JPH0265876A - Cavity type hyperthermia device - Google Patents

Abstract

PURPOSE:To achieve uniform heating and to prevent a hot spot phenomenon by supplying high frequency powers shifted in a phase by the same angle as the open angle between adjacent power supply points to a plurality of the respective power supply points provided to a cavity resonator. CONSTITUTION:Two power supply points 3A, 3B are separated by 90 deg. around an axis and a high frequency electric field is applied to a cavity resonator 2 from the first power supply point 3A through a high frequency distributor 7 and a high frequency electric field is also applied to the cavity resonator 2 from the second power supply point 3B through a 90 deg. phase shifter 9 in such a state that a phase is shifted by 90 deg.. The synthetic electric field of the high frequency electric field from the first power supply point 3A and that from the second power supply point 3B is rotated in a counterclockwise direction with the elapse of time and the cycle of said rotation is same to that of each high frequency electric field. Since the synthetic electric field is rotated, in spite of the complicated distribution of a dielectric constant and conductivity in the heating region within the cavity resonator 2, the heating pattern in each region is made homogeneous to make it possible to eliminate a hot spot phenomenon.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application This invention relates to a cavity-type hyperthermia device used for thermal treatment of cancer tissue.

B. Prior art In the cavity-type hyperthermia device conventionally considered, high-frequency power generated in the excitation section is supplied to the cavity resonator through one feeding point while the patient is inserted into the cavity resonator. This creates electric and magnetic fields within the cavity resonator and within the patient's body, and heats and kills cancerous tissue using high-frequency electric fields of tens to hundreds of MHz, which are involved in thermotherapy.

C1 Problems to be Solved by the Invention Since the dielectric constant and conductivity distributions are complicated in the /lI region, the electric field pattern becomes complicated, and as a result, the heat generation pattern also becomes complicated. That is, in the patient's body, there are various areas where the electric field strength is very strong, areas where it is very weak, and areas where the electric field intensity is intermediate between these areas, and the heating/I! ! The temperature becomes extremely non-uniform, resulting in an excessive temperature rise in areas where the electric field strength is strong.

In conventional cavity type hyperthermia devices,
Because there was a single power feeding point, the direction of the applied electric field within the cavity resonator was always constant, and as a result, the heating pattern remained the same during heating (usually for 30 minutes or more), and the electric field There is a problem in that a so-called "true spot" phenomenon, which causes pain to the patient, occurs in areas where the strength is strong.

When a true spot occurs, it becomes necessary to interrupt the heat treatment in order to relieve the patient from pain, which leads to a problem in that the therapeutic effect is reduced.

The present invention has been made in view of the above circumstances, and aims to achieve uniform heating and prevent the hot spot phenomenon.

01 Means for Solving the Problems In order to achieve the above object, the present invention has the following configuration.

In other words, the cavity type hyperthermia device of the present invention includes a cavity resonator, a plurality of power supply points provided in the cavity resonator at different positions, and a gap between the indirect power supply points for each power supply point. The present invention is characterized by comprising an excitation section that supplies high frequency power that is out of phase by the same angle as the angle.

80 effects The effects of the configuration of this invention are as follows.

That is, since the phases of the high-frequency power supplied from each feeding point are shifted, the combined electric field of the high-frequency electric field formed in the cavity resonator by each feeding point rotates over time.

F. Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Nail tip application (circular polarization type) Figure 1 is a schematic diagram of a cavity type hyperthermia device.

As shown in this figure, the opening l for inserting the patient M
A first cylindrical cavity resonator 2 has a first . Second
Two feeding points 3A and 3B are provided at 90 degrees apart around the axis of the cavity resonator 2.

The excitation section 4 for the refeed points 3A and 3B is configured as follows. That is, a high frequency amplifier 6 is connected to a high frequency generator 5 of tens to hundreds of MHz, a high frequency distributor 7 is connected to the high frequency amplifier 6, and a first and a second power supply derived from the high frequency distributor 7 are connected. coaxial cable 8A, 8
B, each of which corresponds to the first. It is connected to second feed points 3A and 3B.

A 90″ phase shifter 9 is connected to the second coaxial cable 8B.
is inserted.

In addition, lO is a bend drive device, and 11 is a bend drive device l.
This is a patient hand that is driven by O and moves in and out of the opening 1 of the cavity resonator 2.

Next, the operation of the first embodiment will be explained based on the high-frequency electric field waveform diagram in FIG. 2 and the diagram for explaining changes in the composite electric field distribution in FIG. 3.

The high frequency power output from the high frequency generator 5 is amplified by the high frequency amplifier 6, and the high frequency power output by the high frequency distributor 7 is
5 is distributed to second coaxial cables 8A and 8B.

Then, a high frequency electric field EA as shown in FIG. 2 is applied to the cavity resonator 2 from the first feeding point 3A via the first coaxial cable 8A, and the second coaxial cable 8B and the 90° phase shift are applied to the cavity resonator 2. The high frequency electric field E from the second feeding point 3B to the cavity resonator 2 via the device 9 is higher than the high frequency electric field EA.
The signals are applied with a 0° phase shift.

At time L1, the high frequency electric field EA from the first feeding point 3A is zero, the high frequency electric field E from the second feeding point 3B,
Since is the maximum value on the negative side, the high frequency electric fields EA and E formed within the cavity resonator 2.

The resultant electric field E (t+) is directed to the left as shown in FIG. 3(A).

At time t2, the high-frequency electric field EA from the first feeding point 3A increases to the positive side, and the high-frequency electric field EIl from the second feeding point 3B increases slightly from the maximum value on the negative side, so that the combined electric field E ( t2) is diagonally downward to the left as shown in FIG. 3(B).

Although the period from time L1 to t2 is not shown, since both the high-frequency electric fields EA and ER change, the composite electric field E(L) is directed in all directions from E D+ ) to E (tz ). It turns out. That is, the combined electric field E(t) rotates counterclockwise.

At time 13+, the high frequency amplifier reaches its maximum value on the positive side and the high frequency electric field E becomes zero, so the composite electric field E (t3) becomes downward as shown in (C) in Figure 3. . At time L4, the high-frequency electric field E slightly decreases from its maximum value, and the high-frequency electric field E increases, so that the combined electric field E
(t4) is diagonally downward to the right as shown in FIG. 3(D). At time t, the high frequency electric field EA is zero and the high frequency electric field E.

is the maximum positive value, so the composite electric field E (ts)
is directed to the right as shown in FIG. 3(E).

Furthermore, the composite electric field E (t6) at time L6 is shown in the same figure (F).
The composite electric field E (t
t ) is directed upward as shown in (G) in the same figure, and the composite electric field E (ts ) at time t is directed diagonally upward to the left as shown in (H) in the same figure, and at time 1. The resultant electric field E (tq) at time L9, when one round 1 has elapsed since then, is directed to the left, the same as the resultant electric field E (t,) at time L1, as shown in (I) of the same figure.

As described above, the high frequency electric field EA from the first feeding point 3A
and the high frequency electric field E from the second feeding point 3B.

The combined electric field E(t) rotates counterclockwise with the passage of time, and the period of rotation is equal to the high-frequency electric fields EA, E,
It is the same as the period of

Since the composite electric field E(t) rotates, the dielectric constant and conductivity of the heating region inside the cavity resonator 2 change. 1. Despite the rough distribution, it is possible to homogenize the fever pattern in each region, eliminate the true spot phenomenon, relieve the patient from pain, and finally /l! 1. Heat therapy can be carried out efficiently without interruption.

First disaster coal application (amplitude modulation type) Figure 4 is a schematic diagram of the cavity type hyperthermia device.

The excitation section 4' in this embodiment is constructed as follows. That is, the high frequency amplifier 6 is connected to the high frequency generator 5, the high frequency divider 7 is connected to the high frequency amplifier 6, and the high frequency divider 7 is connected to the first and second amplitude modulators 12A, 1.
2B are connected, the first and second amplitude modulators 12A, 12B
are the first. It is connected to each feed point 3A, 3B connected to the cavity resonator 2 via a second coaxial cable 8A, 8B. Then, the sine wave generator 13 outputs a modulation signal Sl of sin ω to the first amplitude modulator 12A, and the sin (ωLπ
/2) is configured to output a modulated signal S2. Assuming ω-2πr, the frequency r is approximately I Hz to IKHz.

The first feeding point 38 and the second feeding point 3B are connected to the cavity resonator 2.
This is the same as in the first embodiment in that they are spaced 90'' apart from each other around the axis.

In the case of this second embodiment, the amplitude-modulated high-frequency electric field EA applied from the first feeding point 3A to the cavity resonator 2
' and the amplitude-modulated high-frequency electric fields E and r applied from the second feeding point 3B are as shown in FIG. 5, respectively.

High frequency electric field EA Combined electric field E' of 5 high frequency electric fields EB'
(t) (not shown) rotates in the same manner as in the first embodiment.However, the period of rotation is 1/f.In addition,
Since the amplitude of the composite electric field E'(t) increases or decreases with each successive rotation angle, the homogenization of the heat generation pattern at each location is further promoted than in the first embodiment.

In addition, in the above two embodiments, the first power feeding point 3A
Although the refeeding points 3A and 3B are arranged 90 degrees apart from each other, the opening angle of the refeeding points 3A and 3B is arbitrary. Assuming that the opening angle is θ°, in the case of the first embodiment, a phase shifter of θ° is used, and in the case of the second embodiment, the modulation signal from the sine wave generator 13 is sin ωL, si
n (ωL−θ) is used. However, the opening angle is 180
°, the combined electric field E(t) is both high-frequency electric fields EA, E
Since it is canceled by l and always becomes zero or close to it, this is excluded.

In addition, in the above embodiment, the number of feeding points is two, but it may be three or more, and the phase shift of the high frequency electric field from adjacent feeding points is the same as the opening angle of both feeding points. Make it. For example, as shown in FIG. 6, there are four feeding points 3A, 3B, and 3C.

The 3Ds may be arranged so as to be shifted from each other by 90°, and high frequency power having a phase shifted by 90° may be applied to each of the 3Ds.

Further, in the above embodiment, the cavity resonator is cylindrical, but the shape of the cavity resonator is not limited to this, and may be any shape such as square or hexagon.

Effect of G1 invention According to this invention, the following effects are exhibited.

In other words, the cavity resonator is configured to have multiple feed points located at different positions, and each feed point supplies high-frequency power with different phases to each other, so each feed point causes cavity resonance. It is possible to rotate the composite electric field of the high-frequency electric field formed inside the device.

Therefore, despite the complex distribution of permittivity and conductivity in the heating region inside the cavity resonator, the heat generation pattern in each region can be homogenized, eliminating the hot spot phenomenon and preventing the Φ person from suffering. release and thus thermal treatment can be carried out efficiently without interruption.

[Brief explanation of the drawing]

Figures 1 to 3 relate to the first embodiment of the present invention, with Figure 1 being a schematic configuration diagram of a cavity type hyperthermia device, Figure 2 being a waveform diagram of high frequency electric fields at each feeding point, and Figure 3 being a composite diagram. FIG. 3 is an operation explanatory diagram showing how the electric field rotates. 4 and 5 relate to the second embodiment, where FIG. 4 is a schematic configuration diagram of a cavity type hyperthermia device, and FIG. 5 is a waveform diagram of a high frequency electric field at each feeding point. FIG. 6 is an explanatory diagram of the main part of the embodiment in which there are four feeding points. 2...Cavity resonators 3A to 3D...Feeding point 4.4'...Excitation section 5...High frequency generator 6...High frequency amplifier 7...High frequency distributor 9...90° Phase shifter 12A, 12B... Amplitude modulator I3... Sine wave generator EA, Es, EA, CI+'...
・High-frequency electric field E (t), E' (t)...Composite electric field Figure 2 t+ t2 b t4ts t6b ta
t9 (A) Figure 3 (B) (C) Terutaneyuki (G) (H)

Claims (1)

[Claims] (1) A cavity resonator, multiple feed points provided at different positions in this cavity resonator, and a phase shift for each feed point by an angle equal to the opening angle between adjacent feed points. What is claimed is: 1. A cavity type hyperthermia device comprising: an excitation section that supplies high-frequency power;