Shoe-fitting fluoroscope

In the second half of the 20th century, growing awareness of radiation hazards and increasingly stringent regulations forced their gradual phasing out.

Clarence Karrer, the son of an X-ray equipment distributor, claims to have built the first unit in 1924 in Milwaukee, but had his idea stolen and patented by one of his father's employees.

[4] The X-ray Shoe Fitter Corporation of Milwaukee and Pedoscope Company became the largest manufacturers of shoe-fitting fluoroscopes in the world.

The risk of radiation burns to extremities was known since Wilhelm Röntgen's 1895 experiment, but this was a short-term effect with early warning from reddening of the skin (erythema).

The long-term risks from chronic exposure to radiation began to emerge with Hermann Joseph Muller's 1927 paper showing genetic effects,[5] 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.

[10] 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.