JP2007260310A - Heating needle electrode and heating device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating needle electrode which can locally heat, can support cancer of a variety of shapes and can expand a heating area, and a heating device using the same. <P>SOLUTION: The heating needle electrode 1 is formed of a shape memory alloy, a body portion 1A which has become a film portion and a tip portion 1B which has become a nonfilm portion. The tip portion 1B is structured so as to deform in the direction of expanding the heating area at the time when the tip portion 1B is heated to a prescribed temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a warming needle electrode needle and a warming device using the same, and more particularly to a warming needle electrode needle having a needle electrode formed of a shape memory alloy. Moreover, it is related with the heating apparatus using this. And it is suitable if it uses for the cancer hyperthermia treatment of medical technology.

  Conventionally, local heating for heating a specific part has been widely performed in various technical fields. For example, in the medical field, high-frequency energy is applied to the affected area of the human body to heat it and treat blood circulation disorders, inflammatory diseases, neuralgia, and the like.

  In particular, cancer (malignant tumor) is sensitive to heat, and it is medically recognized that the cancer (malignant tumor) will die when heated at a temperature of 42 to 43 ° C. for a certain period of time. Thermal therapy (hyperthermia) has been performed in which the thermal energy from the above is applied to cancerous tissue to increase its temperature.

  As described above, the hyperthermia using electromagnetic waves depends on the frequency of the electromagnetic waves used. (1) Microwave heating method (several hundred MHz band), (2) RF (Radio Frequency) heating method (several hundred MHz) It is divided roughly into. The former (microwave heating method) is effective for the treatment of superficial cancer that occurs near the surface of the human body (location close to the skin), but because the attenuation of electromagnetic waves in the living body is large, It is difficult to heat deeply occurring cancer tissue, and the effect cannot be expected for deep cancer.

  On the other hand, as shown in FIG. 25, since the latter (RF heating method) apparatus 50 heats the human body A with a pair of flat electrodes (ground electrodes) 56, cancer tissue that occurs relatively deeply. It is possible to kill. However, the human body A, which is a body to be heated, has a fat layer on the body surface, and this fat layer tissue is heated more strongly than other tissues because of its high electrical resistance. Accordingly, it is difficult to sufficiently heat the deep tissue of the human body A away from the electrode 56, and it is still impossible to effectively cope with deep cancer.

Therefore, there is known a hyperthermia applicator configured to insert a needle-like electrode into a deep part of a human body and heat the needle-like electrode (see, for example, Patent Document 1). As shown in FIG. 26, the applicator for hyperthermia disclosed in Patent Document 1 is formed as a needle-like electrode 100 having a sharp tip 100A for insertion into a tissue. The high frequency cable 102 is connected to the high frequency connector 102. Further, the portion excluding the distal end portion 100A of the needle electrode 100 is covered with an insulator 103 as a member for limiting the electromagnetic wave radiation region.
Since the applicator has the structure as described above, the tissue only in the vicinity of the distal end portion 100A of the needle electrode 100 is selectively heated. That is, local heating is possible.

Japanese Patent Laid-Open No. 10-277163

However, in the hyperthermia applicator disclosed in Patent Document 1 described above, the shape, such as the diameter and length of the needle-shaped electrode 100 during heating, is constant, and is heated in the constant state. There is a problem that a heating pattern corresponding to cancers having various shapes cannot be obtained.
In addition, since the applicator is the needle electrode 100 and only the periphery thereof is heated, the heating area is narrow and effective treatment is difficult. Therefore, in order to expand and control the heating region using the needle-shaped applicator, it is necessary to use a plurality of needle-shaped applicators. In this case, a heavy burden is imposed on normal cells and patients, Difficult treatment is required.

  For this reason, in the present invention, the disadvantages of the above-described conventional example can be improved, and it is possible to locally heat, to cope with various shapes of cancer, and to expand the heating region. An object of the present invention is to provide a warm needle electrode needle and a heating device using the same.

  Therefore, in the heating needle electrode for heating the heating needle electrode according to the present invention after inserting the tip portion into the heated portion, the heating needle electrode is formed of a shape memory alloy, The tip portion is stored so as to be deformed in a direction in which the heating region expands when the tip portion reaches a predetermined temperature.

By adopting such a configuration, the needle electrode is formed of a shape memory alloy, and the tip portion thereof is deformed in a direction in which the heating region is expanded at a set temperature. Therefore, by preparing needle electrodes having shapes corresponding to various shapes of cancer in advance, it is possible to use needle electrodes having an optimal shape for shallow and deep cancers that have occurred in each part. As a result, heating control corresponding to the shape of the cancer can be performed.
Moreover, since the front-end | tip part of a needle electrode deform | transforms at the set temperature, a heating area | region can be expanded during heating. Therefore, if the set temperature is set to around 42 to 43 ° C., the cancer around the enlarged portion of the needle electrode can be efficiently killed, and particularly effective for hyperthermia of brain tumors.

At this time, the deformation of the tip is preferably bent with respect to the linear main body, and the bent shape is preferably a fishhook.
Moreover, it is preferable that the bending of the tip portion is an L shape that is bent in a direction orthogonal to the main body portion.

  As a result, the heating area is expanded in any case, so that it is possible to cope with various shapes of cancer, and cancer around the expanded heating area can be killed, so that an efficient treatment can be achieved. it can.

Moreover, it is preferable to deform | transform the front-end | tip part of the needle electrode for heating in spiral shape. Furthermore, it is preferable that the warming needle electrode is formed of a hollow member and the tip portion thereof is deformed so as to bulge in the radial direction.
Thereby, the heating region can be expanded, especially when the needle electrode for heating is formed of a hollow member and the diameter of the tip portion is changed, the diameter of the tip portion changes in size, Can correspond to the shape of the cancer.

Further, it is preferable that the warming needle electrode is used for the treatment of brain tumor and that the tip of the warming needle electrode is memorized so as to be deformed around 42-43 ° C.
As a result, when the warming needle electrode is inserted into the brain tumor and then heated to around 42 to 43 ° C., the tip of the warming needle electrode is deformed in the direction in which the warming region expands. Therefore, cancer around the warmed area can be killed, and an effective effect can be obtained particularly when used for the treatment of a brain tumor.

  Further, as a configuration of the heating device according to the present invention, a high-frequency oscillator that oscillates a high frequency for the needle electrode, and a main control unit that variably controls a high frequency oscillated from the high frequency oscillator, amplification of the high frequency, and an output level thereof It has a configuration that is equipped with.

As a result, high frequency is supplied from the high frequency oscillator to the needle electrode while the high frequency and output level are variably controlled by the main control unit, so that the temperature around the needle electrode can be easily and surely killed. Can be warmed.
In addition, since a needle electrode is used and the needle electrode can be inserted and heated even in deep cancer such as a brain tumor, an effective effect can be obtained particularly when used for the treatment of a brain tumor. it can.

  Since the present invention is configured and functions as described above, the needle electrode is formed of a shape memory alloy, and the tip end portion of the needle electrode is deformed in a direction in which the heating region is expanded at, for example, around 42 to 43 ° C. By memorizing, the needle electrode expands after being inserted into, for example, a brain tumor. Therefore, the present invention has an unprecedented excellent effect that it can be locally heated, can cope with cancers of various shapes, and can expand the heating region.

  The present invention supplies high frequency power to a needle electrode attached to a body to be heated (mainly a human body), and locally heats the body to be heated by the action of an electromagnetic field generated in the needle electrode. The present invention relates to a heating device and a needle electrode for a heating device.

In particular, according to the present invention, the needle electrode is formed of a shape memory alloy, and the tip thereof is memorized so as to be deformed in a direction in which the heating region is expanded at a predetermined temperature. In the case of the tumor part, the tumor part can be locally heated at a temperature of about 42 to 43 ° C. at which the cancer tissue is killed, and has particularly excellent effects in such applications.
(First embodiment)

  First, a heating device needle electrode (hereinafter simply referred to as a needle electrode) 1 and a heating device 10 according to the present invention will be described with reference to FIGS. FIG. 1 is an overall schematic view of the heating device 10, and FIGS. 2A and 2B are overall side views of the needle electrode 1.

  As shown in FIG. 1, the heating device 10 includes the needle electrode 1 formed of a needle-like member, a high-frequency oscillator 11 and an RF amplifier 12 that oscillate a high frequency in the needle electrode 1, and the oscillated high-frequency power. A matching box 13 for controlling the operation, a computer 14 as a main control unit for controlling the operation of the entire apparatus, and an extracorporeal electrode arranged on a bed 15 on which a human body A as a body to be heated is placed, that is, a ground electrode 16. It is prepared for. Reference numeral 14 denotes a monitor.

As shown in FIGS. 2A and 2B, the needle electrode 1 is made of, for example, a needle-shaped shape memory alloy having a diameter of 1 mm. The needle electrode 1 is composed of a main body portion 1A and a tip portion 1B, of which the tip portion 1B is an uncoated portion, and the dimension L is set to about 30 mm, for example. The dimension L is not limited to 30 mm. In order to correspond to the size and shape of the cancer B, a dimension L of 30 mm or less or 30 mm or more may be prepared.
And the front-end | tip part 1B has memorize | stored the shape so that it may deform | transform in the direction which a heating area | region expands beforehand, when it heats around 42-43 degreeC as preset temperature, for example.

That is, as shown in FIG. 2A, the shape of the needle electrode 1 is linear in a normal state, that is, in a state other than the set temperature, but is heated to around 42 to 43 ° C. which is the set temperature. When this is done, as shown in FIG. 2 (B), the tip 1B is deformed into a fishhook shape with respect to the main body 1A.
The distance D between the parallel portions of the fishhook is 7 mm, for example, and the rising dimension h of the short fishhook portion is 10 mm, for example. The distance D is preferably set to 4 mm to 18 mm, for example, because the heating region is divided into two if it is too far away.

  As a result, it is possible to create a state where two needle electrodes are used at the tip 1B and one end thereof is connected by the third needle electrode in the lateral direction, so that the angle between the hooks is optimal. By doing, it can be set as the heating area | region more than twice as much as the heating area | region at the time of using one needle electrode.

Here, the heating principle in the needle electrode 1 will be described.
Heat generation in the RF heating system is caused by the energy of the applied RF being absorbed by the living tissue (here, the human body A) and changing to thermal energy. Since the distribution of the high-frequency current varies depending on the electric conductivity, the distribution tends to differ depending on the physical property value or the like in the living tissue. Then, when a high-frequency current flows in the living body, Joule heat is generated, and the tissue is heated.
In the present embodiment, since high frequency in the RF band flows between the needle electrode 1 and the ground electrode 16, Joule heat is generated around the needle electrode 1 as in the above principle, and the needle electrode 1 is generated by the energy. The surroundings will be heated.

The method of using the warming device 10 as described above is, for example, after laying a patient (human body A) receiving treatment for a brain tumor on the bed 15, the surgeon in charge prepares various preparations for the brain tumor part. The needle electrode 1 is inserted toward B, and the tip 1B of the needle electrode 1 is inserted into the brain tumor part B.
Next, power is supplied while controlling the high frequency power supplied from the high frequency oscillator 11 and the RF amplifier 12 with the matching box 13 until the tip portion 1B of the needle electrode 1 reaches about 42 to 43 ° C., and the periphery of the tip portion 1B. Warm up.

Since the needle electrode 1 is formed of a shape memory alloy and the tip portion 1B is stored so as to be deformed when heated to around 42 to 43 ° C., electric power is supplied, and the temperature of the tip portion 1B is When it becomes around 42-43 degreeC, the front-end | tip part 1B deform | transforms into a fishhook shape.
As a result, it is possible to produce the same result as if two needle electrodes were inserted, and the heating area is greatly expanded.

According to the first embodiment as described above, the following effects can be obtained.
(1) When the needle electrode 1 is formed of a shape memory alloy and the tip 1B is heated to around 42 to 43 ° C., it is deformed into a fishhook shape. As a result, it is possible to produce the same result as if two needle electrodes were inserted and connected with the third needle electrode inserted horizontally, greatly expanding the heating area. In addition, by heating the tip portion 1B of the fishhook shape, cancer cells in the surrounding brain tumor portion B can be killed, and a great therapeutic effect can be obtained.

  (2) According to the shape of the cancer B, after the needle electrode 1 is inserted from one side of the cancer B, for example, when the needle electrode 1 is heated, the tip 1B is deformed in the shape of a fishhook on the opposite side, It can correspond to the shape of the cancer, and the therapeutic effect can be further improved.

  (3) Since the deformation of the tip 1B of the needle electrode 1 is a fishhook shape and a relatively simple shape, the operation at the stage of storing is easy.

  In the first embodiment as described above, the demonstration that the heating region of the needle electrode 1 having the tip portion 1B in the shape of a fishhook is expanded is confirmed from the computer simulation and the experimental result described below. .

(First computer simulation)
FIG. 3 shows an experimental heating apparatus 20. The heating device 20 includes a high-frequency oscillator 22, and a high-frequency current of 13.56 MHz RF band is output from the high-frequency oscillator 22, and the high-frequency current is distributed to the electrodes by a connection box 23.

As an experimental method for analysis, a phantom 24 cut in two in the radial direction is used, the needle electrode 21 is sandwiched in the center of the cut phantom 24 and tied with a band 25, and the phantom 24 is cross-sectioned. A heating experiment was conducted so that no air entered the part.
As the phantom 24, a muscle equivalent agar phantom simulating the human body A was used. The parameters of this agar phantom 24 are shown in Table 1.

Here, the normalization temperature of 0.8 or more was set as a range where effective heating was possible.
This is because the target temperature in the present invention is around 42-43 ° C. at which the tumor tissue is killed. Here, the body temperature of the human body is 37 ° C., and the maximum temperature for heating is around 43 ° C. This is because when normalization is performed based on this, 42 ° C. becomes a normalization temperature of 0.83.

First, as shown in FIG. 4, two needle electrodes 21 are inserted vertically with a distance D into a cylindrical agar phantom 24 having a diameter (φ) of 180 mm and a height (H) of 135 mm. Warmed up.
Here, in FIG. 4, the distance D is 4 mm, and the length L of the tip portion 21 </ b> B that is a portion where voltage is applied to the needle electrode, that is, the non-coated portion, is 30 mm. Further, the distal end portion 21B of the needle electrode 21 is inserted with the distal ends aligned. Further, the condition of a potential boundary of 100V was applied to the tip 21B and 0V to the ground electrode 16.

  A thermo camera (not shown) was used for measuring the temperature distribution. At this time, since it is difficult to examine unless the temperature distribution of the phantom contour is clear, a cloth having a lower temperature than the phantom 24 is placed around the phantom 24, and the temperature difference between the phantom 24 and its surroundings is sharpened. Moreover, as heating conditions, the heating output was 4 W and the heating temperature was 5 minutes.

Next, the temperature distribution analysis of the computer simulation performed as described above will be described.
FIG. 5 shows a temperature distribution image obtained when the distance D between the two needle electrodes 21 and 21 is 4 mm, which is obtained from the first simulation. As can be seen in FIG. 5, since the distance D between the two needle electrodes 21 and 21 is narrow, there is no difference from the fact that there is only one heating region, and the needle electrodes are also heated to a high temperature. Recognize.

The analysis was performed when the distance D was 8 mm and 12 mm in addition to 4 mm.
When the distance D was 8 mm, although not shown, the temperature rise between the needle electrodes was small compared to the case where the distance D was 4 mm, and it could not be said that the temperature was high.
In addition, when the distance D is 12 mm, although not shown, the heating region is completely divided into two, and the distance D is lower than that of each of 4 mm and 8 mm, and it can be said that it is heated to a high temperature. No results were obtained.

  The graphs obtained by normalizing the above analysis results are shown in FIG. 6 as normalized temperature profiles. From FIG. 6, in all cases (distance D is 4 mm, 8 mm, 12 mm), the periphery of the needle electrode 21 is heated to a high temperature, but as the needle electrode interval D increases, the needle electrodes 21, 21 are increased. It can be seen that the minimum temperature is low. In any case, it can be seen that the center between the needle electrodes (phantom center) is the lowest temperature point between the needle electrodes.

FIG. 7 shows graphs obtained by taking the temperature at the center between the needle electrodes (phantom center) when the distance D between the needle electrodes is 4 mm, 8 mm, and 12 mm.
From FIG. 7, it can be seen that the center temperature between the needle electrodes decreases in proportion to the increase in the distance between the needle electrodes.

  As is clear from the above description, it can be seen that when the needle electrode interval D is 12 mm, the hot spot, that is, the heating region is completely divided into two, and the heating region cannot be expanded. Further, as can be seen from FIG. 7, when the needle electrode interval D is 7.5 mm or more, it can be predicted that the minimum temperature between the needle electrodes is lower than the normalized temperature 0.8. As a result, if the needle electrode interval D is 7.5 mm or less, it is considered that a large therapeutic effect can be obtained, such as heating the tumor sandwiched between the needle electrodes to a high temperature to kill it.

Although not shown, analysis was also performed in a state where the tips of the two needle electrodes were shifted in the longitudinal direction of the needle electrodes. In this case, the displacement dimension was set to a plurality, but in each case, the vicinity of the needle electrode displaced downward was heated to a higher temperature.
This is considered to be because the distance to the ground electrode 16 is shortened by shifting downward, and the lines of electric force are concentrated by the shifted needle electrode. In addition, even if there is a deviation of 10 mm in the insertion depth, effective heating can be performed near both needle electrodes. However, if the deviation increases, the heating characteristics become biased, and the vicinity of the needle electrode on one side It is conceivable that the heating area of the needle will be small, and if it is desired to obtain a nearly equivalent high temperature heating area near the two needle electrodes, it will be understood that the deviation of the insertion depth must be as small as possible. Yes.

(Results of the first experiment)
Next, the results of the first experiment conducted under substantially the same conditions as described above will be described.
In the experiment, as shown in FIG. 8, the agar phantom 24 was used as an agar phantom 24A as an experimental model, and the two needle electrodes 21 and 21 were attached to the agar phantom 24A. The needle electrodes 21 and 21 were inserted vertically to heat the periphery of the tip portions 21B and 21B, and the results were obtained.
Here, the interval D was 13 mm, and the length L of the tip 21B was 30 mm. The tip portions 21B and 21B of the needle electrodes 21 and 21 are inserted with the tips aligned. As heating conditions, the heating output was 4 W and the heating temperature was 5 minutes.

Next, the temperature distribution analysis obtained from the first experiment result as described above will be described.
FIG. 9 shows a temperature distribution image when the distance D between the two needle electrodes 21 and 21 is 13 mm. As can be seen from FIG. 9, when the distance D is 13 mm, the needle electrodes 21 and 21 are heated to a high temperature, and it is understood that there is one hot spot.
Although not shown, when the distance D is 17 mm, the needle electrodes 21 and 21 are heated to a high temperature as in the case where the distance D is 13 mm, and there is one hot spot.
As a result of an experiment also in the case of 20 mm, it has been found that the space between the needle electrodes 21 and 21 is not heated to a high temperature, and the hot spot is divided into two.

  A graph obtained by normalizing and graphing the above experimental results is shown in FIG. 10 as a normalized temperature profile. From FIG. 10, when the needle electrode interval D is 17 mm and 13 mm, the vicinity of the needle electrode is heated to a high temperature, but only when the needle electrode interval D is 20 mm, the normalized temperature is 0.8. It turns out that it is below.

FIG. 11 is a graph showing the relationship between the minimum temperature between needle electrodes and the distance D between needle electrodes.
From FIG. 11, it can be seen that the needle electrode interval D must be about 18 mm or less in order to set the minimum temperature between the needle electrodes to a normalized temperature of 0.8 or more.

Next, based on FIG. 12, 2nd Embodiment of the needle electrode of this invention is described.
The needle electrode 2 of the present embodiment and the needle electrodes 3 and 4 of the third and fourth embodiments described below are formed of the same members as the needle electrode 1 of the first embodiment.
The needle electrode 2 of the second embodiment has a linear shape as shown in FIG. 2A in the normal state, that is, in a state of a temperature other than the set temperature. When heated to around 43 ° C., as shown in FIG. 2 (B), a part of the tip 2B bends in a direction perpendicular to the main body 2A and deforms into an overall L-shape. ing.
Here, the dimension L of the front end portion 2B is, for example, 30 mm, and the dimension of the rising part is set to 10 mm, and the dimension of the laterally extending part is set to 20 mm.

  As a result, the vertical heating portion and the horizontal heating portion can be created by the rising portion and the laterally extending portion of the tip portion 2B, so that the heating region can be expanded.

  According to the second embodiment as described above, it is possible to obtain substantially the same effects as (1) to (3) in addition to the same operation as that of the first embodiment.

  In the second embodiment as described above, the demonstration that the heating region of the needle electrode 1 in which the distal end portion 2B is orthogonal to the main body portion 2A is expanded is the second simulation by the computer described below. It can be understood from the experimental results.

(Second simulation by computer)
The computer simulation was performed using the same equipment as described above and under the same conditions.

In the experiment for analysis, first, the two needle electrodes 21 and 21 were inserted horizontally and vertically into the agar phantom 24A, and the analysis was performed by a computer.
Here, in FIG. 13, the tip of the horizontal needle electrode 21 is separated from the vertical needle electrode 21, the distance a is 4 mm, and the length of the tip portion 21 </ b> B that applies a voltage to the needle electrodes 21 and 21. L was 30 mm. Further, a potential boundary condition of 100 V was applied to the tip and 0 V was applied to the ground electrode 16.

Next, the temperature distribution analysis of the second simulation of the computer performed as described above will be described.
FIG. 14 shows a temperature distribution image when the distance a is 4 mm. As can be seen in FIG. 14, it can be seen that the vicinity of the tips of the two needle electrodes 21 and 21 are both heated to a high temperature, and the needle electrode 21 was inserted horizontally rather than the vicinity of the needle electrode inserted vertically. It can be seen that the vicinity of the needle electrode is heated to a higher temperature over a wider range.

The analysis was performed when the distance a was 6 mm and 8 mm in addition to 4 mm.
When the distance a is 6 mm, although not shown, it was confirmed that the vicinity of the horizontally inserted needle electrode was heated to a higher temperature over a wider range, as in the case where the distance a was 4 mm. . However, the maximum temperature was lower than when the distance a was 4 mm.
Further, when the distance a is 8 mm, although not shown, the same tendency as in the case where the distance a is 4 mm and 6 mm was confirmed. However, the maximum temperature was lower than when the distance a was 6 mm.

The graphs obtained by normalizing the above analysis results are shown in FIG. 15 as normalized temperature profiles. FIG. 15 shows a profile in the r-axis direction at the center of the needle electrode inserted horizontally.
And from FIG. 15, only when the distance a is 4 mm, the minimum temperature between the tips of the needle electrodes is a normalized temperature of 0.8 or more, and the minimum temperature between the tips decreases as the distance a between the tips increases. I understand.
In addition, when the distance a is 6 mm and 8 mm, the high-temperature heating area having a normalized temperature of 0.8 or higher is shifted by the amount of movement of the needle electrode, and the size of the heating area does not change substantially. I understand.

FIG. 16 shows a profile normalized in the z-axis direction at the center of a horizontally inserted needle electrode. When normalization is performed, the maximum temperature (the maximum temperature near the needle electrode horizontally inserted) is used as the maximum temperature.
From FIG. 16, it can be seen that as the tip distance a increases, the maximum temperature in the vicinity of the vertically inserted needle electrode also increases, and the region having a normalized temperature of 0.8 or more also increases.

FIG. 17 is a graph showing the relationship between the needle electrode tip distance and the minimum temperature between the needle electrodes.
From FIG. 17, it can be seen that the minimum temperature between the needle electrodes decreases proportionally as the needle electrode tip distance a increases.

As is clear from the description of FIG. 15 above, when the distance between the tips is increased, the minimum temperature between the needle electrodes is lowered, and as a result, there are two hot spots, so that the heating region cannot be expanded. I understand.
Further, as can be seen from FIG. 17, in order to obtain a normalized temperature of 0.8 or higher, it can be predicted that the distance a between the tips should not be 4.9 mm or less.

Although not shown in the figure, a simulation was also performed when the vertically inserted needle electrode was separated from the horizontally inserted needle electrode.
This result shows that the expansion of the heating region can be expected when the distance between the two needle electrodes is 5 mm or less.
(Second experiment result)

Next, the result of the second experiment carried out under the same conditions as those described above when inserted in the vertical and horizontal directions will be described.
In the experiment, using the experimental heating device 20, two needle electrodes 21, 21 are inserted into the agar phantom 24A from the vertical and horizontal directions, and the tip portions 21B, 21B of the needle electrodes 21, 21 are inserted. The result was warmed.
FIG. 18 shows a state where two needle electrodes 21 and 21 are inserted into the agar phantom 24 of the experimental model.
Here, in FIG. 18, the tip end distance a is 4 mm, and the tip end length L is 30 mm. As heating conditions, the heating output was 4 W and the heating temperature was 5 minutes.

Next, the temperature distribution analysis obtained from the results of the second experiment will be described.
FIG. 19 shows a temperature distribution image when the tip distance a of the two needle electrodes is 4 mm. As shown in FIG. 19, when the tip distance a is 4 mm, there is one hot spot, and the temperature near the needle electrode inserted horizontally is higher than the vicinity of the needle electrode inserted vertically. You can see that it is warm.

Although not shown, when the tip distance a is 7 mm, there is one hot spot, and the vicinity of the needle electrode inserted vertically is heated to a higher temperature than the vicinity of the needle electrode inserted horizontally. I know that
Furthermore, although not shown, when the tip distance a is 11 mm, the hot spot is divided into two, and the vicinity of the needle electrode inserted vertically is heated to a higher temperature than the vicinity of the needle electrode inserted horizontally. I know that

FIG. 20 shows a profile taken in the r-axis direction at the center of a horizontally inserted needle electrode.
From FIG. 20, when the distance a is 4 mm or 11 mm, a high temperature heating region having a normalized temperature of 0.8 or more can be confirmed near the horizontally inserted needle electrode, but when the distance a is 7 mm. It can be seen that there is almost no high-temperature heating region with a normalized temperature of 0.8 or higher near the horizontally inserted needle electrode. Further, only when the distance a is 11 mm, there are two peaks in the graph, and it can be confirmed that the heating region is divided into two.

FIG. 21 shows a profile taken in the z-axis direction at the center of a vertically inserted needle electrode.
From FIG. 21, in any case where the distance a is 4 mm, 7 mm, or 11 mm, a high-temperature heating region having a normalized temperature of 0.8 or more can be confirmed near the vertically inserted needle electrode. It can be seen that when the distance a is 4 mm, the high-temperature heating region is small compared to the cases of 7 mm and 11 mm.

FIG. 22 is a graph showing the relationship between the needle electrode tip distance and the minimum temperature between the needle electrode tips.
From FIG. 22, it can be seen that the minimum temperature between the needle electrode tips decreases as the needle electrode tip distance a increases.

  As is clear from the description of FIGS. 19 to 22 above, when the needle electrode tip distance a is 4 mm, there is a maximum temperature observation point in the vicinity of the needle electrode horizontally inserted, and when the tip distance a is 7 mm, the needle electrode is vertically inserted. It can be seen that there is a maximum temperature observation point near the needle electrode.

Therefore, if the needle electrode tip distance a is about 4 mm or less, the vicinity of the needle electrode inserted horizontally is heated to a higher temperature, and if the tip distance a is 7 mm or more, the needle inserted vertically It is conceivable that the vicinity of the electrode is heated to a higher temperature, and the point at which this is switched can be predicted that the tip distance a is between 4 mm and 7 mm. In addition, when the tip distance a is 4 mm, there is one hot spot, and a high temperature is confirmed in the vicinity of both needle electrodes. Therefore, if the needle electrode tip distance a is about 4 mm or less, the heating region is expanded. Can be expected.
As described above, the information obtained from the experimental results almost coincides with the information in the computer simulation.
Thereby, it has been demonstrated that the shape in which the distal end portion 2B of the needle electrode 2 is L-shaped in the second embodiment can expand the heating region.

Further, although not shown, an experiment was conducted in a state where the tip of the vertical needle of the two needle electrodes was spaced from the tip of the horizontal needle.
In this case, if the distance between the tips of the needle electrodes is 1 mm, the vicinity of the needle electrode inserted horizontally has a larger high-temperature heating area, and if the distance between the tips of the needle electrodes is about 5 mm or less, the needle is inserted vertically. It is considered that the high-temperature heating region is larger in the vicinity of the inserted needle electrode, and it can be predicted that the tip-to-tip distance is between 1 mm and 5 mm.

  From the above results, when the distance between the tips of the needle electrodes is increased, the minimum temperature between the needle electrodes is less than 0.8 at the normalized temperature, and the hot spot is divided into two. Conceivable. In this case, if the distance between the tips of the needle electrodes is about 1 mm or less, it is considered that the minimum temperature between the needle electrodes does not fall below 0.8 at the normalized temperature, and expansion of the heating region can be expected.

Next, a third embodiment of the needle electrode of the present invention will be described based on FIG.
When the shape of the needle electrode 3 of the present embodiment is a normal state, that is, a state other than the set temperature, as shown in FIG. 23 (A), the main body 3A and the tip 3B are linear. However, when it is heated to around 42 to 43 ° C., which is the set temperature, as shown in FIG. 23 (B), the tip 3B is spiral and has an L-shape with the main body 3A. Form and deform.

As a result, the tip portion 3B has a spiral outer diameter size φ, so that the heating region can be expanded.
In addition, although the computer simulation and experiment were not performed about the needle electrode 3 of this 3rd Embodiment, from the computer simulation and experiment result corresponding to the said 1st, 2nd embodiment, the needle electrode 3 is also a heating area | region. It can be inferred that this can be expanded.

According to the third embodiment as described above, the same effects as in (1) and (2) can be obtained in addition to the same effects as in the first embodiment, and the following effects can be further obtained. Can do.
(4) By appropriately changing the size of the outer dimension φ of the spiral in the length direction of the distal end portion 3B, it is possible to correspond to the shape of the cancer, and more effective treatment is possible.

Next, based on FIG. 24, 4th Embodiment of the needle electrode of this invention is described.
The needle electrode 4 of this embodiment is formed of a hollow member having an outer diameter dimension of, for example, 1 mm. In the normal state, that is, in a state other than the set temperature, the shape of the needle electrode 4 is such that the main body 4A and the tip 4B are linear as shown in FIG. When the temperature is raised to around 42 to 43 ° C., as shown in FIG. 24 (B), a part or all of the tip portion 4B bulges in the radial direction and deforms.
Here, the bulging dimension in the radial direction may not be constant over the entire length of the distal end portion 4B, and the radial dimension may be different.

As a result, the distal end portion 4B bulges and deforms in the radial direction, so that the heating region can be expanded.
In addition, although the simulation and experiment of a computer are not performed about the needle electrode 3 of this 4th Embodiment, from the simulation and experiment result of the computer corresponding to the said 1st, 2nd embodiment, the needle electrode 3 is also a heating area | region. It can be inferred that this can be expanded.

  In addition, in 4th Embodiment, although the main-body part 4A and the front-end | tip part 4B of the needle electrode 4 become a shape which continues linearly, like the said 1st-4th embodiment, a fishhook shape and L-shape Or may be stored so as to bulge in the radial direction in each state.

  According to the fifth embodiment as described above, it is possible to obtain substantially the same effect as the above (1), (2), and (4) in addition to substantially the same operation as the first embodiment.

The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in each of the above embodiments, the needle electrodes 1 to 4 are mainly used for treatment of a brain tumor, but the present invention is not limited to this. For example, the present invention may be used to heat a food to be heated and to locally heat the food. Further, the needle electrodes 1 to 4 may be inserted into the trunk of a plant such as a pine and heated to extinguish the pine beetle inside.

Further, in the needle electrode 2 of the second embodiment, the main body portion 2A and the tip portion 2B are deformed so as to have an overall L shape, but may not necessarily have an overall L shape. For example, it may be bent and deformed into a generally square shape. In short, what is necessary is just to deform | transform in the direction which can expand a heating area | region.
And even if it does in this way, a heating area | region can be expanded.

  The warming needle electrode needle and the warming device using the same according to the present invention can warm the warming needle electrode needle by the supplied high-frequency power, and can locally warm. Therefore, it can be used, for example, for tumor treatment, particularly for brain tumor treatment.

It is the whole schematic figure which shows the structure of the heating apparatus of this invention. It is a figure which shows 1st Embodiment of the needle electrode for heating devices of this invention, FIG. 2 (A) is a normal state, FIG.2 (B) is a figure which shows a state when it reaches set temperature and deform | transforms. is there. It is the whole schematic which shows the experimental machine for test | inspecting the performance of a common needle electrode. It is sectional drawing which shows the analysis model used in order to observe a heating state using two general needle electrodes. It is a figure which shows the temperature distribution image obtained from the 1st simulation. It is a figure which shows the normalized temperature profile obtained by the 1st simulation. It is a figure which shows the relationship between the needle electrode space | interval obtained by the 1st simulation, and the center temperature between needle electrodes. It is sectional drawing which shows the experimental model used for the 1st experiment. It is a figure which shows the temperature distribution image obtained from the 1st experiment. It is a figure which shows the normalized temperature profile obtained from the 1st experiment. It is a figure which shows the relationship between the needle electrode space | interval obtained from the 1st experiment, and the center temperature between needle electrodes. It is a figure which shows 2nd Embodiment of the needle electrode for heating devices of this invention, FIG. 12 (A) is a state in normal temperature, FIG.12 (B) is a figure which shows a state when reaching preset temperature. It is. It is sectional drawing which shows the analysis model which used two needle electrodes from different directions. It is a figure which shows the temperature distribution image obtained from the 2nd simulation. It is a figure which shows the normalized temperature profile of the r axis | shaft obtained by the 2nd simulation. It is a figure which shows the normalized temperature profile of z-axis obtained by the 2nd simulation. It is a figure which shows the relationship between the needle electrode space | interval obtained by the 2nd simulation, and the center temperature between needle electrodes. It is sectional drawing which shows the experimental model used for the 2nd experiment. It is a figure which shows the temperature distribution image obtained from the 2nd experiment. It is a figure which shows the normalized temperature profile of the r axis | shaft obtained from the 2nd experiment. It is a figure which shows the normalized temperature profile of z-axis obtained from the 2nd experiment. It is a figure which shows the relationship between the needle electrode space | interval obtained from the 2nd experiment, and the center temperature between needle electrodes. It is a figure which shows 3rd Embodiment of the needle electrode for heating devices of this invention, FIG. 23 (A) is a normal state, FIG.23 (B) is a figure which shows a state when reaching preset temperature. It is a figure which shows 4th Embodiment of the needle electrode for heating devices of this invention, FIG. 24 (A) is a normal state, FIG.24 (B) is a figure which shows a state when reaching preset temperature. It is the schematic which shows a general RF dielectric heating apparatus. It is the schematic which shows the applicator for hyperthermia using the conventional acicular electrode.

Explanation of symbols

1, 2, 3, 4 Needle electrode 1A, 2A, 3A, 4A body portion 1B, 2B, 3B, 4B Tip portion 10 Heating device 11 High-frequency oscillator 12 RF amplifier 13 Matching box 14 Computer 16 Ground electrode A Covered Human body B that is a warming body Tumor part that is a target for warming

Claims (8)

In the heating needle electrode that heats after inserting the tip portion into the heated portion,
The heating needle electrode is formed of a shape memory alloy, and the tip portion is memorized so as to be deformed in a direction in which a heating region is expanded when the tip portion reaches a predetermined temperature. Heating needle electrode.   2. The heating needle electrode according to claim 1, wherein the distal end portion is deformed so as to be bent with respect to the linear main body portion.   3. The warming needle electrode according to claim 2, wherein the tip portion is bent into a fishhook shape.   3. The heating needle electrode according to claim 2, wherein the tip portion is bent in an L shape that is bent in a direction orthogonal to the main body portion. Needle electrode.   The heating needle electrode according to any one of claims 1 to 4, wherein the tip is deformed in a spiral shape.   The warming needle electrode according to any one of claims 1 to 5, wherein the warming needle electrode is formed of a hollow member, and its tip is deformed to bulge in a radial direction. Needle electrode.   The warming needle electrode according to any one of claims 1 to 6 is used for treatment of a brain tumor, and the tip of the warming needle electrode is memorized so as to be deformed around 42 to 43 ° C. A needle electrode for heating, characterized in that A heating device comprising the heating needle electrode needle according to any one of claims 1 to 7,
A heating apparatus comprising: a high-frequency oscillator that oscillates a high frequency for the needle electrode; and a main control unit that variably controls a high-frequency oscillated from the high-frequency oscillator, amplification of the high-frequency, and an output level thereof .

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