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Backscatter Radiation

Backscatter radiation can have a significant effect on the quality of a radiograph. Backscatter radiation is radiation that is scattered from an object on the film side of the specimen. This exercise can be used to develop an appreciation for just how significantly backscatter radiation can affect radiograph quality.

  1. Load a film cassette that does not have lead foil screens built-in with a piece of film.
  2. Place a lead letter "B" on the back side of the cassette.
  3. Locate a piece of aluminum plate or similar material of uniform thickness and place it on the film for the exposure.
  4. Place a piece of corrugated cardboard on the backside of the film.
  5. Expose the film to produce a density of 2.0 to 3.0.
  6. Process the film
  7. Evaluate the film to determine if the letter "B" and features of the cardboard are visible.

Teaching Tips

Signal Interpretation
DAC Curve

Eddy Current
Depth of Penetration
Lenz Law

Backscatter Radiation
Film Handling Artifacts
Focal Spot Size
Lead Screens
Source/Object Orientation