Which item is not a beam restrictor?

Which item is not a beam restrictor?

• A. Collimator
• B. Cone
• C. Aperture diaphragm
• D. Filter

Answer: (D)

The concept being tested is which devices control the size and shape of the x-ray beam. A collimator, a cone, and an aperture diaphragm all actively define and limit the geometric field that reaches the patient, shaping the beam to the area of interest and reducing unnecessary exposure. A filter, on the other hand, does not restrict the beam’s geometry. Its job is to attenuate low-energy photons to improve image quality and reduce patient dose by changing the beam’s energy spectrum, not by limiting the beam’s size or shape. Therefore, the item that is not a beam restrictor is the filter.

The concept being tested is which devices control the size and shape of the x-ray beam. A collimator, a cone, and an aperture diaphragm all actively define and limit the geometric field that reaches the patient, shaping the beam to the area of interest and reducing unnecessary exposure. A filter, on the other hand, does not restrict the beam’s geometry. Its job is to attenuate low-energy photons to improve image quality and reduce patient dose by changing the beam’s energy spectrum, not by limiting the beam’s size or shape. Therefore, the item that is not a beam restrictor is the filter.