What is the purpose of collimation in dental radiography?

• A. To reduce patient exposure by restricting the beam to the area of concern
• B. To maximize beam divergence
• C. To increase exposure time
• D. To colorize the beam

Answer: (A)

Collimation shapes and limits the x-ray beam to the smallest area needed for the image. By restricting the beam to the area of interest, fewer tissues are exposed to radiation, which lowers the patient dose and helps meet ALARA. It also reduces scattered radiation, which improves image contrast and sharpness. That’s why this option is the best: it directly describes both the safety and quality benefits of beam restriction. The other ideas don’t fit because collimation does not increase beam divergence, does not determine exposure time, and has nothing to do with coloring the beam.