Dr Richie Abel BSc MSc PhD

Biography

Employment history

2008-Present   Micro-Tomography Specialist, Mineralogy Department, EMMA Division, NHM.

2006-2007        Teaching Fellow in Anatomy, Faculty of Life Sciences, The University of Manchester.

Qualifications

PhD  Growth and development of the primate ilium. The University of Liverpool.
MSc    Early Hominid Studies, The University of Liverpool.
BSc    Honours Zoology, The University of Wales, Cardiff.

Micro-CT Basics

1. Micro-Computed Tomography (Micro-CT)

1.1 Micro-CT Introduction and basic principles

Micro-CT provides an invaluable non-destructive technique for visualising the external and internal structure of objects in three dimensions. The technique is becoming increasingly used to study palaeontological, zoological, mineralogical, entomological and botanical specimens. The NHM is the only museum to possess a state of the art scanner and is uniquely placed to carry out such research.

Micro-CT produces two-dimensional representations of a slice of an object based on material density, measured by X-ray transmissions. The resulting slice is made up of voxels, i.e. three dimensional pixels. The size of the voxels largely determines the resolution of a scan which is in the order of 5-125μm. Each voxel is assigned a CT (grey) value derived from a linear attenuation coefficient (i.e. density) of the material(s) being scanned. Hence a micro-CT scan is not a true image, unlike a radiograph, but rather a mathematical representation of an object.

Scan of a Gold crest skull

1.2 Micro-CT Reconstruction

Slices from a scanned object can be stacked to produce a three dimensional reconstruction.

Micro-CT reconstruction of a crocodile skull. Specimen courtesy of Angela Milner.

The reconstruction can be digitally dissected (segmented) as if in the hand.

Micro-CT reconstruction of a caecilian (amphibian). Specimen courtesy of Mark Wilkinson, David Gower and Emma Sherratt.

Specimens can also be sliced open to reveal the sometimes remarkable internal structure.

Micro-CT reconstruction of a fossil viviparous snail (ca 750,000 years). Specimen courtesy of Baruch Spiro.

Red green stereo-perspective images can be used to fully explore the 3D geometry of an object.

Stereo-perspective micro-CT reconstruction of a fossil viviparous snail (ca 750,000 years). Specimen courtesy of Baruch Spiro. Use red and green spectacles to view this specimen in 3D.

1.3. Micro-CT @ the NHM

In March 2009 the NHM acquired a state of the a Metris X-Tek HMX ST 225 System PDF (696.0 KB)

. Researchers, curators and business persons use micro-CT scans for research, conservation and commerce. Interested parties should take a look at the scanning application tab (above).

1.4 More Information about CT

If you would like to know more everyone is welcome to join the or for less technical users the Metris X-Tek Micro-CT Users Group

or for less technical users the NHM Micro-CT Collective

. There are also several excellent Micro-CT related sites for example:

• Metris X-Tek
• Digital Morphology at The University of Texas (Digimorph)

Scanning Requests

2. Scanning Applications

2.1 Application Form

If you wish to apply for scanning time read this word document about Micro-CT @ the NHM PDF (25.0 KB)

. The file contains information about: 

• scanning requests
• specimen mounting
• scanning parameters
• scanning costs
• data storage and/or transfer
• copyright

To arrange scanning time with Richie Abel please fill out and return the application form Word (44.0 KB)

2.2. Technical Information

For technical information read this document about the NHM's Metris X-Tek HMX ST 225 System PDF (696.0 KB)

2.3 Micro-CT Forums

If you have any questions, comments or opinions about micro-CT in general please join the Metris X-Tek Micro-CT Users Group

or for advice or comments on museum related research and curation the NHM Micro-CT Collective

.

X-Tek Micro-CT System

3. NHM Micro-CT Scanner

The NHM micro-CT system was supplied by Metris  X-Tek. The instrument can be used to visualise a wide range of biological, mineralogical and man-made materials such as; chitin, bone, dentine, fossils, rock cores, plastic, carbon-fibre and metal. Furthermore, because a typical scan takes between 10-20 minutes it is possible to scan large numbers of specimens for scientific research and curation in the museum. For more detailed info about the technical specifications of the scanner please download this document about theMetris X-Tek HMX ST 225 System PDF (696.0 KB)

3.1 Metris X-Tek HMX ST 225 System

Photo shots of the the system - courtesy of Kevin Webb

The NHM micro-CT scanner - long shot IMAGE/JPEG (764.0 KB)

The NHM micro-CT scanner - full view IMAGE/JPEG (599.0 KB)

The NHM micro-CT scanner - close up IMAGE/JPEG (536.0 KB)

3. 2 Exemplar micro-CT renderings produced using VG Studio Max 2.0.

Egyptian Mummy - specimen courtesy of Richard Sabin

Ancient Egyptian mummified cat (ca 4000 yrs) IMAGE/JPEG (502.0 KB)

Ancient Egyptian mummified cat (ca 4000 yrs) IMAGE/JPEG (415.0 KB)

Egyptian Cat Mummy (ca 4000 yrs) IMAGE/JPEG (456.0 KB)

Rhinoceros Beetle - specimen courtesy of Alex Ball

Rhinoceros Beetle IMAGE/JPEG (106.0 KB)

Rhinoceros Beetle Clipped IMAGE/JPEG (118.0 KB)

Publications

Macho GA, ABEL RL and Schutkowski H. (2005). Age changes in bone microstructure: do they occur uniformly? International Journal of Osteoarchaeology 15:421-430.

McColl DJ, Abel RL, Spears IR and Macho GA. (2006). Automated method to measure trabecular thickness from microcomputed tomographic scans and its application. Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology 288:982-8.

Butler RJ, Barrett PM, ABEL RL, Gower DJ. (2009). A possible ctenosauriscid archosaur from the Middle Triassic Manda Beds of Tanzania. Journal of Vertebrate Paleontology 29:1022–1031.

Ashkenazi S, Klass K, Mienis HK, Spiro B and Abel RL. (2010). Fossil embryos and adult viviparids from the Early-Middle Pleistocene site of Gesher Benot Ya‘aqov, and their ecology, longevity and fecundity. Lethaia 43:116–127

ABEL RL, Xuan BV, Cotton R, Young PG, Baker M, Tabor G, Nickels TB and Cox JPL. (In press). Fluid flow in and around the olfactory organ of a hammerhead shark. Comparative Biochemistry and Physiology A - Molecular & Integrative Physiology doi:10.1016/j.cbpa.2009.10.029.