American Board of Orthodontics (ABO) Practice Exam 2025 - Free Orthodontics Practice Questions and Study Guide

The beam of Cone Beam Computed Tomography (CBCT) is designed to have a cone shape, which is fundamental to its imaging technology. This conical beam allows for the acquisition of three-dimensional images by projecting a series of 2D X-ray images from various angles around the area of interest. The cone shape is essential as it enables the capture of a wider field of view in a single rotation of the X-ray source and detector, maximizing the data collected for constructing the 3D image.

In contrast to other shapes, such as cube or spherical, which do not accurately represent the geometry needed for efficient data collection in volumetric imaging, the conical shape optimally balances coverage and resolution. The pyramid shape, while reminiscent of the multi-planar reconstructions that can be derived from the data, does not accurately describe the direct output or the beam's physical form used during the scanning process.

Therefore, a cone-shaped beam is intrinsic to the operational design of CBCT, facilitating high-quality imaging while minimizing radiation exposure to surrounding tissues.