RAD-171- RADIOGRAPHIC FILM

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the simplest form of radiographic film consists of what

a base and an emulsion
what is a covering that is applied to the emulsion
what is the purpose of this
- supercoating
- protects the emulsion from minor scratches and abrasions resulting from the handling of the film
what is the purpose of the base

provides support for the emulsion and supercoat
what were the material of a base originally

glass plates (wet and dry)
what dye is used in the film base to reduce eye strain

blue dye
what are the 4 characteristics of the base

flexible and tough - to permit easy handling and make good contact with the cassette pressure pads

stable - so it doesnt change dimensions during heating and immersion in chemicals

rigid - so it can be placed in a view box

uniformly lucent - so that it permits the transmission of light without adding artifacts to the diagnostic image
what does emulsion contain

contains silver halide crystals that will make the radiographic image
what is the crystal construction chemical reaction formula
what happens to potassium nitrate
- AgNO3 + KBr - AgBr + KNO3
- gets wasted and thrown away
what is the chemical formula for silver halide crystals

AgBr (silver bromide precipitate)
what is the structure of the emulsion
what is the purpose of the adhesive
- crystal lattice structure
- sensitivity specks
glues the emulsion to the base and prevents bubbles and other distortion when the film is bent during the processing or handling or when it is we and heated during development
in the emulsion the halide crystals are suspended in what

gelatin
in the manufacturing of a film explain the crystal production

it is accomplished in total darkness by combining silver nitrate and potassium bromide in the presence of gelatin
what is the shape of silver halides
a cubic millimeter contains how many halides
what is the impurity added to silver halide and forms what
- triangular and flat
- over half a billion
- gold silver sulfide forms sensitivity speck
what is ripening stage when processing a film
the size of the crystal determines what
the longer the ripening period ______
after emulsion is shredded and washed what is removed
- period in which crystals are allowed to grow
- total photosensitivity
- the larger the crystal or grains and the more sensitive the emulsion
- potassium nitrate
what crystal is used to get a better detail and which has less detail
- small crystal much slower and more radiation
- big crystal faster more sensitive to light less radiation
what stage follows the ripening stage (explain it)
what substances are mixed in with the emulsion
- mixing stage
- additives are mixed into the shredded emulsion
- colored dyes - to match the wavelengths of the photons striking the emulsion during exposure
- hardners - prevent physical trauma
- bacterides and fungicides to inhibit growth of these organisms
- antifogging agents to decrease the sensitivity to environmental factors such as heat
what is the fourth stage in manufacturing

coating - requires extremely precise and expensive coating equipment
what are impurities
what two ions does crystal lattice structure consist of
- chemical sensitivity speck
- Ag+ ions (bound silver ion or free silver ion)
- Br (Bromine ion halide 9could be iodine also)
what is a latent image

image that is formed by the interaction between xray photons and light. It is invisible and cannot be seen by the eye
when does the latent image become the visible image

during the development process
what is oxidation and reduction in the process of manifesting image formation
- developer diffuses into the emulsion
- transfer of electrons to sensitivity speck
- change of silver atoms to metallic silver
we should never do what to a wet cassette

close
film should be stored at a temperature of ____
what should humidity be
what material is used for cassettes
- 20 degrees celsius (68 degrees F) or lower
- 30-60%
- low attenuation graphite carbon fiber
speed is controlled by the ____ of the silver halide and the ____ thickness of the emulsion layer

size and thickness
smaller crystals and thinner emulsion films are considered to be ______ in speed or sensitivity
this provides the image with what detail
- slow
- high contrast with increase resolution
______ crystals and ____ emulsion films are considered ______ in speed
what image do they produce
what affects speed contrast and detail in the same fashion in the intensifying screen
- larger and thicker fast
- low contrast radiograph with decreased resolution
- phosphors
describe the gurney mott theory of latent image formation
- step 1: photon interacts with silver halide crystal which frees the electron
- step 2: electron migrates to sensitivity speck
- step 3: silver ion accepts electron and becomes metallic silver
- step 4: silver ion accepts electron and becomes metallic silver
- step 5: process continues until all silver ions become metallic silver forming a latent image
what are the three types of film
- direct exposure film
- inderect exposure films
- special application film
how do we clean films
what can cause films to fog
- with electrostatic cleaning solution
- a loaded cassette stored near heat bright sunlight or in an ionizing radiation activates screen phosphors

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anatomy12

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RAD-171- RADIOGRAPHIC FILM

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Updated

12/4/2013, 8:57:15 PM

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