01 Aug 2003
An Israeli team has operated on two rats using concentrated solar rays.
Scientists in Israel have successfully performed solar surgery on live animals for the first time (Nature 424 510).
Jeffrey Gordon and colleagues at the Ben-Gurion University of the Negev applied the incoherent sunlight to destroy liver tissue in two healthy rats.
By a combination of ablation and coagulation mechanisms, the sunlight destroyed about 1 cm3 of liver tissue in the two animals. After surgery, the rats were revived and, according to Gordon and colleagues, behaved normally until they were killed for pathological analysis.
In Gordon’s setup, concentrated sunlight is collected (see related story) and then transmitted into the operating theater through a flexible, high-transmission optical fiber. The fiber is 20 m long and has a numerical aperture of 0.66.
According to the team, the key factor in most photothermal surgery is not the coherence or monochromaticity of the light, but attaining a sufficiently high power density. In sunny weather, Gordon’s fiber delivers a power density of several watts per mm2 - a power density that is similar to the levels produced by surgical lasers.
In the pilot experiment, the rats were irradiated for between 40 and 180 seconds. After examining the tissue, the lesion created during the surgery was found to be similar to conventional laser treatment.
Gordon says that apart from solar surgery costing far less than a comparable medical laser system, it is also better from a safety point of view. “Solar surgery does not carry the risk of eye injury to the operating team because concentrated light is delivered over a large angular range.”
Michael Hatcher is technology editor of Opto & Laser Europe magazine.