The team at Queen Mary University of London started working on microtomography over 40 years ago with the purpose of accurately quantifying and 3D-mapping the concentration of mineral in teeth. Improvements in accuracy have come through three research pathways. Firstly, unique time-delay integration scanners have been created, overcoming ring artefacts and many of the errors associated with third-generation scanning geometry. Secondly, considerable effort has gone into designing calibration and beam-hardening correction methodology; every scan is individually calibrated to allow for small changes in the X-ray spectra over time and beam hardening correction uses a “2-dimensional” technique to handle both the organic and inorganic phases in dental tissue. Thirdly, careful attention is paid to scanning protocols; how a specimen is fixed and re-positioned for multiple scans can have as much effect on image quality and accuracy as some of the major developments in analytical algorithms.
Although designed for dental research, the system has attracted interest from other disciplines, most notable are those within cultural heritage. Unusual specimens scanned include historical scrolls (damaged beyond the ability to unroll), decaying 16mm film and stacked photographic plates. As a technology demonstration, a short length of 16mm found with an optical soundtrack was scanned. Both the moving image and sound were recovered from the tomographic reconstruction.
Queen Mary University of London
Graham Davis began work on the development of X-ray microtomography (XMT) in 1988 shortly after beginning at the London Hospital Medical College (now part of Queen Mary University of London). Designing scanners and software algorithms with accuracies exceeding commercially available systems, he is well recognised in this area of development and has served on the European Standards Committee CEN/TC 138/WG 1/AH 1 Computed Tomography. He also serves as a program committee member for the "Developments in X-ray Tomography" conference held every 2 years as part of SPIE Optics and Photonics conferences. He is currently the lead for Imaging Sciences in the Centre for Oral Bioengineering, which includes electron microscopy, X-ray imaging, and facial scanning. His chief aim is to work alongside clinicians towards better understanding and treatment of dental conditions.