Photofluorography (sometimes called just fluorography) is photography of X-ray images from a fluorescent screen.Photofluorography
/ref> It is commonly used in some countries for chest X-ray screening, e.g. to diagnose tuberculosis (see Abreugraphy 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 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 electrons 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. 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. 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 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, kinescope, TV, or display.

References

{{Medical imaging Fluoroscopy

Method of image formation in photofluorography

See also

References