Project History

The National Library of Medicine began a project in 1986 to provide access to medical images that would supplement the bibliographic information that the library already supplied digitally through Medline and other biomedical databases.  Images would be collected and stored in a repository to serve as a test bed as well as a database for end users.  Increasing technology has given end users the capability to search and manipulate images with more ease than in the past.  The benefit of having high quality images for medical education and research was seen as extremely important, and the Visible Human Project was born.  It would be several years before the image databases were completed.

The University of Colorado at Denver was awarded a contract in 1991 to create the images from two representative cadavers, one male and one female.  It took almost two years to locate a "normal" male cadaver (a 39 year old convicted murderer) and two and a half years to locate a "normal" female (a 59 year old woman from Maryland) cadaver.  The images were collected by taking one millimeter "slices" of the frozen male cadaver and 1/3 mm slices of the female cadaver.  The male data set is 15 gigabytes and over 1800 cross-sectional images.  The female data set is 40 gigabytes and over 5100 images.

Dr. Victor Spitzer of the University of Colorado describes the process:

                        "Following selection of a suitable male cadaver, it was encased in a
                        special gelatin and frozen to minus 160 degrees Fahrenheit. On August 5,
                        1993, imaging of the cadaver began, from head to toe, using the same
                        magnetic resonance imaging (MRI) and computed tomography (CT) equipment
                        used in medical diagnosis. A custom-designed cryogenic macrotome
                        was then used to remove one millimeter (1mm) sections of the
                        frozen cadaver, revealing slice-by-slice the beauty and detail
                        within."

Image specifications

The images are a combination of axial Magnetic Resonance Interferometry (MRI), Computerized Tomography (CT), and anatomical images.  The MRI images are 256x256 pixels, the CT images are 512x512 pixels, and the axial anatomical images are 2048x1216 pixels.  The male and female data sets are the same with the exception of the width of the cross sections.  The female cross sections are much thinner, resulting in more images.
 

Projects

The male and female image sets are available from the National Library of Medicine for download by FTP.  A license agreement must be signed in order to obtain the images.  The images are in raw data form (in axial "slices" and CT and MRI scans) and in order to use them in a meaningful way a browser/viewer is necessary.  Many universities and private companies have developed applications and products that provide still image viewing as well as 2D and 3D animations.  By combining the axial images with longitudinal CT and MRI data, the body can be recreated and viewed from all angles based on the needs of the user.  This is proving useful in creating virtual surgery applications, anatomy lessons, and other educational uses.

Two of the more interesting and user-friendly applications are listed below:

Visible Human Male
University of Colorado Health Sciences Center
Click on the body to select a region and view the source images.
http://www.uchsc.edu/sm/chs/browse/browse_m.html

Visible Human Slice Web Server
Ecole Polytechnique Federale de Lausanne, Switzerland
Amazing animated journey through the body in the direction and plane that you specify.
http://visiblehuman.epfl.ch/
 

Long-term project goals

It is hoped this data will be a reference point for the study of human anatomy, a test bed for medical imaging and digital image library development.  More than 1400 licensees are currently working with the Visual Human image data and new uses are continually being discovered.  According to the NLM the long term goal of the project is:  "to transparently link the print library of functional-physiological knowledge with the image library of structural-anatomical knowledge into one unified resource of health information."

References

Visible Human Project Home Page - National Library of Medicine
http://www.nlm.nih.gov/research/visible/visible_human.html

Visible Human Project Fact Sheet
http://www.nlm.nih.gov/pubs/factsheets/visible_human.html

Tucson.org - Information about the process of collecting images and the quote from Dr. Spitzer:
http://access.tucson.org/~michael/vh_1.html