Question

What does “film-screen” mean?

The goal is to be able to understand what the question is asking, be able to understand the answer, and also use your own words as much as

possible.

                 

Answer 1

X-rays were discovered by W.C. Roentgen because of their ability to cause fluorescence.
X-ray photons cannot be seen. The image produced by X-rays may be captured on a film, may
be viewed directly (fluoroscopy) or on a monitor with digital radiology.
Roentgen initially used a sheet of platinocyanide to view the fluorescence produced by X-ray
photons. It was shortly thereafter that photographic plates were adapted for radiographic
purposes.
The combination of screen films, intensifying screens and cassettes are used in making extraoral
images. The main function of screens is to reduce radiation to the patient.
Currently, there are two groups of X-ray films for dental purposes:

1. Non-screen - Those with emulsions more sensitive to direct exposure of X - rays.
These are primarily used as intraoral films and provide excellent image quality.

2. Screen - Those with emulsions more sensitive to blue [standard] OR green [rare
earth] light. Emitted when X-rays strike the intensifying screens. The X-ray
photons are converted to visible light photons.

Screen film is used for extraoral views, such as panoramic, cephalometric and TMJ imaging. It is
manufactured with dyes in the emulsion that absorb specific wavelengths of visible light.
Unfortunately, it does not produce the image detail of non-screen films. Screen films are always
used in combination with intensifying screens.
With screen-film, it is mainly the light photons from the intensifying screens that produces the
image on the film and not the photons. Intensifying screens permit a good radiograph to
be produced with the patient receiving a much lower dose of radiation. This film is
very sensitive to both X-ray photons and light photons but much more sensitive to light photons