It uses software and X-rays to produce fast, accurate results, study says
TUESDAY, Nov. 27 (HealthDay News) -- In a development that could dramatically cut the time needed to identify victims of mass disasters, Japanese researchers have developed an automated identification system that uses X-rays and image-correcting software to produce fast, accurate matches of dental records.
The researchers say the speed and reliability of the computerized approach significantly improves on current dental identification methods, which rely on painstakingly slow body-by-body forensic work.
And the new approach should enable public health workers to better respond to the aftermaths of earthquakes, tsunamis, plane crashes or acts of terrorism, the researchers said.
"In the event that a person's body is damaged beyond recognition -- facial features, clothing, personal possessions -- then often a person's teeth are our last chance to identify the victim," explained study lead author Dr. Eiko Kosuge, a dentist, radiologist and lecturer with the department of oral and maxillofacial radiology at Kanagawa Dental College in Japan. "Teeth are very hearty in nature and tend to keep their features even when the body is severely damaged."
"Manual dental identification works fine when the number of victims are few," she said. "For example, a house fire or single auto accident." However, as the number of victims increases, the time required to identify the bodies increases exponentially, and the risk of identification error increases sharply as well, she added.
Kosuge pointed to the 2004 Southeast Asian tsunami disaster and the crash of Japan Air Lines flight 123 in 1985 as two examples of the identification challenges posed by mass disasters. She noted that after the JAL crash, 325 of the 520 victims had to be identified by dental X-rays. In that case, "more than 2,800 doctors, dentists and forensic scientists worked for over three months to identify all of the bodies," she said.
"Our system will cut the workload of forensic scientists by 95 percent [and] will drastically reduce the chance of error," Kosuge said.
Kosuge and her team are to present their findings Tuesday at the Radiological Society of North America's annual meeting, in Chicago.
To develop the new dental identification system, the researchers relied on "Phase-Only Correlation" (POC) technology. This image-matching software automatically adjusts and corrects the kind of distortions that commonly appear in dental X-rays.
Kosuge and her colleagues tested the viability of POC software while analyzing the dental X-rays of 60 Japanese patients both before and after dental treatment. Following POC image corrections, the computerized system generated a list of the three closest identification matches for each set of X-rays. Total computation time needed to generate the match list was just 3.6 seconds per pair, on average.
Next, a group of forensic experts evaluated each of the three matches to arrive at a final identification decision. They found that 87 percent of the patients were correctly "recognized" by the POC method's first match. The success rate rose to 98 percent by the second match. A perfect 100 percent identification match rate was achieved by the third go-round.
Kosuge and her colleagues estimated that by accurately zeroing in on just three X-ray-to-patient matches from among all possible combinations, their computerized approach would effectively reduce the forensic workload by 95 percent.
The team said the system would be available for use in Japan within a year.
Kosuge said the new system could also ease some of the emotional turmoil caused by a mass disaster.
"In Japan -- primarily a Buddhist nation -- tradition dictates that we cremate a deceased loved one within a few days to a week at the most," she said. "Imagine the compounded pain of not only loosing a loved one but then not being able to perform proper funeral proceedings. When our system is employed, no one will know about us, no one will know about our system. What they will know is -- as sad as it was to loose a loved one -- they were still able to properly perform funeral proceedings."
Dr. Norman "Skip" Sperber, chief forensic dentist for California's Department of Justice, said the new technique sounded "very promising and worthwhile.
"This could certainly revolutionize our armament and help us greatly in the event of a mass disaster," he said. "The numbers are very impressive, and the researchers deserve a lot of credit."
But Sperber cautioned that every dental identification system has its limits.
"This method they developed would greatly enhance dealing with mass disasters where bodies were in relatively good condition," he said. "It'll work for traumas that didn't destroy the bodies, or where bodies have decomposed but the teeth are intact, such as in situations involving poison, radiation, a boat disaster, that kind of thing.
"But I was one of the senior people working on identifying people in New York after 9/11, and, based on dental records, we were able to identify only about 1,500 of the 3,000 missing people," Sperber added. "A lot of the bodies were just vaporized. And if you get a trauma like we did in New York, no system is going to work, because there are no teeth left. So, this sounds very good, but it won't help in every situation."
To learn more about forensics and dental records, visit Forensic Dentistry Online.
SOURCES: Eiko Kosuge, D.D.S., dentist, radiologist, lecturer, department of oral and maxillofacial radiology, Kanagawa Dental College, Japan; Norman "Skip" Sperber, D.D.S., chief forensic dentist, Department of Justice, State of California and San Diego and Imperial counties; Nov. 27, 2007, presentation, Radiological Society of North America annual meeting, Chicago
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