What is the purpose of a collimator in radiography?

The purpose of a collimator in radiography is primarily to limit the radiation field. By controlling the size and shape of the x-ray beam that exposes the patient and the image receptor, the collimator helps focus the radiation only on the area of interest. This not only improves the quality of the diagnostic image by eliminating unnecessary scatter radiation but also helps in protecting surrounding tissues from unnecessary exposure.

When the radiation field is restricted, it also plays a crucial role in dose management, as limiting the area being irradiated reduces the overall amount of radiation that a patient receives. The collimator achieves this by using lead shutters that can be adjusted to define the beam shape, allowing for optimal imaging with minimal exposure. Therefore, option B accurately describes the essential function of collimators in radiographic practices.