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- Millimeter Wave (MMW) Technology, which utilizes radio-frequency waves that penetrate clothing and reflect off the body to produce a 3-D image on a computer screen. A typical scan would expose a traveler to 10,000 times less radio-frequency than is emitted from a cell phone during a typical three minute conversation.
- Backscatter Technology utilizes X-rays which similarly travel through clothing and reflect off the body to produce a 3-D image on a computer screen. A typical scan of this type exposes the traveler to 10 microrems of radiation, which is 150 times less radiation than a traveler is exposed to on a typical flight between New York and Los Angeles at 35,000 feet.
TSA currently has 40 MMW scanners in use at 19 airports, and four backscatter units in use at two airports in the United States. TSA is expanding the use of total body scanners at airports and has 150 more units on order.
Both millimeter wave and backscatter scans produce a fairly detailed anatomic silhouette image of the body, including profiles of breasts, buttocks, genitalia and surgical implants. This of course generates concerns about privacy, which have to be balanced with the need for increased airport security. It is important to note that TSA has procedures in place to protect and maintain the privacy of traveler being screened. The TSA agent reading the scan is located in a remote location, removed from the scanner so that the reader can not correlate the image with the person being scanned. Further, the facial features of the person being scanned are selectively blurred on the image while it is generated so as to be indistinguishable and therefore eliminate the possibility of recognition by the agent reading the scan. Finally, the images generated are not stored on the computers and agents reading the scans are not allowed to have cell phones or cameras in the locations where scans are read, so presumably, no actual record of the scans is recorded Surveys conducted at airports employing total body scanners have shown that 90% of travelers that fail metal detector screening have chosen to have total body scans performed over a physical pat-down by a TSA agent. This particularly was the case with elderly passengers with metallic hip and knee replacements who considered physical pat-downs much more invasive. Regulations surrounding privacy are still being developed by TSA as the use of total body scanners for screening at US airports continues to expand. Most of the airport total body scanners currently in use by TSA in the US are the millimeter wave type which utilize radio-frequency waves and their radiation effects are considered negligible. Backscatter technology total body scanners in use emit non-penetrating, very low level X-rays which reflect off skin and do not penetrate as in the case of diagnostic medical X-rays. The radiation effects from these scanners is also considered negligible. According to the National Council on Radiation Protection (NCRP), a traveler would have to undergo 2,500 backscatter scans per year to to reach what they classify as a Negligible Individual Dose. It seems then that even the ultra-frequent flier would not have to be concerned with radiation exposure from the total body scan. Further, the American College of Radiology (ACR) concurs and states, "The ACR is not aware of any evidence that either of the scanning technologies that the TSA is considering would present significant biological effects for passengers screened.Privacy Concerns for Airport Total Body Scanners
Radiation Concerns for Airport Total Body Scanners
Ever since the underwear bomber on a Northwest Airlines flight failed to ignite a powdery substance Christmas Eve, airport security regulations have been put into question.
When airport authorities claimed high-tech security scanners could have prevented this from ever happening, the scanning devices that used terahertz (THz) technology attracted some eyeballs.
A number of the new body scanning machines have been deployed in major airports in the United States. However, privacy advocates worry the see-through-your-clothes scanning machines reveal way too much.
Besides exposing the outline of a person’s nude body, THz waves can penetrate and see almost any material that isn’t liquid or metal.
THz waves essentially pick up where metal detectors fail and detect images that x-rays and microwaves can’t.
Currently, people must go through specialized machines, so the THz waves can be measured.
Rensselaer Polytechnic Institute researchers may have a way around that. The scientists discovered how to use THz technology to detect explosives, drugs, and chemical spills 20 meters away.
“It will be very competitive technology. Terahertz can immediately tell you the fingerprint of the chemical compounds,” the Center for THz Research’s Jingle Liu says. “We can extend the sensing range of current machines.”
While the device has only been tested in the lab, the researchers want their device to be portable in the future. For instance, the device could be used to search luggage for illegal drugs.
“With our new technique, you don’t have to stand close to the machine because our method remotely detects terahertz,” Liu says. “Before this method was invented, there was no single method that could do that.”
Two years ago, Liu and his adviser, kept trying different methods. “We failed first several times until we thought of using fluorescence,” he admits.
Fluorescence has high atmospheric transparency and emits in every direction. Liu found THz waves could emit waves in a plasma. This made it easy to read the waves indirectly. The plasma emitted a fluorescent spectrum that could be read using a spectrometer to identify the questionable substance.
Liu says he wants to make the mission impossible, possible. “Right now we can offer a solution for the problem with our broadband THz sensing method. This was considered pretty challenging before.”
The problem with measuring THz directing is a humidity problem — THz waves can not propagate in the air and moisture absorbs them.
“This new method can circumvent this limitation,” Liu says. Instead of sending the THz from the operator to the object, the researchers test it indirectly.
When the researchers send laser beams in the air, they create a plasma which then emits florescence. The signal is read from a computer monitor and identifies the chemical’s unique fingerprint.
The research group has been heavily funded by The U.S. Army, The Department of Homeland Security, The Defense Threat Reduction Agency, and the U.S. Air Force as well as a number of commercial entities.
“It’s very useful because it can penetrate clothes and suitcases. It’s used in a noninvasive security screening. It works because there are a lot of chemical compounds and drugs that have a clear signature,” Liu says.
But it’s by no means perfect. The water content in the human body absorbs THz waves, so it’s hard to detect if illegal drugs are indeed stuffed up someone’s cavities.
THz waves may have applications beyond security devices. Research has been done to determine the feasibility of using the radiation to detect tumors underneath the skin and for analyzing the chemical properties of various materials and compounds. The potential marketplace for THz driven technological applications may generate many billions of dollars in revenue.
| Title: | DNA breathing dynamics in the presence of a terahertz field | |
| Authors: | Alexandrov, B. S.; Gelev, V.; Bishop, A. R.; Usheva, A.; Rasmussen, K. Ø. | |
| Affiliation: | AA(Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States), AB(Harvard Medical School, Boston, MA 02215, United States), AC(Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States), AD(Harvard Medical School, Boston, MA 02215, United States), AE(Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, United States) | |
| Publication: | Physics Letters A, Volume 374, Issue 10, p. 1214-1217. | |
| Publication Date: | 02/2010 | |
| Origin: | ELSEVIER | |
| DOI: | 10.1016/j.physleta.2009.12.077 | |
| Bibliographic Code: | 2010PhLA..374.1214AAbstractWe consider the influence of a terahertz field on the breathing dynamics of double-stranded DNA. We model the spontaneous formation of spatially localized openings of a damped and driven DNA chain, and find that linear instabilities lead to dynamic dimerization, while true local strand separations require a threshold amplitude mechanism. Based on our results we argue that a specific terahertz radiation exposure may significantly affect the natural dynamics of DNA, and thereby influence intricate molecular processes involved in gene expression and DNA replication. |
While the application of scientific knowledge creates technology, sometimes the technology is later redefined by science. Such is the case with terahertz (THz) radiation, the energy waves that drive the technology of the TSA: back scatter airport scanners. Emerging THz technological applications THz waves are found between microwaves and infrared on the electromagnetic spectrum. This type of radiation was chosen for security devices because it can penetrate matter such as clothing, wood, paper and other porous material that’s non-conducting. THz waves may have applications beyond security devices. Research has been done to determine the feasibility of using the radiation to detect tumors underneath the skin and for analyzing the chemical properties of various materials and compounds. The potential marketplace for THz driven technological applications may generate many billions of dollars in revenue. Because of the potential profits, intense research on THz waves and applications has mushroomed over the last decade.This is Insane. Don’t ever get scanned by TSA.
This type of radiation seems less threatening because it doesn’t penetrate deeply into the body and is believed to be harmless to both people and animals.
Health risks
The past several years the possible health risks from cumulative exposure to THz waves was mostly dismissed. Experts pointed to THz photons and explained that they are not strong enough to ionize atoms or molecules; nor are they able to break the chains of chemical bonds. They assert—and it is true—that while higher energy photons like ultraviolet rays and X-rays are harmful, the lower energy ones like terahertz waves are basically harmless. [Softpedia.com]
While that is true, there are other biophysics at work. Some studies have shown that THZ can cause great genetic harm, while other similar studies have shown no such evidence of deleterious affects.
Boian Alexandrov at the Center for Nonlinear Studies at Los Alamos National Laboratory in New Mexico recently published an abstract with colleagues, “DNA Breathing Dynamics in the Presence of a Terahertz Field ” that reveals very disturbing—even shocking—evidence that the THz waves generated by TSA scanners is significantly damaging the DNA of the people being directed through the machines, and the TSA workers that are in close proximity to the scanners throughout their workday.
From the abstracts own synopsis:
“We consider the influence of a terahertz field on the breathing dynamics of double-stranded DNA. We model the spontaneous formation of spatially localized openings of a damped and driven DNA chain, and find that linear instabilities lead to dynamic dimerization, while true local strand separations require a threshold amplitude mechanism. Based on our results we argue that a specific terahertz radiation exposure may significantly affect the natural dynamics of DNA, and thereby influence intricate molecular processes involved in gene expression and DNA replication.”
In layman’s terms what Alexandrov and his team discovered is that the resonant effects of the THz waves bombarding humans unzips the double-stranded DNA molecule. This ripping apart of the twisted chain of DNA creates bubbles between the genes that can interfere with the processes of life itself: normal DNA replication and critical gene expression.
Other studies have not discovered this deadly effect on the DNA because the research only investigated ordinary resonant effects.
Nonlinear resonance, however, is capable of such damage and this sheds light on the genotoxic effects inherent in the utilization of THz waves upon living tissue. The team emphasizes in their abstract that the effects are probabilistic rather than deterministic.
Unfortunately, DNA damage is not limited only to THz wave exposure. Other research has been done that reveals lower frequency microwaves used by cell phones and Wi-Fi cause some harm to DNA over time as well. ["Single- and double-strand DNA breaks in rat brain cells after acute exposure to radiofrequency electromagnetic radiation."] //Terrance Aym