Fluoroscope

Fluoroscope (pronounced floor-uh-skohp, flawr-uh-skohp or flohr-uh-skoph)

(1) In laboratory physics, a device used to measure the fluorescence of a solution (now rare).

(2) In medicine (and later commerce), a radiologic instrument (originally built as a tube or box) equipped with a fluorescent screen on which opaque internal structures can be viewed as moving shadow images formed by the differential transmission of x-rays through the body.

1896: A word coined in US English to describe a newly introduced device, the construct being fluoro- + -scope and adapted from the German Fluorescop.  Fluro- was from the Italian fluoro, from the Latin fluor (flow).  Scope was from the Italian scopo (purpose), from the Latin scopus (target), from the Ancient Greek σκοπός (skopós) & σκοπέω (skopéō) (examine, inspect, look to or into, consider), from σκέπτομαι (sképtomai), from the primitive Indo-European speḱ-.  Etymologically, the word is related to both skeptic and spectrum.  Fluoroscope & fluoroscopy are nouns, fluoroscopically is an adverb and fluoroscopic is an adjective; the noun plural is fluoroscopes.

The shoe-fitting fluoroscope

From the podological safety of the twenty-first century, the idea that part of the shoe-buying process once involved having one’s feet blasted with radiation probably seems strange but for decades they were a fixture in shoe-shops.  The idea has a certain compelling logic because under x-rays, the bones and flesh of the feet were clearly visible as was the outline of the shoe, all guesswork about the fit thus removed, customers able to choose a perfect pair.

Shoe-fitting fluoroscope, circa 1940.

The design of the fluoroscope also had great appeal as a sales device because unlike many of the uses of the technology in clinical medicine, the ones in shoe shops were designed so the images could be seen by the customer.  Indeed, they featured three viewing ports so simultaneously the x-rayed foot could be seen by the owner, the sales staff and one other which the manufacturers said was to allow a parent and a child to share the experience.  Shoe-fitting fluoroscopes were made with an upward-facing x-ray tube which sat inside the bottom of a metal housing, the images fed to a fluorescent screen at the top, viewable through the three ports.  At foot level was an aperture which opened into a space between x-ray tube fluoroscopic screen and it was in this space the foot rested.  When triggered, the x-rays penetrated both shoe and foot, the fluorescent screen lighting up with the image.

The original specifications of the machines included lead-shielding as well as a section in the manual explaining the importance of these protective fittings but, shoe shops being commercial spaces where displays are often moved (and over the years, renovations effected), it was subsequently found it wasn’t unusual for the heavy shields to be removed so the machines were easier to maneuver into another place.  Additionally, shop staff soon noted that the less shielding fitted, the higher the quality of the image.  That obviously conferred some commercial advantage but also meant that with every scan (and daily there could be dozens), bursts of radiation were scattered in all directions bathing the bodies of customers, staff and innocent bystanders.  In perfect order, maintained according to the manufacturer’s recommendations, the specified 20-second scan delivered around half the dose of radiation of a typical CT (computed tomography) chest scan but not being in a clinical environment where they received regular servicing from qualified technicians, many of the machines in shoe shops were poorly maintained and some subsequently were found to be delivering potentially hazardous doses, registering several hundred times above the permissible limit.  Worse, some shoe-fitting fluoroscopes were positioned next to a wall so those in the shop next door were also irradiated and, to attract those passing the shop, some scans were even conducted with the machine in the store’s front window, radiation blasting all walking past.  For the individual customer who received anyway the highest dose, there was also a multiplier effect because women in particular rarely try just the one pair and could therefore be subject to many dangerous blasts.  Statistically though, most at risk were the staff who, given the machines had been in use since the 1920s, might have been exposed to the risk for decades, papers in the medical literature first documenting the issue in the mid-1950s, the case notes mentioning that not only did one patient report operating the fluoroscope as many as twenty times as day but also the common practice among staff to give their own feet a demonstrative scan just to assure sceptical children the process was painless.

Lindsay Lohan in stiletto heels an an image of how an x-ray of her foot might appear.

It was German mechanical engineer and physicist Wilhelm Röntgen (1845–1923) who in 1895 produced and detected electromagnetic radiation in a wavelength range which could “see through” material including human flesh.  He found the phenomenon so strange and the rays weird beyond immediate comprehension so named them “x-rays”, the implications of his discovery immediately understood and in 1901 it gained him the inaugural Nobel Prize in Physics.  Still, neither Herr Doktor Röntgen nor any other scientist probably pondered x-rays as something useful in shoe shops and that they ended up there was something serendipitous.  The tale of the migration is contested but the most accepted (and certainly the one supported by patent applications and registrations) is that of a World War I (1914-1918) doctor who adapted an x-ray machine so that the feet of soldiers with foot wounds could be scaned without them having to remove their boots, something which rendered the triage process much more efficient.  After the war, he modified the device to suit the shoe-buying process, demonstrating one at a Boston retailer convention in 1920, eventually being granted a US patent.  The UK authorities about the same time issued a patent for a similar device (where it was called the Pedoscope) and with mass-production lowering the unit cost, by the late 1920s they had proliferated on both sides of the Atlantic.  Although the take-up rate slowed during the depressed decade of the 1920s, sales accelerated in the consumerist culture of the post-war years and by the late 1950s, there were reputedly over ten-thousand in North America, three thousand in the UK and close to a thousand spread between Australia & New Zealand.

Remarkably, although it had been known since the 1920s that x-rays could be harmful, the research was fragmentary and the data insufficient to quantify the risk.  Consumer protection and concerns about public health were nothing like those of today and it was only in 1946, after the aftermath of the A-bomb attacks on Hiroshima and Nagasaki (1945) provided graphic examples of the effects of exposure to radiation in high-doses that the American Standards Association (ASA) issued guidelines for the manufacture of shoe-fitting fluoroscopes, setting an upper limit on the amount of radiation the devices can emit.  Shortly afterwards, shoe shops were required to place warning signs on the machines cautioning customers to have no more than twelve scans a year, an early example of a nation-wide edict at at time when most public-health measures were usually administered by state and local governments.  The concerns remained and in 1948, a survey of the fluoroscopes operating in Detroit revealed most were emitting hazardous doses of radiation, something confirmed by wider tests and the first warnings were issued in 1950 although remarkably, the last wouldn’t be withdrawn from service until the 1970s.