Scatter radiation

1. Off focus radiation can be reduced with a stage entrance shuttering device.

2. Collimators utilize positive beam limitation

3. Should see 4 sides of collimation

4. A collimator will add the equivalent of 1mm of aluminum filtration.

5. Compton effect:

1. Occurs between moderate energy photons and an outer shell electron.

2. Photon changes direction and loses energy, thus creating a Compton electron.

3. Adds to film fog and increases with increased KvP.

6. Classical Scatter:

1. Thompson scattering between low energy photon and an atom.

2. Photon changes direction, but doesn’t lose any energy. No ionization.

7. Photoelectric effect:

1. Between moderate energy photon and inner shell electron

2. Photon loses all of its energy and creates a photoelectron.

3. produces secondary (characteristic) xrays which behave like scattered xrays.

8. Pair production occurs when a photon interacts with a nuclear force field.

9. Photodisintegration occurs when a photon is absorbed by the nucleus itself, and emits a subsequent nuclear fragment.

Category: Radiology Notes