One of the Ben Gurion team shines the solar-powered tool at the camera (Image: Ben-Gurion University)
Chicken breasts were used in initial tests (Image: Ben-Gurion University)
Posted on 08/02/2003 2:18:27 PM PDT by yonif
A cheap alternative to the lasers used in surgery has been devised using an energy source that is free and abundant - sunshine.
The working prototype made by Israeli physicists concentrates sunlight down a fibre-optic cable to provide a tool for surgeons. Jeffrey Gordon and his colleagues at Ben-Gurion University in Israel hope it might one day replace the expensive surgical lasers used in operations such as the destruction of tumours in the liver.
The light for the surgical "suntrap" is gathered by a parabolic mirrored dish, 20 centimetres across. This concentrates the light, which is then focused on to the tip of an optical fibre. The fibre can be up to 100 metres long.
The device delivers less than a third of the light flux densities of surgical lasers, which have a typical output of 100 Watts per square-millimetre. "But in our clinical trial, we found that the optimal light density was just 3 W/mm2 for destroying liver cells," Gordon told New Scientist. "We were able to reach temperatures of 60 °C in the cells, which is enough to kill them."
Short bursts
The idea was first mooted in 1999 (New Scientist print edition, vol 161, p 20), but since then the team have improved their design following tests on butcher-bought chicken breasts. Furthermore, they have now successfully carried out surgery on live, healthy rats.
"We inserted the end of the optic fibre into the centre of the rat's liver and delivered two short bursts of light," says Gordon. "The surgery produces very little bleeding and any blood that is produced is immediately stemmed, because the light cauterises vessels during the incision."
He says that post-mortem examination of the rats showed that the light surgery had killed the right amount of tissue. "It works as well as laser surgery at coagulating and burning away tissue and could be used on other organs in the future," he suggests.
The equipment relies on a commercially available sun-tracker and can only be used on cloudless days. But Gordon points out that "in Israel, we have clear skies for 300 days of the year. And most laser surgery is not emergency surgery, it is scheduled and so can be rearranged to fit with climatic conditions."
They believe the equipment can be produced for a few thousand dollars, compared to about $120,000 for laser equipment. The team will now test their device on rats with tumours, and then on other animals including pigs, which have similar-sized livers to humans.
One of the Ben Gurion team shines the solar-powered tool at the camera (Image: Ben-Gurion University)
Chicken breasts were used in initial tests (Image: Ben-Gurion University)
I really would like to see just how they feed the powerful light into the fiber optic cable. Every fiber optic use I am familiar with involves very low levels of energy. I can't quite imagine how they would be able to channel the high power from concentrated sunlight.
I imagine it is very expensive to operate a laser scalpel (I'm not a doctor). Perhaps they could make a laser scalpel using this technology cheap enough so that it could be used instead of the old-fashioned scalpel. It could be used for relatively minor surgery -- if this helps the patient to bleed less -- even in minor surgery, that is a big advantage, yes? This could also be used in field hospitals and poor countries where the electricity supply is not dependable or conventional lasers are too expensive. I hope this will develop into affordable technology that will help many people.
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