General Rule for Replacement of Tube
Adjust the tube so that the CR is right angles to the structures in the focal spot at a distance that will project the best definition of the structures
Collimation of the x-ray beam
2 reasons why you must collimate the x-ray beam
1. To minimize the amount of radiation to patients and reduce scatter radiation.
2. Allows radiograph that show clear structural delineation and increased contrast by:
a. preventing secondary rad’n from unnecessary exposing surrounding tissues so that the film fog may be avoided.
b. reducing scatter rad’n thereby producing a short-scale radiograph.
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