Fluoroscopy is similar to radiography and X-ray computed tomography (X-ray CT) in that it generates images using X-rays.
The original difference was that radiography fixed still images on film whereas fluoroscopy provided live moving pictures that were not stored.
However, today radiography, CT, and fluoroscopy are all digital imaging modes with image analysis software and data storage and retrieval.
The use of X-rays, a form of ionizing radiation, requires the potential risks from a procedure to be carefully balanced with the benefits of the procedure to the patient.
Because the patient must be exposed to a continuous source of X-rays instead of a momentary pulse
a fluoroscopy procedure generally subjects a patient to a higher absorbed dose of radiation than an ordinary (still) radiograph.
Only important applications such as health care, bodily safety, food safety, nondestructive testing
and scientific research meet the risk-benefit threshold for use. In the first half of the 20th century shoe-fitting fluoroscopes were used in shoe stores
but their use was discontinued because it is no longer considered acceptable to use radiation exposure
however small the dose, for nonessential purposes. Much research has been directed toward reducing radiation exposure
and recent advances in fluoroscopy technology such as digital image processing and flat panel detectors-
have resulted in much lower radiation doses than former procedures.