Archived - Shoe-fitting fluoroscope

[Carl Willis]

Not fusion, but nonetheless relevant to the high-voltage and ionizing-radiation fetishes most of us fusioneers share. Enjoy these pics while they last!

Back in the '30s, '40s, and '50s, shoe-fitting fluoroscopes were a common feature in shoe stores. They were a sales gimmick designed primarily to entertain children at the store and lend the mystique of modern science to the simple art of fitting shoes. And they could deliver a heinous x-ray dose to the feet, 'nads, and whatever other body parts were exposed to the beam emanating from the 50 kV x-ray tube located below the foot stand!

This Adrian machine is one of the later models in which some lead shielding was actually incorporated in the design. An antiquities collector who shall go nameless here wanted his machine returned to operability, with the strict understanding between us that applicable laws are to be followed and human appendages are never to find their way into the machine. The fluoroscope came to me with a nearly mint Patterson Type B screen but missing the original air-cooled Coolidge tube. I made a replacement for the air-cooled tube by taking a lightly-used modern line-focus, self-rectifying dental tube and mounting it in a custom oil-filled reservoir that fits into the tube cradle in the machine. The original filament probably ran at 10V. I added some dropping resistors to limit the plate current to 5 mA and run the modern 2 A filament under its maximum rating.

Pics follow.

1. Back of the fluoroscope. Transformer is black box at bottom.
2. Replacement tube insert. The syringe is a "compliance volume" to expand when oil heats up in use. The resistors are added ballast for the filament.
3. Tube on, cranking out the rads. Ion chamber is reading 80 R / hr. Plastic rod on right is defeating an HV safety interlock for tube compartment door.
4. Anode current just under 5 mA on the meter.
5. Image through the viewing portal of a steel leaf thickness gauge.
6. Image though "salesman's portal" of the screen with a piece of solid 1" acrylic rod (on left) and a piece of 1" Sch. 40 PVC pipe (on right). Notice how the chlorine in the PVC stops x-rays better even though the pipe is hollow.

Best regards,
Carl

Finally the obligatory disclaimer for the haters. The work and testing described here was carried out in a state-licensed radiation facility as required by law. Kids, feel free to try this at home; just keep in mind that burning your little trotters so bad that the flesh sloughs off the bone when you pull your socks off...(A) maybe that ain't the best feeling in the world; and (B) Carl Willis shall not be responsible for repair or replacement of aforementioned "trotters" nor any other anatomy inconvenienced by ludicrous overexposure to x-rays.

[Jon Rosenstiel]

Nice work Carl, thanks for sharing this with us.

In the early 50's (when I was 10 ~ 12 years old) these types of machines were still common in our small mid-western town’s shoe stores. I will never forget the thrill of sticking my feet into the x-ray shoe-fitting machine and watching the bones in my feet move about as I wiggled my toes. I wonder if that was the “spark” that caused me to build a fusor 50-years later?

Jon Rosenstiel

[richnormand]

I remember those units too. Much fun for the kids and a measure of entertainment while mom tried several pairs of shoes.

Although the dose is very large by today’s standards and you could potentially play for hours with it has there been any documented studies of ill effects from these? A comparison between regions that had them vs those that did not? From the photos here, it looks that shielding was not particularly intensive so scattered x-rays must have been everywhere…

[philstro]

There was one in my home town clothing/shoe store that I remember. I don't remember it working though, it may have been after they were banned and thus unplugged, but not removed from the store yet. Late 50's probably, in Iowa.

By coincidence, I was Googling around for information on these several weeks ago. There was a case of a woman who apparently received a high dose to her feet because she was a shoe flouroscope "model." I presume she was helping to sell shoes in a large store. As the story went, her feet had to be amputated.

Nonbelievers should also check out the "radium girls." These were the women whose job it was to paint radium-phosphor onto watch dials (1920's?) In order to keep their small brushes pointed on the end they had to moisten the brushes on their tongue. This while their managers carefully stayed clear of the stuff. I guess it has always been all about the money but that seems to go farther.

Phil

[Richard Hull]

Like all the rest who chimed in, I stuck my little developing feet into one of these many times. The various store owners and shop people kept kids limited to a fitting view and maybe one more for fun, but would not let kids play on it. Why?

Not for one minute were they concern about health issues....Not they...........They were intensely concerned about repair bills or damage of their machine from over use by us indolent kids.

Our health was the least of their concern, I assure you, for at that time, children were to be seen and not heard. A hearty slap on the face in public attended any idle or ill-timed outburst.

The damage caused by these machines is an effective non-issue even if abused by the ocassional child. Too long a spell between exposures to pile up the rads. I am sure old retired machines in the public domain might have done far more harm than installed base machines in shoe stores.

Finally, any comparison to any possible damage casued by these x-ray "shoe fitters" and the so called radium girls is laughable. Bone lodged, multi-uCi radium as a 24-7 body burden is a vastly different animal to highly intermittent x-ray blasts.

I would rather take a 30 roentgen absorbed does of X-rays than have a 0.5 millirem/hr fleck of radium lodged in me.

The x-ray dose would be severe and alter my blood chemistry for a wek or so, leaving me "wiped out" feeling, but I would recover fully.

The little fleck of radium would never, ever be noticed for years until the cancer that killed me developed as sure as death itself.

The probability of long term injury by the intense x-ray exposure is close to zip, but the bone lodged radium is a gift that keeps on giving, internally, with all the soluable daughters drifting through my body and bloodstream.

X-ray machines can be turned off or walked away from. Bone lodged radium will still be at half strength 1600 years from now in my long dead skeleton. No comparison at all.

Archived due to historical and general interest

Richard Hull

[richnormand]

Nice summary Richard. How times have changed....

[regass]

They used to have one of those at Hoffhiemer's in Norfolk when I was a kid. I don't think it worked at the time though. At least I never saw it in operation. Pretty cool item and quite collectable.

Bob

[rkhertz]

I also remember watching the bones as I wiggled my feet in a fluoroscope in Van Wert, OH in the early 50's. My first dentist, born in the 1890's, was missing a finger from holding film in patients' mouths as he x-rayed their teeth. He made me hold my own film.

[derekm]

Even if the risk was known in the 50's I doubt that anything would be done. That era's approach to risk was radically different (at least to my knowledge in Europe).
An interview with a British racing car driver at that time after one of the frequent fatal accidents asked if he worried about the risk. He said no he wasn't ,after all no one was shooting at him while he did it.
No concerns about product liablilty for him !

[lutzhoffman]

Ref: The radiation hazard, these were not that bad for the "customer" since the MPD (Max Perm. Dose) for radiation workers is a whopping 50 rem for hands and feet. This is because there is no radiosensitive tissue in these body parts. For an adult the big ones are bone marrow in the hips, the testicles, and the thyroid, followed by the lens of the eye. The marrow dose from 50KV scatter would be very low. The key would be to do a good radiation survey, with the machine running to put things in to perspective.

Also since the machine did have shielding, and since it opperated at 50 KV the radiation level in the surrounding area should be very low. Scattered X-rays are always of a lower energy than the primary beam, and much of it is the secondary K edge spectrum of the irradiated object. Thus the scattered beam energy would be maybe 20KV average, and even several feet of air would attenuate this low energy scatter to a large extent.

Thanks for posting, and for the pics, this one was interesting. Who knows with modern PMT imaging one could be built today which would be pretty safe from a radiobiological point of view, but it would probably NOT be accepted by the public out of fear. Maybe they could put a modern version at the airports for "voluntary" use for folks who do not wish the hassle of removing their shoes?

In medicine they have a low dose PMT fluoroscope on the market, which runs at about 60KV, at micro amp tube current levels. It delivers a very low radiation dose, so low that shielding is not even required for the patient, or the operator. Ortho MD's love this thing for bone fracture reductions. It does not require licensing so even paramedics have used these in the field, very handy. Its funny how modern technology, may even bring back some of these old unsafe ideas, back to life.