Which component is used to shape the x-ray beam and limit exposure to the area of interest?

• A. Collimator
• B. Filtration
• C. Cassettes
• D. X-ray tube

Answer: (A)

Collimation is used to shape the x-ray beam and limit exposure to the area of interest. The collimator sits at the end of the x-ray tube and uses adjustable lead shutters to create a defined field size that matches the anatomy you intend to image. This light field helps you align the exposure precisely to the region of interest, so only the necessary tissues are irradiated. Limiting the beam in this way reduces patient dose and also lowers scatter production, which improves image contrast and sharpness. Filtration, by contrast, sits in the beam to remove low-energy photons and improve beam quality without changing the field size. The x-ray tube generates the radiation but does not shape the beam. Cassettes hold the imaging receptor and are not part of beam shaping.