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Record: 1
Title:CT scans for Sts 14 provide the potential for manufacturing casts.
Authors:Yates, Simon C.
Kirkbride, Anthony N.
Source:South African Journal of Science; Apr97, Vol. 93 Issue 4, p178, 2/3p, 2bw
Document Type:Article
Subject Terms:*CASTS
Abstract:Presents the results of a study on manufacturing a cast of the vertebral column of a partial skeleton discovered at Sterkfontein in South Africa. Application of an industrial X-ray computed tomography scanner; Comparison to other moulding techniques.
Full Text Word Count:531
Accession Number:9710054059
Persistent link to this record: http://0-search.ebscohost.com.innopac.up.ac.za:80/login.aspx?direct=true&db=aph&AN=9710054059&site=ehost-live&scope=site
Cut and Paste: <A href="http://0-search.ebscohost.com.innopac.up.ac.za:80/login.aspx?direct=true&db=aph&AN=9710054059&site=ehost-live&scope=site">CT scans for Sts 14 provide the potential for manufacturing casts.</A>
Database: Academic Search Premier


Sts 14 is a partial skeleton of Australopithecus africanus, discovered in 1947 at Sterkfontein by Broom and Robinson.[1,2] It represents the South African counterpart to 'Lucy', a partial skeleton of Australopithecus afarensis. Although casts have been made of the pelvic bones and sacrum of Sts 14, the fragility of most of the vertebrae has prevented the manufacture of moulds of the vertebral column. Here we report the results of a feasibility study, using an industrial X-ray computed tomography (CT) scanner to manufacture a cast of one vertebra (Sts 14e), which could be used as one of many master positives for the mass production of casts of Sts 14.

CT images of Sts 14e were generated using an Actis+ industrial tomography system (Bio-Imaging Research Inc., Lincolnshire, Illinois), and a Philips 320 kV X-ray tube with a 0.8-mm focal spot size. A linear array solid state detector was used, having 2048 detectors in a 50-mm length and an entrance slit approximately 0.2 mm wide, enabling high resolution images to be obtained. For the examination of Sts 14, the source was operated at 250 kV, 2 mA, with a 1.8-mm copper filter in the beam. Images were taken at 0.5-mm intervals with a slice thickness of 0.2 mm. Figures 1 and 2 show two images which were used as part of the three-dimensional reconstruction of Sts 14e. The use of dilute acetic acid during preparation has led to the partial dissolution of lime in the centre of the vertebra. The fragility of this vertebra is most noticeable in areas where calcite has been dissolved. The master positive was produced using a Stratsys fused deposition modeller (Fig. 3).

The production of casts of other elements of Sts 14 (or indeed of other fragile and valuable fossils) by means of CT scanning clearly is an advantage over conventional moulding techniques, which require direct contact with the fossils. Readers interested in obtaining such casts should contact J.F.T.

This work is supported by the CSIR, the Foundation for Research Development and the Transvaal Museum.

PHOTO (BLACK & WHITE): Fig. 1. (Left) CT scan of Sts 14e, a vertebra of Australopithecus africanus, discovered in 1947 by Robert Broom and John Robinson at Sterkfontein. Imaging with a slice thickness of 0.2 mm has revealed detail of trabecular bone with unprecedented high resolution. Fig. 2. (Right) Another CT scan of Sts 14e.

PHOTO (BLACK & WHITE): Fig. 3. The original and cast of Sts 14c. The cast (on the right) was obtained by means of high resolution CT scanning. Scale in centimetres.

  1. Broom R. and Robinson J.T. (1950). Notes on the pelves of fossil ape-man. Am. J. phys. Anthrop. 8, 489.
  2. Robinson J.T. (1972). Early Hominid Posture and Locomotion. University of Chicago Press, Chicago.


By Anthony N. Kirkbride, Simon C. Yates and J. Francis Thackeray

Anthony N. Kirkbride and Simon C. Yates are in the Division of Materials Science and Technology, CSIR, P.O. Box 395, Pretoria, 0001 South Africa; J.F. Thackeray is in the Department of Palaeontology and Palaeoenvironmental Studies, Transvaal Museum, P.O. Box 413, Pretoria, 0001 (e-mail: mrsples@global.co.za).

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