New (as of 2019) airport CT scanners

[wiltw]

Of interest in this very thread, a post in 2019 in which radiation dose of hand luggage was MEASURED using dosimeters. This measurement without implication on visibility (or lack thereof) of radiation damage to film. I link to this for the benefit of those recently joining this lengthly thread, who have not taken the time to read it in its entirety, since it does contain very relevant factual information

New (as of 2019) airport CT scanners

thank you guys for your thoughts but how about hesitations from security personnel for films manual checking ?

www.photrio.com

Additionally, one person published on YouTube a report in which he deliberately subjected film to 16 passess thru X-Ray without much more that some increase in grain evident. And in that same thread, a 18 year veteran professional pilot relates his freedom from any evidence of damage to his film during his career

 

[wiltw]

The report does, but your post offering the quote of the person interpreting the report does contain a somewhat haphazard assumption that's presented as if it's a firm conclusion:

The report lists (page 24 of the pdf) measurements for baggage passed through hold luggage CT ('CTX') vs. regular hold luggage x-ray scanners ('L3 EDS'), with a passing remark about carry-on regular x-ray machines which your conclusion seems to rely on. CT scanners for carry-on luggage were not included in the report because none were in use at the time of the study (late 2003/early 2004). The conclusion in blue quoted above relies on the assumption that the x-ray dosage and profile of today's carry-on CT scanners will be the same or similar to that of checked luggage CT machines in use 20 years ago. In reality, we don't know this. Your conclusion may or may not be correct. We just don't know, and we sure can't tell much about machines installed in the 2020s based on a 2004 report. The person you quoted picked his words more carefully and said "The newer carry-on screening systems are expected to deliver similar doses." (emphasis mine; note the somewhat cautious formulation signaling an assumption on his part).

Btw, the defects I encountered are easy enough to miss if you don't process your own film and don't examine it closely. I first noticed it on the empty leader part of the film that is typically not returned to the customer after processing, unless the customer requests uncut film. This is a typical black swan scenario; one might assume on the basis of observations of only white swans that all swans are white. Observations of white swans, however, do not demonstrate the absence of black ones.

I drew no conclusion about the amount of dose from current carry-on scanners at all. I provided the link primarily because of the validation of the low X-ray dose in hand luggage examination devices.

In fact, I *speculate* that they may in fact have a preliminary very-low dose that they selectively can increase for better imaging and analysis of the density/composition of contents for explosives detection. That is, initial use of X-ray detection, with initialization of CT only when automated detection warrants, to speed up examination of handluggage. That would account for why so many reports of 'no damage' from carryon CT, while other reports have exhibited patterned artifact. It is known that there are multiple technologies of detection involved in luggage examination systems. The volume of caryon CT was about 10 bags per minute.

 

[koraks]

Whatever. I deleted the post you quoted for the reason I mentioned.

 

[wiltw]

You're overlooking the fact that film rolls aren't necessarily fed neatly vertical or horizontal through the machine.


Empirical evidence of CT damage shows overall fog with no clear geometry. Empirical evidence of regular X-ray damage looks exactly like what I linked to in my experience.

Single or dual- view systems usually scan baggage as it moves on a conveyor using a fan beam or a scanning pencil beam of X-rays in a fixed geometry. Multi-view CT sensors, on the other hand, usually scan stationary or moving baggage in a fixed geometry of scan angles and process
data corresponding to the absorption of X-rays to reconstruct selected slices of the baggage.

Use of a fan beam irradiates uniformly an area under the beam, leaving the entire field irradiated. A scanning pencil beam of X-rays could leave the sinusoidal pattern. But unless employ multiple sources or a mobile source, the result is only a 2-D image X-ray, yet the carry-on CT is 3-D in view.

 

[wiltw]

Whatever. I deleted the post you quoted for the reason I mentioned.

Censorship of objectively obtained information, with no political commentary?!

 

[MattKing]

Censorship of objectively obtained information, with no political commentary?!

He deleted his own post.

 

[koraks]

He deleted his own post.

Indeed ; I realized I was only adding to an already meaningless word salad.

 

[MattKing]

Gentlemen.
Can we agree that you don't agree about the reliability of the warnings or lack of warnings re: lower than ISO 1600 speed films, or the methods used to challenge or support those warnings?

 

[wiltw]

Gentlemen.
Can we agree that you don't agree about the reliability of the warnings or lack of warnings re: lower than ISO 1600 speed films, or the methods used to challenge or support those warnings?

I see no 'disagreement' other than the question if X-ray security scanner was truly the cause of the artifacts seen in his film. Going back decades, there were some reports of damage to film supposedly from passing thru security X-ray, and to magnetic media transport on their belts. So the fact that damage occurred is uncontestable...the question is the true source of the damage. That is why I cited folks saying 16 deliberate passes or an 18 year tenure as a pilot, both withour harm to film, as the counterpoint. And also the variety of results seen with CT security machines!
We have, after all, decades of refusal to hand inspect while pointing to the signage disavowing film harm. and in spite of that there seems to be few complaints about damaged film!

 

[wiltw]

Censorship of objectively obtained information, with no political commentary?!

...said in jest, posted without the accompanying smilie!

 

[ntenny]

I’m in the final legs of an itinerary to Wuhan, China: PDX-SEA-PVG-WUH and back. I’m writing this from the lounge in Shanghai (PVG), so I have one more security check to go when I enter the US in Seattle, but I expect that to be the same as previous trips and uninteresting from the film pov (plain X-ray, I never ask for hand check at it).

PDX outbound: all CT, no problem with hand check, as always. They knew what my film was (four rolls of 135 in canisters, in a plastic bag with folded HP5+ and D3200 boxes for identification).

SEA: didn’t have to clear security, but all I’ve ever encountered there is old X-ray machines.

PVG: X-ray again when I entered China and transferred to the domestic section of the terminal. I didn’t ask for a hand check. They are very picky about making sure that all battery packs/power banks come out and are hand-checked (this seems to be general to China) but the camera and film didn’t excite any comment.

WUH: no security check on arrival from a domestic flight.

WUH return: basically the same as PVG, plain X-ray with their apparent main concern being power banks. The staff in my line didn’t seem very communicative, and I wouldn’t have a lot of confidence in asking for special treatment, especially without speaking Chinese. (Phone translator apps are a godsend in China, but not always reliable…)

PVG return: you go through passport control to leave China, and there is a security check afterwards. Similar to the outbound, it was a plain X-ray; no reaction to film or camera.

Wuhan turns out to be an OK photographic city, by the way. I was in the Optics Valley area, where there’s a very large lake with green spaces around it, so I was able to do some light populated landscapes. The streets were unrewarding for me, but I’m not a very good street photographer and someone with a better eye might have found some stuff. The Yellow Crane Tower was worth a visit and offered some cityscape views, and maybe more for someone with an eye for architectural details.

-NT

 

[Dr. no]

Trip report:
Albuquerque: the new precheck line has brand-new CT scanners, and no problem with a hand check (he swabbed each of 20 rolls of 120 in two baggies).
Schiphol (Amsterdam): all new CT scanners on departure, one person didn't recognize film when I asked for a hand check but her partner said "I'll take care of it".
San Fransisco precheck: old machines, didn't bother with hand check.
No fogging/artifacts (except for a roll of Fuji 800 35mm of completely unknown vintage that came along by mistake, it was in the bag of Superia 200)

 

[loccdor]

CT scanners in Buffalo, New York and Charlotte, North Carolina. I was able to send film through the mail so it didn't matter this time for me.

I kind of wanted to put some 50 speed through the scanner to see if the fog level was no big deal for me, but I didn't.

 

[Dr. no]

I have a bag of FP4 (no plus) bulk rolls...I might just keep a roll in each bag and pull off a foot to develop after each trip. Just for kicks. I know it has some base fog, but I would look for CT artifacts.

 

[wiltw]

I have a bag of FP4 (no plus) bulk rolls...I might just keep a roll in each bag and pull off a foot to develop after each trip. Just for kicks. I know it has some base fog, but I would look for CT artifacts.

I have two rolls of exposed and unprocessed NPH 400 rollfilm which I will be deliberately placing inside my carryon luggage, with the hopes that I identify that the carry-on is indeed going thru a security CT scanner at the gate, and I will deliberately NOT ask for hand inspection in choosing not to bypass the CT imaging. We are leaving SFO, travel thru Toronto, to Lisbon outbound this later week. Then returning Lisbon thru Montreal to SFO two weeks later. I will have roll 1 go thru CT only outbound, with roll 2 going thru CT only upon return if I encounter CT in both directions. so that each roll independently will represent a different CT scan in a different location.

 

[Dr. no]

And just because we love complexity...
The film that was loaded in holders went through the scanners. No discernible artifact from ABQ on Arista EDU Ultra 400, and the return trip is not developed yet.

 

[wiltw]

And just because we love complexity...
The film that was loaded in holders went through the scanners. No discernible artifact from ABQ on Arista EDU Ultra 400, and the return trip is not developed yet.

Was it positively identified to be CT scanner that was used for security inspection?

 

[Agulliver]

I'm currently in Tokyo having travelled from London Heathrow to Kansai International via Helsinki then a week later taking the shinkansen (bullet train) from Kyoto to Tokyo

LHR terminal 3 seems to still have old x-ray scanners. I asked the security bod and he said it's safe up to 800 ISO. I'm carrying nothing faster than 400 so was ok with it being x rayed.


No security check transiting through HEL (lovely airport). No security check for the train to Tokyo

There are older x-ray scanners in some lines for the Expo 2025 in Osaka but my group included a wheelchair user and we all got hand checked. Security man was older and thrilled to see film cameras.

I'll report on Tokyo next week after I return home.

BTW the expo is not worth it and in my opinion transport and queuing are so disorganised that someone is going to be killed in a crush