Scientists harness sunlight to replace medical lasers

A mirror gathers sunlight, transfers the rays to a small, flat mirror above a dish and sends the solar energy through a fiber optic cable in the laboratory’s floor.The sun may offer a cheaper alternative to traditional medical lasers, Israeli …

A mirror gathers sunlight, transfers the rays to a small, flat mirror above a dish and sends the solar energy through a fiber optic cable in the laboratory’s floor.The sun may offer a cheaper alternative to traditional medical lasers, Israeli researchers have discovered. According to Dr. Jeffrey Gordon, a researcher at Ben-Gurion University in Negev, Israel, who led the study, solar-powered lasers can kill tissues as well as medical lasers, but at a lower cost.

The group of physicists at the Department of Solar Energy and Environmental Physics, Jacob Blaustein Institute for Desert Research at Ben Gurion University of the Negev – Dr. Daniel Feuermann, Gordon, and Mahmoud Huleihil – have developed a device that could emulate the actions of laser surgical tools, using only sunlight.

The procedure, explained in the journal Nature, would only work in sunny climates, but could one day provide a low-cost alternative to conventional laser treatments.

Laser surgery is used often to remove tumours by simply burning them out, instead of traditional techniques of physically cutting them out of the body with a scalpel. This latest research shows it could be possible to produce similar results with concentrated sunlight instead of costly laser treatment.

In their experiment, Gordon and colleagues transported sunlight into the operating theatre from outside through a system of optical fibres. These concentrated rays – which contained several watts of energy – were then directed on to the livers of two rats for just a few minutes. The tissue was seen to wither and die in the same way as it would after laser treatment.

The rats recovered well following the surgery; and after detailed analysis of the livers, the scientists found the treatment had worked as well as a laser. Not only could this solar surgery be a cheap alternative to laser therapy in sunny countries, it also appears to be safer for the surgeons to use.

The solar system uses a collector called the Tracker outside the laboratory window. A mirror gathers sunlight, transfers the rays to a small, flat mirror above the dish and sends the solar energy through a fiber optic cable in the laboratory’s floor.

“This is only for sunny climates and even then for clear sky periods,” Gordon told Reuters. “I do not wish to project the impression that we’re offering some universally applicable solution.”

Traditional medical lasers can cost up to $150,000 apiece, which has made it prohibitive for all but those who can afford advanced medical treatments. While its is becoming increasingly rare to see a scalpel in operating theaters in the Western World, as they are replaced by lasers, virtually all surgery in the Third World is done with knives. Even in Israel, most hospitals have only a few laser devices.

The device’s great advantage is its low cost. “We’ve built one prototype,” says Feuermann. “If a commercial entity is interested in applying it, I estimate a device could be marketed within a year or two. As for cost, the prototype cost $7,500 to build. Commercial production would probably lower that.”

“Based on conversations I’ve had with manufacturers, I would project that if the solar surgery prototype could be mass produced, it has the potential to cost around $1,000 per unit,” Gordon said in a statement.

“Over the years, we developed techniques to move sunlight from place to place,” Feuermann told Globes. “We went to hospitals to watch lasers being used after we were asked to design an optical system that would move the laser from place to place. When we saw what they were doing, the question arose why not do the same thing with sunlight?”

The Tracker is at the core of the device they developed. This is a system of receptors that follow the sun, and concentrates its light, intensifying it 15,000-fold. The concentrated sunlight is delivered to the operating room through a fiber-optic cable. From there on, the surgery is identical to laser surgery. Laboratory tests to destroy tumors in rats have been successful.

The Tracker can easily be installed on a hospital’s roof, even if the operating theaters are on the lower floors. Writing in the journal Applied Physics Letters, Gordon and colleagues said the solar-powered laser has been able to deliver about 5 watts to 8 watts of energy, similar to the power of some conventional medical lasers. Most surgery does not require more than 3 watts, according to Gordon.

Safety is another advantage to using the Tracker, its developers claim.

“Lasers are dangerous to the eyes,” says Feuermann. “In our device, the concentrated light exits the optical fiber at wide angles. There is no beam. We aren’t replicating the laser, but what it does – heating the tissue. The spread of light across several centimeters after the light exits the optical fiber means the rays are no longer dangerous. You could place your hand in front of the optical fiber and nothing would happen. If you touched the end of the optical fiber, you’d make a hole in your finger.”

These advantages carry a cost. The dependence on sunlight, for instance. “You can’t start surgery when there’s a risk of cloud,” notes Feuermann. “The device is designed only for regions where you know in advance that the day will be sunny. This is one reason why businesses are hesitating to enter the project. The market isn?t the traditional market, but those countries that can’t afford laser systems for every hospital, but have lots of sunlight. Business-wise, the market is in poor regions where 2 billion people live, but lack the resources to pay.”

Ben Gurion University has decided not to patent the device, so the know-how to build it is freely available. Prof. Solly Mizrahi and Dr. Ruthy Shaco-Levy of Soroka Medical Center joined the development team to test the device. So far, only tests on animals have been conducted. The next stage is trials on pigs, followed by clinical trials on humans. Meanwhile, the inventors are seeking financing for further research.

(Based on a report in Globes)