentially lethal irradiation. Taken together, oral supplementation with antioxidants appears to be an effective approach for radioprotection of hematopoietic cells and improvement of animal survival, and modulation of apoptosis is implicated as a mechanism for the radioprotection of the hematopoietic system by antioxidants.

Antioxidant diet supplementation starting 24 hours after exposure reduces radiation lethality.

Brown SL, Kolozsvary A, Liu J, Jenrow KA, Ryu S, Kim JH.

Henry Ford Hospital, Department of Radiation Oncology, Detroit, Michigan 48202, USA. sbrown1@hfhs.org

Abstract

Antioxidants mitigate radiation-induced lethality when started soon after radiation exposure, a delivery time that may not be practical due to difficulties in distribution and because the oral administration of such agents may require a delay beyond the prodromal stage of the radiation syndrome. We report the unexpected finding that antioxidant supplementation starting 24 h after total-body irradiation resulted in better survival than antioxidant supplementation started soon after the irradiation. The antioxidant dietary supplement was l-selenomethionine, sodium ascorbate, N-acetyl cysteine, alpha-lipoic acid, alpha-tocopherol succinate, and co-enzyme Q10. Total-body irradiation with 8 Gy in the absence of antioxidant supplementation was lethal by day 16. When antioxidant supplementation was started soon after irradiation, four of 14 mice survived. In contrast, 14 of 18 mice receiving antioxidant supplementation starting 24 h after irradiation were alive and well 30 days later. The numbers of spleen colonies and blood cells were higher in mice receiving antioxidant supplementation starting 24 h after irradiation than in mice receiving radiation alone. A diet supplemented with antioxidants administered starting 24 h after total-body irradiation improved bone marrow cell survival and mitigated lethality, with a radiation protection factor of approximately 1.18.

PMID: 20334518 [PubMed – indexed for MEDLINE]PMCID: PMC2874934 [Available on 2011/4/1]

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