Which device is primarily used for limiting the exposed field size during radiographic procedures?

The primary function of a collimator in radiographic procedures is to limit the size of the exposed field, which helps to focus the beam on the area of interest and reduce radiation exposure to surrounding tissues. By constricting the x-ray beam to a specific area, the collimator improves image quality by minimizing scatter radiation and enhances patient safety by reducing unnecessary radiation exposure.

In contrast, a grid is designed to reduce scatter radiation from reaching the image receptor, improving contrast, but it doesn’t limit the field size. A filter is used to selectively absorb certain wavelengths of x-rays, which can reduce patient dose and enhance image quality, but it does not control the beam size either. Lastly, a monitor is not involved in the limiting of the exposed field; it is used to display the images for viewing. Thus, the collimator is the correct choice for the purpose of limiting the exposed field size during radiography.