Collimation of 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.