latent image

latent image,

an invisible image produced in a film emulsion by x-rays or visible light that can be converted into a visible image by development.

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latent,

adj hidden; beneath the surface; not obvious or active.

latent image,

n See image, latent.

latent period,

n See period, latent.

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image

the picture reproduced on the x-ray film or by other radioimaging methods such as ultrasonography.

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image amplifier system

includes amplifer and viewer or television camera and tape player.

image display modes

see ultrasonography, A-mode, B-mode and M-mode.

image formation

exposure of the film to the x-ray beam ionizing radiation or to other radiant energy forms causes ionic changes in the silver bromide crystals in the film emulsion so that it acquires a silver atom. It is the deposition of reduced silver atoms in particles or zones that causes the black zones or foci on the film. The amount of silver deposited depends on the intensity of the initial radiation x-ray exposure.

image intensification

a technique used to increase the brightness of the image while maintaining its sharpness. Used particularly in fluoroscopy and viewing directly or indirectly through a television camera and monitor, cineradiography, videotape or split-film device.

latent image

the invisible picture on the film after it has been exposed to the x-ray beam. It requires exposure to a developer and fixer before the image is visible and permanent.

weak image

said of x-ray films which lack density due to underexposure, too brief period of development, insufficient developer or developer temperature too low.