JPH03143453A - Hyperthermia apparatus - Google Patents

Abstract

PURPOSE:To suppress an unnecessary hot spot by providing two antennas generating round polarizations and crossing perpendicularly each other, a high-frequency generator, two modulators each modulating a high-frequency signal and high-frequency amplifiers each feeding its output signal to two antennas. CONSTITUTION:Antennas 11-14 surrounding a patient 2 each provides a circularly polarized wave and facing antennas 11, 13 and 12, 14 cross perpendicularly each other in a relation of reversely polarized wave to enhance each other an electric field. High-frequency signals amplified by means of high-frequency amplifiers 81-84 are fed to these antennas 11-14, and same modulated high-frequency signals E61 output from an modulator 61 are sent to each high-frequency amplifier 81 or 83 and same modulated high-frequency signals E62 output from an modulator 62 are sent to each high-frequency amplifier 82 or 84. These synthesized electromagnetic field turns to a round polarization with a period thetaon a plane being 45 deg. to a plane X. Namely, an angle formed with the plane X changes with a period omega and the direction of the synthetic electric field changes three dimensionally in all direction with periods theta and omega.

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to a hyperthermia device for treating cancer and the like by heating the affected area to about 42°C. [Prior art] Conventionally, the affected area is heated by irradiating electromagnetic waves,
Devices that perform hyperthermia treatment are known. In this case, if the direction of the electric field radiated from the antenna is fixed, the current generated by the electric field will always pass through the same place in the human body, and there will be a large imbalance in heat generation between places where it is easy for the current to pass and places where it is difficult for the current to pass. This results in localized heating areas (hot spots) in unwanted locations. Therefore, hyperthermia devices that apply a rotating electromagnetic field to the heating area have been proposed (
(Refer to Japanese Patent Application Laid-Open No. 195870/1999).

[Problems to be solved by the invention]

However, even when applying a rotating electromagnetic field as in the past, since the rotating electromagnetic field rotates on a two-dimensional plane, unnecessary hot spots may occur within the human body, which has a three-dimensionally complex structure. cannot be said to be sufficient to effectively suppress An object of the present invention is to provide an electromagnetic wave irradiation heating type hyperthermia device that can sufficiently effectively suppress the generation of unnecessary hot spots.

[Means to solve the problem]

In order to achieve the above object distantly, the hyperthermia device according to the present invention includes two antennas that generate circularly polarized waves arranged orthogonally to each other, a high frequency generator, and a high frequency wave generated from the high frequency generator. Two modulators that modulate signals with predetermined modulation signals, and high frequency amplifiers that supply output signals of the modulators to the two antennas, respectively, are provided.

[For production]

Two antennas that generate circularly polarized waves are arranged to be orthogonal to each other, and a high frequency signal is supplied from a high frequency amplifier to these antennas, so the circularly polarized waves are combined with the electromagnetic waves radiated from the two antennas. On the other hand, the high frequency signals supplied to these two antennas are
These are obtained from two modulators. These two modulators each modulate a high frequency signal with a predetermined modulation signal, and obtain a high frequency signal with an amplitude corresponding to the modulation signal. Therefore, for example, if the amplitude and width of a high-frequency signal supplied to two antennas as DC signals with different levels is constant over time, the combined electric field will be generated on a plane with an angle corresponding to the difference in amplitude. If the direction of the two high-frequency signals rotates and the modulation signals are sinusoidal waves whose phases differ by 90' from each other, the amplitudes of the two high-frequency signals change over time, so the plane on which the combined electric field rotates itself. As a result, the plane in which the direction of the combined electric field rotates can be changed or fixed over time as desired, which eliminates the possibility of fixing the local imbalance of heat generation by not fixing the flow of current. Alternatively, it is possible to apply an electric field that avoids the flow of current that would cause a local imbalance in heat generation, and it is possible to effectively suppress the formation of hot spots.

【Example】

Next, an embodiment of the present invention will be described with reference to the drawings. In one embodiment of the present invention, as shown in FIG. 1, four bright antennas 11 to 14 are arranged to surround the patient 2. These antennas 11 to 14 are each composed of an antenna, for example, a helical antenna, which provides circularly polarized waves.
4 are in a relationship of opposite rotational polarization so that the electric fields are strengthened, and these two pairs of antennas facing each other are arranged so as to be orthogonal to each other. In other words, the antenna 11
．． 13 are placed along the Y axis, and the electric field Ex□ created by them becomes circularly polarized waves in the XZ plane.Antennas 12 and 14 are placed along the X axis, and the electric field E yz from them is It becomes a circularly polarized wave within the YZ plane. These antennas 11 to 14 are equipped with high frequency amplifiers 81 to 84.
A high frequency signal amplified by is supplied. Further, the same high frequency signal E6□ after modulation outputted from the same modulator 61 is sent to each of the high frequency amplifiers 81 and 83 through the phase shifter 71.
．． The same modulated high frequency signal E62 outputted from the same modulator 62 is sent to each of the high frequency amplifiers 82 and 84 via phase shifters 72 and 74. The high frequency signals sent as modulated signals to these modulators 61 and 62 are the high frequency signals s generated from the high frequency generator 3.
inθt is distributed by the distributor 4. The modulation signals of these modulators 61 and 62 are 9
Signals with a phase shift of 0°, that is, sinωt, CO8ωt
It becomes. Therefore, the output signals E61 and E62 of the modulators 61 and 62 are modulated by the modulation signals shown in FIG.
The waveform is width modulated. Here, the output signal E61. of the modulator 61.62. Considering the point in time when E62 has the same amplitude, antennas 11 to 1
The resultant electromagnetic field by the electromagnetic waves from 4 becomes a circular flattened wave with a period θ on a plane making an angle of 45° with the X plane as shown by the dotted line in FIG. In other words, the direction of the electric field rotates on the plane indicated by the dotted line. However, the amplitude of this signal Et>t, E6□ changes over time according to the waveform of the sine wave, and as shown in FIG. The plane indicated by the dotted line rotates as shown by the arrow in Figure 3, and the angle it makes with the The phase shift amounts φI, φ2, φ3, and φ4 in the phase shifters 71 to 74 are all set to zero when it is desired to heat the center, and the electromagnetic waves radiated from the opposing antennas are the same at the center. When you want to heat parts other than the center, adjust these phase shifts to shift the position where they are in phase and shift the heating position.In addition, in the above, the direction of the composite electric field is 3 over time
Dimensions are varied in all directions, but when it is known that generating circularly polarized waves in a specific plane will result in the least number of hot spots and the most therapeutically effective heating. It is also possible to fix the plane to a particular plane without rotating it as described above. In this case, the modulation signal applied to the modulators 61 and 62 is not a sine wave but a direct current, the amplitude of the output signals E61 and E62 of the modulators 61 and 62 is kept constant over time, and the level of the DC signal serving as the modulation signal is changed. The amplitudes of E61 and E62 may be made different from each other. In addition, in order to change the direction of the composite electric field three-dimensionally in all directions over time, the modulation signals given to the modulators 61 and 62 should be sine waves with the same frequency but a phase difference of 90" as described above. It is not necessarily necessary to use waves, and modulation signals of mutually different frequencies may be used. [Effects of the Invention] According to the hyperthermia device of the present invention, a living body is irradiated with circularly polarized electromagnetic waves, and the Since the plane that generates the combined circularly polarized waves can be varied or fixed as desired, the area to be heated can be heated effectively by reducing the number of hot spots. ,
Effective hyperthermia treatment can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a waveform diagram showing an output signal of a modulator, and FIG. 3 is a diagram for explaining a synthesis plane of circularly polarized waves.

Claims (1)

[Claims] (1) Two antennas that generate circularly polarized waves arranged orthogonally to each other, a high frequency generator, and two modulation devices that modulate the high frequency signals generated from the high frequency generator with predetermined modulation signals, respectively. and a high frequency amplifier that supplies the output signals of the modulator to the two antennas, respectively.