79 Collimation A collimator is an x-ray beam limitation device. It confines the primary beam before it enters the patient.
Proper collimation improves image quality and reduces the amount of scattered radiation produced.
Using too large a collimator increases fogging by x-ray scatter from surrounding material that is not of interest. In fluoro, you should see the edges of the collimator in all mag and non-mag imagining modes otherwise exposure outside the area shown on the imaging screen is occurring.