Jewish World Review Oct. 2, 2002 / 26 Tishrei, 5763

Solar-powered surgery may save lives

By Lidia Wasowicz | (UPI) In the future, when doctors tell patients to catch some sun, they may not mean fresh air but concentrated sunlight beams that burn away tumors.

Physicists and physicians in Israel are developing a new technique called "solar surgery" that may not only save lives but also cost 1,000 times less than similar laser procedures.

"The majority of patients are being deprived of minimal risk, minimally invasive laser fiber-optic surgery simply because of the exorbitant price of surgical laser systems," researcher Jeffrey Gordon, a physicist at Ben-Gurion University of the Negev in Sede Boqer, told United Press International. "We may be able to produce a potentially inexpensive simple alternative."

In principle, solar surgery is similar to when children use magnifying glasses to focus sunlight and kill bugs. Gordon and co-inventor Daniel Feuermann have finished a prototype where a reflective parabolic dish 8 inches wide collects and focuses sunlight onto a point, funneling it down an optical fiber to come out as a cone of sunshine from the 1-millimeter-wide tip of a surgeon's tool.

Earth receives about 950 watts of sunlight per square yard. "Inside the laboratory, the beam is close to 12,000 times that," Gordon said.

Experimental tests on raw chicken breasts show these sunlight beams pack effectively as much punch as laser surgery for most purposes.

"The price I know my university paid for its medical laser unit is about $120,000," Gordon explained. "Based on discussions I've had with manufacturers, in large volume production, what we have now could be made for about $1,000."

The researchers are working on amplifying the beam's power density to more than 22,000 suns, or 20 watts per square millimeter, by using better surgical tips for the system. While the 12,000-sun beam is strong enough to operate on human livers, the researchers want the flexibility to work on tougher tissues, since "any idiot can figure out how to make the beam weaker," Gordon said.

Solar surgery's most obvious weakness is any potential absence of sunlight. "This is completely useless for Seattle or London or any place as cloudy as that," Gordon said, and nighttime is out of the question.

Still, laser surgery is often a planned procedure, not an emergency one, and in sun-belt areas there should be operating windows of seven to 10 hours a day for 250 days per year or more, Gordon said. "Yes, the method is constrained to clear midday hours in sun-belt climates, but that represents a significant fraction of this planet," he explained. "Areas like India, Pakistan, the south of China, belts across South America, the southwest United States and all of Australia can benefit."

Nevertheless, solar surgery will not replace laser surgery for all applications. A few surgical techniques rely on the pure colored light that lasers can provide. Also, while laser beams are columns, solar beams are cones that get much weaker over distance. This makes them useless for retinal surgery, where for safety's sake the tip of the surgeon's tool must remain remote.

A medical team at Ben-Gurion University hopes to test the system on liver tumors in live rats in 2003. Mechanical engineer Agami Reddy at Drexel University in Philadelphia says while solar surgery has a lot of potential, at first he predicts it will be "a cheap and convenient way of removing tumors and performing surgery with animals -- cows, or something like that."

Reddy added the solar collector the researchers use could help improve solar power farms, which typically use huge dishes 15 to 50 feet wide to focus sunlight onto small, expensive photovoltaic cells.

"Those have very massive structural frames that require a lot of maintenance," he said. "Instead of one large dish, you could have many small dishes. You could stamp them out like headlights, and they would become very cheap."

The scientists describe their findings in the Sept. 30 issue of Applied Physics Letters.

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© 2002, United Press International