GB2165428A - Microwave heating apparatus - Google Patents

Abstract

The present invention relates to a microwave heating apparatus for the remedy of cancer by irradiating an affected part of cancer with microwaves to heat the cancer tissue at about 43 DEG C. This microwave heating apparatus is characterized in that a dielectric antenna 50 formed of a ceramic material, which has a tapered shape, is arranged in an irradiation portion to increase the focusing property of microwaves. An arm 38 is arranged in the upper portion of a support 30 oscillating with a motor 32 being as a power source and the irradiation portion provided with the dielectric antenna, a wave generator 48 and a wave guide 46 is attached to the top end of the arm so that the irradiation portion can oscillate integrally with the support. When the microwave heating apparatus having this structure is used, pencil beam-shaped microwaves can be applied from the dielectric antenna and even a part having a depth of about 5 to about 7 cm from the skin surface can be promptly heated at about 43 DEG C, and a high curative effect can be attained. <IMAGE>

Description

SPECIFICATION Microwave Heating Apparatus The present invention relates to a microwave heating apparatus effective for the remedy of cancer.

From the results of various experiments made in the past, it has been confirmed that cancer cells become atrophied when heated at about 43 C. Since cure of cancer is expected by this heating treatment in combination with the radiotherapy, various studies have been made on the method (hyperthermia) for locally heating cancer cells from the outside of the human body.

As one effective therapeutic means adopted at the present, there can be mentioned a method in which microwaves of about 2450 MHz are applied at close range outside the human body. A conventional microwave heating apparatus utilizing this method will now be described with reference to Fig. 1.

Fig. 1 is a side view illustrating diagrammatically the conventional microwave heating apparatus. An irradiation portion 10 provided with a wave guide and an electromagnetic horn is supported on the top end of an adjustable arm 12. The irradiation portion 10 is connected to a wave generator 14 through the wave guide, a converter and a coaxial cable 16.

Reference numerals 18, 20 and 22 represent a cooler, a patient and a cancer cell, respectively.

When the medical treatment is carried out by using this microwaver heating apparatus, the cooler 18 is brought into contact with the surface of the human body above the cancer cell 22, and the adjustable arm 12 is moved so that the irradiation portion 10 confronts the cancer cell 22. If the wave generator 14 is driven in this state, microwaves can be applied to the cancer cell 22 from the irradiation portion 10.

Incidentally, the cooler 18 is disposed to prevent the patient 20 from being burnt by elevation of the temperature in the vicinity of the skin by irradiation with microwaves. Reference numerals 24 and 26 represent tubes for circulating cooling water.

In this conventional microwave heating apparatus, since the irradiation portion is constructed by a wave guide, an electromagnetic horn and a helical antenna or dipole antenna, the capacity of focusing the microwaves is low and the region which can be heated at about 430C is limited to a depth of up to about 1.5 cm from the surface of the skin. Accordingly, a cancer cell located at a deeper part cannot be heated.

As pointed out above, the irradiation portion is connected to the wave generator through the coaxial cable. This coaxial cable is inevitably thick and heavy because a high output is transmitted.

Furthermore, when microwaves pass through the coaxial cable, the energy is lost by generation of heat and the like, and irradiation should be conducted for a long time so as to heat cancer cells at about 430C.

It is considered that if an electromagnetic metal lens is attached to the electromagnetic horn of the irradiation portion, the capacity of focusing microwaves will be increased and the applicable depth will be increased. However, even if this method is adopted, the depth which can be heated at about 430C is about 2 cm at most and cancer cells located at a deeper part cannot be heated.

Furthermore, the size of the electromagnetic metal lens depends on the used frequency and the diameter of the lens has to be increased.

We made research under this background and as the result, it was found that the above-mentioned defects of the conventional techniques can be eliminated if there is adopted a structure in which an arm is arranged in the upper portion of a swinging support, an irradiation portion provided with a wave generator, a wave guide and a dielectric antenna is attached to the top end portion of this arm and this dielectric antenna is formed of a ceramic material to have a tapered shape.

It is therefore a primary object of the present invention to provide a microwave heating apparatus in which a dielectric antenna attached to a wave guide is formed of a ceramic material excellent in the heat resistance to have a tapered shape, whereby microwaves of good focusing property can be locally applied at a relatively high output with reduced irradiation loss and even a portion having a depth of about 5 to about 7 cm from the surface of the human body can be heated at a predetermined temperature in a short time.

A second object of the present invention is to provide a microwave heating apparatus in which irradiation is performed by swinging an irradiation portion around the affected part as the center, whereby heat is concentrated on the affected part without concentrating heat on the neighbouring skin.

A third object of the present invention is to provide a microwave heating apparatus in which a wave generator is directly attached to a waveguide while omitting an intervening coaxial cable, whereby the energy loss during the period of from generation of microwaves to irradiation is controlled to a minimum level and microwaves of high output are obtained.

More specifically, in accordance with the present invention, there is provided a microwave heating apparatus comprising an irradiation portion for application of microwaves, an arm for supporting said irradiation portion and a wave generator for generating microwaves, wherein a dielectric antenna of a ceramic material having an outwardly tapered shape is attached to the irradiation portion.

Brief Description of the Drawings Fig. 1 is a side view illustrating the cbnventional technique.

Fig. 2 is a perspective view illustrating an embodiment of the present invention.

Fig. 3 is a front view showing a wave guide and a dielectric antenna.

Fig. 4 is a perspective view illustrating a wave guide and a dielectric antenna.

Fig. 5 is a front view illustrating an example of the operation of a dielectric antenna.

The present invention will now be described in detail with reference to an embodiment illustrated in the accompanying drawings.

Fig. 2 is a perspective view showing an embodiment of the present invention and Fig. 3 is a side view showing the internal structure of an irradiation portion. Referring to the drawings, a support 30 is connected at a predetermined position on the back face to a shaft 34 of a motor 32 so that the support 30 can swing in a direction of arrow A with the shaft 34 being as the center. Reference numeral 36 represents a base, and an arm 38 is attached to the upper portion of the front face of the support 30, and a supporting fitting 40 is attached to the top end portion of the arm 38 so that the fitting 40 can rotate in an axial direction of arrow B. The supporting fitting 40 can be fixed or released by a knob 42.

Awave guide 46 and a wave generator 48 attached to the wave guide 46 are contained in a case 44, and a solid dielectric antenna 50 of a ceramic material having an outwardly tapered shape is arranged in an opening of the wave guide 46 so that the antenna 50 projects from the case 44.

When the length of this dielectric antenna 50 is 4 to 8 times the wavelength of the microwaves, irradiation can be performed at a highest efficiency.

Accordingly, for example, when microwaves of 2450 MHz are applied, since the wavelength is 12.25 cm, it is preferred that the length of the antenna 50 be at least 49 cm(=12.25 cmx4).

The irradiation portion 52 for application of microwaves in the present embodiment is constructed bythefpregoing members including the case 44 through the electric antenna 50. The irradiation portion 52 is supported on the inner side of the supporting fitting 40 so that the irradiation portion 52 rotates in a direction of arrow C. A knob 54 is arranged to fix or release the irradiation portion 52.

Namely, in the present embodiment, the irradiation portion 52 is rotatable back and forth (in the direction of arrow B) and can swing in the direction of arrow A with the shaft 34 of the motor 32 being as the center.

A balancing weight 56 is attached to the lower end of the support 30, and a cord 58 is laid out to supply an electric power to the wave generator 48 from a power source (not shown).

The operation will now be described with reference to Fig. 5.

A cooler 64 is placed on the surface of the human body above a cancer cell 62 of a patient 60.

Incidentally, reference numerals 64 and 66 represent tubes for circulating a cooling fluid. The irradiation point P of the cancer cell 62 is fixed and the shaft 34 of the motor 32 shown in Fig. 2 is positioned at a height corresponding to the irradiation point P.

The irradiation portion 52 having the dielectric antenna 50 is moved in the directions of arrows B and C to face the top end of the dielectric antenna 50 to the cancer cell 62.

In this state, the irradiation portion 52 is oscillated at a certain angle in the direction of arrow A integrally with the support 30 with the shaft 34 being as the center by means of the motor 32, and simultaneously, the wave generator 48 arranged in the case 44 of the irradiation portion 52 is driven to emit microwaves to the irradiation point P of the cancer cell 62 from the dielectric antenna 50 attached to the wave guide 46.

In the present embodiment, the wave generator 48 is directly attached to the wave guide 46 and microwaves are directly generated from the wave generator 48. Accordingly, a large output can be obtained. The dielectric antenna 50 formed of a ceramic material having a high heat resistance can resist a large output of about 700 to about 800 W, and pencil beam-shaped microwaves having a good focusing property and a reduced irradiation loss can be emitted and applied.

Furthermore, since microwaves are applied while oscillating the dielectric antenna 50, even if the irradiation point P is located deep from the surface of the human body, it is possible to focus microwaves on the irradiation point and heat the cancer cell at about 430C in a shorttime.

From the results of the experiments made by us, it has been confirmed that when the apparatus of the present invention is used, even a part having a depth of about 5 to about 7 cm from the surface of the human body can be heated at about 430C and this can be accomplished in a short time.

As is apparent from the foregoing description, according to the present invention, the irradiation portion is attached to the arm oscillatably attached to the support and microwaves are generated from the wave generator attached directly to the wave guide. Accordingly, enery loss is not caused in the generated microwaves and a large output can be obtained. Moreover, since microwaves having a reduced irradiation loss and a good focusing property are applied with a large outputto cancer cells in the body from the dielectric antenna formed of a ceramic material having a good focusing property while oscillating the dielectric antenna, even a part having a depth of about 5 to about 7 cm from the surface of the human body can be heated at about in a short time.

Still further, since irradiation is performed while oscillating the irradiation portion with the affected part being as the center, concentratiori of heat on a limited part of the surface of the human body is prevented and the skin of a patient is hardly damaged, and the affected part can be heated very promptly. Therefore, the apparatus of the present invention is excellent in the safety.

Claims (6)

1. A microwave heating apparatus comprising an irradiation portion for application of microwaves, an arm for supporting said irradiation portion and a wave generator for generating microwaves, wherein a dielectric antenna of a ceramic material having an outwardly tapered shape is attached to the irradiation portion.

2. A microwave heating apparatus as set forth in claim 1, wherein the length of the dielectric antenna is 4 to 8 times the wavelength of the microwaves.

3. A microwave heating apparatus as set forth in claim 1, wherein a support oscillated by a motor as a power source is attached to the body of the apparatus, the arm is attached to the upper portion of the support and the irradiation portion of emitting microwaves is attached to the top end of the arm so that irradiation is performed while oscillating the irradiation portion.

4. A microwave heating apparatus as set forth in claim 1, wherein the wave generator, a wave guide and the dielectric antenna are arranged in the irradiation portion.

5. A microwave heating apparatus as set forth in claim 4, wherein the wave generator is directly attached to the wave guide.

6. A microwave heating apparatus substantially as herein described with reference to Figures 2-5 of the accompanying drawings.