Comparison of cone beam CT and conventional CT in accuracy of rapid prototype models: Image registration

The purpose of this study was to validate the use of captured images from the Cone Beam Computerized Tomography (CBCT) for accuracy by comparing them to conventional CT images (gold standard) for use with Rapid Prototyping of models and treatment planning software. A standard model was developed by adding fiducial markers (5mm stainless steel balls) at anatomical landmarks on a human skull. The model was then acquired by the Iluma CBCT scanner (Imtec, Ardmore, OK), at 7.8s, 20s, 40s and a Philips Brilliance 40 (Philips Healthcare, Andover, MA). Distances between fiducial points and the markers were determined using rapid prototype software (Magic RP). Differences between the absolute value of differences between the conventional CT and CBCT images taken at 3 different speeds were compared for accuracy. Statistical analysis was performed using a multivariate analysis of variance (MANOVA, α=0.05). The MANOVA analysis did not detect significant differences between spatial deviations in the CBCT scans at different exposures. These results imply that CBCT scans can yield similar 3-D spatial accuracy to MDCT scans in craniofacial modeling applications.