A corpse in cyberspace

WHO says that dead men tell no tales? They do, but in a tearing hurry: cadavers can't be preserved for too long. But now "The Visible Man" -- a cyberspace cadaver, actually a highly detailed atlas of the human body available over Internet-- has been unveiled by American researchers.

The US $1.4 million project is managed and funded by the National Library of Medicine (NLM), Bethesda, Maryland, with work being carried out by researchers at the University of Colorado Health Science Centre.

To people who blanch at the exigencies of the medical world, The Visible Man could be a bit of a ghoul. "This virtual cadaver is composed of about 15 gigabytes of data, and has been created from thousands of images collected with radiographic and photographic techniques, compiled from the body of a man who was killed by a lethal injection in Texas," says NLM director Donald A B Lindberg.

Using computer tomography (CT), the body of the prisoner, which was donated to science, was first imaged from head to toe at 1 mm intervals. CT is a process of showing cross-sections of human organs by electronically detecting the variation in X-ray transmission through the body. The information is then processed in a digital computer to reconstruct the images.

Magnetic resonance imaging (MRI) data was obtained from axial MRI images of the head and neck and longitudinal sections of the rest of the body, taken at 4 millimetre intervals. It was then embedded in gelatin, frozen and sliced at into more than 1,800 sections using a laser-guided method pioneered by researchers from the University of Colorado.

Each slice was then peeled off and newly exposed surfaces photographed. These images, after being converted into digital information, were combined with data from radiological studies. "Reconstructions from the data-set can be rotated in space, viewed in any plane, dissected and even reassembled," says Victor Spitzer, assistant professor in the department of radiology, cellular and structural biology at the University of Colorado.

The unveiling of this cyberspace corpsicle marks the completion of the 1st phase of the Visible Human Project. The 2nd phase -- the Visible Woman -- will be completed by late 1995. The data set from the female cadaver, explains Michael J Ackerman of the Visible Human Project, nlm, will have the same characteristics as the male cadaver, with a single exception: the anatomical images will be obtained at 0.33 millimetre intervals instead of 1.0 millimetre intervals, a total of over 5,000 images making up about 40 gigabytes of data.

"The Visible Human Male and Female will be a powerful tool that will make an important contribution to medical research," says Lindberg. It can also help in planning surgery and monitoring abnormal cell growths to understand how cancer grows in the body.

Although there is no charge for accessing the data, users will be required to sign a licensing agreement with the NLM, explaining the intended use of the data set, adds Ackerman. The license agreement for the use of the male Visible Human Project data set is now available. It can be retrieved from NLM's gopher site -- gopher.nlm.nih.goh. The agreement will be found in the section titled Visible Human Project as a text file and as a downloadable Wordperfect file.