Medical computed tomography (CT) able to image the past: an investigation of diagnostic accuracy and image quality
Date
2018
Authors
Smilg, Jacqueline Scott
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Abstract
The use of X-ray imaging in palaeoanthropology has a long history. Both plain X- rays as well as computed tomography have successfully imaged fossils that have been cleaned and prepared from any encasing materials. There has, however, been very little work done using radiological techniques to image fossils still enclosed in surrounding matrix. Most imaging modalities have been applied post preparation of the fossils. This body of work explores the use of medical computed tomography (XCT) in the pre-preparatory phase of fossil discovery in the South African context. Scanning of breccia blocks from the site of Malapa on XCT concluded that the resultant images were of sufficient quality to enable accurate fossil identification and characterization when measured against the standard of manual preparation. Breccia blocks from Malapa were scanned at high and lower energies using micro CT (μXCT) and XCT respectively. Images were analysed for image quality, artifact and certainty of diagnosis. Results show that lower energy images are deemed superior to higher energy images for this particular application. This finding, taken together with the limitations associated with the use of μXCT for the imaging of the large breccia from Malapa, shows that XCT is the better modality for this specific application. Pre-preparatory XCT scanning can focus both preparation and interpretation of findings. The importance of pre-preparatory XCT imaging is demonstrated by the fact that preparatory techniques and protocols need to be modified from traditional methods in order to minimize the risk of contamination of possible biomolecules. Revision is needed of the peri and post excavation treatment of fossil bones to better preserve the potential of genetic heritage of the past and this research demonstrates the role that XCT can play.
None of the research covered by this body of work has been done before on fossil- bearing matrices. This research should significantly change the way fossil discovery, recovery and preparation is done in the South African context and has potential for application in other palaeontological situations.
Description
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy
Johannesburg, South Africa, May 2018.
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Smilg, Jacqueline Scott (2018) Medical computed tomography (CT) able to image the past: an investigation of diagnostic accuracy and image quality, University of the Witwatersrand, Johannesburg, <http://hdl.handle.net/10539/26056>