Catherine Guthrie, Staff Researcher
Virtual autopsies are on the cutting edge of forensic science. They use computerized reconstructions of the deceased to determine cause and time of death. This digital reconstruction is generated by a combination of highly sensitive modern imaging technologies. Specifically, noninvasive postmortem magnetic resonance imaging (MRI), computed tomography (CT) and photogrammetric scans are taken of the body and assimilated by a computer program into two or three-dimensional digital images.
This technique is being developed and studied at the University of Bern, Institute of Forensic Medicine in Switzerland under the name Virtopsy. Virtopsy is still considered experimental even though more than one hundred such autopsies have been performed. Thus researchers in the field must validate the accuracy and diagnostic value of the digital images through a subsequent, traditional autopsy.
In the most general sense virtual autopsies are an example of forensic radiology which, although perhaps underutilized, is itself not a brand new discipline. Radiology has been used in the forensic context to identify bodies and bitemarks, examine physical evidence, detect signs of abuse, and investigate drug trafficking. Even the United States military has utilized this methodology. Medical examiners in the Department of Defense have used conveyor-belts to move people who died in combat through x-ray scanners to check for shrapnel, bullets and un-detonated explosives.
As one of the most recent developments in forensic radiology, virtual autopsies have several advantages over the traditional autopsy. Virtual autopsies produce clear graphics so that organs and injuries can be viewed without obstruction from blood and other internal matter. The technology is particularly adept at detecting bullet paths, pockets of liquid, hidden fractures, and gasses that are hard to observe with the naked eye. Micro-CT scans can even identify specific toolmarks left in bone. In the legal context, the images are graphic enough to engage and educate jurors but not gruesome enough to risk exclusion in a court of law. Additionally, the noninvasive nature of the technique allows autopsies to be performed that may otherwise have been prevented because of personal or religious beliefs. The lack of incisions also protects examiners from toxic agents sealed within the body.
However, this new technology is not without its drawbacks. The high cost of the machinery and need for specially trained x-ray technicians place virtual autopsies out of reach for most coroners. The examination process is not entirely automated which, despite the perceived infallibility of computers, means there is room for error. For example, operators must use and adjust complicated protocols to extract images from various kinds of body tissues. Virtual autopsies are unable to diagnosis natural deaths caused by heart failure or infection, and it is hard to diagnosis poisoning with this technique.
Furthermore, the use of a digital three-dimensional model to supplement or replace the standard autopsy report has not been addressed by the American legal system. Thus courts may struggle to set standards of admissibility and authentication for virtual autopsy evidence. For example, it is unclear whether virtual autopsies are a novel scientific technique, in which case additional indicia of reliability might be required. Parties could also disagree about how to establish the trustworthiness of the process used to create the computerized images.
This practice is a fascinating development in the field of forensic death investigation. NCSTL offers resources on this subject in its database under Forensic Pathology and Digital Evidence. A bibliography of related materials is also available at www.ncstl.org in the Education and Training section:http://ncstl.org/education/FAME Conference Miami, August 11, 2005