page_title: Shoe-fitting fluoroscope
section_title: Health concerns
hierarchical_section_title: Shoe-fitting fluoroscope / Health concerns
caption_attribution_description: English: This decommissioned Adrian Fluoroscope is part of the collection of the Dufferin County Museum in Ontario, Canada. This image shows the operator's controls and three viewing screens on the top of the device. On the opposite side is a low platform with two half-circle holes cut into the vertical back surface for inserting the fronts of the shoes. The device emitted lots of radiation when operated, so it was sent to Ottawa, where it was rendered harmless by removing the x-ray tube head. w:Shoe-fitting fluoroscope
context_page_description: Shoe-fitting fluoroscopes, also sold under the names X-ray Shoe Fitter, Pedoscope and Foot-o-scope, were X-ray fluoroscope machines installed in shoe stores from the 1920s until about the 1970s in the United States, Canada, United Kingdom, South Africa, Germany and Switzerland. In the UK, they were known as Pedoscopes, after the company based in St. Albans that manufactured them. At the beginning of the 1930s, Bally was the first company to import pedoscopes into Switzerland from the UK. In the second half of the 20th century, growing awareness of radiation hazards and increasingly stringent regulations forced their gradual phasing out.
  A shoe-fitting fluoroscope was a metal construction covered in finished wood, approximately 4 feet high in the shape of short column, with a ledge with an opening where the child would then place their feet in the opening provided and while remaining in a standing position, look through a viewing porthole at the top of the fluoroscope down at the x-ray view of the feet and shoes.
context_section_description: The risk of radiation burns to extremities were known since Wilhelm Röntgen's 1895 experiment, but this was a short-term effect with early warning from erythema. The long-term risks from chronic exposure to radiation began to emerge with Hermann Joseph Muller's 1927 paper showing genetic effects, and the incidence of bone cancer in radium dial painters of the same time period. However, there was not enough data to quantify the level of risk until atomic bomb survivors began to experience the long-term effects of radiation in the late 1940s. The first scientific evaluations of these machines in 1948 immediately sparked concern for radiation protection and electrical safety reasons, and found them ineffective at shoe fitting.
  Large variations in dose were possible depending on the machine design, displacement of the shielding materials, and the time and frequency of use. Radiation surveys showed that American machines delivered an average of 13 roentgen (r) (roughly 0.13 sievert (Sv) of equivalent dose in modern units) to the customer's feet during a typical 20 second viewing, with one capable of delivering 116 r (~1 Sv) in 20 seconds. British Pedoscopes were about ten times less powerful. A customer might try several shoes in a day, or return several times in a year, and radiation dose effects may be cumulative. A dose of 300 r can cause growth disturbance in a child, and 600 r can cause erythema in an adult. Hands and feet are relatively resistant to other forms of radiation damage, such as carcinogenesis.
  Although most of the dose was directed at the feet, a substantial amount would scatter or leak in all directions. Shielding materials were sometimes displaced to improve image quality, to make the machine lighter, or out of carelessness, and this aggravated the leakage. The resulting whole-body dose may have been hazardous to the salesmen, who were chronically exposed, and to children, who are about twice as radiosensitive as adults. Monitoring of American salespersons found dose rates at pelvis height of up to 95 mr/week, with an average of 7.1 mr/week (up to ~50 mSv/a, avg ~3.7 mSv/an effective dose). A 2007 paper suggested that even higher doses of 0.5 Sv/a were plausible. The most widely accepted model of radiation-induced cancer posits that the incidence of cancers due to ionizing radiation increases linearly with effective (i.e., whole-body) dose at a rate of 5.5% per Sv.
  Years or decades may elapse between radiation exposure and a related occurrence of cancer, and no follow-up studies of customers can be performed for lack of records. A 1950 medical article on the machines pointed out though: "Present evidence indicates that at least some radiation injuries are statistical processes that do not have a threshold. If this evidence is valid, there is no exposure which is absolutely safe and which produces no effect." Three shoe salespersons have been identified with rare conditions that might be associated with their chronic occupational exposure: a severe radiation burn requiring amputation in 1950, a case of dermatitis with ulceration in 1957,  and a case of basal-cell carcinoma of the sole in 2004.
caption: An Adrian Fluoroscope at the Dufferin County Museum, Ontario, Canada (2012). This device required lengthy decommissioning work before it could be safely put on public display due to the risk of radiation burn.
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