Why Give a Dead Man a Body Scan?

On one of Kneubuehl’s recent test days, Thali joins him at the Swiss army’s wooded training grounds outside the Alpine village of Thun. The sound of machine-gun fire alternates with that of birdsong as the two men enter the smallest of the site’s three underground ballistic-test tunnels. Built in the early 1990s to minimize noise disturbance to Thun residents, the 100-, 200- and 500-meter tunnels are the largest underground firing ranges in the world.


Kneubuehl’s goals for the day are to study the fleeting expansion of brain tissue caused by the air jet that accompanies a bullet and to measure the velocity of the skull fragments that enter the “victim’s” brain. First he uses high-speed stop-action video to capture the expansion of his skull-brain models as each takes a bullet or shotgun load to the head. He then blasts the same ammo through sheets of synthetic bone strapped to big blocks of glycerin soap. Having thoroughly measured the glycerin’s consistency, Kneubuehl can mathematically determine the energy of the imploding bone fragments by measuring how far they pass into this test material.


The glycerin soap has the added advantage of preserving the cavity created by the expanding jet of air that accompanies a bullet’s passage through soft tissue. Actual brain tissue, in contrast, would immediately collapse on itself. “We know that the dynamic
cavity during the shot is considerably larger than the wound seen on autopsy,” Kneubuehl explains.


Thali’s mission for the day is simpler: He slips a wig onto one of Kneubuehl’s head models for an “execution style” shooting. Thali wants to determine whether it’s better to collect gunshot residue from the hair with adhesive tape or to shave the head and go for the scalp.


To the uninitiated, the test shot appears to result in the ultimate “oops” moment, with the brain ending up on the floor as the shattered skull flies against a far wall. “Actually, we see this sometimes in our cases,” Thali says. “In Europe, we call it kroenlien, or evisceration of the brain.” He retrieves the gunpowder-speckled wig and skull for later analysis and deposits the blob of synthetic brain in a garbage barrel.


As academically interesting, and even entertaining, as these experiments can be, the question remains: How might the Swiss approach to forensics translate in the down-and-dirty world of American murder investigation? Having spent a year working in the U.S., Thali appreciates that few if any American pathologists have the luxury of pursuing experimental methods and exhaustive research studies. “The medical examiner in a city like Baltimore probably sees as many murders in a weekend as I see in a month,” he says.


Try closer to a year. The 10 full-time pathologists at Bern’s Institute of Forensic Medicine oversee a region of southwestern Switzerland with a population of 1.5 million and perform about 500 autopsies a year, 10 to 20 of which turn out to be homicides. The Maryland Medical Examiner’s Office, based in Baltimore, employs a similarly sized staff of 14 full-time pathologists. But the similarity ends there. Overseeing a state with a population of five million, the Baltimore staff performs an average of 4,100 autopsies a year, including 500 to 600 homicides.


Moreover, Switzerland’s six institutes of forensic medicine all come under the auspices of the country’s well-funded university system. The offices of American medical examiners, on the other hand, derive their funding from budget-strapped city, county and state governments.


The equipment required for a virtual autopsy includes an MRI machine costing upward of $1 million, a CT scanner priced at about $500,000, and 3-D surface-scanning equipment worth more than $100,000. “A lot of medical examiners consider themselves lucky if they have an x-ray machine,” says William Rodriguez, deputy chief medical examiner for special investigations at the Armed Forces Institute of Pathology in Washington, D.C. “For the short term, this type of extremely expensive technology will be considered a big luxury.”Meanwhile, the need to be prepared to deal with mass casualties has the U.S. Department of Defense extremely interested in setting up virtual-autopsy facilities—despite their high cost—at its massive morgue at Dover Air Force Base in Delaware, Rodriguez says. “As the technology becomes more efficient, this becomes a way to scan many more bodies in a shorter amount of time with fewer pathologists,” he explains.


Already Department of Defense medical examiners use a conveyor-belt scanner, similar to those used to screen baggage in airports, to look into soldiers’ bodies for bullets, shrapnel and unexploded ordnance. “As the body goes through the machine, we also see skeletal structures and get a pretty good idea of what we have in terms of large injuries,” Rodriguez says. “Something more along the lines of what Dr. Thali is doing would allow us to take this down to levels of minute detail.”

“Perhaps we in Switzerland have this role to play,” says Thali of the opportunity to explore and perfect techniques that might someday transform postmortem exams for the rest of the world. He predicts that virtual autopsy will eventually speed and improve the procedure by guiding the pathologist’s scalpel and preserving a record of what the internal tissues looked like before dissection. Still, the word “autopsy” comes from the Greek for “seeing with one’s own eyes,” and no one believes that virtopsy will ever replace the pathologist’s scalpel completely. “What we see with our own eyes,” Thali says, “will remain the gold standard in autopsy.”