Editorial: Surgical robots at large in the path lab
THE small industrial robot that dominates the room is in many ways much like any other. A robotic arm smoothly wields grippers and probes 鈥� always accurate and never tired. But rather than working on cars or computers, this robot is processing human corpses.
A team of forensic pathologists at the University of Bern in Switzerland reckon it could make autopsies more accurate and also less distressing for families.
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The researchers are already pioneers of virtual autopsies, or 鈥溾��, which use non-invasive imaging of a body inside and out rather than the radical post-mortem surgery typically used to determine cause of death.
Now they are using a robot, dubbed Virtobot, to carry out parts of that process, making it more reliable 鈥� and standardised.
Their virtopsies combine 3D imaging of a body鈥檚 surface with a CT scan of its interior anatomy. The result is a faithful, high-resolution virtual double of the corpse (see diagram). This double can be used to accurately determine what killed someone. And it鈥檚 a more tactful approach: only needle biopsies are used to sample tissues, leaving a body essentially undamaged.
鈥淭his virtual body-double can be used to accurately determine what killed a person鈥�
鈥淐urrently, organs are taken out and sliced for analysis of tumours and lesions, but if something is overlooked you have no chance of seeing it again,鈥� says team member . 鈥淎ll you have afterwards is a huge pile of organ slices.鈥�
By automating virtopsies, he now hopes to free the post-mortem from the influence of the unavoidable human failings of pathologists, which can affect conclusions about cause of death.
鈥淭oo much of an investigator鈥檚 autopsy results depend on their ability to describe in a report what they see 鈥� and they may overlook things,鈥� says Ebert. 鈥淲e want to make the whole procedure more objective and generate digitally stored data that can be re-examined 20 or 30 years later.鈥�
The current virtopsy procedure begins with a surface scan of the body. When a corpse is placed on the table in front of it, the robot places markers on the skin that help calibrate the surface scan and match it up with later internal scans. It then captures a 3D colour model of the body to a resolution of just 0.02 millimetres, using stereoscopic cameras and a projector that casts a mesh pattern onto the body (see picture, above).
This model can be twisted and turned on a computer screen, revealing injuries, tattoos and other identifying marks in detail.
Being able to process those traces digitally is a boon. In one case, recording the pattern of a car fender stamped onto a person鈥檚 skin helped reconstruct the accident that killed them. Furthermore, scanning without robot assistance is a cumbersome process in which someone must carefully position an unwieldy tripod at different points around the body. Virtobot, able to control its movements with great precision, simply glides over the body to build up the 3D picture.
After the surface scan, the table on which the body lies slides through a CT scanner, which takes high-resolution X-ray slices of the entire body, providing a way to see damage or disease in organs or bones. In the case of a car-crash victim, being able to see the patterns of breakage, and damage to bones, can also help work out exactly what happened.
Finally, after analysis of the 3D model and the internal and external scans, a needle biopsy can be used to gather samples from inside the body if further information is required. Wielding a fine needle, the system uses live CT-scan images to grab a biopsy sample from precisely where it is needed. That might be a sample of fluid from the lungs of a victim of drowning, or a piece of liver to look for signs of disease or toxins.
Such biopsies normally require someone to expose their hand to the scanner鈥檚 X-rays. A robot has no such worries. And, like the robots used in surgery on the living, it is more than capable of using small tools with great precision.
Despite its impressive dexterity, Virtobot wasn鈥檛 built with surgery in mind. Robots used for precision surgery on the living must let surgeons maintain absolute control at all times, for safety reasons. Once given a task, Virtobot can be left largely to its own devices.
鈥淭hese people are already dead, so there is no way we can injure them further,鈥� says Ebert. 鈥淭hat means we can use a cheaper industrial robot, drawn from the automobile industry.鈥�
So far, Virtobot has aided virtopsies in 52 real cases, including 26 road deaths, 10 by impacts from a blunt object, six knifings, five shootings, and two throttlings ().
In 19 cases, 3D surface scans were used to make virtual reconstructions of the attack or accident accurate enough to be admissible in the Swiss courts.
However, the president of the UK鈥檚 , Peter Furness, says that much longer term comparisons of virtopsies with conventional procedures are still needed. 鈥淭he circumstances where this might be valuable are not well defined, the reliability of the approach is unclear and the cost can be considerable,鈥� he says, adding that studies to work out just when a conventional autopsy is essential are under way.
Gallery: The sci-fi future of surgery
Editorial: Surgical robots at large in the path lab
