Device promises microwave surgery

Allow a magnifying glass to concentrate the sun's rays and you can burn combustible material. Scientists have used lasers to produce more powerful beams for years.

Researchers from the Hebrew University of Jerusalem in Israel have achieved something similar with microwaves, which can penetrate deeper than lasers, heat rather than burn, and can heat materials that lasers cannot.

Microwave devices also are smaller and less expensive, which opens the possibility of hand-held microwave applicators that are similar in size to cell phones.

The device could be used as a biological soldering iron to heat a mixture of albumin and egg-white into a tissue seam; it could also be used to obliterate cancerous and other unwanted tissues in the body, according to the researchers.

The device could also be used to process polymers, or plastics, including fabricating microlenses, according to the researchers.

The researchers made a prototype device using a near-field microwave probe that was developed as a part for a microscope. The probe emits microwaves through a slit that is one-half to one-thousandth of a millimeter wide.

The prototype can heat a spot as small as 0.3 by 0.5 square millimeters to temperatures as high as 120 degrees Celsius using a few watts of power, according to the researchers.

The researchers are working on a one-watt hand-held microwave device.

The work appeared in the June 21, 2004 issue of Applied Physics Letters.