intensifying screen


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screen

 [skrēn]
1. a framework or agent used as a shield or protector; called also protectant and protective.
2. to separate well individuals in a population from those who have an undiagnosed disease, defect, or other pathologic condition or who are at high risk by means of tests, examinations, or other procedures. See also screening.
Bjerrum screen tangent screen.
fluoroscopic screen a phosphorescent screen that shows the movement and relationship of organs and structures in fluoroscopy.
intensifying screen a fluorescent screen used in conjunction with x-ray film to enhance the effect of the radiation and reduce dosage to the patient. The screen must be matched to the emissivity range; the emissivity of phosphorus is similar to that of the human eye, so that phosphors absorb x-ray energy and convert it to visible light.
tangent screen a large square of black cloth with a central mark for fixation; used with a campimeter in mapping the field of vision.

in·ten·si·fy·ing screen

a screen (6) used in radiography.

intensifying screen

[inten′sifī′ing]
Etymology: L, intensus, tighten, facere, to make; ME, screne
a device consisting of fluorescent material, which is placed in contact with the film in a radiographic cassette. Radiation interacts with the fluorescent phosphor, releasing light photons. These photons expose the film with greater efficiency than would the radiation alone. Thus patient exposure to radiation can be reduced.

in·ten·si·fy·ing screen

(in-tensi-fī-ing skrēn)
Material consisting of phosphors present in the radiographic cassette that converts the invisible energy of an x-ray beam into visible light energy, augmenting the intensity of film exposure.

intensifying screen,

intensity of a radiographic beam,
n the amount of energy in a radiographic beam per unit volume or area.

intensifying screen

calcium tungstate screens which fluoresce and transform the invisible x-ray image to a fluorescent blue or ultraviolet one. This reduces the exposure time a great deal. The image is intensified. Rare-earth intensifying screens are more modern and produce more intensification. They also produce different colored light, depending on the rare earth used.

rare-earth intensifying screen
faster than the standard calcium tungstate screens but much more usable at high kV range. They require the use of special film and safelights.
References in periodicals archive ?
Properly maintained intensifying screens last indefinitely.
In contrast, the intensifying screens employed with the radiographic film reduce the exposure time to no more than 6 seconds, making a survey of many specimens possible each day.
The unit will continue to serve diagnostic imaging applications with such products as x-ray film, intensifying screens, cassettes, processors and chemicals, used in diagnostic imaging departments, cardiac catheterization laboratories, independent imaging clinics, and professional offices such as dental offices.
To increase its efficiency and lower the required dosage of X-rays, the film can be sandwiched between sheets of plastic called intensifying screens.
In addition, the appendices cover special topics such as mobile van processing, the cleaning of intensifying screens and the handling and processing of mammography film.
Chapter topics include vision and perception, beam restriction, the patient as a beam emitter, the pathology problem, the grid, radiographic film, radiographic processing, sensitometry, intensifying screens and film-screen combinations.
The indirect exposure system with salt intensifying screens actually is a light exposure, and the screen does not respond linearly to the radiation.