Cone Beam Computed Tomography (CBCT) or Dental Volume Tomography (DVT) scanners (such as the i-CAT) utilize a cone beam, which radiates from the x-ray source in a cone shape, encompassing a large volume with a single rotation about the patient. Images are then reconstructed using algorithms to produce 3-dimensional images at high resolution.
Conventional CT scanners make use of a fan-beam. Transmitted radiation takes the form of a helix or spiral. The data are then interpolated or re-binned by the scanner into a set of slices making up a volume. Large anatomical regions of the body can be imaged during a single breath hold, reducing the possibility of artifacts caused by patient movement.
Because the i-CAT is a sitting-up machine, it offers more accurate information for dental practitioners. The radiation dose from a conventional CT also does not justify taking a CT scan of, for example, a child in order to make soft tissue measurements.
Conventional CT makes use of a lie-down machine with a large gantry. When patients lie down, the soft tissues tend to collapse.
