Which angle is not considered part of beam geometry?

Which angle is not considered part of beam geometry?

• A. Tilt angle
• B. Tube angulation
• C. Object angle
• D. Rotor angle

Answer: (D)

Beam geometry describes how the X-ray beam is directed relative to the object in a single projection. This includes the tilt angle (how the beam is tilted), the tube angulation (the orientation of the X-ray tube), and the object angle (how the object is oriented with respect to the beam). These parameters define the actual path photons take through the object and the detector setup for that moment. Rotor angle, on the other hand, refers to the gantry’s rotation position as the scan progresses. It determines which projection angle around the object is being acquired, but it is not a static geometric descriptor of the beam’s path for a given projection. So rotor angle isn’t considered part of beam geometry.

Beam geometry describes how the X-ray beam is directed relative to the object in a single projection. This includes the tilt angle (how the beam is tilted), the tube angulation (the orientation of the X-ray tube), and the object angle (how the object is oriented with respect to the beam). These parameters define the actual path photons take through the object and the detector setup for that moment.

Rotor angle, on the other hand, refers to the gantry’s rotation position as the scan progresses. It determines which projection angle around the object is being acquired, but it is not a static geometric descriptor of the beam’s path for a given projection. So rotor angle isn’t considered part of beam geometry.