What are the two configurations of a CBCT you can take?

• A. 90 degrees or 180 degrees
• B. 180 degrees or 360 degrees (higher quality)
• C. 360 degrees or 720 degrees
• D. 120 degrees or 240 degrees

Answer: (B)

In CBCT imaging, image data come from projecting the anatomy as the X-ray source and detector rotate around the patient. The rotation angle defines the acquisition configuration. A 180-degree arc uses only half the rotation, which reduces dose and scan time but provides fewer projection angles, so the reconstruction can be less complete and image quality can be lower with more artifacts in some regions. A full 360-degree rotation collects projections from all directions, yielding more data for the reconstruction, which improves spatial resolution and reduces artifacts, giving higher quality images. That’s why the higher-quality option is the 360-degree configuration, with the alternative being the 180-degree arc.