How is the x-ray beam controlled in panoramic imaging?

• A. Collimated at the receptor only.
• B. Uncollimated and variable.
• C. Collimated at the source only.
• D. Collimated at both the source and the receptor.

Answer: (D)

In panoramic imaging, controlling the beam from both ends is essential to create a narrow, moving field that matches the receptor as it scans around the patient. The x-ray beam is collimated at the source to produce a slender, slit-shaped beam, which limits exposure to just the region that will be imaged. At the same time, the receptor side is collimated, so it only accepts that same narrow portion of radiation. This dual collimation defines the effective beam geometry, keeps scatter and blur to a minimum, reduces patient dose, and ensures consistent magnification and sharpness as the beam travels along the curved path of the jaw.