The fluoroscope is a medical instrument used by physicians to view the internal organss of the body best described as a "motion X-ray". Like an x-ray machine it takes an image of the interior of the body, but unlike the x-ray it uses a powerful radiation source to project the image continuously onto a fluorescent screen.
Although the regular X-ray photograph shows more detail, fluoroscopy is preferable when the physician wants to see the live image, i.e., observe the size, shape, and movement of the patient's internal organs. For a time they could be found in many applications, including several famous motion pictures showing chewing and swollowing, and they were used for some time to fit shoes. However it was soon learned that the radiation used was causing serious burns and cancerous lesions, and the fluoroscope disappeared from most medical uses.
In industry the fluoroscope is used for the examination of materials, manufactured objects, welds, castings, and other objects, principally for flaws.
