Craniofacial computed tomography scanning: technology, applications and future trends

OBJECTIVES: Craniofacial imaging in three dimensions depends on computed tomography (CT) and related technologies. This paper explains the state-of-the-art for medical and dedicated craniofacial cone-beam CT scanners. METHOD: Current medical CT scanners are surveyed, especially the recently announced 16 simultaneous slice models with subsecond source-detector rotation times and spiral/helical third generation geometry. The medical scanner technology is contrasted with dedicated low-cost craniofacial cone-beam CT scanners to delineate the relevant technologies and clarify the differences. RESULTS: CT scanners performance in any task is determined by their detectors and reconstruction algorithm primarily and to a lesser extent by the X-ray source, dose utilization, computational and display electronics, and software for post-processing. Each of these components differs between medical and low-cost cone-beam scanners, and the differences are tabulated and explained. CONCLUSION: Low-cost craniofacial CT scanners are significantly different from general purpose medical CT scanners, with compromises in technical performance. Despite their limitations, these instruments are remarkably useful for their intended application domain and should improve as computers continue to increase their performance.