Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Thermal applicators
Reexamination Certificate
1999-08-19
2001-08-14
Gibson, Roy (Department: 3739)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Thermal applicators
C607S102000, C607S105000
Reexamination Certificate
active
06275738
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to microwave devices used in medical hyperthermia and thermotherapy (referred to collectively herein as “heat therapies”) and diagnostics, and to methods of using such devices.
Localized heat therapies, i.e., hyperthermia (heating to temperatures below 45° C.) and thermotherapy (heating to temperatures above 45° C.), have been intensively investigated for the last two decades for many disease processes.
However, methods of delivering heat including warm fluid, focused ultrasound, radio frequency, and microwave approaches have been applied to abnormal tissue with only limited success. Because microwave energy can be applied with limited invasiveness, this approach is one that is currently being proposed.
For heat therapy to be applied safely, it is very important that the applied heat be confined to a target area alone, to avoid damaging nearby healthy tissue or organs.
Some devices for heat therapy have utilized microwave heating, for example, those disclosed in U.S. Pat. Nos. 4,700,716 and 4,776,086, the disclosures of which are incorporated herein by reference. Microwave energy elevates temperature by increasing the molecular motion within cell structures. As the frequency decreases, tissue penetration increases. Small diameter microwave antenna and other probes have been inserted into the body through normal body passages or, on occasion, directly into diseased tissue, using hollow plastic catheters.
SUMMARY OF THE INVENTION
The invention features a medical treatment system which utilizes microwave energy to provide heat treatment and diagnostic imaging of an arbitrarily shaped tissue mass. The term “microwave”, as used herein, refers to electromagnetic energy in the microwave frequency spectrum of about 300 MHZ to about 300 GHz.
In one aspect of the invention, a medical treatment system for treatment of tissue includes a radiating antenna system, positioned to radiate electromagnetic energy through the tissue, and receiving elements, each configured to be positioned within or on the periphery of the tissue to receive at least a portion of the radiated electromagnetic energy from the radiating antenna system to the tissue. Each receiving element has an interior volume for receiving a heat exchange fluid to change the temperature of the tissue proximal to the receiving element.
In another aspect of the invention, a medical treatment system for treatment of tissue includes a radiating element system, positioned to radiate electromagnetic energy through the tissue, and reflecting elements, each configured to be positioned within or on the periphery of the tissue to reflect at least a portion of the radiated electromagnetic energy from the radiating antenna system to the tissue.
The inventions have numerous advantages. The radiated energy from the radiating antenna system is used to heat a desired area of tissue and the receiving elements are positioned to operate as “heat pipes”, which act as a source or sink for the heated tissue. In addition, the individual receiving elements receive the radiated energy and provide signals which together provide an image and a property map of the area of tissue defined by the positioning of the elements. Thus, the receiving elements improve control of the temperature of the volume of the tissue mass being radiated by the radiating antenna system. With this arrangement a safer, more efficacious delivery of microwave energy is provided. It is important to recognize that although the receiving elements serve as “heat pipes”, in operation, they can provide both heating as well as cooling, depending on whether the fluid (e.g., liquid or gas) flowing through the heat pipe structure is hot or cold.
Embodiments of these aspects of the invention may include one or more of the following features.
At least one of the reflecting elements can include an interior volume for receiving a heat exchange fluid to change the temperature of the tissue proximal to the reflecting element.
One (or more) of the receiving and/or reflecting elements has a conduit for conveying the heat exchange fluid from a heat exchanger to a distal end of the receiving element. The receiving and/or reflecting element also has a transmission line extending from the distal end to a proximal end of the receiving and/or reflecting element. The conduit extends through the transmission line and forms a hollow center conductor of the transmission line. The transmission line also has an outer shield which is coaxial with respect to the conduit. The interior volume of the receiving and/or reflecting element and the conduit are sized to cause capillary action of fluid flowing between the internal volume and the conduit. The heat exchanger can include a condenser and the heat exchange fluid can be a coolant.
One or more of the receiving and/or reflecting elements has a temperature detector for sensing the temperature at a location proximate to that receiving element. In response to the sensed temperature, the detector provides signals for controlling the amount of fluid delivered to the interior volume of the receiving and/or reflecting element by the heat exchanger.
A measurement analyzer, connected to one (or more) of the receiving and/or reflecting elements, measures electrical characteristics associated with the receiving and/or reflecting element. These electrical characteristics include amplitude and phase voltage characteristics. The electrical characteristics can also be magnitude and phase of S
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scattering parameter between the radiating antenna system and the receiving and/or reflecting element. A processor processes the measured electrical characteristic to generate an image of the tissue, and a display then displays the generated image.
One (or more) of the receiving and/or reflecting elements and the antenna system can be configured to deliver a material to the tissue. The material can be a chemotherapeutic agent, a heat sensitizer, or a cyropreservative.
At least one of the receiving elements includes a reflecting structure for reflecting the radiated electromagnetic energy from the radiating antenna system in a desired direction, thereby increasing the uniformity of the radiation applied to the targeted tissue.
The radiating antenna system has a plurality of antennas in the form of a collinear array. The radiating antenna system is configured to be received within the tissue to be treated.
A cannula is provided to receive the radiating antenna system within its inner lumen. The radiating antenna system includes antennas, each in the form of a collinear array.
The electromagnetic energy is radiated at a frequency in a range between 0.3 and 10 GHz, and at a power level in a range between about 100 mwatts and 150 watts.
In another aspect of the invention, a method of treating tissue is provided where a radiating antenna system is positioned within the tissue to radiate electromagnetic energy into a portion of the tissue desired to be heated, and receiving elements are positioned for receiving the radiated electromagnetic energy from the radiating antenna system with each receiving element positioned so that the path of received energy is through the portion of the tissue desired to be heated.
In still another aspect of the invention, a method of treating tissue is provided where a radiating antenna system is positioned within the tissue to radiate electromagnetic energy into a portion of the tissue desired to be heated, and reflecting elements are positioned for reflecting the radiated electromagnetic energy from the radiating antenna system toward the tissue to be treated.
With respect to these methods of treating tissue, the receiving and/or reflecting elements can be substantially positioned around a periphery of the portion of the tissue desired to be heated. The temperature proximate to at least one of the receiving and/or reflecting elements is sensed and, in response to the sensed temperature, the amount of fluid delivered to an interior volume of the receiving and/or reflecting elements is controlled.
Other featu
Kasevich Raymond S.
Selkowitz Stuart M.
Fish & Richardson P.C.
Gibson Roy
KAI Technologies, Inc.
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