Talk:Backscatter X-ray

Question
Alternate references? Reference 1 and 2 are not available. Page showing [404] error. — Preceding unsigned comment added by Mahatasin (talk • contribs) 21:00, 15 February 2013 (UTC)

Discussions are missing the point. The article completely fails to explain how the thing works. No diagrams, no technical explanation. —Preceding unsigned comment added by 80.156.47.38 (talk) 14:35, 24 November 2010 (UTC)

What are the health implications of Backscatter X-Ray Machines? Thadk 17:30, 6 December 2006 (UTC)
 * Like most aspects of this technology there has been little if any discussion of the issue. There may be peer-reviewed studies on the subject and an article I read about the use of this technology in New Jersey's PATH system which seemed typical said something like "there are no health or privacy concerns". The legal ramifications of this technology is potentially enormous as well since the 'plain view' clause of US's search and seizure laws would extend through walls, cars, clothing, etc. if these devices ever became widespread. The US and UK governments have been remarkably successful in keeping this technology under wraps and out of the press, deploying it in airports (most recently a Phoenix AZ airport) with little public notice. And apparently there has been a recent wave of scary Orwellian technologies  Antonrojo 04:06, 7 December 2006 (UTC)

As of March 2007, the short answer is that there are no health implications. This item from the external links give a general idea. I undid this highly irresponsible edit to the contrary. Melchoir 23:42, 3 March 2007 (UTC)


 * I agree that was an irresponsible edit. I think that, equally, it is important to mention when there is little science backing TSA claims about things like 'privacy algorithms', though these are reported as fact by some major news outlets that should know better. Antonrojo 03:27, 22 April 2007 (UTC)


 * No it was not an irresponsible edit. I am very concerned with radiation, and there is obviously a risk here. It is important to restate that there are no safe levels of radiation. BreakthruMarco (talk) 00:12, 3 February 2010 (UTC)

"Health effect" section needs rewriting

"Some people" - who?

"Regulations MAY indicate " - Its absolutely the opposite. It is necessary to limit because it is dangerous. So the concerns are warranted.

the subsection writes: "N43.17 states" ... "per examination"... "0.25 micro Sievert" This is just wrong! I read in the following link that it states clearly 0.25mSv *annually* : http://hpschapters.org/2009AM/program/singlesession.php3?sessid=WPM-D update:Just corrected this mistake BreakthruMarco (talk) 00:42, 3 February 2010 (UTC) Anyone with access to HPS article can contribute?

BreakthruMarco (talk) 00:36, 3 February 2010 (UTC)

units
the units of dose should be changed to Sievert Drickey (talk) 17:44, 3 January 2010 (UTC)

I'm deleting this
An important factor in people's perception of whether a risk is acceptable may be whether it is a risk that they choose and which brings them a personal benefit, or whether it is a risk imposed by someone else and which brings benefit only to other people as in the case of an x-ray airport scan, which might be alleged to benefit other passengers but which clearly doesn't benefit a passenger who knows that they themselves are not carrying any weapon. Wait, airport security now benefits terrorists? That bit makes no sense. An x-ray scan doesn't benefit a person who's carrying a knife; on the other hand, it benefits passengers who do not so they can be sure others are not carrying knives (or shotguns, or drugs, or explosives) either. —Preceding unsigned comment added by 89.175.18.90 (talk) 10:26, 12 March 2010 (UTC)

safe levels of radiation
I'm questioning the following section: 1 mrem per year is a negligible dose of radiation, and 25 mrem per year from a single source is the upper limit of safe radiation exposure

According to : The annual limit on public exposure from a single source of ionizing radiation is 100 milli-rem (1mSv). Medical sources are exempt from this limit. The only medical procedure currently subject to a radiation exposure limit is mammography with a limit of 300 milli-rem per procedure.

According to MIT News : The US Food and Drug Administration's current regulations state, "The amount of radioactive material to be administered shall be such that the subject receives the smallest radiation dose with which it is practical to perform the study without jeopardizing the benefits to be obtained by the study. Under no circumstances may the radiation dose to any adult research subject from a single study, or cumulatively from a number of studies conducted within one year, be generally recognized as safe if such doses exceed the following:

Single dose for an adult-3,000 millirems;

Annual total dose-5,000 millirems.

For a research subject under 18 years of age at the last birthday, the radiation dose shall not exceed 10 percent of that set forth above."

Therefore, the single exposure limit for a child is 300 millirems (whole body equivalent) and the annual total exposure cannot exceed 500 millirems.

I believe it is supposed to be a dose of "1mSv" (Milli Sieverts as questioned by Drickey), not "1 mrem". Are there any radiation experts that can confirm?
 * The statement in question is referenced in the Wikipedia article (also here), and is nearly a direct quote from that reference. nakomaru (talk) 19:41, 16 November 2010 (UTC)

--DACorder (talk) 10:39, 8 January 2010 (UTC) -- 100 mrem = 1 mSv. In canada I can confirm(as a "radiation expert", or in my case a nuclear energy worker) that the allowed dose for the public is 1 mSv per year from non-natural sources(excluding medical ones), and that your background is typically 1 mSv or greater depending on the ground make up in your town. The doses in this case, if they really are as small as they claim, are entirely inconsequential to travelers. For operators this may be another story, but joe public is safe. Your risk of dieing on the way to the airport is substantially larger then your risk of getting cancer from the scanner. Someone else can do the cost-benifit analysis, but once the economic data is taken into account I'm reasonably sure that using these might be reasonable. People hear "radiation" and they freak out. It's embarrassing. For reference, an okay but conservative(as in, an over estimate) estimate of cancer risk per Sv(note that we've been talking msv) is 4%. So 4 / 100 000 for each msv, or 4 / 10^10 per 0.01 microsv dose. I'm not worried. —Preceding unsigned comment added by 24.84.49.182 (talk) 07:06, 20 March 2010 (UTC)

-- The negligible individual dose (NID) from a single source or practice is 0.01mSV or 10microSV. Hence you can have multiple NIDs from multiple sources. A single source is generally considered a single airport. A different airport would be a different source. Note that 100Rem=1Sv. The backscatter units used at the airport have a typical dose of less than 10microRem for the full examination (front and back together). 10microRem=0.1microSV. Hence you could travel through a single airport and be examined 100 times before you reach the NID. All of this is based on the NCRP (National Council on Radiation Protection). —Preceding unsigned comment added by Wiki907 (talk • contribs) 21:36, 8 January 2010 (UTC)

Overall, this article does not seem balanced on the issue of radiation risk. It seems to suggest that some levels of radiation are safe with no scientific basis to justify that position. For example, it advances an original research tautology that, because radiation from flight is greater, and passengers fly, passengers concern for the additional risk of cancer from backscatter X-rays is misplaced. Without additional facts, for instance, concerning the risk of flight exposure itself, or whether risk is scalar at the levels compared, the comparison is meaningless.


 * The worst case assumption is that all exposures add up linearly (see LNT model). It may be that at such small levels as in backscatter scanning, they may be completely ignored. In otherwords, it may over-estimate risk, and the comparison is meaningful. Perhaps a references to the LNT model should be added. nakomaru (talk) 20:05, 16 November 2010 (UTC)

I also note that there is no discussion of risk disclosure and informed consent. Medical X-Rays are now far below cosmic radiation flight exposure as well, but physicians warn patients, obtain consent for their use from patients, and issue lead blankets to protect the gonads, etc. My understanding is that these backscatter machines have been implemented surreptitiously, with no advanced warning to passengers, no opportunity for informed consent and no precautionary measures to protect reproductive tissue from the ionizing radiation. And, while one may sue a doctor for increased cancer risk, governments have sovereign immunity, translating to an unrecoverable, catastrophic loss in the event of cancer or genetic disease in offspring. —Preceding unsigned comment added by 216.91.12.76 (talk) 13:35, 5 August 2010 (UTC)


 * Exactly. If my risk of cancer from the flight is 1 in 1 million, and my risk of dying from the X-ray is 1 in 1 billion, my total risk becomes 1001 in 1 billion (assuming they are independent). OK, so nobody will ever attribute a cancer death to this machine, but I wonder whether the prevention of a terrorist incident will ever be attributed to this machine either. —Preceding unsigned comment added by 219.78.221.233 (talk) 12:08, 13 August 2010 (UTC)


 * The fact is there is no safe dosage of ionizing radiation. Hanxu9 (talk) 18:38, 10 November 2010 (UTC)
 * I am concerned that in these discussions comparing the dose in terms of some other condition for X time, the effect of intensity on cancer risk is ignored. Single dose limits are much lower that year long limits for people who work with radiation.  Deliver 5 minutues of excess upper atmosphere flight time radiation in 5 seconds, and you have a much higher quantity of radiation striking tissues per unit time.66.155.211.158 (talk) 15:11, 16 November 2010 (UTC)
 * Hanxu9: If you really believed that there is no safe dosage of ionizing radiation, you would live underground. 66.155.211.158: the temporal aspect of radiation dosage is important for exposures to the extent of radiation burns, but we are talking about exposures much below this level. For these exposures, the current standard for risk does not care about the rate of exposure, only the quantity of exposure. This portion of the article could perhaps better explain this, but it is not disingenuous as it is. Lectures 5-7 of Physics for Future Presidents (available online for free) talks about the health effects of radiation and how dosages add up together. nakomaru (talk) 22:27, 16 November 2010 (UTC)

terminology
This is supposed to be an encyclopedia. Do we really have to use such immature euphamisms as "private parts"? Are crotch, groin, genitals, breasts, etc really inappropriate terms for a site like this? MrItty (talk) 17:33, 5 January 2010 (UTC)

Incomplete, and an inaccuracy
I have a couple of problems with this article.

Incomplete: the article implies that backscatter x-ray technology only applies to full-body imaging. This is not true; its first (and currently largest) application was to luggage/cargo scanners, to identify plastics and liquids that did not show up well on regular transmitted x-ray images.


 * In addition, there are uses for this technology which do not involve the knowledge or consent of the target, as per http://www.networkworld.com/community/node/65497, so framing the health and safety issues entirely within the context of air travel needs to stop. (140.232.0.70 (talk) 15:21, 27 August 2010 (UTC))

Inaccurate: regarding the statement "Backscatter X-ray was first applied in a commercial security scanning device by Dr. Steven W Smith. Dr. Smith developed the Secure 1000 whole body scanner in 1992...", this is not the first commercial security scanning device (although it may be the first commercial full-body scanner). AS&E developed backscatter X-ray imaging in 1985-1986. As far as I know they were the first to implement this technology commercially, for baggage/cargo inspection, in 1986.

see: http://www.as-e.com/american_science_and_engineering/timeline.asp

98.207.61.5 (talk) 18:25, 14 August 2010 (UTC)

Replace picture?
The picture in the top-right hand corner of the article is of a woman's front. I'm not trying to be sexist or anything, but in almost every secondary-level anatomy textbook I've seen, when the authors want to show a diagram of something non-gender specific in the torso, they use a man instead of a woman. Given that Backscatter X-ray technology allows one to effectively see through one's clothing, I feel as that the same rules of censoring indecency should probably apply here as well. I propose that, if possible, this image should be replaced by a similar one of a man. Pottersson (talk) 05:24, 15 August 2010 (UTC)
 * Encyclopedias show anatomic detail. If the image is of a man it's also going to show full frontal nudity. What's the difference in terms of decency? Let99 (talk) 15:29, 15 August 2010 (UTC)
 * Wikipedia is not censored. nakomaru (talk) 20:08, 16 November 2010 (UTC)

Debate wording
Absolute wording like "in fact" and "it is clear" are personal opinion. Facts only please. Let99 (talk) 10:51, 19 August 2010 (UTC)

The concerns of the UCSF researches have not been refuted
Here is what the current article says:

"In October 2010, The TSA responded to the concerns of UCSF researchers via the white house science advisor. A copy of the response refuting the claims of these researchers can be found at this link:"

However, the TSA has NOT given a figure for the amount of photons per unit area and time that the surface of the human body is exposed to in the backscatter machine. This was the main basis of the researchers' concern. I therefore find the claim that the concerns have been "refuted" to be highly problematic. Hanxu9 (talk) 18:44, 10 November 2010 (UTC)

Hannux9: Your statement is not correct. FDA has provided an explanation. See below...this is from the FDA letter: Fifth is the assertion that “if the key data (flux-integrated photons per unit values) were available, it would be straightforward to accurately model the dose being deposited in the skin and adjacent tissues using available computer codes [. . .]” In fact, we have done better. FDA and NIST used software called PCXMC18 to estimate the individual organ doses and to calculate effective dose. This analysis was part of an evaluation performed under contract for TSA. The input information required by the PCXMC program required considerably more information than simply the x-ray flux. Its parameters include 1) the x-ray tube anode angle, 2) anode voltage, 3) total filtration, 4) x-ray field size, 5) location of the field on the body, 6) focus-to-skin distance (FSD), and 7) entrance skin exposure. Every parameter was measured, calculated, or verified by indirect measurement. The modeling results revealed that the dose to the skin is approximately twice the effective dose19. —Preceding unsigned comment added by 38.96.8.42 (talk) 23:16, 10 November 2010 (UTC)


 * Again, what is the amount of photons per unit area and time that the surface of the human body is exposed to in the backscatter machine? If your employer will not tell you the number, you have no way of knowing whether the machines are safe. You should bring it up with the TSA union. Hanxu9 (talk) 03:18, 11 November 2010 (UTC)

Hannux9: you keep inserting the sentences saying there is no safe level....please use a blockquote from the reference...I see no statements in your reference to support your stated conclusions. —Preceding unsigned comment added by 38.96.8.42 (talk) 23:01, 10 November 2010 (UTC)


 * Here's one recent quote: "No exposure to X-ray is considered beneficial." This is what Dr Michael Love, who runs an X-ray lab at the department of biophysics and biophysical chemistry at Johns Hopkins University school of medicine, told AFP. Source: http://news.yahoo.com/s/afp/20101113/hl_afp/usairportsecurityhealth_20101113020345 Title of article:

"'Naked' airport scanners may be 'dangerous'" —Preceding unsigned comment added by Hanxu9 (talk • contribs) 13:43, 14 November 2010 (UTC)

Sedat, the principal author of the UCSF letter, is also not satisfied. They are preparing a rebuttal. We will have to wait and see what it says. In the meantime, check out the reference I added to Peter Rez's refereed paper, which has been accepted for publication. A draft is online, google the paper's title.Kbk (talk) 04:14, 27 November 2010 (UTC)

Health implications, science vs. justifications for use
I have spent the better part of an hour trying to reword a section of the health implications. After all of this I left with the impression that the health implications section reads less like a description of the actual medical science of the technology and more of a justification for its use in daily society. Justifications for backscatter x-rays use are important in this topic but perhaps they should be a separate section and not a part of a section that should be directly addressing the current medical science of the backscatter x-ray radiation. TheIguana (talk) 18:50, 13 November 2010 (UTC)

incorrect placement
The following section is clearly a justification of use, not an explanation or discussion of the health effects. I've removed it from the Health Effects section. If you insist on adding it back to the article, please add it to the appropriate section. It appears to have been removed several times already.

The additional risk from exposure to backscatter radiation may be more acceptable to the person undergoing the scan if this is an unavoidable activity that is useful to the individual or the community as a whole. For instance, if scans are carried out in the interest of public safety then the potential benefit of discovering a weapon on a person could be to the benefit of the community but not to the person being scanned. In other words, a person may be certain they are not carrying a weapon and may gain little by being scanned but the act of undergoing a scan may benefit other passengers. Quoting from ANSI N43-17: "To put this in perspective, this same risk of death results from about one minute of riding in an automobile. Likewise, this same risk of death is experienced about each ten minutes of working in a “safe” field such as a secretary or office administrator, due to occupational deaths from accidents, homicides, and other causes. (The automobile death rate is calculated from: 250 million people in the U.S, each driving an average of 10,000 miles per year, at an average speed of 30 mph, resulting in 25,000 traffic deaths per year. The occupational death rate is based on 5 deaths per 100,000 employees per year, a typical value for “safe” occupations)." — Preceding unsigned comment added by 69.181.65.94 (talk • contribs)
 * Do not remove the content if you just think it's not in the right place.— Ryūlóng ( 竜龙 ) 07:52, 17 November 2010 (UTC)

The text has the very strong appearance of opinion. It is not welcome in a discussion of effect. It does not belong in this section. A discussion of concerns may be valid and that text would be better served in that section. To that end I preserved the text in whole in the discussion so it could be easily replaced. In the mean time, while the original author is preparing his new entry, the community as a whole is better served by having opinion removed from a series of facts. I hope that you can appreciate that this opinion was placed in the proper location. —Preceding unsigned comment added by 69.181.65.94 (talk) 08:01, 17 November 2010 (UTC)


 * I agree, and thank you for making the correction. It's good to see the article now more balanced and less like a pro-OSI Systems public relations piece. Hanxu9 (talk) 18:56, 17 November 2010 (UTC)
 * This is good! The section really did not belong in health effects at all. The sections original form was very wordy and I tried to make it more clear but those changes have only shown how opinionated the section was.  I was originally advocating for a separate section for justification for use in this article but maybe this section would be better placed in or merged with the usage section in the full body scanner article.  I say this because the justification for use of this technology seems to be more aimed at the actual full body scanner than the underlying technical principle that the scanner uses. The other option I see is setting up the justification for use section as a summary section headed with a wikilink to the full body scanner usage section.  TheIguana (talk) 23:45, 17 November 2010 (UTC)

Reading through the article, I thought that section seemed out of place as well. It doesn't make much sense as worded either. —Preceding unsigned comment added by 12.229.94.3 (talk) 21:47, 23 November 2010 (UTC)

No Technical Details
I came to this article looking for information about backscatter x-ray technology, and specifically the source of x-rays, the detectors, and details about how the full-body scanners in airports achieve the resolution claimed. Unfortunately, this article contains no such details, a grievous omission for an encyclopedia. Jedwards01 (talk) 03:15, 18 November 2010 (UTC)

Agreed, it's pretty bad. I made a start by adding the Smith patent and the recent Rapiscan patent.Kbk (talk) 20:25, 26 November 2010 (UTC)

Health effects section is a mess
It seems that due to the recent news this section has been the result of a lot of edits. The current state is too long, goes back and forth and is sometimes redundant. Please try to limit additional content that is unimportant, redundant or speculative. Also, like information should be combined and organized. For example a paragraph starts as: "However, biochemists and biophysicists at the University of California, San Francisco, in a May 2010 letter..." and then 10 paragraphs later: "However, researchers at the University of California, San Francisco, have argued that the amount of..." Combine. Cut. Organize. Copy edit. Please help. nakomaru (talk) 03:15, 19 November 2010 (UTC)
 * I've combined those two sections and tightened it up a bit. There is still too much here, and it's not NPOV, but it will sort out in time.Kbk (talk) 03:59, 27 November 2010 (UTC)

millimeter wave scanner health effects
Quote: 'Furthermore, other scientists claim the health effects of backscatter are well understood whereas those from millimeter wave scanners are not'

"millimeter wave", that is basically infrared light, making this a 'passive' scanning technology, or not? Would appreciate an explanation or reference for the reasoning behind this claim.

86.171.181.73 (talk) 21:33, 22 November 2010 (UTC)

Lens system?
It sounds like a backscatter x-ray is "just" a camera in the x-ray rather than in the visible band. Is that correct? If so, what is the lens made of? (Or is it just a pinhole lens?) Wouldn't such a security system be vulnerable to attacks based on concealing contraband with x-ray mirrors so the cameras see into the room rather than imaging a concealed object?

Also, I found this quote "Medical X-rays are powerful enough to pass all the way through your body. The airport machines rely on a much weaker beam, says Steven Smith, an electrical engineer." What wavelength are these things operating at? Is Smith conflating the energy of individual photons with the power of the entire system? (i.e., is he really saying that fare fewer photons go through you, but in fact the same fraction go through, just that there are fewer photons total than in, e.g., a dental x-ray.) —Ben FrantzDale (talk) 14:26, 23 November 2010 (UTC)
 * It is not just a camera in the x-ray band. X-rays cannot be focused with lenses (with current human commercial technology). The shortest wavelength lenses we make are ultraviolet. The source can be filtered (and polarized) to produce only parallel rays, though. Instead of focusing light on a small area, the detector is simply made very large (or a small detector moves with the source - same idea). I believe the phenomenon of Compton scattering lets us figure out what the focused image should look like based on knowing the polarization and incidence of the source beam (i.e. it does what the lens would have done).
 * As to your second concern: yes. Photon energy is purely a function of wavelength, and the absorption rate does not change based on beam intensity. He is saying (correctly) that intensity of the source beam is so low that we would not be able to detect the transmitted intensity after it goes through a body as we do in medical x-rays, even though a few pass through. nakomaru (talk) 16:55, 23 November 2010 (UTC)


 * Interesting, particularly Compton scattering. I suppose you could try to focus them with a zone plate; if the x-ray wavelength is 10 nm (the long end of the x-ray band), then the zeroth zone-plate radius for a 50 mm lens would be >20 microns... It can't be easy to stop an x-ray at that feature size, though, even with lead. —Ben FrantzDale (talk) 17:40, 23 November 2010 (UTC)

There is no lensing. The system uses a flying spot scanner with large area detectors adjacent to the x-ray source to detect the backscatter Compton x-rays. See the two patent references I added. Kbk (talk) 20:28, 26 November 2010 (UTC)

ANSI is irrelevant
ANSI norms are irrelevant since these are industrial consensus norms. Only when regulatory law explicitly quotes these norms are they applicable and binding. So, either provide evidence that regulatory law explicitly states that ANSI N43-17 needs to be complied with, or cut it out of this article. And no, the TSA has nothing to say here. The relevant regulatory authority for ionising radiation is the EPA and/or NRC. It is NOT the FHA. As such, 10 CFR Part 20 is legally binding for all States:

§ 20.1301 Dose limits for individual members of the public: (2) The dose in any unrestricted area from external sources, exclusive of the dose contributions from patients administered radioactive material and released in accordance with § 35.75, does not exceed 0.002 rem (0.02 millisievert) in any one hour.

Discuss. --Dio1982 (talk) 15:25, 23 November 2010 (UTC) Backscatter 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. —Preceding unsigned comment added by Gil Zweig (talk • contribs) 16:07, 23 November 2010 (UTC)

This should get an NPOV block...
It reads like it was written by the TSA. Each and every line discussing a concern or criticism of the system is followed by a sentence claiming that such concern or criticism has been definitively refuted --- most often by reference to TSA press releases, or statements of what the "TSA said." —Preceding unsigned comment added by 68.175.78.74 (talk) 21:12, 12 March 2011 (UTC)

With respect, the fact that the concerns have been addressed is surely relevant for the article. The alternative would be either (a) to find new concerns which haven't been addressed or (b) remove information addressing the concerns, which at best would defeat the point of an encyclopaedia and at worst would be spreading disinformation. —Preceding unsigned comment added by 158.143.197.104 (talk) 12:58, 11 April 2011 (UTC)

hereditary effects
The article states in a matter of fact way that medical irradiation (of the gonads) increases risk of childhood leukaemia in offspring. A single case control study is cited to support this. A more balanced argument is required here, due to evidence on the contrary: A 2001 UNSCEAR review (http://www.unscear.org/unscear/en/publications/2001.html) found no evidence of hereditary effects in humans although suggested it was possible based on animal data. No evidence of hereditary effects were found following radiotherapy for childhood cancer (Boice JD jr, Tawn EJ, Winther JF, Donaldson SS, Green DM, Mertens AC et al. Genetic Effects of Radiotherapy for Childhood Cancer. Health Phys 2003 2003 Jul;85(1):65-80.). No evidence of hereditary effects following the atomic bombings of Hiroshima and Nagasaki (Schull W. Effects of Atomic Radiation: A Half-century of Studies from Hiroshima and Nagasaki. (1995) Wiley). The ICRP has downgraded tissue weightings for gonads to as a consequence of recent evidence. If there is a risk of hereditary effects of IR, then it is considerably less than the somatic risk, which is already extremely low in the case of backscatter scans. — Preceding unsigned comment added by Xapbpoh (talk • contribs) 21:10, 18 July 2011 (UTC)

hard and soft
Lead is soft, steel is hard. What will be the difference when observing an X-ray projection? A more striking example: Annealed steel and quenched steel, or better annealed and work-hardened steel -- soft and hard -- same chemical composition and even same metallographical structure, but same X-ray attenuation. Correct would be: "low and high X-ray attenuation" is correct. Not short and sexy? Hmm... ondra (talk) 08:26, 3 December 2012 (UTC)
 * Low and high attenuation would be correct. Hard and soft commonly refers to X-ray energy, where hard are higher energy. Usual luggage scanners are now up to 70keV. I don't know yet the energy here, and it should be in the article. Gah4 (talk) 05:44, 8 May 2023 (UTC)
 * Low and high attenuation would be correct. Hard and soft commonly refers to X-ray energy, where hard are higher energy. Usual luggage scanners are now up to 70keV. I don't know yet the energy here, and it should be in the article. Gah4 (talk) 05:44, 8 May 2023 (UTC)

Perfectly safe....
As long as the machines are operating to spec, well-maintained, free of design flaws, and engineered openly by a responsive honest developer.

That's how these things are always done, right? http://en.wikipedia.org/wiki/Therac-25

Oh...well then. 128.97.68.15 (talk) 21:47, 20 December 2012 (UTC)

Concern
The article doesn't talk about contractors. If they have a little guy that wants to sit around and look at male genitals all day, he has access to hundreds of images. Crooked Q (talk) 05:11, 1 July 2014 (UTC)

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External links modified
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 * Added archive https://web.archive.org/web/20110716203604/http://www.tek84.com/downloads/Holt-Letter2010-12-2.pdf to http://www.tek84.com/downloads/Holt-Letter2010-12-2.pdf
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Redirects
There are some redirects to this article that aren't used in the article, or any other article, and don't seem to be very widely used to refer to the subject: porn scanner, porno scanner and naked machine. Each phrase seems to have seen some use c. 2010–13, but it would probably be hard to find sources mentioning, rather than using, the terms, which is what we'd ideally want to cite. Does anyone have any interest in adding them to the article with sources, in order that readers who search for them and end up here aren't unduly confused, or should some or all of them be deleted? – Arms & Hearts (talk) 17:18, 10 July 2022 (UTC)

"Porn scanner" listed at Redirects for discussion
An editor has identified a potential problem with the redirect Porn scanner and has thus listed it for discussion. This discussion will occur at Redirects for discussion/Log/2022 August 13 until a consensus is reached, and readers of this page are welcome to contribute to the discussion. – Arms & Hearts (talk) 15:50, 13 August 2022 (UTC)

Energy
Can we say the energy and/or wavelength (range) used? I believe somewhat less than the more usual 20KeV, but don't know it close than that. Gah4 (talk) 20:32, 24 August 2022 (UTC)