The device that shapes and limits the size of the x-ray beam at the patient is called the:

The device that shapes and limits the size of the x-ray beam at the patient is called the:

• A. Collimator
• B. Grid
• C. Anode
• D. Filter

Answer: (A)

The device that shapes and limits the x-ray beam at the patient is the collimator. It houses lead shutters that define the exposed field, creating the rectangular beam that reaches the patient. The collimator also provides a light-field indicator so you can see and align the area of interest before exposure. By restricting the beam to the necessary area, collimation lowers patient radiation dose and reduces scatter, which helps improve image quality. Modern systems may automatically adjust the field size to match the exam and patient size (positive beam limitation), keeping the light field aligned with the actual x-ray field. The other options have different roles: a grid cleans up scatter after the patient, the anode is the x-ray source, and a filter removes low-energy photons but does not shape the beam.

The device that shapes and limits the x-ray beam at the patient is the collimator. It houses lead shutters that define the exposed field, creating the rectangular beam that reaches the patient. The collimator also provides a light-field indicator so you can see and align the area of interest before exposure. By restricting the beam to the necessary area, collimation lowers patient radiation dose and reduces scatter, which helps improve image quality. Modern systems may automatically adjust the field size to match the exam and patient size (positive beam limitation), keeping the light field aligned with the actual x-ray field. The other options have different roles: a grid cleans up scatter after the patient, the anode is the x-ray source, and a filter removes low-energy photons but does not shape the beam.