JPH0125582B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating type thermotherapy device used for cancer thermotherapy and the like.

The principle of this device is that when a living body is sandwiched between two electrodes connected to the output terminal of a high-frequency generator, an induced current flows within the living body, and heat corresponding to this flowing current is generated. The aim is to treat the tumor within the body. The inventor has already provided the basic invention of this type of device in Japanese Patent Publication No. 56-38230, but this basic invention is
In order for the power sent out from the output terminal of the high frequency generator to efficiently flow within the living body between the two electrodes,
An impedance matching device consisting of a variable capacitor and a variable coil is interposed between the output terminal and the electrode, and the output impedance of the output terminal and the load impedance of the electrode are adjusted to be equal. All the electric power is made to flow between the electrodes. For example, a 10 MHz high frequency is a frequency that has strong radio wave characteristics between a television frequency and a radio frequency, so this radio wave sent out from the output terminal is reflected by the electrode surface. Now, the reflectance is 20% for 100W output.
In this case, 20W will return to the generator and 80W will flow between the electrodes, so theoretically the output will be 80W.
Only % will have an effect on the living body. Furthermore, if the reflection is large, the reflected power will turn into heat on the output side and melt the output circuit. Therefore, the lower the reflectance, the more desirable it is, so the basic idea is to adjust the impedance on the output side to match the impedance on the electrode side to eliminate reflections and allow 100% of the power to act between living bodies. It is an invention. According to this principle, the heat generation between the electrodes is determined by the electrical resistance of the living body, so uniform heat generation should be obtained in the living body, which can be regarded as a homogeneous body of physiological saline, but in reality, the agar phantom Even in experiments using electrodes, there was uneven heating, and it was common for the area near one electrode to be warm. As a result, it is difficult to heat a predetermined tumor area, which not only makes the clinical effect unstable, but also causes burns if an attempt is made to increase the output to improve the effect.

Therefore, as a result of various experiments and discussions on why the uneven heat generation occurs in the past, the present invention has found that the impedance matching means of the basic invention eliminates power loss between the output terminal of the high frequency generator and the electrode. However, it is not possible to control and determine the flow of current between the electrodes itself. For example, the current between the electrodes not only flows within the living body, but also requires grounding the cable connecting the output terminal and the electrode. It has been found that when a person touches a living body, a living body is lying on an iron bed, or the electrodes are close to the ground, these cables, living bodies, and electrodes can easily leak into the ground, and in this case, one side They found that the ground potentials of the electrodes close to the ground were different, and by generating the same ground potential for each electrode, they succeeded in creating a uniform heating field inside the agar phantom. Based on this, the electrodes A thermotherapy device using a high-frequency heating method that allows a uniform heating field with no bias in temperature distribution to be obtained between the electrodes, and also allows the heating field to be freely moved to a position biased toward one electrode. This is what we are trying to provide.

The present invention will be described in detail with reference to the embodiments shown below. Reference numeral 1 denotes a high frequency generator with a frequency of 13.56 MHz and an output of 500 W, whose output is connected to pressurizing electrodes 5 and 6 by copper wires 2 and 3 from its output terminal. Pressure electrode 5,
In the case of the example, 6 is constituted by a circular copper electrode plate with a diameter of 10 cm. Reference numeral 4 denotes a potential control device for the pressure electrodes 5 and 6, which may be any circuit that can adjust the impedance between the output terminal of the high frequency generator 1 and the pressure electrodes 5 and 6;
Variable capacitors 7 and 8 of 200 pF are interposed between copper wires 2 and 3, respectively. Of course, it is possible to replace the variable capacitors 7 and 8 with suitable elements that can change impedance, such as variable coils and variable resistors. 9
is a monitor device for monitoring the adjustment of the potential control device 4, and in the embodiment, the applied voltage 5,
The configuration is such that the voltage waveform of 6 is observed with a dual channel oscilloscope 10 connected to the ground.
11 is a living body to be subjected to heat treatment.

In the above embodiment, if the impedance matching between the output terminal of the high frequency generator 1 and the pressurizing electrodes 5, 6 is performed by the variable capacitors 7, 8 in the same manner as in the conventional basic invention, then the pressurizing electrodes 5, 6 When the voltage waveforms of 6 are out of phase with each other by 180°, the current will flow the most between the two electrodes, but for example, if the voltage waveforms are out of phase with each other by 180° with respect to the ground, this pressure electrode 6
Therefore, the current flows directly to the ground, which is a much larger electrode than the other pressurizing electrode 5, and heating of the deep part of the living body 11 becomes impossible. In this case, in the device of the present invention, the voltage waveform to the ground of the pressure electrodes 5 and 6 is observed by the monitor device 9, and it can be immediately detected that the phase of the voltage waveform of the pressure electrode 6 is shifted by 180 degrees with respect to the ground. Therefore, the variable capacitors 7 and 8 of the potential control device 4 are adjusted again to make the phase of the pressure electrode 6 shifted by 0° or 360° with respect to the ground (that is, the same phase state), and the ground is can prevent leakage. Furthermore, if a phase difference between the pressure electrode 6 and the ground is intentionally created, the current will flow to the ground by that amount and the current will not flow into the other pressure electrode 5, but the current will flow from the pressure electrode 6 to the ground. Since the current flowing through the pressurizing electrode 6 including the electric power used for heating the pressurizing electrode 6 does not change, biased heating in which only the pressurizing electrode 6 is heated is possible, which is effective for heating treatment of superficial areas such as skin cancer. In addition, if the phase difference is eliminated as described above and the outflow of current from the pressure electrode 6 to the ground is eliminated, all of the current will flow through the living body 11 and into the other pressure electrode 5, causing the living body 11 to be deep inside. This means that it can be heated evenly.

In the apparatus of the present invention having the above configuration, a heating experiment was conducted using an agar phantom instead of the living body 11, and the ground voltage waveforms of both pressurizing electrodes 5 and 6 were observed with the oscilloscope 10 of the monitor device 9. The variable capacitor 7 of the potential control device 4 is set so that the ground potential of the pressurizing electrode has a 180° phase difference in the voltage waveform, and the phase of the voltage waveform of the pressurizing electrode closer to the ground is equal to that of the ground. , 8 were adjusted to uniformly heat the inside of the agar phantom. Furthermore, by controlling the ground potential of the pressure electrodes 5 and 6 using the control device 4, it has become possible to generate a heating field biased near any pressure electrode.

As described above, according to the device of the present invention, the heating field was not constant and the clinical effect was unstable as in the past, but by controlling the ground potential of the pressure electrode with the potential controller, It is possible to set an arbitrary heating field that is uniform or biased towards one pressure electrode, and by observing the settings with a monitor device, the heating state can be directly recognized without any time delay, and treatment This has the effect of providing a highly effective thermotherapy device using a high-frequency heating method.

Of course, it is also possible to electrically integrate the potential control device of the pressurizing electrode and the monitoring device to automatically set the heating state.
This can be easily done by those skilled in the art as needed.

[Brief explanation of drawings]

The drawings are schematic explanatory diagrams showing one embodiment of the present invention. 1... High frequency generator, 4... Potential control device, 5, 6... Pressure electrode, 9... Monitor device.

Claims (1)

[Claims] 1 A high frequency generator, two pressure electrodes that are brought into contact with the human body, a potential control device for the pressure electrodes provided between the output terminal of the high frequency generator and the pressure electrodes, and a ground potential of the pressure electrodes. The monitor device monitors the potential to the ground of the pressure electrode, and the potential control device is activated to control the potential to the ground of the pressure electrode, thereby controlling the potential of the two pressure electrodes in contact with the human body. A thermotherapy device using a high-frequency heating method configured to control the distribution of heat generation between piezoelectrodes.