1. Radiographic Contrast and Density Flashcards
Radiographic Density also known as
optical density, photographic density, or film density
a measure of the degree of film darkening
Radiographic Density
the degree of darkness
Radiographic Density
the degree of density difference between
two areas on a radiograph
Radiographic Contrast
difference between those x-rays absorbed and those transmitted to the IR (image receptor)
Differential Absorption
the most important characteristic of a radiograph
Technical balance
In a radiographic sense, balance is the relationship between ______, ______, and ______
contrast, density, and sharpness
abrupt density differences
Short scale contrast
subtle details can be missed
Short scale contrast
produce visibility of detail
variations in density (contrast)
2 Major Elements that Make up Radiographic Contrast
Subject Contrast and Film Contrast
is the amount of differential absorption that has taken place among the various body structures lying in the path of the x-ray beam
Subject Contrast
Image Receptors (IR) can either be ______ or _______
Film Cassettes, CR IP (Computerized Radiography Imaging Plates)
one element that remains constant and will determine radiographic contrast
Differential Absorption of Subject Contrast
denotes the inherent sensitivity a given emulsion has to variations in the intensity of remnant photons striking its surface
Film Contrast
Harmony must exist between ____ and ____ before a good radiographic result can be gained
Film and Subject Contrast
durable protection layer
Super coat
contains the black metallic silver,
radiation and light-sensitive layer
Emulsion
adheres layers together
Adhesive
polyester layer that gives the film physical stability
Film base
made of mixture of gelatin and silver halide crystals (fluorine, chlorine, bromine and iodine)
Film Emulsion
most of x-ray film emulsions are made of:
Silver Bromide (90%), Silver Iodine (10%)
activated by light and radiation to create image
Photographically active layer
the degree of blackness over the area being viewed
Radiographic density
the third major characteristic
Sharpness or Definition
the radiographic image has 2 types of detail:
Visibility of detail, Sharpness of detail
how well we can see the structures that have been transferred to the film’s emulsion by the quantity and variation of remnant photons.
Visibility of detail
The more pronounced/noticeable these absorption differences are,
the ______ the subject contrast will be.
greater
Other things remaining constant, the _______________ will determine radiographic
contrast.
degree of differential absorption (subject contrast)
Assuming all factors are held constant – as subject contrast is increased, radiographic contrast will ______.
increase
There must be an overall ______ present in the radiographic
image to produce optimal detail visualization
Density
It is obtained when a sufficient accumulation of black metallic silver
crystals is present in the film
Density
The accumulation of silver is directly related to the number of _________ that struck the film during an exposure
remnant photons
if a small number of x-ray photons strike the film, the
accumulation of black silver crystals will be ____ and when the film is placed on the x-ray illuminator, the eye will have great _____ seeing the intended detail
sparse,
difficulty
If a remnant beam is sufficiently intense, the overall accumulation
of silver would be ______ along with associated detail.
evident
The film’s inherent ability to emphasize intensities of the remnant
beam will determine _________
Radiographic Contrast
