Radiographic Film - PowerPoint PPT Presentation

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Radiographic Film

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Title: Radiographic Film


1
Radiographic Film
Arino Celjhon B.
Joanna Miranda Celjhon Ariño
2
X-ray film
  • Film is a media that makes a permanent record of
    the image.
  • Image recorded on film is caused by exposure to
    photons
  • Radiographic film is/was most common image
    receptor

3
Radiographic Film Base
  • First Film
  • Glass Plates
  • WW1
  • Cellulose Nitrate
  • Highly Flammable
  • Easily Torn
  • Responsible for many fires in hospital basements
  • Cellulose Triacetate

4
Film construction BASE
  • Made of polyester plastic
  • Must be clear, strong, consistent thickness
  • Tinted pale blue or blue-gray (reduces eye
    strain)
  • Coated on 1 or 2 sides with emulsion

5
Film Construction - EMULSION
  • Film emulsion can be on one side or both sides of
    base (single emulsion/double emulsion)
  • Protective overcoat layered on top of emulsion
  • Emulsion is a gelatin, containing the film
    crystals
  • Emulsion is the active layer of the film

6
FILM COMPOSITION
  • SINGLE OR DOUBLE EMULSION
  • COATED ON A BASE
  • EMULSION GELATIN
  • WITH SILBER HALIDE CRYSTALS
  • BASE SUPPORT (POLYESTER)

7
FILM EMULSION
  • Made of mixture of gelatin silver halide
    crystals (fluorine, chlorine, bromine, iodine)
  • Most x-ray film emulsions are made of
  • Silver Bromide (98)
  • Silver Iodide (2)
  • Photographically active layer activated by
    light radiation to create image

8
Silver Halide Crystals
  • Crystals are cubic in structure
  • Crystal lattice containing ions

9
FILM CONSTRUCTION
  • Film is manufacture to have specific
    characteristics of speed, contrast and
    resolution.
  • Film is also manufactured to be sensitive to
    specific colors of light spectral matching
  • Direct-exposure film thicker emulsion with more
    silver halide crystals

10
FILM CONSTRUCTION
  • BASE WITH EMULSION
  • CAN BE ON 1 (SINGLE EMULSION)
  • OR 2 SIDES (DOUBLE EMULSION)
  • MUST BE MATCHED WOTH 1 OR 2 SIDED INTENSIFYING
    SCREENS

11
PICTURE OF CROSS SECTION OF FILM
12
2 CLASSIFICATIONS OF FILMS
  • PANCHROMATIC PAN LIKE PANORAMIC COLORS
    SENSITIVE TO ALL COLORS OF LIGHT
  • ORTHOCHROMATIC MOST COMMONLY USED IN MEDICAL
    IMAGING NOT SENSITIVE TO THE RED SPECTRUM
    MOSTLY ON BLUE AND GREEN

13
IMAGE FORMATION
  • X-RAY PHOTONS CONVERTED TO LIGHT PHOTONS
  • IMAGE BEFORE PROCESSING LATENT IMAGE
  • MADE VISIBLE BY CHEMICAL PROCESSING
  • AFTER PROPER CHEMICAL PROCESSING MANIFEST IMAGE

14
IMAGE ON FILM
  • SINGLE EMULSION BETTER DETAIL
  • DOUBLE EMULSION LESS DETAIL
  • PARALLAX
  • WITH DOUBLE EMULSION AN IMAGE IS CREATED ON
    BOTH EMULSIONS- THEN SUPERIMPOSED SLIGHT
    BLURRING OF EDGES

15
RADIATION INTERACTS RELEASING ELECTRONS
  • SILVER ATOMS BUILDUP AT THE SENSITIVITY CENTER,
    BUILDING THE LATENT IMAGE CENTER
  • THE GROUP OF SILVER ATOMS IS CALLED THE LATENT
    IMAGE CENTER

16
LIGHT VS DARK AREAS ON FILM
  • DARK SPOTS- SLIBER HALIDE CRYSTALS THAT HAVE BEEN
    EXPOSED TO PHOTONS TURN TO BLACK METALLIC
    SILVER AFTER PROCESSING
  • LIGHT AREAS- NO CRYSTALS EXPOSED SILVER HALIDE
    IS WASHED AWAY WITH PROCESSING

17
End
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