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Cone beam computed tomography

Cone beam computed tomography (or CBCT, also referred to as C-arm CT, cone beam volume CT, or flat panel CT) is a medical imaging technique consisting of X-ray computed tomography where the X-rays are divergent, forming a cone.

CBCT has become increasingly important in treatment planning and diagnosis in implant dentistry, interventional radiology (IR), among other things. Perhaps because of the increased access to such technology, CBCT scanners are now finding many uses in dentistry, such as in the fields of oral surgery, endodontics and orthodontics. Integrated CBCT is also an important tool for patient positioning and verification in image-guided radiation therapy (IGRT).

During dental imaging, the CBCT scanner rotates around the patient’s head, obtaining up to nearly 600 distinct images. For Interventional Radiology, the patient is positioned offset to the table so that the region of interest is centered in the field of view for the cone beam. A single 200 degree rotation over the region of interest acquires a volumetric data set. The scanning software collects the data and reconstructs it, producing what is termed a digital volume composed of three-dimensional voxels of anatomical data that can then be manipulated and visualized with specialized software.

There are three commercially available systems of C-arm CBCT in the US: DynaCT (Siemens Medical Solutions, Forchheim, Germany), XperCT (Philips Medical Systems, Eindhoven, the Netherlands), and Innova CT (GE Healthcare, Waukesha, Wisconsin). The systems differ with regard to their rotation time, number of projections acquired, image

quality, and time required for reconstruction.