A new system in development at the US Department of Energy's Oak Ridge National Laboratory, or ORNL, combines laser and radar systems -- called lidar -- to spare burn victims some of their pain.
Researchers hope that the Coherent Frequency-Modulated Continuous Wave Laser Radar Mapping System will make the treatment known as debrading -- scraping and cutting away of dead and damaged skin and flesh -- obsolete.
The new system would create a three-dimensional lidar map of a burn and the surrounding tissue to assess the damage. Using the map as a guide, the laser would automatically remove dead tissue so healing can begin.
Glenn Allgood and colleagues Eric Grann, Don Hutchinson, and Bill Dress have developed the diagnostic part of the system. Their next step is to create the laser component that follows the lidar map.
"What they're trying to do would really benefit the patient. They'd be able to do skin grafting a lot sooner and it would also allow them to know how deep they have to cut," said John Lott, head nurse at the Miller-Dwan Burn Center in Duluth, Minnesota.
"You like to remove that burned tissue as quickly as possible because that's the media that infection likes to grow in," he added.
With current procedures, it's difficult for surgeons to tell which tissue is dead and needs to be removed and which is still alive and can heal on its own. When debrading, surgeons only know to stop cutting when they see the blood that indicates live tissue.
"When you go to graft and you're removing that burned tissue, you may be removing more than you need to," Lott said.
The ORNL system's lidar will detect hemoglobin to let surgeons know the tissue is alive. The researchers have developed the system to a 50 micron resolution, and they hope to soon reach the 5 micron level, which would be sensitive enough to see blood cells.
Within the next few years, the researchers hope to complete the next phase of the system -- a laser pulse which would ride on top of the lidar. The laser would look at the map and translate that into how much power the laser needs to use and how deeply it should remove the dead cells.
"We've developed a novel algorithm for looking at the information as it comes back [from the lidar]," Allgood said.
Doctors have some tools to help them measure the live tissue in burn victims, like active triangulation. This method uses a laser to measure the extent of a burn, but it's prone to errors because light tends to scatter inside the tissue. Auto-focus techniques can profile skin, but they can't measure a liquid like hemoglobin. Ultrasound is also used but is often not precise.
"I think we have a finer resolution in that I think we can do it in real time," Allgood said. "No matter what technology you use if you really want to beat the time aspect, that's what you'd really like to have."
The system could also assess other types of tissue damage, Allgood said, such as wounds, punctures, scrapes, and lesions from chemical and biological contaminants.
