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In this study a computer aided navigation technique for accurate positioning of oral implants was assessed. An optical tracking system with specially designed tools for monitoring the position of surgical instruments relative to the patient was used to register 5 partially or completely edentulous jaw models. Besides the accuracy of the tracking system, the(More)
Registration of single slices from FluoroCT, CineMR, or interventional magnetic resonance imaging to three dimensional (3D) volumes is a special aspect of the two-dimensional (2D)/3D registration problem. Rather than digitally rendered radiographs (DRR), single 2D slice images obtained during interventional procedures are compared to oblique reformatted(More)
Computer-aided surgery (CAS), the intraoperative application of biomedical visualization techniques, appears to be one of the most promising fields of application for augmented reality (AR), the display of additional computer-generated graphics over a real-world scene. Typically a device such as a head-mounted display (HMD) is used for AR. However,(More)
PURPOSE To correlate torque forces during insertion of screw-type dental implants with bone mineral density (BMD) values determined preoperatively. MATERIALS AND METHODS Dental quantitative computed tomography (CT) was performed with simultaneous imaging of five postmortem mandibles and a calibration standard containing defined concentrations of calcium(More)
INTRODUCTION Our aim was to implement standards for quality assurance of IGRT devices used in our department and to compare their performances with that of a CT simulator. MATERIALS AND METHODS We investigated image quality parameters for three devices over a period of 16months. A multislice CT was used as a benchmark and results related to noise, spatial(More)
Development of complex software applications in image guided therapy (IGT) is often complicated by the fact that providing basic functionality for image processing and user interaction from a graphical user interfaces (GUI) requires considerable manpower for software development. We present a programming environment that combines the high-level image(More)
3D/2D registration, the automatic assignment of a global rigid-body transformation matching the coordinate systems of patient and preoperative volume scan using projection images, is an important topic in image-guided therapy and radiation oncology. A crucial part of most 3D/2D registration algorithms is the fast computation of digitally rendered(More)
The temperature dependence of water equivalent phantom materials used in radiotherapy and diagnostic imaging has been investigated. Samples of phantom materials based on epoxy resin, polyethylene, a polystyrene-polypropylene mixture and commercially available phantom materials (Solid Water, Gammex RMI and Plastic Water, Nuclear Associates) were scanned at(More)
OBJECTIVE The aim of this study was to establish a correlation between bone mineral density measured preoperatively with dental computed tomography (CT), and insertion torque of screw-shaped dental implants. MATERIAL AND METHODS In eight human mandibles obtained postmortem, bone mineral density (BMD) was measured with dental quantitative CT (DQCT) and(More)
Technical quality assurance (QA) is one of the key issues in breast cancer screening protocols. For this QA task, three different methods are commonly used to assess image quality. The European protocol suggests a contrast-detail phantom (e.g. the CDMAM phantom), while in North America the American College of Radiology (ACR) accreditation phantom is(More)