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Conventional and digital fluoroscopy


Fluoroscopy is the method that provides real-time x-ray imaging that is especially useful for guiding a variety of diagnostic and interventional procedures. The ability of fluoroscopy to display motion is provided by a continuous series of images produced at a rate of 25-30 complete images per second. This is similar to the way conventional television or video transmits images.

The radiation dose rates for fluoroscopy are relatively high and the exposure times can be long, depending on the complexity of the procedure, and the skill and experience of the imaging physician responsible for the procedure. Consequently, a thorough understanding of the technology and radiation doses from fluoroscopy is essential.

Conventional and digital fluoroscopy differ primarily in the imaging system, i.e., an image intensifier-video camera system versus a digital imaging chain which may have neither an image intensifier nor video camera. In general, all other portions of the equipment are similar.

Important Principles

Fluoroscopic imaging involves the use of complex imaging equipment including sophisticated automatic exposure control systems and equipment designed to capture a single image or multiple images. Many fluoroscopic procedures are complex, and the equipment is used for diagnostic as well as therapeutic (interventional) applications.

Doses from fluoroscopic equipment, especially for interventional purposes, can be high resulting in both stochastic and deterministic effects. Use of the fluoroscopic imaging system at higher than necessary kilovoltages and tube currents, heavy or obese patients producing high dose rates from the automatic exposure control system, and long fluoroscopy times as a result of complex examinations or imaging physicians with limited experience or fluoroscopy skills, can all result in high patient (and staff) radiation doses. Consequently, optimization is essential to assure that the image quality provides adequate information for the procedure while the patient dose is maintained at an acceptable level.

Introduction to References

The references include information on conventional and digital fluoroscopic systems, dosimetry, and quality control. The AAPM-RSNA Physics Tutorials for Residents provide excellent information on fluoroscopy.