film

• Image forming x-rays

  1. rays that exit the patient and interact with the image receptor
• Exit beam


  1. rays that remain as useful beam exits the patient, consisting of x-rays scattered away from the image receptor and image forming x-rays
• Image Receptor


  The medium that converts the x-ray beam into visible image
• Radiographic Film


  • The most common IR, although solid state digital IRs are finding increased application
• Film Construction


  1. Base

  2. Emulsion
• Base


  The foundation of radiographic film, providing a rigid structure for the emulsion
• Base


  • Flexible and fracture resistant, 150-300 micrometer thick, semi-rigid, lucent, made of polyester, maintains size and shape, uniform lucency and nearly transparent to light
• Emulsion


  The heart of the x-ray film, consisting of a homogeneous mixture of gelatin and silver halide crystals
• Gelatin


  • Provides mechanical support for silver halide crystals, clear and porous
• Silver halide crystal


  • The active ingredient of the radiographic emulsion, typically 98% silver bromide and 2% silver iodide, with tabular, cubic, octahedral, polyhedral, or irregular shapes
• Formation of Latent Image


  1. Photographic effect

  2. Silver halide crystal structure

  3. Photon interaction with silver halide crystal
• Latent Image


  The invisible image present immediately after exposure, which becomes visible after chemical processing
• Types of Film

  • Screen-film
  • Direct exposure film
  • Special application film
• Standard Film Sizes


  • 8x10 inches
  • 10x12 inches
  • 11x14 inches
  • 14x17 inches