The present invention relates generally to the field of radio frequency (RF) circuits, and more specifically to an RF transmitter and receiver system and method for inducing hyperthermia in a target area.
Hyperthermia is characterized by a very high fever, especially when induced artificially for therapeutic purposes. It is known in the art to use contact antennas to direct RF electromagnetic radiation to intentionally induce hyperthermia in human tissue for therapeutic purposes, e.g., destroying diseased cells. There are also RF heating devices known in the art (e.g., the Thermotron RF-8 system, Yamamoto Viniter Co. of Osaka, Japan, and the 3KCTPATEPM system, Russia).
When RF radiation is absorbed by matter it causes molecules to vibrate, which in turn causes heating. More specifically, RF waves interact with matter by causing molecules to oscillate with the electric field. This interaction has proven to be most effective for molecules that are polar, i.e. having their own internal electric field, such as water. Water molecules lose rotational energy via friction with other molecules, which causes an increase in temperature. This effect is the basis for microwave cooking. RF radiation absorbed by the body typically occurs as a result of the interaction of the RF radiation with water fluids contained in vivo.
The amount of RF radiation absorbed by tissue depends on a number of things, including the power and specific frequency of RF radiation used. Some frequencies of RF radiation have high absorption rates in tissue. A typical microwave oven emits RF radiation at about 2500 MHz, which is readily absorbed by water, fats and sugars to generate heat in food. RF radiation at lower frequencies, e.g., medium frequency (“MF”; 300 to 3000 kilohertz) RF radiation and high frequency (“HF”; 3 to 30 megahertz) RF radiation have generally low absorption rates in human tissue, even at relatively high powers, as evidenced by people safely standing near radio station tower transmitters, which transmit tens of thousands, and even hundreds of thousands, of Watts of RF power at lower frequencies.
RF ablation uses RF induced thermal energy to destroy tumor cells and involves placing a special needle into a tumor, often using image guidance. U.S. Pat. No. 4,800,899 discloses a system including a needle-like antenna that is inserted into a patient's body and into a tumor, permitting microwave RF energy supplied by a microwave generator to be applied directly to the tumor via the needle-like antenna to induce hyperthermia in the tumor. The RF energy generates heat in a volume (e.g., sphere) of tissue surrounding the needle. Ideally, the generated heat kills the tumor in a manner that spares the healthy tissue surrounding the tumor. RF ablation has several drawbacks, including the fact that treatment involves direct contact with the patient, i.e., insertion of a needle-like antenna into the patent for the duration of the procedure, which can require sedation and possibly an overnight stay in a hospital.
In accordance with one embodiment of the present invention, a system for inducing hyperthermia in at least a portion of a target area is provided. The system includes an RF transmitter having an RF generator and a transmission head, and an RF receiver having a resonant circuit and a reception head. When the transmission and reception heads are arranged proximate to and on either side of a target area and an RF signal is transmitted from the transmission head, through the target area, to the reception head, at least a portion of the target area is warmed without direct contact of the heads to the target area.
In accordance with another embodiment of the present invention, a method of inducing hyperthermia in at least a portion of the target area is provided. The method includes providing an RF transmitter having an RF generator and a transmission head. The method further includes providing an RF receiver having a resonant circuit and a reception head. The transmission head and reception heads are insulated from the body part and arranged proximate to and on either side of a target area. An RF signal is transmitted via the transmission head to the reception head so that it passes through and warms at least a portion of the target area.
In accordance with another embodiment of the present invention, a methodology of inducing hyperthermia in a specific target portion of the target area of a patient's body is provided. This embodiment includes providing an RF transmitter, generator and transmission head. It also includes, providing an RF receiver, resonant circuit, and reception head wherein the reception head is selected in accordance with the shape and size of the target area. Once again, the transmission and reception heads are insulated from the body part and arranged proximate to and on either side of the body part containing the target area. The methodology further includes providing antibodies bound to an RF absorption enhancer and injecting the antibodies into the patient. Waiting for a period of time for the antibodies to bind to at least one type of cells within the target area and transmitting an RF signal from the transmission head to the reception head thereby warming the specific target portion of the target area of the body part.
In accordance with yet another embodiment of the present invention, a method of inducing hyperthermia in at least target cells of a patient is provided. The methodology includes providing an RF transmitter, generator and transmission head. It also includes providing an RF receiver, resonant circuit and reception head. Providing antibodies bound to an RF absorption enhancer and injecting the antibodies into the patient. Waiting for a period of time for the antibodies to bind to at least one type of cells within the target area and transmitting an RF signal from the transmission head to the reception head thereby warming the specific target area.
In accordance with still yet another embodiment of the present invention, a method of inducing hyperthermia in at least target cells of a patient is provided. The methodology includes extracting target cells from the patient. Providing an RF transmitter, generator and transmission head. It also includes providing an RF receiver, resonant circuit and reception head. Providing antibodies bound to an RF absorption enhancer and introducing the antibodies to the extracted target cells. Waiting for a period of time for the antibodies to bind to at least one of the extracted target cells and transmitting an RF signal from the transmission head to the reception head thereby warming the target cells.
In yet another embodiment of the present invention, a method of separating target cells of a patient is provided. The methodology includes removing material from the patient containing at least the target cells and providing antibodies bound to a magnetic material that bind to the target cells. The methodology further includes exposing the target cells to the antibodies bound to the magnetic material, waiting for the antibodies to bind to some of the target cells and providing a magnetic field to attract or repel some of the target cells to thereby separate the target cells.
In the accompanying drawings which are incorporated in and constitute a part of the specification, exemplary embodiments of the invention are illustrated, which, together with a general description of the invention given above, and the detailed description given below, serve to example principles of the invention.
Referring to the drawings, and initially to
In exemplary system 100, the RF transmitter 102 generates an RF signal 120 at a frequency for transmission via the transmission head 104. Optionally, the RF transmitter 102 has controls for adjusting the frequency and/or power of the generated RF signal and/or may have a mode in which an RF signal at a predetermined frequency and power are transmitted via transmission head 104. In addition, optionally, the RF transmitter 102 provides an RF signal with variable amplitudes, pulsed amplitudes, multiple frequencies, etc.
The RF receiver 110 is in circuit communication with the reception head 108. The RF receiver 110 is tuned so that at least a portion of the reception head 104 is resonant at the frequency of the RF signal 120 transmitted via the transmission head 104. As a result, the reception head 108 receives the RF signal 120 that is transmitted via the transmission head 104.
The transmission head 104 and reception head 108 are arranged proximate to and on either side of a general target area 106. General target 106 is general location of the area to be treated. The general target area 106 is any target area or type of cells or group of cells, such as for example, tissue, blood cells, bone marrow cells, etc. The transmission head 104 and reception head 108 are preferably insulated from direct contact with the general target area 106. Preferably, the transmission head 104 and reception head 108 are insulated by means of an air gap 112. Optional means of insulating the transmission head 104 and reception head 108 from the general target area 106 include inserting an insulating layer or material 310 (
The general target area 106 absorbs energy and is warmed as the RF signal 120 travels through the general target area 106. The more energy that is absorbed by an area, the higher the temperature increase in the area. Generally, the general target area 106 includes a specific target area 130. Specific target area 130 includes the tissue or higher concentration of cells, such as, for example, a tumor, that are desired to be treated by inducing hyperthermia. Preferably, the general target area is heated to for example, to between 106° and 107°. Thus, preferably, the specific target area 130 receives higher concentrations of the RF signal 120 then the general target area 106. As a result, the specific target area 130 absorbs more energy, resulting in a higher temperature in the specific target area 130 than in the surrounding general target area 106.
Energy absorption in a target area can be increased by increasing the RF signal 120 strength, which increases the amount of energy traveling through the general target area 106. Other means of increasing the energy absorption include concentrating the signal on a localized area, or specific target area 130, and/or enhancing the energy absorption characteristics of the target area 130.
One method of inducing a higher temperature in the specific target area 130 includes using a reception head that is smaller than the transmission head. The smaller reception head picks up more energy due to the use of a high-Q resonant circuit described in more detail below. Optionally, an RF absorption enhancer 132 is used. An RF absorption enhancer is any means or method of increasing the tendency of the specific target area 130 to absorb more energy from the RF signal. Injecting an aqueous solution is a means for enhancing RF absorption. Aqueous solutions suitable for enhancing RF absorption include, for example, water, saline solution, aqueous solutions containing suspended particles of electrically conductive material, such as metals, iron, various combination of metals, irons and metals, or magnetic particles. These types of RF enhancers are generally directly introduced to the target area. Preferably, these types of RF enhancers are directly injected into the target area by means of a needle and syringe.
Other means of enhancing RF absorption include providing antibodies with associated RF absorption enhancers, such as metal particles. The antibodies target and bind to specific target cells in the target area 130. Generally, antibodies can be directed against any target, e.g., tumor, bacterial, fungal, viral, parasitic, mycoplasmal, hisocampatabiltiy, differentiation and other cell membrane antigens, pathogen surface antigens, toxins, enzymes, allergens, drugs and any biologically active molecules. Binding RF enhancers to the antibodies permits the injection of the antibodies into the patient and the targeting of specific cells. Once a high enough concentration of RF enhancers 132 are attached to the target cells, the RF signal 120 is passed through the specific target area 130. The RF enhancers induce the absorption of more energy, creating a localized temperature in the specific target area 130 that is higher than the temperature created in the general target area 106. In addition, a combination of antibodies bound to different metals can be used allowing for variations in the RF absorption characteristics in localized areas of the target areas. These variations in RF absorption characteristics permit intentional uneven heating of the specific target area 130.
Doping or bonding antibodies with RF enhancers can be used to improve current RF capacitive heating devices as well as current RF ablation. Antibodies bound to metals RF absorption enhancers can be obtained through commercially available channels. One such commercial channel includes, for example, Research Diagnostics, Inc. located at Pleasant Hill Road, Flanders N.J.
The antibodies bond to RF enhancers are applicable for both in-vivo and in-vitro applications. In one in-vitro application the antibodies and RF enhancers are in introduced to the target area prior to the target area being removed from the patient. After the antibodies bind to the target area, the target area is removed from the patient and treated with one or more RF signals. In another in-vitro application the target area is removed from the patient before the RF enhancers are introduced to the target area. Once the target area is in a suitable vessel, the antibodies and RF enhancers are introduced to the target area. The target area is then treated with one or more RF signals.
Optionally, multiple frequency RF signals 120 are used. Multiple frequency RF signals can be used to treat target areas. Multiple frequency RF signals allow the energy absorption rate and absorption rate in different locations of the target area to be more closely controlled. The multiple frequency signals can be combined into one signal, or by use of a multi-plated transmission head, or multiple transmission heads, can be directed at one or more specific regions in the target area. This is useful for treating target areas that have specific regions of various shapes, thicknesses and/or depths. Similarly, pulsed RF signals, variable frequency RF signals and other combinations or variations of the RF signals can be used to more precisely control and target the heating of the specific target areas. These and other methods of increasing RF absorption can be used independently or in any number of combinations to increase the energy absorption rate of the specific target area 130.
In addition, antibodies bound with magnetic particles can be steered to specific locations using magnets or magnetic resonant imaging (MRI) machines. Thus, the antibodies can be directed toward specific target area or target cells. Furthermore, once the antibodies bind to the specific target cells, the target cells can be separated from the other cells by use of a magnetic force. The magnetic force can be either an attracting force, or a repelling force. Magnets, or MRI machines can also be used to steer injected magnetic particles to specific locations.
RF transmitter 200 includes a second RF signal generator 208. Second RF signal generator 208 generates a second signal at a second frequency F2, such as, for example a 6 megahertz signal. Second signal generator 208 is in circuit communication with band pass filter B.P. 2210, which is also in circuit communication with the RF combination circuit 212. Band pass filter B.P. 2210 prevents signals at other frequencies from reaching second RF signal generator 208. Optionally, RF combination circuit 212 includes circuitry to prevent the first and second signals from flowing toward the other signal generators and thus eliminates the need for band pass filter B.P. 1206 and band pass filter B.P. 2210.
RF combination circuit 212 combines the first and second signal at frequency F1 and frequency F2 and outputs RF signal 270. Preferably, RF combination circuit 212 is in circuit communication with first meter 214. First meter 214 is used to detect the signal strength of RF signal 270. The RF signal 270 is transmitted via transmission head 218 through the target 280 to reception head 268. Optionally, plug type connectors 216, 266 are provided allowing for easy connection/disconnection of transmission head 218, and reception head 268 respectfully. Reception head 268 is preferably in circuit communications with a second meter 264. Second meter 264 detects the RF signal strength received by the reception head 268. The difference in RF signal strength between first meter 214 and second meter 264 can be used to calculate energy absorbed by the target area 280. Reception head 268 is also in circuit communication with an RF splitter 262. RF splitter 262 separates the RF signal 270 into back into its components, first signal at frequency F1 and second signal at frequency F2. RF splitter 262 is in circuit communication with band pass filter B.P. 1256, which is in circuit communication with first tuned circuit 254. Similarly, RF splitter 262 is in circuit communication with band pass filter B.P. 2260, which is in circuit communication with second tuned circuit 258. Optionally, band pass filter B.P. 1, 256 and band pass filter B.P. 2260 can be replaced with a splitter or powered tee.
First tuned circuit 254 is tuned so that at least a portion of reception head 268 is resonant at frequency F1. Similarly, second tuned circuit 258 is tuned to that at least a portion of reception head 268 is resonant at frequency F2. Since the reception head 268 is resonant at frequencies F1 and F2 the RF signal 270 is forced to pass through the target area 280.
Optionally, an exemplary embodiment having an RF transmitter, similar to that illustrated above, that does not include an RF combination circuit is provided. Instead, the RF transmitter uses a multi-frequency transmission head. In this embodiment, one portion of the transmission head is used to transmit one frequency signal, and a second portion is used to transmit a second frequency signal. In addition, optionally, the reception head and resonant circuits are constructed without the need for a splitter, by providing a reception head having multiple portions wherein the specific portions are tuned to receive specific frequency signals. An example of such a transmission head in more detail illustrated below.
Obviously the transmission head can contain any number of individual transmission heads. Moreover, the transmission heads can transmit signals at a plurality of frequency, and include, but are not limited to transmission heads that transmit signals at one, two, three, etc. different frequencies. All of which have been contemplated and are within the spirit and scope of the present invention.
Preferably, a variety of different shapes and sizes of transmission and reception heads are provided. The transmission head is selected at block 806. The selection of the transmission head may be based in part on the type of RF transmitter provided. Other factors, such as, for example, the depth, size and shape of the general target area, or specific target area to be treated, and the number of frequencies transmitted may also be used in determining the selection of the transmission head.
The RF receiver is provided at block 808. The RF receiver may be tuned to the frequency(s) of the RF transmitter. At block 810, the desired reception head is selected. Similarly to the selection of the transmission head, the reception head is preferably selected to fit the desired characteristics of the particular application. For example, a reception head with a small cross section can be selected to concentrate the RF signal on a specific target area. Various sizes and shapes of the reception heads allow for optimal concentration of the RF signal in the desired target area.
The RF absorption in the target area is enhanced at block 812. The RF absorption rate may be enhanced by, for example, injecting an aqueous solution, and preferably an aqueous solution containing suspended particles of an electrically conductive material. Optionally, the RF absorption in the target area is enhanced by exposing the target cells to antibodies bound to an RF absorption enhancer as discussed above.
Arrangement of the transmission head and reception head are performed at blocks 814 and 816 respectfully. The transmission head and reception heads are arranged proximate to and on either side of the target area. The transmission head and reception heads are insulated from the target area. Preferably the heads are insulated from the target area by means of an air gap. Optionally, the heads are insulated from the target area by means of an insulating material. The RF frequency(s) are selected at block 818 and the RF signal is transmitted at block 820. In addition to selecting the desired RF frequency(s) at block 818, preferably, the transmission time or duration is also selected. The duration time is set to, for example, a specified length of time, or set to raise the temperature of at least a portion of the target area to a desired temperature/temperature range, such as, for example to between 106° and 107°, or set to a desired change in temperature. In addition, optionally, other modifications of the RF signal are selected at this time, such as, for example, amplitude, pulsed amplitude, an on/off pulse rate of the RF signal, a variable RF signal where the frequency of the RF signal varies over a set time period or in relation to set temperatures, ranges or changes in temperatures. The methodology ends at block 822 and may be ended after a predetermined time interval and/in response to a determination that a desired heating has been achieved.
An RF transmitter and RF receiver are provided at blocks 910 and 912 respectively. The transmission head is arranged proximate to and on one side of the target cells in the vessel at block 916. At block 918 the reception head is arranged proximate to and on the other side of the target cells. An RF signal is transmitted at block 918 to increase the temperature of the target cells to, for example, to between 106° and 107°.
Finally,
While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in some detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, modulating the RF signal with another signal, such as, for example, a square wave (e.g. a 300-400 Hz square wave). Modulating the RF signal with a square wave stimulates the tissue and enhances heating. Another example includes total body induced hyperthermia to treat the patient's entire body. In this example, the transmission and reception heads are as large as the patient and hyperthermia is induced in the entire body. Cooling the blood may be required to prevent overheating and can be accomplished in any manner. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept.
This application claims priority to, and the benefits of, provisional application Ser. No. 60/569,348 filed on May 7, 2004, which is also entitled System and Method For Rf-Induced Hyperthermia, and is incorporated herein by reference.
Number | Date | Country | |
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60569348 | May 2004 | US |