Fluoroscopy

A fluoroscope produces a video x-ray. During a fluoroscopic exam, a continuous X-ray beam is used to view an organ or part of the body in real time. The live images are displayed on a computer screen or television monitor. Fluoroscopes are used for interventional procedures such as guiding the placement of a catheter during an arteriography, for assessing stomach and bowel movement and function, and for detecting obstructions in the airway or blood vessels. A contrast agent may also be used to enhance the images.

Fluoroscopy is most often used to view the upper GI tract, which includes the stomach, esophagus, duodenum, and the upper small intestine. It is also used to view the lower GI tract.

How fluoroscopy works
The fluoroscope is a type of x-ray machine that can use either a continuous or a pulsing x-ray beam. The x-ray machine has an x-ray tube that is constructed of glass or metal and has a vacuum seal inside. It generates x-rays by converting electricity from its power line (AC current of 120-480 volts) into electricity that falls into the 25-150 kilo volt range. This creates a stream of electrons that are shot against a tungsten target. When the electrons hit this target (called an anode) the atomic structure of the tungsten stops the electrons, causing a release of x-ray energy. This energy is focused by the x-ray tube onto the area of the body to be imaged.

These very energetic electromagnetic waves can pass through the body and create images of internal structures. Because the different tissues within the body are of different densities, those waves are attenuated (weakened) at differing rates as they pass through. Bone, for example, is very dense and absorbs a lot of the x-rays, while the tissues surrounding the bone are less dense and absorb less of the x-ray.

It is this difference in the absorption of the waves that creates variations in the exposures and allows the detail of the image to be formed.

With a fluoroscope, when the beam passes through the body it hits an image intensifier that increases the brightness of the image many times (e.g. x1000 to x5000) so that it can be viewed on a display screen. The image intensifier itself is coupled to a video camera that captures and encodes the two-dimensional patterns of light as a video signal from the x-ray machine. The signal is converted back into a pattern of light seen as the image on the monitor. The camera output can be digitized for computer image enhancements.

The fluoroscope produces a low dose of radiation, slightly higher than a regular x-ray so it is very important that you let the doctor know if you are pregnant or think you might be.

What to expect when you have fluoroscopic imaging:
Fluoroscopic imaging is painless. Before the imaging you will need to remove any jewelry or clothing that are in the area being scanned. For GI studies, you will usually need to drink barium, or have a barium enema. The barium provides the contrast needed to produce a clear image that can detect polyps and other abnormalities or obstructions.

You will then lie on a table or stand depending on the purpose and area being imaged. The camera will be moved to a position above or in front of you in order to get the proper angle for the images. The procedure will take anywhere from a few minutes to an hour depending on the purpose of the imaging. For example, fluoroscopy is often used in interventional radiology to aid the positioning of a needle for a biopsy or other procedure.

IMPORTANT: If you are pregnant, or if you think you MIGHT be pregnant, tell the RRA technician or radiologist. While x-rays are safe for you, they are not safe for the developing embryo.

An RRA radiologist will interpret the images and contact your physician to discuss the results. You will be contacted by your physician.