JPH0256106B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a heating device for hyperthermia, and in particular, uses electromagnetic waves to locally heat cancer tissue in a living body, thereby heating the cancer tissue. This invention relates to a heating device for hyperthermia that stops the regeneration function of the body and causes death.

[Conventional technology]

In recent years, treatment methods using heating therapy (also known as "hyperthermia") have been in the spotlight, in particular in which malignant tumors are continuously heated to around 43°C for 1 to 2 hours, and this is repeated at regular intervals. A number of research reports have been published showing that this can inhibit the regenerative function of cancer cells and at the same time kill many of them (Measurement and Control).
Vol. 22, No. 10). This type of heating therapy is
There are general heating methods and local heating methods. Among these, methods using electromagnetic waves, methods using electromagnetic induction, methods using ultrasound, and the like have been proposed as local heating methods for selectively warming only the cancerous tissue and its surroundings.

On the other hand, as is already known among researchers in the art, the heating effect on cancer tissue is said to be around 43°C, and if it is lower than this, the effect will be diminished; If the concentration is too high, it may cause harm to normal tissue and is undesirable. That is, in hyperthermia, the temperature of the body must be maintained within a narrow temperature range that causes fatal damage to cancerous tissues but does not cause much harm to normal tissues.

[Problem that the invention seeks to solve]

However, in the conventional technology, deep heating within the body cannot be performed by heating the target area due to the specificity of biological functions, such as the cooling effect of blood flow.
It is not easy to maintain a constant temperature of around 43°C for one to two hours. In particular, heating therapy using electromagnetic waves has been abandoned for a long time because the electromagnetic wave absorption rate of the surface of a living body is extremely high, so conventional techniques were considered unsuitable for deep heating.

[Purpose of the invention]

The present invention takes such prior art into consideration, and provides a hyperthermia heating device that gradually irradiates electromagnetic waves to a predetermined heating location in a living body, thereby relatively easily warming the deep part of the living body. That is its purpose.

[Means for solving problems]

Therefore, the present invention provides an applicator that directs and propagates the electromagnetic waves output from the electromagnetic wave generating means from the biological surface side into the living body via the cooling means, and the electromagnetic waves sent to this applicator and the application generated based on the applicators. The apparatus includes an electromagnetic wave level detection means for detecting each level value of the reflected wave from the data side, and a temperature measurement means for measuring the temperature of the heating location. Furthermore, the main control section controls the electromagnetic wave generation means to stop when the temperature detected by the temperature measurement means is higher than a predetermined set value until the temperature drops to the set temperature. Then, this control unit further outputs a progress start signal for the heating treatment time immediately when the temperature of the heating area first becomes higher than the set value, and also outputs a progress start signal for the heating treatment time step by step at regular intervals. A first function of decreasing the output level of the electromagnetic wave generating means, and setting the output of the electromagnetic wave generating means to an operating state when the temperature of the heating point becomes lower than a set value, and controlling the output level of the electromagnetic wave generating means at regular intervals. A second function that controls the increase step by step and operates based on the output signal from the electromagnetic wave level detection means to control the output of the electromagnetic wave generation means so that the output of the electromagnetic wave generation means does not exceed a predetermined maximum output level. The third function is to perform the following functions. This aims to achieve the above-mentioned purpose.

[Effect]

After the applicator is brought into contact with the surface of the heating section, the cooling device is activated, and then the output of the electromagnetic wave generating means is gradually increased. As a result, first, the temperature of the living body surface and the electromagnetic wave irradiated portion inside the living body on the contact surface rises. In this case, the temperature measuring means constantly measures the temperature inside the living body at regular intervals. When the temperature at this heating point exceeds a predetermined temperature, for example 43.5°C, the output of the electromagnetic wave generating means is immediately lowered by, for example, one step by the action of the first function of the main control section, thereby increasing the temperature. It is intended to automatically prevent excessive heating of hot spots.

Furthermore, when the temperature of the heating point in the living body falls below the set temperature, the electromagnetic wave generating means is immediately activated by the second function of the main control section, and its output is controlled to increase one step at a time.

On the other hand, these series of electromagnetic wave output controls are
The third function of the main control section always suppresses the output level below the maximum output value. For this reason,
Overall, the temperature rise at the heating point is gradual, and therefore, the heating treatment can be applied more effectively to deeper parts.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

In the embodiment shown in FIGS. 1 to 7, electromagnetic waves output from a magnetron 8 as an electrode wave generating means are irradiated and propagated from the living body surface side into the living body via a cooling mechanism 34 as a cooling means. applicator 20 and this applicator 20
a directional coupler 10 as an electromagnetic wave level detection means for detecting each level value of an electromagnetic wave sent into the device and a reflected wave from the applicator side generated based on the electromagnetic wave, and a directional coupler 10 as a temperature measurement means for measuring the temperature of the heated area and a temperature sensor 30.

The main control unit 18 further includes a main control unit 18 that controls the magnetron 8 to stop when the temperature detected by the temperature sensor 30 is higher than a predetermined set value until the temperature drops to the set temperature.

The main control unit 18 further outputs a progression start signal for the heating treatment time immediately when the temperature of the heating area first becomes higher than the set value, and also outputs a progression start signal for the heating treatment time, and increments the heating treatment time by one step at a fixed time interval. The first function is to control the output level of the magnetron 8 to decrease automatically, and the output level of the magnetron 8 is set to the operating state when the temperature of the heating point becomes lower than the set value, and the output level is controlled to decrease by one step at a fixed time interval. a second function that performs upward control; and a third function that operates based on the output signal from the directional coupler 10 and controls the output of the magnetron 8 so that the output of the magnetron 8 does not exceed a predetermined maximum output level. It has the following functions.

To explain this in more detail, first, FIG. 1 is an overall system diagram showing one embodiment of the present invention. In FIG. 1, the hyperthermia heating device is
The main components include a microwave generator 2, a controller 4 including first to fourth control means, and a microwave irradiator 6.

The microwave generator 2 includes a magnetron 8 as an electromagnetic wave generating means, a directional coupler 10 installed on the output side of the magnetron 8, and detects the output level of the magnetron 8 via the directional coupler 10. A diode 12 as a sensor,
The power control unit 14 adjusts the output of the magnetron 8. Of these, the power control unit 14 is a control circuit that adjusts the output of the magnetron 8 by changing the anode voltage of the magnetron 8 under control using a thyristor. Further, the directional coupler 10 is a device that separately separates and takes out incident waves and reflected waves, and the electromagnetic waves taken out here are detected by a diode 12, converted into voltage, and then converted to an analog-to-digital converter (hereinafter referred to as , simply referred to as an "A/D converter") 16 to the main control section 18 in the control section 4.

The main control unit 18 calculates the power of the microwave effectively supplied to the applicator 20, which will be described later, by calculating the difference between the power level value of the extracted incident wave and the power level value of the reflected wave. Then, based on this result, the main control unit 1
The first to fourth control means in the magnetron 8 function to control the output of the magnetron 8.

On the other hand, in this embodiment, the microwave irradiation unit 6 includes an applicator 20 that irradiates the living body with microwaves, and
It is configured to include a cooling mechanism 34 for cooling the opening side of the applicator 20, that is, the surface of the living body, and is further equipped with a temperature sensor 30 as a temperature measuring means for detecting the temperature of cancer tissue.

As shown in FIG. 2, the applicator 20 is in close contact with a living body 32 and irradiates the living body 32 with electromagnetic waves,
An antenna for heating the target cancer tissue,
As described above, the cooling mechanism 34 is provided on the contact surface with the living body 32 in order to prevent skin burns due to heating due to dielectric loss in the skin portion. This cooling mechanism 34 is provided with a pipe 36 for passing water, which is used as a cooling liquid in this embodiment. And the cooling device 21
By forcibly circulating the water cooled by the pump 22 and passing it through the cooling mechanism 34, the opening surface of the applicator 20, that is, the living body 32.
surface is cooled.

The temperature sensor 30 inside the living body 32 is a sensor for detecting the temperature of cancer tissue. Based on the information obtained here, the output of the magnetron 8 is adjusted by the first to fourth control means of the main control section 18, as described above.

On the other hand, the main control section 18 further includes a coolant control means. In this main control section 18, the information obtained from each of the sensors 12 and 30 is transferred to an A/D converter.
When input via the transducers 16 and 42, the rotational speed of the pump 22 is adjusted to maintain the temperature of the cancerous tissue at a desired value based on this information and information from the input/output section 44 that receives instructions from the operator. and magnetron 8
In order to control the output of the
It is set to be sent at 4.

Next, the overall operation of the above device will be explained based on FIG. Here, the heating for the cancer tissue is set to 43.5 [°C].

In this embodiment, as explained below, the first control function of the main control section 18 mainly functions as an output decrease control function, the second control function mainly functions as an output increase control means, and the third control function mainly functions as an output increase control function. The control functions are configured to each function as a maximum level control function, and the coolant control means is configured to function as a coolant flow rate control means.

First, the cooling device 21 is operated (FIG. 3 50),
After the water has been sufficiently cooled, the rotation speed of the pump 22 is controlled by the coolant control means of the main control section 18 (52 in the same figure). Thereafter, the operator determines the maximum output level of the magnetron 8 in advance according to the deep part of the cancer tissue, and sets the maximum output level of the magnetron 8 to the input/output section 44.
(54 in the same figure).

Here, the reason why the maximum output of the magnetron 8 is set to match the deep part of the cancer tissue is that if the microwave output is large, the temperature peak during heating will be near the surface, but if the output is small, the temperature peak will be near the surface. This is because the temperature gradually penetrates deeper and the temperature peak moves deeper. Figure 4 shows the results of experiments conducted on a phantom model that approximates a living body.
Temperature distribution (A) obtained when microwaves of 2450 [MHz] are irradiated based on a certain reference amount, and the temperature distribution obtained when the output of microwaves is reduced by 3 [dB] from the reference amount in this case. A comparison with the temperature distribution (B) obtained using this method is shown. This frequency band is the highest frequency range for heating therapy, and therefore the heating depth is limited to the superficial layer. Nevertheless, the temperature distribution (B) with the output reduced by 3 [dB] is about 0.25
[cm] It can be seen that the temperature has reached its peak at the back.
However, when the output is reduced, it takes a considerable amount of time to bring the cancer tissue to the desired temperature.

FIG. 5 is an experimental example showing temperature changes in the heating section measured at regular intervals, and the curve represents the properties of the heating characteristic curve in this example.

On the other hand, setting of the maximum output during operation of the magnetron 8 is performed by a third control function within the main control section 18 based on information from the directional coupler 10. That is, from the difference in the power values of the incident wave and the reflected wave detected by the directional coupler 10, the output of the microwave that is effectively supplied to the applicator 20 is determined, and this output is sent to the operator via the input/output section 44. The maximum output of the magnetron 8 is then set by matching the set value. In this case, the output may be set to a predetermined level using a phantom model in advance.

After the output of the magnetron 8 is set, microwave irradiation is performed for a certain period of time (Fig. 3, 56).
After that, turn off the output of magnetron 8 (see Figure 5).
8), then temperature measurement is started (60 in the same figure).

This temperature measurement is performed by a temperature sensor 30 for measuring the temperature of cancer tissue. The reason why microwave irradiation is not performed during temperature measurement is that the temperature sensor 30 inserted into the living body is influenced by microwaves and errors occur. Therefore, when using a temperature sensor that is less affected by microwaves, the above-described operation of "turning off the magnetron output" (FIG. 3, 58) is not necessary.

After the temperature is measured, it is determined whether the internal temperature of the heated area is higher than the internal temperature set value (43.5°C) input by the operator (see Figure 6).
2).

Here, when the internal temperature is lower than the internal temperature set value input by the operator, the main control unit 1
In the magnetron 8, the second control function immediately acts to give an instruction to the power control unit 14 to increase the output setting value of the magnetron 8 (64 in the same figure).
However, in this case, the maximum input power set initially will not be exceeded. Then, when the next microwave irradiation time comes, the microwave irradiation is performed based on this set value. That is, microwave irradiation and measurement are repeated until the cancer tissue becomes higher than the set value, and this measurement time is used to increase the set value of the output of the magnetron 8 step by step. Microwave irradiation is performed according to the output set in .

As a result, if the temperature of the cancerous tissue becomes higher than the internal set temperature, the output reduction control function provided in the main control unit 18 operates and the microwave irradiation is stopped until the temperature of the cancerous tissue falls below the set value. Interrupt and repeat the temperature measurement loop. All such controls are performed by the main control section 18. Then, using this time, the main control section 18 uses the first control function to lower the output setting value of the magnetron 8 one step at a time (68 in the same figure), and sets the output for the next irradiation.

By the way, the correlation between the heating time and the lethality of cancer tissue depends on the time it takes for the cancer tissue to reach a temperature around 43°C. Therefore, in this embodiment, the heating time is measured from the time when the cancerous weaving exceeds the set value, and the heating is terminated when the heating time inputted by the operator in advance has arrived (as shown in the same figure). 72).

FIG. 6 shows the relationship between the temperature state of the cancer tissue and the output state of the magnetron 8 during each microwave irradiation and measurement. In this figure, the intervals where the temperature distribution is rising are during microwave irradiation, and the intervals where the temperature distribution is falling are during temperature measurement. At the time of temperature measurement, the output of the magnetron 8 is zero. Point B in the figure indicates the point at which the internal temperature exceeds the set temperature for the first time as a result of microwave irradiation using the maximum output of the magnetron 8, and measurement begins, and the above-mentioned heating time starts from this point ( Figure 3 66). And after this, the internal temperature is 43.5
Continue measuring until the temperature drops below [℃] (in the figure, B,
C) During this time, the first control function in the main control section 18 acts to control the output of the magnetron 8 to drop by one step (68 in Fig. 3), thereby reducing the amount of microwave to be irradiated next. Settings are made. Therefore,
The slope between CD and AB is lower.

In addition, if the output setting value of the magnetron 8 was lowered too much during temperature measurement and the temperature did not reach 43.5 [℃] at the next irradiation (for example, EF in the figure), the flowchart in Figure 3 As shown in step 64 in FIG. 6, since the output is increased in the next measurement period (for example, FG in FIG. 6), the slope rises again (GH in the same figure). By repeating such control, temperature control with less ripple can be obtained.

During the microwave irradiation time, it is necessary to set the maximum output of the magnetron 8 and the irradiation time so that even if the temperature exceeds 43.5 [°C] for the first time, it will not rise more than 1.5 [°C]. be. This is because if the temperature rises by more than 1.5 degrees Celsius, it will exceed 45 degrees Celsius, which will have an adverse effect on normal cells. As a method of determining this set value, for example, the temperature rise at the initial stage of microwave irradiation (OP in Figure 6) is
One possible setting method is to set the temperature below [°C].
This is based on the fact that, as shown in Figure 5, the temperature increase rate for each hour tends to increase in the early stages, and the rate of increase becomes about 1/2 at around 43.5 [℃]. .

Figure 7 shows the cancer tissue temperature state when the maximum output of the magnetron 8 is set lower than in Figure 6, and the start of heating is delayed compared to that in Figure 6. .

In addition, since it is sufficient to use a relatively low frequency to perform deep heating, an oscillator and a linear amplifier suitable for oscillating low-frequency microwaves were used instead of the magnetron 8 used in the above embodiment. May be used. In that case, the power is varied by changing the power of the oscillator or the plate voltage of the linear amplifier under control using a thyristor, as in the case where the magnetron 8 is controlled. However, in this case, it is necessary to use an isolator to eliminate the influence of reflected waves.

〔Effect of the invention〕

Since the present invention is configured and functions as described above,
According to this, it is possible to continuously heat a predetermined location within a living body to a preset temperature for a certain period of time, and the function of the main control unit allows the temperature to be set with few ripples. It is possible to reduce the prickling pain that occurs in the body, and by heating slowly without exceeding the maximum level, it is possible to effectively treat the deep parts of the body. It is possible to provide a hyperthermia heating device that is unprecedented and excellent in that it is possible to effectively suppress the occurrence of overheating in the body, and therefore it is possible to set the optimum output according to the properties of the living body.

This has the advantage that the heating section is maintained at the optimal treatment temperature for a long time.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram showing an embodiment of the present invention, FIG. 2 is a perspective view showing an example of an applicator,
FIG. 3 is a flowchart showing the operation of FIG. 1, and FIGS. 4 to 7 are diagrams showing the action and operation of the embodiment of FIG. 1, respectively. 8...Magnetron as a means of generating electromagnetic waves,
18... Main control unit, 20... Applicator, 30
...Temperature sensor as a means of temperature measurement.

Claims (1)

[Scope of Claims] 1. An applicator for directing and propagating electromagnetic waves output from an electromagnetic wave generating means from the living body surface side into the living body via a cooling means, and an electromagnetic wave sent to the applicator and generated based on the applicator. In a heating device for hyperthermia, comprising an electromagnetic wave level detection means for detecting each level value of a reflected wave from the applicator side, and a temperature measurement means for measuring the temperature of the heating point, the temperature measurement means a main control unit that controls the electromagnetic wave generating means to stop until the detected temperature falls to the set temperature when the detected temperature is higher than a predetermined set value; A first function that immediately outputs a progression start signal for the heating treatment time when it first becomes higher than the set value, and also controls the output level of the electromagnetic wave generating means to decrease step by step at fixed time intervals. and a second function that sets the output of the electromagnetic wave generating means to an operating state when the temperature of the heating point becomes lower than a set value, and controls the output to increase by one step at fixed time intervals, and the electromagnetic wave level a third function that operates based on the output signal from the detection means and controls the output of the electromagnetic wave generation means so that the output of the electromagnetic wave generation means does not exceed a predetermined maximum output level; A hyperthermia heating device featuring: