DE/EN

Computed tomography (CT) is used as a non-destructive technique to visualize and study external and internal structures of objects. In investigating rare fossil material, this method is state-of-the-art. By combining micro-CT scanning with different techniques of staining, also soft tissue, e.g. muscles and tendons, can be visualized non-invasively. Researchers from the University of Vienna and other research institutions as well as curators of natural history museums apply this technique to realize a wide variety of research and conservation objectives. It is a multipurpose technique to allow in-depth investigation of objects without destroying the investigated material.

The Department of Palaeontology at the University of Vienna holds a state-of-the-art reflection micro-CT.

Micro-CT

In December 2010 the Department of Palaeontology acquired a Skyscan 1173 Desktop-Micro-CT (Bruker), which is a high energy spiral scan micro-CT for analysing both dense and low dense materials. It includes a 130kV microfocus X-ray source with improved stability of focal spot position, a large format (>5Mp) flat panel sensor with special protection by lead-glass fiber-optic window for long lifetime under high-energy X-ray and a precision object manipulator for large (up to 140mm) and heavy (several kg) objects with embedded micropositioning stage.

Micro-CT team
Univ.-Prof. Dr. Jürgen Kriwet - Head of micro-CT Facility
Dr. Cathrin Pfaff - Micro-CT Specialist

Specifications are:
- X-ray source: 40-130kV, 8W, <5µm spot size
- X-ray detector: distortion-free Flat Panel sensor 2240x2240 pixels, 12-bit
- Maximum object size: 40mm in diameter, 200mm in length (100-140mm scanning length)
- Spatial resolution : <4-5µm detail detectability (depending on sample size), 7-8µm low-contrast resolution
- Reconstruction: single PC or cluster volumetric reconstruction (Feldkamp algorithm)
- Radiation safety: <1µSv / h at any point on the instrument surface

Basic principles
The process of micro-computer tomography includes:
- Scanning of object
- Reconstruction
- Visualisation
- Data collection and storage

During scanning 2D representations of an object based on material density measured by X-ray transmission is produced. Slices are then stacked by using different programs of virtual reconstruction to produce a virtual 3D cast by assigning CT (grey) values to each voxel (3D pixels of 2D slice). The resulting 3D image is a mathematical depiction of the object and thus is suitable for quantitative analyses.

Scanning requests, costs and protocol
- Download and complete the micro-CT scanning request for applying for scanning time.
- Email complete form to Cathrin Pfaff.
- Duration and costs of scanning are based on specimen size, specimen dimensions, special requests
  concerning the field or region of interest, material, object preservation, measurement and analysis,
  required format, etc.
- Objects must be stored in a sealed box or airtight bags or boxes for wet specimens.
- Specimen mounts are provided by the facility.
- Slices can be exported in a wide variety of formats and can be collected using hard drives (NTFS format).
- External hard drives must be formatted prior to use and all hard drives, cables, etc. must be labelled with
  user's name.
- Contact Jürgen Kriwet to discuss your project and costs if necessary.