New (as of 2019) airport CT scanners

Agulliver

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Hospital X-ray machines can be set to deliver different intensities (or doeses). I personally saw this during the Medical Physics course of my degree in Applied Physics. Though that was the 1990s I doubt it's entirely unique to hospital X-ray machines.

Whether that applies to any security X-ray scanners may be something none of us here really knows.
 

koraks

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Agulliver said:
Whether that applies to any security X-ray scanners may be something none of us here really knows.
Click to expand...

No, that's true, but since security personnel are unlikely to have to go through the kind of training a radiologist receives, I presume that these security scanners are dumbed down to the point where the operator cannot really directly adjust the dose. Either the machine does it on its own accord, within very strict limits, or it always scans at the highest permissible dose and does any adjustments afterwards in digital post processing. One obvious way they (i.e. the machine & its developers) could alter the dose is by simply letting the conveyor run a little slower. This would increase resolution - and coincidentally also the total dose delivered to the sample.

Anyway, it's kind of a moot point; all we know is that CT doses can be problematically high, and we can reasonably expect that the effect is variable - which means you may sometimes just get away with it, and other times you don't, but you can never be quite sure prior to seeing the developed film if you'll be lucky this time.
 

BrianShaw

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The vendor doucmentation on the screening equipment is not secret and is publically available. It is known if one goes and looks at it. None of the vendor documentation supports anything except fixed dosage, although the belt can be stopped, started, and reversed. I can't recall if belt speed is adjustable or not. The available vendor documentation is not clear how the x-ray behaves during those maneuvers since it is marketing rather than operator documention. When discussing the imaging options, the vendor doc are clear that those are software processing of a captured x-ray image and not repeated re-xrays. When our stuff is taken off the belt exit and put back on teh belt entrance... an addition dose is guaranteed.

Unlike medical/dentl x-ray, the baggage screening operator is completely shielded by the machine design.

At one time there was a two-stage screening for checked bagage, where the quick screen was traditional x-ray and if needed a CT was then performed. This was an effort to spped up through-put. It was never applied to checked baggage adn there is no evidence that it has been included in the current lines of products.

EDIT: At least one vendor offers a "dual view" system which has 2 x-ray generators, unlike the single x-ray generator and diagonal slice in older legacy systems. Top view and side view at the same time. Those probably exposed the parcel to a double-dose in a single pass.
 
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titrisol

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At least in the US, if the scanner looks like a round tunnel (new ones) it's not safe for any film, if it is square it might work for film less than 800
BUT in either case hand-check is better
 

loccdor

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The Lina Bessonova video was very thorough and informative. I have had the opportunity to have my 35mm film CT scanned on two separate occasions now. Here are images.



1st trip, 2023, Kentmere 100 @ 100, fresh film.





2nd trip, 2024, Fuji Acros 100 @ 100, expired 2015.

All shots standard development in 1+100 510-pyro. They all had one pass of CT scanning. The first shot also had one standard X-ray.

I didn't detect much in the way of base fog on either occasion. The reason they got CT scanned is because they were loaded in cameras which were in my carry-on luggage. The other film on these trips was either hand checked or mailed in advance. I couldn't really tell the difference with 100 speed film, if there was one it seemed to be less than the effect I notice from a decade of expiration.

But I wouldn't use faster than 100 speed for film I knew was going to be scanned.

I would have expected more effect especially on the bottom shot, because most of the image is made up of shadow detail.

On one occasion, my hand-checker forgot about my bag of film and it almost got lost. There are risks involved in the hand-checking process as well. What was really reassuring in Lina's video is that the metal 35mm cassettes help a lot.
 

ntenny

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titrisol said:
At least in the US, if the scanner looks like a round tunnel (new ones) it's not safe for any film, if it is square it might work for film less than 800
BUT in either case hand-check is better
Click to expand...

Not all CT scanners are round. PDX uses a model, whose name now escapes me, that looks like a big rectangle with slightly rounded corners in cross-section. They are noticeably different from the “classic” X-ray scanners, bigger and with more exterior plastic, but they don’t look like the “round tunnel” models.

I think the only reliable criterion (in the US) is whether laptops can stay in; if so, it’s a CT scanner.

-NT
 

Fatih Ayoglu

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For the last 15 years or so working in the cath labs, the most common thing I hear was, the doctor shouts “I can’t see, can you do something”, and radiologists say “I can’t except changing the mode”

Yes it can be dialed up or down but not for regular one shot XRay images (which is security scanners), usually the machines have single shot XRay like XRay film or live cine recordings, a different mode in general which uses slightly more XRay but even then I’m not quite sure if the total XRay is increased due to frame per second or just the tube shoots more.
 

Steve Goldstein

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Here's a picture I snagged from somewhere a couple of years ago showing the various models then available.
 

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stuwilmur

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MFstooges said:
Mail it home? I assume the X-ray machine is even stronger for unattended mail and package, no?
Click to expand...

I did start to worry about this after the fact. However, I’m happy to report that all four rolls have developed nicely with no immediately apparent effects.
 

peter16

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this film was scanned 3 times in the carry on scanner - twice at LAX, once in Salt Lake City. It's ilford X-p2. This was a particularly bad frame - Overexposed even more than the 200 I would normally shoot it at. But a rude reminder for me that carry on scanners aren't harmless if you are trying to wet print.
 

Prest_400

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An interesting video from RealEngineering that explains the works and rollout of CT scanners:
 

Daniela

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As of this month:
CDG terminal 2 - old x-ray scanners. I asked for hand inspection & the guy declined saying it's just fine. He wouldn't drop the conversation. It would have been faster to just open the d#*& bag and look.
Ezeiza, Buenos Aires, Argentina. New and super modern terminal...but old x-ray scanners still.
 
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grain elevator

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Please report back when the film is developed!
 

Daniela

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grain elevator said:
Please report back when the film is developed!
Click to expand...

Will do, but I've never had an issue, so I don't expect to have one now. However....I just found an exposed roll in the checked luggage. I can't understand how that happened...it's a first. I guess I can look forward to some special effects
 

reddesert

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The older airport scanners for carry-ons, the new CT scanners, and the more powerful checked-bag scanners all use X-rays. The difference is in the intensity and maybe the spatial distribution. Many of you know this, I'm just pointing out that if one says at such and such airport there were "x-ray scanners," it doesn't tell us whether you mean the old ones (generally safe for film) or the new ones (sometimes damage film).
 

Daniela

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Good point! CT scanners also use x-rays...I have edited my post accordingly.
 

FredK

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The older carry-on x-ray scanners actually user a single, higher intensity, x-ray "blast". The newer CT scanners use a lower energy scan beam, BUT the beam remains on much longer resulting in the film's grains absorbing much more energy than from the older models. In tests we performed in Rochester, we saw density increases of gross fog / D-min on 50D which would be noticeable in uniform areas. The amount of energy collected in 200 speed and above is very noticeable in one single pass through the newer machines. Hand examination of film is the only means of ensuring no images will be affected.
 

BrianShaw

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FredK said:
In tests we performed in Rochester,
Click to expand...

Hi Fred. It's good to know that testing has been done. So far just a bunch of random experiences seems abailable. Who did the testing and are reports available? Back in the olden days, the I3A Committee for Integrity in Transportation of Imaging Products and FAA made their study publically available, which underpinned the industry guidance on potential film damage for the scanning devices of that time. Seeing the rerports and transparency really helps folks understand the current situation. Internet comments without much more information aren't quite as useful. Can you please elaborate?
 

FredK

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Brian,

The testing was performed by my team at EK Co. with the assistance of the TSA in Rochester. The report of those tests was provided to management of the company and TSA so that they (TSA) could adjust their procedures, as hand inspection would be required far more than they initially anticipated. Others in the company shared those results with a European group working on the issue with the various airport agencies there. The EK Co internet site may have been updated with information - I haven't checked that since my retirement from that wonderful, magical, place. Ah, the stories I wish I could tell...
 

koraks

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FredK said:
Others in the company shared those results with a European group working on the issue with the various airport agencies there.
Click to expand...
Is there any information that can be shared as to the nature of that European group? As remarked earlier in this thread, there's no EU policy like there is in the US or the UK that entitles passengers to a hand inspection. Evidently, policies and arrangements are different here. This makes me wonder whether the European group you mention is somehow associated with the EU or EP.
 

BrianShaw

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For clarification: there is no US policy that "entitles" hand inspection of film. The US TSA has practice (a much lower lower level than act, law, or policy and revokable without redress) to allow passengers to request hand inspection of film. TSA tends to be rather cooperative but there is no formal mandate that they must.

If the research was EK-internally funded, it might be a challenge to get a copy of the report. I did a bit of searching with no results more recent than 2020 summary statements on the CT threat. That testing seems to have been a bit constrained. If FAA-funded, then a Freedom-Of-Information-Act request might be possible. Like you, I'm very interested in the details...

Kodak and Fujifilm Issue Warnings About Airport Scanners

rps.org

Kodak posts advisory on how to travel with film through new airport CT scanners

Kodak posts advisory on how to travel with film through new airport CT scanners
www.diyphotography.net

Following a link in this Kodak reseource probably answers your question about the European entity:

CT Scanning X-Ray Technology and Film | Kodak Alaris

kodakprofessional.com

X-Ray Download / I&P Europe

www.ip-europe.com

And (you probably aware of this already) a bit of private testing from that same era:

Testing CT Scanners: Here's how badly they can damage your photographic film

Recently, a number of film companies have issued warnings about new and enhanced scanning technology (CT scanners). As I was travelling through Amsterdam's Schiphol airport recently, I thought I would sacrifice a roll of film to see what the damage looks like.
emulsive.org

Unless @FredK corrects me, it seems that he refers to the 2020 (or so) study. That study appeasr to have been quite a bit less comprehensive than the 2008 studies but just as telling as to the threat of CT to film.
 
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loccdor

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Just went through yesterday; at the New York JFK international terminal they seemed to be using a bunch of old-style scanners, not CT, still. I asked for and received a hand check. It was a zoo, they had about 20 lines going at once, the agent remarked, "Oh boy, makin' me work" at the request and the agents all seem to be fairly well trained on recognizing film. I have never been denied a hand check in the USA.

They want you to scan your cameras separately from the rest of your luggage, but if you tell them they're not electronic (even if they are) they don't require it.

They also have rules against carrying extra lithium batteries but the small camera ones have never caused a problem for me and I do pack a handful.

In Athens, they still use old style and since they had turned down previous hand requests and are less trained on film, I just let it go through the rays.
 

Arthurwg

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It's enough to make me buy a digital camera. Besides airports, I've found that some institutions, particularly in France, insist on scanning all film and film cameras, no mater what.
 
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