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Medical Uses of Perfect Lens

IP.com Disclosure Number: IPCOM000004449D
Publication Date: 2000-Nov-13
Document File: 2 page(s) / 5K

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Chris Phoenix: INVENTOR

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http://composite.about.com/industry/composite/library/PR/2000/blucsd1.htm?terms=negative+dielectric+constant: URL [+2]

Abstract

Recent advances in physics present the possibility of delivering microwave energy to small (sub-wavelength) areas inside the body without surgical implantation of antennae. This would seem to be useful for several classes of medical treatments, including tumor therapy. Recent experimental work has produced a structure with a negative index of refraction and negative magnetic constant for electromagnetic waves in the microwave domain. More recent theoretical work has indicated that such a material could form a "perfect lens"--creating a sub-wavelength image of the source on the opposite side of the lens, by transmitting both the near-field (non-radiatively-propagating component) and the far-field. Electromagnetic waves can have a source far smaller than the wavelength. The "perfect lens" would create a precise image of the source at a certain distance from the lens, thus allowing the reconcentration of emitted radiation inside a body. The effect would be similar to surgically implanting the source at the focal point. This should allow the delivery of energies on the order of watts to volumes on the order of cubic millimeters.

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Medical applications of "perfect lens" technology for delivery of microwave energy or near-field components

Chris Phoenix

November 13, 2000

Keywords: tumor, cautery, perfect lens, diathermy, microwave

Recent advances in physics present the possibility of delivering microwave energy to small (sub-wavelength) areas inside the body without surgical implantation of antennae or other invasion. This would seem to be useful for several classes of medical treatments, including tumor therapy.

Recent experimental work [1] has produced a structure with a negative index of refraction and negative magnetic constant for electromagnetic waves in the microwave domain. More recent theoretical work [2] has indicated that such a material could form a "perfect lens"--creating a sub-wavelength image of the source on the opposite side of the lens, by transmitting both the near-field (non-radiatively-propagating component) and the far-field. (In fact a flat slab (of appropriate thickness) of a material with index of refraction = magnetic constant = -1 would be such a lens.)

Electromagnetic waves can have a source far smaller than the wavelength--for example, visible light photons can be emitted by individual atoms, and radio waves can be generated by antennas of fractional wavelength. The "perfect lens" would create a precise image of the source at a certain distance from the lens, thus allowing the reconcentration of emitted radiation, perhaps inside a body. The effect would be similar to surgically implanting the source at the focal point. However, with an external source and focusing mechanism, the source could easily be relocated and could be fairly large. Note that the energy would be injected from the entire surface of the lens, so the normal problems of a beam path through the body would be avoided--the "beam" would be very diffuse except near the focal point.

With a sufficiently small source, and a sufficiently efficient lens, this should allow the delivery of energies on the order of joules with rates on the order of watts to volumes on the order of cubic millimeters. This could allow precise destruction of tissues. This may be useful for several kinds of medical therapy, including tumor killing and cautery of internal bleeding. It might also be useful for mitigation of local cysts or pockets of infection (maybe even in cases of appendicitis); smoothing ragged cartilage; destroying unwanted adipose tissue; destroying stones by heat stress or local boiling causing sonic shock waves; inducing temporary sterility. Many other uses will be obvious to a surgeon.

When electromagnetic radiation is emitted, it contains both near-field and far-field components. The near-field components usually do not propagate radiatively (they are insubstantial at any significant distance from the source). The electromagnetic radiation we're used to dealing with is entirely far-field...