Fluoroscopy is an imaging modality that allows real-time x-ray viewing of a patient with high temporal resolution. It is based on an x-ray image intensifier coupled to a still/video camera. In recent years flat panel detectors (which are similar to the digital radiography used in projection radiography) have been replacing the image intensifiers.

Fluoroscopic apparatus uses low current (0.5-5 mA) for continuous or near-continuous x-ray exposures. Resultant images have relatively low signal to noise ratio (SNR) but are of sufficient quality for patient positioning and certain diagnostic/therapeutic procedures.

Overview of a fluoroscopy system

  • x-ray generator
  • x-ray tube, including filters and collimation
  • patient table (which may be horizontal or erect)
  • image intensifier: converts x-rays emerging from the patient into an optical image
  • optical distributor: used to couple the output image from the image intensifier to receiving devices:
    • video camera: converts the image into an electronic signal, which can be fed into the image display/record device
    • spot-film camera recording static images onto film, which may incorporate a film changer (radiography and fluoroscopy (R&F) system)
    • cine camera: to record a sequence of images onto a roll of film/digital medium
    • image displaying/recording device
      • video monitor: for immediate display of image (videofluoroscopy)
      • videotape recorder: for storage and subsequent replay
    • computer: for digital image processing, analysis and storage (digital fluorography), e.g. digital subtraction angiography (DSA)
Design of the x-ray tube and image intensifier assembly

There are various setups of fluoroscopy machines:

  • ceiling-suspended image intensifier and under-table tube (most common)
  • ceiling-suspended tube and under-table image intensifier
  • C-arm assembly: either ceiling-suspended or floor-mounted (for DSA and interventional procedures)
  • mobile C-arm system (for operating theater)

See also

Siehe auch: