Geometric accuracy of digital volume tomography and conventional computed tomography.

Digital volume tomography is a recently established imaging method that is based on the principle of cone beam computed tomography (CBCT). One of its main applications is imaging in dental and maxillofacial surgery. The objective of this study was to compare the geometric accuracy of digital volume tomographic imaging with that of conventional CT and to assess the suitability for image-guided operating. A calibration cube with a defined pattern of tubes inside was scanned using CT and digital volume tomography. Spatial accuracy was analysed with a software evaluation tool. The positions of the intersections of the tubes were detected in imaging data and registered to the real positions in the calibration body. The deviation was calculated and compared for CT and digital volume tomography. Resolution of spatial images was similar for both methods. However, the spatial accuracy in digital volume tomography was slightly lower than that of CT but still in the submillimetric range. The accuracy was better in the middle, but lower in the margins of the volume. This is a disadvantage in technical image quality, but does not affect the diagnostic image quality. The geometric accuracy is sufficient for digital volume tomography-based image-guided surgery.