Palaeopathology of dinosaur bone
Pathology of dinosaur bone: reviewing the pathologies from a Tenontosaurus tilletti specimen (Cloverly Formation, Montana). The specimen shows examples of infection and physical trauma (tendon avulsion). The use of non-invasive, high resolution imaging techniques are providing new information on the response of dinosaur bone to trauma. Working on this research are Emma Schachner (PhD student) at the University of Pennsylvania (USA), Dr Paul Mummery and Dr Sam McDonald at the Schools of Materials (University of Manchester) with assistance from colleagues at The Manchester Museum (University of Manchester).
X-ray micro-tomography (XRT) is a non-destructive evaluation technique that allows the internal structure of an object to be imaged by reconstructing the spatial distribution of the local linear X-ray absorption coefficients of the materials/phases contained within. This provides a virtual 3D representation of an objects internal architecture from which two-dimensional (2D) cross-sectional slices can be viewed through the three orthogonal directions of the volume. In conventional radiography, the image plane is approximately normal to the X-ray beam, and the image represents total X-ray attenuation through the object. Computed tomography (CT) creates a digital representation of a thin slice of the object parallel to the X-ray beam. This image is reconstructed from a series of 2D radiographs taken at different orientations. The CT slice is stored as an array of numbers representing local X-ray attenuation values for each of the small volume elements (voxels) that make up the slice, and represented in a reconstructed image as a series of grey level values. Linking the 3D data obtained directly to a finite element mesh allows one to predict the loads experienced for an object of exact size, shape and volume.
The XRT data is viewed in a visualisation package and all observed structures compared with pathologies in extant vertebrates. The study is ongoing and part of a wider study on the mechanical properties of biomaterials (See dromaeosaur limb mechanics research page).