The invention of the fluoroscope was very useful in the medical world. Doctors and physicians use the machine for a variety of reasons. The first fluoroscopes consisted of an x-ray source and fluorescent screen between which the patient would be placed. As the x rays pass through the patient, they are attenuated by varying amounts as they interact with the different internal structures of the body, casting a shadow of the structures on the fluorescent screen. Images on the screen are produced as the unattenuated x rays interact with atoms in the screen through the photoelectric effect, giving their energy to the electrons. While much of the energy given to the electrons is dissipated as heat, a fraction of it is given off as visible light, producing the images. Early radiologists would adapt their eyes to view the dim fluoroscopic images by sitting in darkened rooms, or by wearing red adaptation goggles. 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.
A fluoroscope consists of an x-ray source and fluorescent screen. The patient either lies down or stands between the source and screen. The ability of fluoroscopy to display motion is provided by a continuous series of images produced at a maximum rate of 25-30 complete images per second. This is similar to the way conventional television or video transmits.
Because x-rays are a form of ionizing radiation they can have risks. While physicians always try to use low dose rates during fluoroscopic procedures, the length of a typical procedure often results in a relatively high absorbed dose to the patient. Therefore, the total fluoroscopic time is one of the major factors that determines the exposure to the patient from fluoroscopy. Exposure times vary depending on the procedure being performed, but procedure times up to 75 minutes have been documented. Because of the long length of some procedues, in addition to standard cancer-inducing stochastic radiation effects, deterministic radiation effects have also been observed ranging from mild erythema , equivalent of a sun burn, to more serious burns. While deterministic radiation effects are a possibility, radiation burns are not typical of standard fluoroscopic procedures.
Most procedures sufficiently long in duration to produce radiation burns are part of necessary life-saving operations.The advantages of realtime imaging and the freedom to freely position the Xray field during examination makes fluoroscopy a very powerful diagnostic tool.
However, due to the length of the fluoroscopic examinations, the exposure rate must be kept very much lower than in common radiography.Common procedures involving fluoroscopy include 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 contrst media. Fluoroscopy may be performed on an outpatient basis or when u stay at the hospital. The most common fluoroscopy procedures are upper GI series, Barium Meal, Barium swallow, Small Bowel Meal (SBM), and Barium Enemas.
