Everybody is now used to three-dimensional images in computer-aided design, graphic design and the games people play, but arguably far more important is the use of imaging in the field of medicine. IBM Corp believes it has the answers for the problems medicine throws up and is pushing Tosca, its Tool for Segmentation, Correlation and Analysis of three-dimensional digital images. into this expanding market that, until revently, had been ignored by the commercial vendors. Tosca originated from a European Commission-funded project on medical image analysis carried out in 1992 to 1994, and adapted by IBM’s Applied Science & Technology Group. It is used for segmentation, the outlining of structures of areas of interest for visualisation and measurement purposes. Correlation is the combination of images taken at different times, or from different scanners, and analysis consists of measurements, statistics and graphs. The most common images used are are derived from Computer Tomography, Magnetic Resonance Imaging and Ultrasound, in medical physics, radiology and pharmaceutical research, but the package also has uses in material sciences and other arenas – IBM being open to any sensible suggestions. One of the main features of Tosca is its semi-automatic segmentation tools. Peter Elliott, Tosca team leader at the company’s Hursley Laboratory near Winchester, Hampshire, said the tool is suited to clinically-trained users who can use their skills to fill in the gaps left by the semi-automatic segmentation. A user clicks on a series of points around an image of an organ or a tumour for example. Once the image has been highlighted in one slice the system will automatically locate the outline in the corresponding slices.
Identical functions
If the algorithm strays off line at all, the user can adjust the outline accordingly. Dr Robin Richards, senior research fellow at University College London’s department of medical physics and bio-engineering agreed that Tosca’s features were key requirements in many areas of bio-engineering and surgical planning, but implied that IBM was a bit late to the party. The university had been using an in-house system to perform virtually identical functions for years, running a network of Transputers on a host personal computer. At ú19,500 per workstation, Tosca costsmore than twice what most academic institutions would be able to pay. Richards said, however, that the price tag was reasonable, but many departments had needed, and consequently developed, the technology years ago. Tosca can be accessed from IBM’s longer-established DX Data Explorer visualisation and analysis tool kit, which is due for its next release shortly. DX can analyse any form of data. Dave Barry of pharmaceutical company Zeneca Plc’s imaging group, which uses the two systems for the analysis of ultrasound and MRI images said Tosca and DX sit very well together. He demonstrated sliced images of cartilage that can be used to determine its average thickness. It was originally a Tosca image that was rendered using DX. Further slices were available in DX across planes not specified in the original Tosca image. DX also enabled false colours to be added to the image that reflected a computed value, in this case thickness. Both DX and Tosca can be bought from Data Cell Ltd, a Maidenhead, Berkshire-based company established in 1987 that also markets its own 3-D-E imaging product. Things started to happen for Data Cell once it decided to focus on imaging and has grown from a dozen employees three years ago to 45 at the moment. 3-D-E comes in two parts; an editor and a viewer. Standard graphics formats such as GIF, TIFF, BMP and PCX are supported by the product, which runs on a high-end personal computer under Windows. It is not nearly as advanced as the Unix variants mentioned earlier, but then it runs on a high-end personal computers and is considerably cheaper, costing ú1,000. A version of 3-D-E is also available that provides a link to another product that Data Cell offers, Bothell, Washington Optimas Corp’s eponymo
us product. Optimas provides the measuring element that 3-D-E lacks. This version costs ú1,500. – Nick Patience
