A History of Fluoroscopy

The beginning of fluoroscopy can be traced back to 8 November 1895 when Wilhelm Röntgen noticed a barium platinocyanide screen fluorescing as a result of being exposed to what he would later call x rays. Within months of this discovery, the first fluoroscopes were created. Thomas Edison quickly discovered that calcium tungstate screens produced brighter images and is credited with designing and producing the first commercially available fluoroscope. In its infancy, many incorrectly predicted that the moving images from fluoroscopy would completely replace the still x-ray radiographs, but the superior diagnostic quality of the earlier radiographs prevented this from occurring.


Ignorance of the harmful effects of x rays resulted in the absence of standard radiation safety procedures which are employed today. Scientists and physicians would often place their hands directly in the x-ray beam resulting in radiation burns. Trivial uses for the technology also resulted, including the Shoe-Fitting Fluoroscope used by shoe stores in the 1930s-1950s.

Due to the limited light produced from the fluorescent screens, early radiologists were required to sit in a darkened room, in which the procedure was to be performed, accustomizing their eyes to the dark and thereby increasing their sensitivity to the light. The placement of the radiologist behind the screen resulted in significant radiation doses to the radiologist. Red adaptation goggles were developed by Wilhelm Trendleenburg in 1916 to address the problem of dark adaptation of the eyes, previously studied by Antoine Beclere. The resulting red light from the goggles' filtration correctly sensitized the physician's eyes prior to the procedure while still allowing him to receive enough light to function normally.


The development of the image intensifier and the television camera in the 1950s revolutionized fluoroscopy. The red adaptation goggles became obsolete as image intensifiers allowed the light produced by the fluorescent screen to be amplified, allowing it to be seen even in a lighted room. The addition of the camera enabled viewing of the image on a monitor, allowing a radiologist to view the images in a separate room away from the risk of radiation exposure.

More modern improvements in screen phosphors, image intensifiers and even flat panel detectors have allowed for increased image quality while minimizing the radiation dose to the patient. Modern fluoroscopes use CsI screens and produce noise-limited images, ensuring that the minimal radiation dose results while still obtaining images of acceptable quality.

Check out ancient fluoroscopy artifacts at:
www.orau.org/ptp/collection/Radiology/radiology.htm

Fluoroscopy

What is fluoroscopy?

Fluoroscopy is a study of moving body structures - similar to an x-ray "movie." A continuous x-ray beam is passed through the body part being examined, and is transmitted to a TV-like monitor so that the body part and its motion can be seen in detail.

Fluoroscopy, as an imaging tool, enables physicians to look at many body systems, including the skeletal, digestive, urinary, respiratory, and reproductive systems. Fluoroscopy may be performed to evaluate specific areas of the body, including the bones, muscles, and joints, as well as solid organs such as the heart, lung, or kidneys.

Fluoroscopy is used in many types of examinations and procedures, such as barium x-rays, cardiac catheterization, arthrography (visualization of a joint or joints), lumbar puncture, placement of intravenous (IV) catheters (hollow tubes inserted into veins or arteries), intravenous pyelogram, hysterosalpingogram, and biopsies.

Fluoroscopy may be used alone as a diagnostic procedure, or may be used in conjunction with other diagnostic or therapeutic media or procedures.

In barium x-rays, fluoroscopy used alone allows the physician to see the movement of the intestines as the barium moves through them. In cardiac catheterization, fluoroscopy is added to enable the physician to see the flow of blood through the coronary arteries in order to evaluate the presence of arterial blockages. For intravenous catheter insertion, fluoroscopy assists the physician in guiding the catheter into a specific location inside the body.

Other uses of fluoroscopy include, but are not limited to, the following:
locating foreign bodies
viscosupplementation injections of the knees - a procedure in which a liquid substance that acts as a cartilage replacement or supplement is injected into the knee joint
image-guided anesthetic injections into joints or the spine
percutaneous vertebroplasty - a minimally invasive procedure used to treat compression fractures of the vertebrae of the spine

How is fluoroscopy performed?

Fluoroscopy may be part of an examination or procedure that is done on either an outpatient or inpatient basis. The specific type of procedure or examination being done will determine whether any preparation prior to the procedure is required. Your physician should notify you of any pre-procedure instructions.

Although each facility may have specific protocols in place and specific examinations and procedures may differ, fluoroscopy procedures generally follow this process:

An intravenous (IV) line will be inserted in the patient's hand or arm.

The patient will be positioned on the x-ray table.

For procedures that require catheter insertion, such as cardiac catheterization or catheter placement, an additional line insertion site may be used in the groin, elbow, or other site.

A special x-ray scanner will be used to produce the fluoroscopic images of the body structure being examined or treated.

A dye or contrast substance may be injected into the IV line in order to better visualize the structure being studied.

The type of care required after the procedure will depend on the type of procedure done. Certain procedures, such as cardiac catheterization, will require a recovery period of several hours with immobilization of the leg or arm where the cardiac catheter was inserted. Other procedures may require less time for recovery. The physician will give more specific instructions related to care after the examination or procedure.

Tomography

Tomography
otherwise known as body section radiography, planigraphy, laminography or stratigraphy, is the process of using motion of the X-ray focal spot and image receptor (e.g. film) in generating radiographic images where object detail from only one plane or region remains in sharp focus. Details from other planes in the object which would otherwise contribute confounding detail to the image, are blurred and effectively removed from visual consideration in the image. A variety of tomography techniques have been developed, which differ primarily in the manner in which the X-ray source and film move.

Linear tomography is one of the most basic techniques. As the tube and film move from the first position to the second, all points in the focal plane project to the same position on X-ray film. Thus, points a, b and c project to points a', b' and c' in the first position and a", b" and c" in the second position. Points above or below the focal plane do not project to the same film positions and are blurred. By changing the relative motion of the film and tube, the focal plane can be adjusted upward or downward.

A somewhat more complicated technique known as multidirectional tomography produces an even sharper image by moving the film and X-ray tube in a circular or elliptical pattern. As long as both tube and film move in synchrony, a clear image of objects in the focal plane can be produced. These tomographic approaches have been used to study the kidneys and other abdominal structures that are surrounded by tissues of nearly the same density and so cannot be differentiated by conventional X-ray techniques. They have also been employed to examine the small bones and other structures of the ear, which are surrounded by relatively dense temporal bone.