What is the function of the collimator in radiographic imaging?

The function of the collimator in radiographic imaging is primarily to reduce radiation exposure to the area outside of the target. This is achieved by narrowing the x-ray beam to the anatomical area being examined, thereby minimizing unnecessary exposure to surrounding tissues. This is not only a crucial aspect of patient safety but also enhances image quality by limiting scatter radiation, which could otherwise blur the image and compromise diagnostic accuracy.

While collimators can influence image contrast by managing the scatter and ensuring that only the relevant area is irradiated, their primary role remains focused on reducing extraneous radiation exposure. Additionally, filtering low-energy photons or attempting to focus the x-ray beam are not the principal functions of the collimator.