There are a lot of reasons I’m not a doctor today. For one thing, I’m just the tiniest bit squeamish. The sight of anything even remotely illness-related--needles, bandages, rice pudding with raisins--makes me instantly weak-kneed. For another thing, some of the routine parts of a doctor’s job have always struck me as rather unattractive. I’m pretty sure I could go through my entire life without ever speaking the words, Turn your head and cough, or, Now, let’s have a look at that polyp, shall we?
More important, however, the science of anatomy has always left me baffled. From grammar school on, I’ve had only the roughest idea of how the human body is put together, even when that body is my own.
I’m pretty certain I’ve got the standard heart, lungs, and kidneys; pretty sure I don’t have a crop, gizzard, or brood pouch; and as for my gallbladder, pineal gland, and jejunum, I’ll take it as an article of faith that they’re where they ought to be, but I couldn’t find them with a copy of Gray’s Anatomy and a sextant.
In fairness, my anatomical illiteracy is not entirely my fault. My first exposure to the mysteries of the human innards was an educational toy (translation: no batteries, decals, or suction-cup darts) I acquired in childhood, called The Visible Man. The Visible Man was a tiny model of a human being with snap-in and snap-out organs that was supposed to show you precisely how the average person is put together. By and large, the little model did a pretty good job--provided, of course, that the average person is 11 inches tall, completely transparent, and able to accept an organ donation from a Lego set. In my house, The Visible Man lasted only a week or so before becoming The Visible Man Minus Key Organs, and it was eventually taken away from my brothers and me altogether after tiny plastic glands started turning up in the Chex mix.
For even the most anatomically unschooled, however, all this confusion may soon come to an end. Recently the U.S. Department of Health and Human Services went The Visible Man of my childhood one better, announcing the creation of the intriguingly named--and now gender-neutral-- Visible Human Project, a government program designed to simplify and standardize the study of human anatomy once and for all. The Visible Human Project is sort of the medical equivalent of the Miss America contest, in which one man and one woman will be selected from the general population to serve as science’s archetypes of the human form. These two perfect specimens will be scanned, photographed, and data-based and then used as anatomy models in classrooms and laboratories across the country.
For anyone looking for a line of work that doesn’t exactly require four years of graduate school, the two openings sound promising. But before typing up a résumé and submitting Polaroids of your pancreas, be aware of the fine print in the employment contract. The perfect pair chosen for the project will be X-rayed from head to toe, spend hours lying still in a magnetic resonance imaging machine for soft-tissue pictures, and later spend at least half a day submitting to a series of full-body CT scans. Finally (and here’s the part that some fussier applicants might object to), both lucky winners will be steadily ground to dust by a planing machine and photographed as different parts of their bodies are exposed. Not surprisingly, this last step may discourage even the hardiest candidates, and to get through this final part of the process, project organizers recommend that an applicant be either a) a really, really good sport, or b) dead.
As you might expect, there have been very few applicants from the first category, and the sponsors of the Visible Human Project have thus been concentrating exclusively on candidates from the second. In the past 18 months government doctors have examined 2,000 contending bodies that had been donated to science in three different states, looking for the perfect former people to serve as models for the human form.
All across the country, there are researchers who could benefit from standardized anatomical models like these, says University of Colorado medical imager Victor Spitzer, one of the principal investigators on the project. Oncologists planning cancer treatments could determine the maximum radiation load a certain area of the body can tolerate and then tailor the dosage to the needs of the particular patient. Designers working on artificial joints or limbs could learn everything possible about how, say, a femur head works and then apply that knowledge to the unique needs of an individual implant recipient. Students learning about anatomy or doctors practicing surgery could manipulate the computer images the same way they could manipulate actual tissue, and all know that they were learning from the same body, with no misleading abnormalities. For once, science can have specific reference bodies everyone can be familiar with.
The Visible Human Project got its start five years ago, when people at the National Library of Medicine in Bethesda, Maryland, first came up with the idea of making the study of the human form uniform. The U.S. government is usually rather picky about the kinds of scientific research it chooses to support, typically providing funding to only those projects that cost slightly more than the gross national product of Spain and have slightly fewer technical applications than a Slinky. (In recent years, this kind of bold thinking has led Congress to appropriate billions of dollars for the space station Freedom, an orbiting laboratory that could find numerous uses--as an attractive ashtray or a decorative planter, for example--and the Superconducting Supercollider, a gigantic particle accelerator that could provide new clues to the origins of the universe, provided the universe originated in a large hole in the ground in Waxahachie, Texas.)
The idea of a Visible Human Project met none of the usual criteria, and yet as soon as it came up it caught the government’s fancy. Researchers around the country had long been cataloging individual organs or groups of them, but nobody had ever before thought of studying one body in one place with one group of researchers. In 1988 the national medical library gathered anatomists and medical imagers from a dozen or so schools and labs to see how the project might be tackled. The hardest part, the researchers knew, would be finding just the right ex-people for the two job openings. The bodies the researchers were looking for had to meet some pretty stiff requirements.
The cadavers we need have to be as typical of the population at large as possible, says Spitzer. That means they have to be between 21 and 60 years old, less than six feet tall, a normal weight for their height, and have no traumas, significant surgery, or visible abnormalities. Additionally, they couldn’t have died of a disfiguring accident or of any illness that would change the appearance of the body in any appreciable way. This would limit the bodies we could use to people who had died of things like poisoning, asphyxiation, or a coronary occlusion that didn’t change the appearance of the heart muscle.
A bigger problem, of course, was just how the actual images of the bodies would be rendered. The CT scans, X-rays, and MRIs would not be too difficult. Though few researchers have much experience creating the comprehensive, whole-cadaver pictures that the Visible Human Project needed, with a little practice the skill could be mastered. And there was some consolation in knowing that with these particular patients you could work for hours at a time without once having to say, Now, hold still. Much tougher was the part of the job that came after the scans--the planing part.
There aren’t too many groups of researchers, Spitzer says understatedly, who can cut a body the way the project needed it to be cut.
To get as many minds as possible working on the problem, in 1990 the national medical library opened up the Visible Human Project to competitive bidding. A dozen teams submitted bids, including Spitzer and his colleague David Whitlock, a University of Colorado anatomist. Each team was required to turn in a detailed prospectus describing how the bodies would be rustled up and whittled down, and just what the price of all this slice-and-dice work would be. It took more than a year before the government judges made up their minds, but ultimately they crowned Spitzer and Whitlock the winners.
Even on paper, it’s clear that Spitzer and Whitlock are indeed the right men for the job. When a potential body is located for the Visible Human Project, Spitzer explains, their proposal calls for first preserving it with a light fixative. You don’t want to fully embalm a body, Spitzer says, because this can cause the tissue to shrink. Instead, the chemicals he and Whitlock use--sort of the mortician’s equivalent of a delicate balsamic vinaigrette--are able to maintain the shape and appearance of flesh and organs while at the same time slowing their decomposition.
After being chemically treated, the body is taken for the battery of full-body X-rays, MRIs, and CT scans. The X-rays and MRIs can be conducted pretty quickly since the necessary machines are usually readily available in any good hospital or research facility. CT scans, however, can be a problem.
CT scan machines are in enormous demand and are thus not always available when you need them, Spitzer says. Sometimes it can take days before a machine is freed up, and you can’t just leave a body lying around that long.
To preserve their perished perishables for extended periods, Spitzer and Whitlock must freeze them. The job of making a six-foot Ben & Jerry’s out of an ordinary Ben or Jerri is relatively easy and involves little more than suspending the bodies vertically in a freezing chamber with cables supporting the head, chest, and hips (No wire hangers, ever!), packing the chamber with dry ice, and allowing the temperature of the tissue to drop to -70 degrees. When the CT machine becomes available, the bodies are simply rolled into place and scanned.
From this point on, though, things get a little messy. The most difficult part of the Visible Human work--the part that separates the men from the boys (not to mention the cadavers from their limbs)--involves the body grinding techniques. The first step in cutting the frozen remains down to size involves using a surgical saw to slice them horizontally into four sections, none taller than a foot and a half. These four sections are then immersed in separate blocks of gelatin, each measuring 14 inches by 18 inches by 18 inches. The gelatin itself is then frozen, helping to keep the tissue cold and stable throughout the upcoming slicing. (Evidently, in some cases there’s not just always room for Jell-O, but always room in Jell-O.)
Once the quiescently frozen human cubes have solidified, they are inserted in a machine that uses a blade to shave a one-millimeter layer off the top of the block in much the way a carpenter planes wood. Spitzer and Whitlock then photograph and videotape that newly exposed surface. Next another millimeter is planed off, and the new surface duly photographed and videotaped; then another, and another. It takes up to 1,800 planings to complete a photo album of the frozen innards, and when the last layer of erstwhile person has been scraped away, there are at least two photographs and one video image of each millimeter, for a total of up to 5,400 pictures in all, each of which gets translated into computer code.
We want to be as thorough as possible, Spitzer says, and make sure we have some backup pictures and quality control over the images we get.
It’s a good thing Spitzer and Whitlock are as thorough as they are in making images of their cadavers, because when they’re done with their work, the bodies aren’t much to look at. Unlike wood, which is reduced to curled shavings when it’s planed, frozen flesh turns into something more like sawdust. While it might be tempting simply to inter these final remains in the first handy Dustbuster, Spitzer and Whitlock are more respectful of their donors than that and plan to turn the shavings over for a proper cremation.
Of course, before any of this scanning, shredding, and toasting can take place, the lucky stiffs who will be the center of all the attention still have to be chosen. Before submitting their proposal to the national medical library, Spitzer and Whitlock contacted colleagues on the Texas anatomical boards and secured their cooperation in the hunt for the competing corpora. Texans (later joined by accommodating Marylanders and Coloradans) are apparently generous with their remains, providing a pool of about 2,000 former citizens each year from which the Visible Human researchers can choose. When a body donor who fits the general criteria dies, the state board immediately contacts the two researchers. Preliminary X-rays and MRIs are then conducted in the home state, or if no scanning equipment is handy (and if the local board has a lot of change for the stamp machine), the body is shipped to Spitzer and Whitlock, who do this initial scanning themselves. If these relatively cursory exams look promising, the researchers submit the scans to the national medical library, which gives the thumbs-up or thumbs-down on any candidate.
According to their contract, Spitzer and Whitlock are to provide a total of six bodies--three male and three female--to the national medical library, from which the two winners will be selected. The four runners-up will be kept on ice in case anything happens to the first two choices (though the likelihood of either of the winners phoning in sick or getting a better offer elsewhere seems remote at best). So far, the system appears to be working well--Spitzer and Whitlock have already submitted three males and one female for approval.
But even after Spitzer, Whitlock, and the national medical library carcass caucus choose the remaining bodies, the Visible Human Project will by no means be home free. Once word of the project gets around, will people who would ordinarily leave their bodies to science suddenly have reservations? Shuffling off the mortal coil is one thing, but shuffling off your skin, bones, and major organs is something else entirely. Spitzer, however, is not concerned and believes donors might even be honored to have their remains used in this way. The bodies chosen for this project will become the archetypes for the human form, he says. They’ll be used for research and study for years to come.
Spitzer may have a point, but when the line for Visible Human candidates forms, don’t expect to see this future cadaver anywhere near it. I don’t especially mind throwing my hat into the ring, but I’d prefer not to throw my head in with it.