Fluorography

 Fluorography (or photofluorography) is the technique of photographing an image produced by light emitted from a fluorescent screen or material. Light is produced by the excitation of a fluorescent material by ionizing radiation, which is produced when charged particles (electrons or beta particles( emitted from radionuclides such as tritium (³H), carbon-14 (¹⁴C), phosphorus-32 (³²P), sulfur-35  (³⁵S), or iodine-125 (¹²⁵I) interact with the material. The emitted light exposes the film, and an image is recorded.

 Fluorography is a common technique used in molecular biology blotting experiments to increase the sensitivity of medium-to-low energy beta-particle-emitting radioisotopes embedded in gel slices. A fluorescent screen is sometimes used to amplify the amount of light produced. A fluorescent screen is a sheet of material that is coated with fluorescent reagents (fluorophores, luminophores, or fluorochromes. (

Fluorescence enhances the intensity of the image recorded in the film and makes it possible to obtain images in shorter time periods and with less radioactivity than conventional autoradiography. Fluorographic detection of blotted samples can reduce exposure times by factors of 5 to 10 and can increase sensitivity by factors of 3 to 5 over the use of dried gels (1). Fluorography works best with flashed film and exposures of film at –70°C. Film flashing helps to detect weak bands or spots. Flashing also helps to reduce the threshold of detection. Before fluorography, gels should be fixed with 30% isopropyl alcohol and 10% acetic acid to immobilize the separated proteins and to remove non-protein components that might interfere with subsequent staining.

 Radiation-free fluorographic techniques for Southern blots have been developed using  chemical luminescence. Samples are placed on a chemiluminescent substrate sheet, and the blot exposed to X-ray film for about 70 min at 37°C.

 In other industrial and medical applications, fluorescent materials respond also to radiation from gamma-emitting radioisotopes, X-ray sources, electron beams, and charged particles. A fluorograph is the photograph produced by the light from fluorescent materials, and a fluoroscope is a device for viewing the light from fluorescing materials. A fluorescence digital imaging microscope is an instrument for viewing microscopic images of fluorescing substances, which are stimulated by ultraviolet light and filtered so that the observer sees only the fluorescence emission and not the stimulating light.

Fluorography is sometimes called abreuography in honor of Manuel de Abreau, a Brazilian physician who discovered the technique.

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