Every parent will want to hear this important news! Now, at last, you can be certain that your children's foot health is not being jeopardized by improperly fitting shoes.Wow! How could any parent resist this call to action? If you're not convinced, consider this quote by J.J. Lowe:
With this apparatus in his shop a shoe merchant can positively assure his customers that they never need wear ill-fitting boots and shoes; that parents can visually assure themselves as to whether they are buying shoes for their boys and girls which will not injure and deform the sensitive bone joints.Fortunately, there's no need for alarm. The product being hawked in the quotes above -- a shoe-fitting fluoroscope -- is no longer used.
The idea of using X-ray technology to improve the fit of shoes probably arose during World War I. Shoe-fitting fluoroscopes were patented in the U.S. and the U.K. in the 1920's and were common fixtures in shoe stores throughout North America and Europe from the late 1920's through the 1950's.
In an excellent review of this topic, Duffin and Hayter state:
In our opinion, however, the shoe-fitting fluoroscope was nothing more nor less than an elaborate form of advertising designed to sell shoes. It entered a well-established culture of shoe-selling hucksterism that relied on scientific rhetoric; it took advantage of the woman client newly accustomed to the electrification of her home and the patter of experts' advice about "scientific motherhood"; it neatly sidestepped the thorny problem of truth in advertising that became an issue in the interwar years; and it enticed thrill-seeking children into shops where salesmen could work their magic.
I can still remember looking at my 6 year-old feet through one of these devices in my local Sears store. It was extremely cool to watch my toes wiggle on the green glowing screen, and I was very disappointed when the machine was eventually removed from the store. However, I felt much differently about these devices once I became a radiologist and began to learn more about radiation and its effects on the body.
Physicians use fluoroscopy to perform all sorts of patient procedures ranging from barium enemas to cardiac catheterizations to the placement of prosthetic joints. However, we only expose our patients to the minimum amount of radiation necessary and we keep ourselves way the heck out of the way of the X-ray beam.
By contrast, shoe-fitting fluoroscopes were badly designed, meant to be used by barely-trained shoe salesmen, and gave a considerable dose of radiation to one's feet and other body parts. A customer using this machine would be essentially standing on the the X-ray tube, separated from it only by 1 mm of aluminum shielding. Body parts in the main X-ray beam (customer's feet and salesman's hands) received most of the dose.
But wait -- there's more! These X-rays not only went up through the feet to the fluoroscopy screen, but continued upwards, through the heads, thyroids and eyes of the users. Not exactly an optimal design. Even body parts not directly exposed to the main beam could receive a considerable dose from scatter radiation. As an exercise in discomfort, look at the diagram below and visualize just what sort of dose your own personal gonads would get while standing on this thing.
Drawing after Bushong SC and West WD. Exposure from a Shoe-Fitting Fluoroscope. Health Physics 1970;18:575-576.
Duffin and Hayter state:
In addition to the dose received by the feet, the entire body of the customer -- along with her parent and the attending salesman -- was bathed in radiation; others in the shop were also being irradiated through the walls of the machine. In the waiting-room chairs, the permissible daily dose could be received by a single person in one hour.It's therefore ironic that these machines were targeted at two of the more radiation-sensitive segments of the customer base: children and women in their child-bearing years. The following quotation is excerpted from the installation instructions of one machine:
Of course, it should face the ladies' and children's departments by virtue of the heavier sales in these departments.
With the machines of the time, a child could be exposed to 10 to 116 R in a 20-second period, a dose sufficient to cause radiation burns to the skin. If one considers further that a given child might try on several pairs of shoes per visit with several visits per year, these multiple exposures could add up to an even higher yearly dosage. To put this in perspective, the daily permissible dose for radiation workers in 1946 was 0.1 R.
By the way, the question, "Dude, what's my radiation dose?" is not unlike another question: "Dude, how much does it cost to fly to Chicago?". The answer to both questions is, "It depends." I've paid anywhere from $300 to $1500 to get to Chicago, depending on factors such as how long before the flight I booked my ticket, coach vs. first class, one-way vs. round-trip ticket, and my length of layover. The effective radiation dose depends upon a similar number of variables, such the type of radiation, the length of the exposure and just which body part is exposed. Exposure to critical tissues such as the eye, thyroid and gonads is a much bigger deal than exposure to a relatively radiation-insensitive area like the foot.
Were the medical experts of the day asleep at the wheel while all of this was going on? Not really. The British X-Ray and Radium Committee of Great Britain issued recommendations for workplace radiation dosage in 1921, and Americans followed suit in 1922. However, these machines remained unregulated until 1948, when New York became one of the first jurisdictions to regulate their use. The American College of Radiology published a warning editorial in the Journal of the American Medical Association in April 1949. Its conclusion:
The bitter fact remains that fluoroscopy simply cannot be really safe in the hands of those untrained to its use and relatively ignorant of its dangers.This was also a time of growing post-war public concerns about radiation safety, likely related to WWII events such as the Manhattan Project and the atomic bombing of Japan. Pennsylvania became first state to ban these shoe-fitting fluoroscopes in 1957. Thirty-three other states followed suit with some form of legislative action. In 1963, these devices were finally banned in the U.S.
Has anyone ever actually been harmed by shoe store fluoroscopy? Alas, only anecdotal evidence is available to help answer this question. In 1957, Kopp described a case of a shoe saleswoman who developed chronic radiation dermatitis on her own feet. More recent reports of basal cell carcinoma of the foot attributed to shoe store fluoroscopy have been reported by Oster-Schmidt in 2002 and Smullen in 2007.
From what we know of radiation exposure in animal experiments and from studies of atom bomb survivors and nuclear industry workers, a number of other problems can be hypothesized: foot-bone deformities in child customers, and testicular tumors and leukemia in salespeople. Unfortunately, due to the undocumented dosage and time course of the exposure, and to the long lag period between radiation and some of its side effects (e.g. cancer), the long term health consequences of shoe store fluoroscopy will likely never be known.
Although shoe-fitting fluoroscopes are no longer used, their story remains a cautionary tale in the ongoing struggle against quack medicine. The storyline of shoe-store fluoroscopy follows an arc familiar to woo-watchers:
- a real physical phenomenon or technology is discovered
- unsubstantiated health claims are made about it
- the potential dangers are discounted
- quack usage becomes popular and spreads widely
- government regulation catches up slowly, if not circumvented politically