Photofluorography (sometimes called just fluorography) is

photography Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed ...

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

images from a

fluorescent Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...

screen.Photofluorography
/ref> It is commonly used in some countries for chest X-ray screening, e.g. to diagnose

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...

(see

Abreugraphy Chest photofluorography, or abreugraphy (also called mass miniature radiography), is a photofluorography technique for mass screening for tuberculosis using a miniature (50 to 100 mm) photograph of the screen of an X-ray fluoroscopy of the th ...

for more information on such usage of this technique).

Method of image formation in photofluorography

X-ray beams from the tube get attenuated by the patient producing a transmitted

radiation intensity In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visib ...

corresponding to the part of the body traversed by the X-ray beam. Transmitted intensities now fall on the

photocathode A photocathode is a surface engineered to convert light (photons) into electrons using the photoelectric effect. Photocathodes are important in accelerator physics where they are utilised in a photoinjector to generate high brightness electron be ...

stimulating it to produce

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no kn ...

s in quantities external to the light intensities emitted by the input. This is caused by the formation of a light image of the transmitted

radiation pattern In the field of antenna design the term radiation pattern (or antenna pattern or far-field pattern) refers to the ''directional'' (angular) dependence of the strength of the radio waves from the antenna or other source.Constantine A. Balanis: “A ...

. Electrons from the photocathode are accelerated and focused electronically out on the output

phosphor A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or vi ...

which emits light as a result of

electron bombardment Electron ionization (EI, formerly known as electron impact ionization and electron bombardment ionization) is an ionization method in which energetic electrons interact with solid or gas phase atoms or molecules to produce ions. EI was one of th ...

. This shows a magnified image of what appears on the input phosphor. The semitransparent mirror splits the image in which one part is focused by the

camera lens A camera lens (also known as photographic lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capab ...

onto the

film A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere ...

to form the image. The image size depends on the

focal length The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative foca ...

of the camera lens. At the same time, the

TV camera A professional video camera (often called a television camera even though its use has spread beyond television) is a high-end device for creating electronic moving images (as opposed to a movie camera, that earlier recorded the images on film). O ...

lens focuses the light to form an image on the TV camera photoreceptor where the image is transformed to a complex electronic signal and sent to the electronic image distributor. This then passes the image to the various display or recording devices, e.g. a

videotape recorder A video tape recorder (VTR) is a tape recorder designed to record and playback video and audio signal, audio material from magnetic tape. The early VTRs were reel-to-reel, open-reel devices that record on individual reels of 2-inch-wide (5.08& ...

kinescope Kinescope , shortened to kine , also known as telerecording in Britain, is a recording of a television program on motion picture film, directly through a lens focused on the screen of a video monitor. The process was pioneered during the 1940 ...

, TV, or display.

References

{{Medical imaging Fluoroscopy

Method of image formation in photofluorography

See also

References