Visible Human Project
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The Visible Human Project is an effort to create a detailed data set of cross-sectional photographs of the human body, in order to facilitate anatomy visualization applications. A male and a female cadaver were cut into thin slices which were then photographed and digitized. The project is run by the U.S. National Library of Medicine (NLM) under the direction of Michael J. Ackerman. Planning began in 1989; the dataset of the male was released in November 1994 and the one of the female in November 1995.
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The data
The male cadaver was frozen and cut into 1 871 axial slices (at 1 millimetre intervals) which were then photographed and digitized, yielding 15 gibibytes of data. In 2000, the photos were rescanned at a higher resolution, yielding more than 65 gibibytes. The female cadaver was cut into slices at .33 millimetre intervals, resulting in some 40 gibibytes of data.
The data is supplemented by axial sections of the whole body obtained by computed tomography, axial sections of the head and neck obtained by magnetic resonance imaging, and coronal sectioms of the rest of the body also obtained by magnetic resonance imaging.
The scanning, slicing and photographing took place at the University of Colorado's Health Sciences Center.
The donors
The male cadaver is from Joseph Paul Jernigan, a 38-year-old Texas murderer who was executed by lethal injection on August 5, 1993. At the prompting of a prison chaplain he had agreed to donate his body for scientific research or medical use, without knowing about the Visible Human Project. Some people have voiced ethical concerns over this.
The female donor, 59-year-old, remains anonymous. In the press she has been described as a Maryland housewife who died from a heart attack and whose husband requested that she be part of the project.
Problems with the data sets
Freezing caused the brain of the man to be slightly swollen, and his inner ear occicles were lost during preparation of the slices. Nerves are hard to make out since they have almost the same color as fat. Small blood vessels were collapsed by the freezing process. The male has only one testicle. The reproductive organs of the woman are not representative of those of a young woman.
Discoveries
By studying the data set, researchers at Columbia University found several errors in anatomy textbooks, related to the shape of a muscle in the pelvic region and the location of urinary bladder and prostate.
License
The data may be bought on tape or downloaded free of charge; one has to specify the intended use and sign a license agreement that allows NLM to use and modify the resulting application. NLM can cancel the agreement at any time, at which point the user has to erase the data files.
Applications using the data
Various projects to make the raw data more useful for educational purposes are under way. It is necessary to build a three-dimensional virtual model of the body where the organs are labeled, may be removed selectively and viewed from all sides, and ideally are even animated. The commercial application VOXEL-MAN 3D-Navigator from the University of Hamburg accomplishes most of these goals. NLM itself has started the open source project Insight Toolkit whose aim is to automatically deduce organ boundaries from the data.
The data was used for Alexander Tsiaras's book and CD-ROM Body Voyage which features a three-dimensional tour through the body.
Other applications include virtual surgery, where endoscopic procedures or balloon angioplasty are simulated: the surgeon can view the progress of the instrument on a screen and receives realistic tactile feedback according to what kind of tissue the instrument would currently be touching.
External links
- Home page of the project (http://www.nlm.nih.gov/research/visible/visible_human.html), including links to the various other projects that use the data
- Visible Human Viewer (http://www.dhpc.adelaide.edu.au/projects/vishuman2/VisibleHuman.html), Java applet that allows to view axial, sagittal and coronal slices