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 data set of the
male was completed in November
1994 and the one
of the female in November
1995. The project can
be viewed today at the National Museum of Health and Medicine in
Washington, DC. There are currently efforts to repeat this project
with higher resolution images but only with parts of the body
instead of a cadaver.
Data
The male cadaver was encased and frozen in a gelatin and water
mixture in order to stabilize the specimen for cutting. The
specimen was then “cut” in the
axial plane at
1
millimeter intervals. Each of the
resulting 1,871 “slices” were photographed in both analog and
digital, yielding 15
gigabytes of data. In
2000, the photos were rescanned at a higher resolution, yielding
more than 65 gigabytes. The female cadaver was cut into slices at
.33 millimeter intervals, resulting in some 40 gigabytes of
data.
The term “cut” is a bit of a
misnomer, yet
it is used to describe the process of grinding away the top surface
of a specimen at regular intervals. The term “slice,” also a
misnomer, refers to the revealed surface of the specimen to be
photographed; the process of grinding the surface away is entirely
destructive to the specimen and leaves no usable or preservable
“slice” of the cadaver.
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 sections 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, where additional cutting of
anatomical specimens continues to take place.
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.
One of the most notable statements came from
the University of
Vienna
which demanded that the images be withdrawn with
reference to the point that the medical profession should have no
association with executions, and that the donor's informed consent
could be scrutinised.
The 59-year-old female donor 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
ossicles were lost during preparation of the
slices.
Nerves are hard to make out since they
have almost the same color as
fat, but many have
nevertheless been identified. Small
blood
vessels were collapsed by the freezing process.
Tendons are difficult to cut cleanly, and they
occasionally smear across the slice surfaces.
The male has only one
testicle, is missing
his
appendix, and has tissue deterioration
at the site of lethal injection.
The reproductive organs of the woman are not representative of
those of a young woman. The specimen contains several
pathologies, including
cardiovascular disease and
diverticulitis.
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 the
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-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 were used for Alexander Tsiaras's book and CD-ROM “Body
Voyage” which features a three-dimensional tour through the
body.
A "Virtual Radiography" application creates
Digitally Reconstructed
Radiographs and “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.
ImageVis3D an open source volume rendering
application developed at the Scientific Computing and Imaging
Institute
can be used to interactively visualize the various
data sets, converted and processed versions of the data set are
included in the ImageVis3D data set archive for
download.
See also
References
- Roeggla G., U. Landesmann and M. Roeggla: Ethics of
executed person on Internet. [Letter]. Lancet. 28. January
1995; 345(0):260.
- Hoehne K. H. et al.: VOXEL-MAN 3D-Navigator: Inner Organs. Regional, Systemic
and Radiological Anatomy. Springer Electronic Media, New York,
2003 (DVD-ROM, ISBN 978-3-540-40069-1).
- Tsiaras A.: Body Voyage: A Three-Dimensional Tour of a Real
Human Body. Warner Books, New York, 1997 (ISBN 0-446-52009-8).
- [1]
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