Now you may like me remember as children going to your friendly shoe shop and being measured by the shop assistant using a fantoosh x-ray machine. A fluorescent image of the feet was reflected to three viewing ports at the top of the x ray cabinet, where the customer, the salesperson, and a third person usually accompanying adult could gaze with wonderment at the foot sitting in the new shoe. Tres space age. The Pedoscope remained in vogue for well over 40 years, but are nowhere to be seen now. Where did they come from, and perhaps more importantly where are they now?
By the end of the nineteenth century medicos in the military were befuddled by a new disease, which affected servicemen leaving them crippled and unable to march. The condition was called Pied Force. Doctors were taken with a new technology involving X-rays and set to investigate the mysterious foot injury that had been endemic in all infantries. They soon discovered it was a subtle fracture of the second metatarsal bone caused by prolonged marching (March fracture).
Once they understood the cause they could treat soldiers already injured as well as prevent new cases. By the end of the Great War however there was a large surplus of Army portable X-ray units. Keen to sell these off, the surplus industry found the ready to wear shoe sector, eager customers. The shoe-fitting fluoroscope (or Pedoscope) was thought to be developed around 1924 by Clarence Karrer while he worked with his father, selling surgical supplies and x-ray equipment. After building and selling several to shoe manufacturers and retailers, he was asked by the Radiological Society of North America and some radiologists to stop because it "lowered the dignity of the profession of radiology." Karrer complied, but another of his father's employees quit the company and patented the device.
The primary component of a shoe-fitting x-ray unit was the fluoroscope which consisted essentially of an x-ray tube mounted near the floor and wholly or partially enclosed in a shielded box. When feet were stuck in they struck the fluorescent light and an image of the feet inside the shoes was seen through the view boxes. Curiously they had buttons marked "Man", "Woman" and "Child" but the radiation dosages were all equal. The machines were often out of adjustment and were constructed so radiation leaked into the surrounding area. By the 50s, radiation hazards associated with shoe fitting x-ray units were recognized and concerns for safety from exposure to radiation grew until by the sixties these were banned in many places and regulated in others. The kV would have been on the lower end and emitted radiation only occurring when the electric current was applied. This would not be acceptable by today's standards; many experts believe there was no actual radiation risk. Studies suggest cases of radiation-induced leukemia tend to peak 7-15 years after exposure. So it is unlikely if at=re reading this and were exposed to radiation via the fluoroscope as a child , then you are passed the critical stage. Those most at risk were the salespeople, who were exposed to radiation on a daily basis but there is no evidence to support associated death and disease. Shoe store fluoroscopes were typical of the careless and in some cases frivolous attitude toward X rays that prevailed for decades.