JP4098594B2 - Microwave surgical device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microwave surgical apparatus that performs operations such as coagulation, hemostasis, and excision by irradiating a living tissue with microwaves, for example.
[0002]
[Prior art]
Conventionally, a microwave surgical apparatus is known together with an electrosurgical apparatus (electric scalpel), a laser surgical apparatus (laser scalpel), and the like.
A microwave surgical device is a surgical device that performs coagulation, hemostasis, excision, etc., using dielectric heat generated in a tissue by irradiating the microwave into the living tissue. It is suitable for the operation of the parenchymal organ.
[0003]
By the way, when performing a surgical operation or treatment of a living tissue using the above-described microwave surgical apparatus, it is preferable to perform the operation while observing the state of the surgical operation / treatment site.
It is conceivable to combine a microwave surgical apparatus and a magnetic resonance imaging (MRI) apparatus in order to observe an operation / treatment site while performing an operation / treatment with a microwave surgical apparatus.
[0004]
However, a nuclear magnetic resonance imaging apparatus (hereinafter referred to as “MRI apparatus”) applies a high-frequency magnetic field (RF magnetic field) in a state where the human body is placed in a static magnetic field, and excites nuclei having spin in the human body. This is a device for displaying a tomographic image of a human body by detecting MR signals having a predetermined frequency while the excited nucleus returns to its original state.
For this reason, in general, a strong static magnetic field emitted from a magnet is not emitted from a predetermined region to the outside, and an extremely small amount of RF signal emitted from a human body is efficiently received inside a shield room provided with an electromagnetic shield. It is necessary to configure such that a small amount of MR signal is not affected by noise or the like by being installed.
[0005]
Therefore, in the conventional microwave surgical apparatus, a microwave oscillator is provided outside the MR examination room, and this microwave oscillator and a microwave application used in the MR examination room are connected by a microwave relay cable. In addition, by installing a coaxial filter in the middle of the microwave relay cable connecting the microwave oscillator and the microwave application, the microwave output from the magnetron becomes noise before entering the MRI observation space in the MR examination room. There has also been proposed a method for cutting the surface (Patent Document 1).
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 11-267133 (pages 12 to 13, FIGS. 31 to 37)
[0007]
[Problems to be solved by the invention]
However, for example, when performing surgery using the microwave surgical apparatus described in Patent Document 1 as described above, usually other therapeutic devices or biological monitoring devices are used together. If an abnormality occurs in the ground circuit of any of the included devices due to some cause, there is a risk that the surgeon or patient may cause an electric shock (electric shock, electric shock) due to a leakage current and be in a dangerous state.
[0008]
Also, in the microwave surgical apparatus, the affected part such as a tumor is irradiated with microwaves using a microwave surgical electrode to perform operations such as coagulation, hemostasis, and excision of the affected part. It is desirable to check the state with an MR image (tomographic image).
[0009]
However, when the microwave surgical apparatus and the MRI apparatus are used at the same time, if an instrument that affects the magnetic field is used as the surgical instrument of the microwave surgical apparatus, the distortion of the local magnetic field generated by the surgical instrument is reduced. It becomes a problem.
For this reason, surgical electrodes made of non-magnetic material are used. However, in surgery under MR imaging, it is essential to be able to confirm a clearer image in real time. The use of a magnetic field MRI apparatus is desired. As a result, the disturbance of the MR image obtained by the MRI apparatus still remains a problem only by using a surgical instrument compatible with MRI.
[0010]
Also, depending on the type of MRI apparatus, there is an apparatus that can secure a region that is not affected by a magnetic field even in a narrow operating room due to the leakage magnetic field. In that case, a normal surgical instrument can be used. However, in that case, surgery is performed on the bed facing the outside of the gantry of the MRI apparatus, and the imaging is premised on equipment and a system that enables quick work of moving the bed quickly into the gantry, and in real time. Thus, it was difficult to confirm the MR image.
[0011]
Therefore, the present invention has been made in view of the above points, and even when used at the same time as an MRI apparatus, a high-resolution image can be displayed in real time without affecting the MR image. An object of the present invention is to provide a safe microwave surgical device even when the above device is used in combination.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the microwave surgical apparatus of the present invention can be used in a state where a tomographic image is being captured by a nuclear magnetic resonance imaging apparatus.
And a microwave oscillation means configured by a magnetron and provided with an electrical insulator that cuts off direct current in an output circuit that oscillates and outputs a microwave signal of a predetermined frequency, and irradiates the lesion tissue site with the microwave signal A surgical electrode configured to be capable of being configured, and a frequency for tomographic imaging from continuous noise included in a microwave signal output from the microwave oscillating means provided between the microwave oscillating means and the surgical electrode; Noise filtering means for removing only resonating noise components by guiding them to an external ground The noise filter means is inserted into each of a pair of transmission paths for transmitting the microwave signal from the microwave oscillating means to the surgical electrode, and can pass the microwave signal having a frequency of 2300 MHz to 2500 MHz. Of the continuity noise generated between the first band-pass circuit formed by the capacitor, the transmission line and the external ground, and generated by the magnetron, the frequency that resonates with the imaging frequency of the tomographic image A tuning circuit formed by connecting a capacitor and an inductor in series so as to allow only a noise component to pass therethrough and a second bandpass circuit formed by a correction capacitor. The
[0013]
Further, the noise filter means removes a noise component that affects the tomographic image taken by the nuclear magnetic resonance imaging apparatus, thereby enabling the temperature distribution of the lesion tissue site to be displayed in real time in the nuclear magnetic resonance imaging apparatus.
The noise component removed by the noise filter means is determined by the magnetic field strength of the nuclear magnetic resonance imaging apparatus.
[0015]
According to the present invention, the noise filter means is provided between the microwave oscillating means and the surgical electrode, and the tomographic imaging frequency and resonance are detected from the continuous noise included in the microwave signal output from the microwave oscillating means. Only the noise component is removed by guiding it to the external ground.
As a result, even when the microwave surgical apparatus is used at the same time as the MRI apparatus, a high-resolution image can be obtained, so that the temperature distribution of the diseased tissue site can be displayed in real time.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the microwave surgical apparatus according to the present embodiment will be described.
This embodiment will be described in the following order.
1. Surgical system using the microwave surgical apparatus of the present embodiment
2. Configuration of microwave surgical device
2-1 External configuration of microwave surgical device
2-2 Internal structure of microwave surgery device
2-3 Structure of microwave surgical electrode
3. Background to the present invention
4). Noise filter configuration
4-1 Noise filter structure
4-2 Filter characteristics
[0017]
1. Surgical system using the microwave surgical apparatus of the present embodiment
First, an outline of a surgical system using a microwave surgical apparatus as an embodiment of the present invention will be briefly described with reference to FIG.
The surgical system shown in FIG. 1 includes a microwave surgical apparatus 1 and an MRI apparatus 6 as the present embodiment.
The microwave surgical apparatus 1 according to the present embodiment is generated in a living tissue by convergently irradiating the affected part of the subject 7 with a 2450 MHz microwave signal generated in the surgical apparatus main body 2 from the microwave surgical electrode 5. For example, it is suitable for operating coagulation, hemostasis, excision, etc., on a substantial organ such as a liver containing a lot of blood by using the dielectric heat.
In this case, the surgical apparatus body 2 is connected to the high-frequency coaxial cable 4 via the noise filter 3, and the microwave surgical electrode 5 is connected to the high-frequency coaxial cable 4.
[0018]
The MRI apparatus 6 is a so-called open-type MRI apparatus including an MRI apparatus main body 6a and magnet portions 6b and 6b. The MRI apparatus main body 6a performs main control, and applies a static magnetic field to a subject (patient) 7. The magnet parts 6b and 6b are connected by a signal line 6c. Moreover, the monitor 6d which displays the tomographic image (MR image) of the test subject 7 is provided.
Advantages of the MRI apparatus 6 are that there is no X-ray exposure, and a tomographic image of the human body can be obtained from any angle without moving the subject's body, so the extent and size of the lesion, the relationship with the surrounding tissue, and the temperature image And the like can be displayed on the monitor 6d.
In addition, the open type MRI apparatus 6 as shown in FIG. 1 is different from the closed type (tunnel type) MRI apparatus in that the surgeon operates between the magnet parts 6b and 6b that form the static magnetic field of the MRI apparatus. Can access the subject 7 in a static magnetic field. That is, since a space for an operator (not shown) to access the subject 7 is provided in the vertical direction, the surgeon is positioned in front of the space, so that the lesion portion displayed on the monitor 6d is displayed. It is possible to easily, accurately and safely perform various procedures such as surgery while visually confirming the MR image in real time.
[0019]
In this embodiment, the MRI apparatus 6 is an open-type MRI apparatus as shown in FIG. 1, and the magnet parts 6b and 6b are arranged vertically so that the surgeon accesses the subject in the static magnetic field. An example of a vertical (double donut) device in which spaces are provided in the vertical direction is given as an example, but this is only an example.
For example, the MRI apparatus 6 may be a horizontal type (hamburger type) apparatus in which the magnet units 6b and 6b are arranged horizontally and a space for the operator to access the subject is provided in the horizontal direction. Moreover, a closed type (tunnel type) MRI apparatus may be used.
[0020]
The microwave surgical apparatus 1 of the present embodiment constituting the surgical system shown in FIG. 1 is configured so as not to affect the MR image even when used at the same time as the MRI apparatus 6. Thus, for example, it is possible to perform an operation such as coagulation, hemostasis, and resection of a lesioned part in real time with an MR image by irradiating an affected part such as a tumor with a microwave signal using a microwave surgical electrode. It is a thing.
Further, even when other devices are used in combination, the operator and patient are configured to be safe so as not to give an electric shock due to leakage current.
[0021]
2. Configuration of microwave surgical device
2-1 External configuration of microwave surgical device
Hereinafter, the configuration of the microwave surgical apparatus according to the present embodiment will be described with reference to FIGS.
First, the external configuration of the microwave surgical apparatus according to the present embodiment will be described with reference to FIGS.
2A and 2B are diagrams showing an external configuration of the microwave surgical apparatus according to the present embodiment. FIG. 3A is a front view of the surgical apparatus body, and FIG. 3B is a rear view thereof. is there.
As shown in FIG. 2, the surgical device main body 2 of the microwave surgical device 1 is small and can be placed on the gantry 10. Further, the operation device body 2 and the foot switch 9 (9a, 9b) are connected by the foot cable 8 so that the on / off operation by the foot can be performed.
[0022]
As shown in FIG. 3A, the main operation panel unit 11 is provided on the upper side and the sub operation panel unit 12 is provided on the lower side on the front of the surgical apparatus main body 2.
The main operation panel unit 11 is divided into an alarm area 13, a mode area 14, a coagulation area 15, a dissociation area 16, and a memory area 17.
The alarm area 13 is provided with various alarm lamps 21 for notifying the state of the microwave surgical apparatus 1.
[0023]
The mode area 14 is an area for switching the operation mode of the microwave surgical apparatus 1, and the operation mode by the foot switch 9 shown in FIG. 2 is a normal (no stepping) mode and an auto repeat (once and once). A mode changeover switch 22 for switching to a mode and a repeat count display section 23 for displaying the repeat count are provided.
[0024]
The coagulation region 15 is an area for performing various settings of microwaves to be irradiated when performing surgery (coagulation) on the subject 7 from the microwave surgical electrode 5. Therefore, microwave output setting, microwave output setting switches 24 and 25 for resetting the output setting, coagulation time reset, or microwave output while gradually raising the microwave output to the output set value step by step The change-over switches 26 and 27 for switching to the slow coagulation mode for irradiating the light are provided.
Further, as a display unit, a coagulation confirmation lamp 28, an output display 29 for displaying the microwave output value, a coagulation time display 30 for displaying the coagulation time, and a coagulation time unit confirmation for displaying the unit (second / min) of the coagulation time. A lamp 31 is provided.
[0025]
The dissociation region 16 is a region for performing various settings for preventing the biological tissue from adhering to the microwave surgical electrode 5 when the microwave surgical electrode 5 is pulled out from the living body of the subject 7. A dissociation time display 33, a dissociation time setting switch 34, a dissociation current display 35, and a dissociation current setting switch 36 are provided.
[0026]
The memory area 17 is provided with a memory switch 37 for storing the setting of coagulation conditions (wattage, coagulation time, dissociation time, etc.).
[0027]
On the other hand, the sub-operation panel unit 12 has two output connectors 40 and 41 capable of outputting microwaves, a simultaneous energization switch 38 for energizing these output connectors 40 and 41 simultaneously, and a microwave surgical electrode 5. A URS switch 39, a foot switch connection connector 42, and a main power switch 43 are provided for energizing the output connectors 40 and 41 when a load is applied.
[0028]
In this case, microwave surgical electrodes 5 and 5 are connected to the output connectors 40 and 41 via high-frequency coaxial cables 4 and 4, respectively. Then, microwaves are output from the microwave surgical electrodes 5 and 5.
In this embodiment, the noise filter 3 is provided between the output connector 40 (or 41) and the high-frequency coaxial cable 4.
The foot switch 9 is connected to the foot switch connector 42 via the foot cable 8 described above.
[0029]
As shown in FIG. 3B, a volume adjustment knob 45, a fuse holder 46, a ventilation hole 47, and an equipotential terminal 48 are provided on the back side of the surgical apparatus main body 2. Further, grips 44 are provided on both sides of the surgical apparatus main body 2, respectively.
[0030]
2-2 Internal structure of microwave surgery device
Next, the internal configuration of the microwave surgical apparatus according to the present embodiment will be described with reference to the block diagram shown in FIG. In addition, the same number is attached | subjected to the site | part same as FIG. 3, and description is abbreviate | omitted.
As shown in FIG. 4, the commercial AC voltage (rated voltage) from the commercial AC power supply is supplied to the set output stabilizing device 53 via the fuse 51, the main power switch 43, and the leakage breaker 52. The earth leakage breaker 52 is provided with a ground warning light 21a for notifying the earth leakage. The ground warning light 21a is provided as the alarm lamp 21 in the alarm region 13 shown in FIG.
[0031]
The set output stabilizing device 53 sets the voltage level supplied to the high voltage power source 56 in accordance with the setting of the output setter 54. The output timing of the set output stabilizing device 53 is controlled by the output control device 55. The output display 29 is a display that displays the set value of the output setting unit 54.
[0032]
The high voltage power source 56 is constituted by a high voltage transformer or the like, and boosts the voltage from the set output stabilizing device 53 and outputs it to the microwave oscillator 57.
The microwave oscillator 57 is configured by a magnetron, and generates a microwave of 2450 MHz, for example, using a boosted voltage from the high-voltage power supply 56. The output circuit is provided with an electrical insulator so as to block direct current.
[0033]
The microwave generated by the microwave oscillator 57 is supplied to the microwave surgical electrode 5 via the noise filter 3 of the microwave transmission unit 58, the coaxial relay 59, and the high-frequency coaxial cable 4 surrounded by a broken line, and the microwave operation is performed. The subject 7 is irradiated from the working electrode 5.
[0034]
The contact checker 61 detects whether the microwave surgical electrode 5 is in contact with the subject 7 in order to prevent erroneous microwave output from the microwave surgical electrode 5, The detection result is output to the output control device 55.
[0035]
The output control device 55 performs control so that a predetermined level of voltage is input from the set output stabilization device 53 to the high voltage power source 56 for the time set by the output time setting device 63 when the foot switch 9a is operated. Yes. Further, the output control device 55 performs output control based on the detection result of the contact checker 61 described above. The operating voltage of the output control device 55 is supplied from the low voltage power supply circuit 62.
[0036]
The magnetron forced cooling device 64 is configured to forcibly cool the magnetron of the microwave oscillator 57. The magnetron forced cooling device 64 is provided with a cooling fan monitoring lamp 21b for monitoring the state of the cooling fan and notifying when an abnormality occurs in the cooling fan.
[0037]
The low voltage power supply circuit 62 converts the commercial voltage input via the earth leakage breaker 52 into a predetermined low voltage level and outputs it. The output voltage is supplied as drive power to the output control device 55, the foot switch 9a, the audio output device 65, and the like.
[0038]
The sound output device 65 outputs an alarm sound from the speaker 66 when an abnormality is detected when the output control device 55 outputs a microwave, or when an abnormality is detected in the ground detection circuit 67 or the tissue dissociation device 69.
The sound output device 65 is configured to output an alarm sound from the speaker 66 when the earth detection circuit 67 detects a leakage current.
[0039]
In the microwave surgical apparatus 1 according to the present embodiment, the microwave surgical electrode 5 is inserted into the tissue for surgery, and then the microwave surgical electrode 5 is extracted from the tissue. A tissue dissociation device 69 is provided to prevent the tissue from adhering to the microwave surgical electrode 5.
[0040]
The tissue dissociation device 69 applies a cathode direct current of about several mA to the microwave surgical electrode 5 via the coaxial relay 59 after the operation is completed, so that the tissue dissociation device 69 is connected between the tissue and the microwave surgical electrode 5. The adhesion of tissue to the microwave surgical electrode 5 is prevented by the water that aggregates around the center electrode, which will be described later, which becomes the negative side due to the electropermeation phenomenon with the cell membrane as a boundary.
The energization time of the tissue dissociation device 69 can be set by the energization time setting device 70, and the energization time is normally set to a short time (for example, about 60 seconds).
The tissue dissociation device 69 is turned on / off by, for example, operating the foot switch 9b and turning on / off the DC power supply 68.
[0041]
2-3 Structure of microwave surgical electrode
Here, the structural example of the electrode for microwave surgery is shown using FIG.
FIG. 5A is an overall structural view of the surgical electrode, and FIG. 5B is an enlarged view of the distal end portion of the surgical electrode.
The microwave surgical electrode 5 shown in FIGS. 5A and 5B is a surgical electrode made of, for example, a non-magnetic material compatible with MRI.
In such a microwave surgical electrode 5, a substantially cylindrical external electrode 72 is attached to a connector main body 71. A center electrode 74 is attached to the tip of the external electrode 72 via an insulator 73.
The center electrode 74 is connected to a center electrode (not shown) in the connector main body 71 via a center conductor 75 formed in the insulator 73 and a center conductor (not shown) in the external electrode 72. The external electrode 72 is connected to the external electrode of the connector main body 71. The external electrode 72 and the center electrode are insulated.
[0042]
3. Background to the present invention
By the way, as described above, when an operation is performed by the microwave surgical apparatus 1 while simultaneously displaying MR images by the microwave surgical apparatus 1 and the MRI apparatus 6, the above-described MRI compatible surgical operation is performed. If only the instrument is used, the disturbance of the MR image obtained by the MRI apparatus is still a problem.
[0043]
Therefore, as a result of pursuing the cause of this problem, the present inventors have clarified the following.
The MRI apparatus 6 generates a weak electromagnetic wave (RF) having the same frequency as the resonance frequency of protons in the living body (for example, 21.28 MHz in the case of an MRI apparatus having a static magnetic field strength of 0.5 T (Tesla)). A transmission device (not shown) for sending to protons as an imaging frequency and a reception device (not shown) for receiving electromagnetic waves of the same frequency re-radiated from protons when transmission is stopped are provided.
[0044]
On the other hand, the magnetron for generating microwaves in the microwave surgical apparatus 1 is used frequently in microwave ovens and the like because of its high efficiency and high output and stable operation. However, the magnetron oscillation waveform is low. Although it is a level, a unique noise waveform is superimposed to generate continuity noise.
For this reason, when the MRI apparatus 6 and the microwave surgical apparatus 1 are used in combination, an electromagnetic wave having the same frequency as the proton resonance frequency is generated from the continuous noise superimposed on the magnetron oscillation waveform described above. It was found that a correct MR image could not be obtained because the signal entered in resonance with the receiving device and mixed with the received signal re-emitted from protons to interfere with this.
[0045]
Therefore, when the same electromagnetic wave as the resonance frequency of biological protons (noise component resonating with the MR imaging frequency) appears in the continuity noise of the magnetron, the noise component is guided to the external ground by the noise filter 3 and removed. Then, the MR image is not affected, that is, the high-resolution image and the temperature distribution image of the lesion tissue site irradiated with the microwave from the microwave surgical apparatus 1 can be displayed in real time by the MRI apparatus 6. Turned out to be.
[0046]
In general, in the MRI apparatus 6, when the MR signal is processed in the MRI apparatus body 6 a and the MR image of the subject 7 is displayed on the monitor 6 d, it is between the imaging frequency f of the MRI apparatus 6 and the magnetic field strength T of the static magnetic field. Has the following relationship:
1.0T = 42.56MHz
0.5T = 21.88MHz
0.3T = 12.768MHz
0.2T = 8.512MHz
[0047]
This is because, for example, when the magnetic field strength T of the MRI apparatus 6 is 1.0 T, the continuous noise in the band near 42.56 MHz generated in the microwave oscillator 57 of the microwave surgical apparatus 1 is generated by the microwave surgical electrode 5. This means that the MR image of the MRI apparatus is disturbed.
[0048]
Therefore, in the microwave surgical apparatus 1 according to the present embodiment, the noise filter 3 is provided between the microwave oscillator 57 and the microwave surgical electrode 5 so that the required band that affects the MR image generated by the magnetron is continuous. I try to remove sexual noise.
[0049]
In addition, as described above, in the device disclosed in Patent Document 1, when another treatment device or a biological monitoring device is used in combination, the ground circuit of any of the devices is caused by some cause. If an abnormality occurs, the surgeon or patient may receive an electric shock due to leakage current.
For this reason, in the microwave surgical apparatus 1 according to the present embodiment, in order to prevent an electric shock due to a leakage current to a patient and an operator, an electric circuit made of silicon rubber that cuts off a direct current is not shown in the output circuit of the microwave oscillator 57, although not shown. An insulator is provided. As a result, the microwave oscillator 57 is floated from the ground of the microwave surgical apparatus 1.
[0050]
That is, in a general noise filter including a coaxial filter as described in Patent Document 1, an unnecessary signal is generated from a microwave signal component that has a good ground and is transmitted using an internal conductor having a coaxial structure. While the component is removed, as described above, the microwave surgical apparatus 1 according to the present embodiment connects the outer skin portion of the high-frequency coaxial cable 4, that is, the outer conductor portion to the ground in a direct current manner. I try not to. However, in that case, an unnecessary high-frequency signal transmitted to the external electrode 72 of the microwave surgical electrode 5 through the external conductor of the high-frequency coaxial cable 4 cannot be removed.
[0051]
Therefore, in the present embodiment, the noise filter 3 is configured as follows in order to remove noise components generated in the magnetron and affecting the MR image after being formed to be floating from the ground. .
[0052]
4). Noise filter configuration
4-1 Noise filter structure
Hereinafter, the structure of the noise filter provided in the microwave surgical apparatus of the present embodiment will be described.
In this embodiment, the noise filter 3 that can be externally attached to the surgical apparatus main body 2 will be described as an example. However, the noise filter may be provided inside the surgical apparatus main body 2 as a matter of course. It is also possible to provide the noise filter 3 between the high frequency coaxial cable 4 and the microwave surgical electrode 5.
Since the noise filter 3 described in the present embodiment can be externally attached to the surgical apparatus main body 2, the appearance is covered with a shield case 81 as shown in FIG. 6. The shield case 81 and the connector 82 are insulated by an insulating member such as glass epoxy resin.
[0053]
The noise filter 3 has a circuit configuration in which a connector 82 on the side connected to the output connectors 40 and 41 of the surgical apparatus main body 2 and a connector 83 on the side connected to the connector main body 71 of the microwave surgical electrode 5 are provided. An internal transmission path 84 corresponding to the internal conductor and an external transmission path 85 corresponding to the external conductor are formed respectively.
As shown in the figure, capacitors C1 and C2 are connected to the transmission lines 84 and 85, respectively, as a first bandpass circuit formed so as to be able to pass microwave signals.
Between the internal transmission line 84 between the connector 82 and the capacitor C1 and the shield case 81, a tuning circuit formed by connecting the coil L1 and the capacitor C3 in series is provided as a second band-pass circuit. .
Also, a tuning circuit formed by connecting a coil L2 and a capacitor C4 in series is provided as a second band-pass circuit between the external transmission path 85 between the connector 82 and the capacitor C2 and the shield case 81. ing.
Further, between the external transmission line 85 and the shield case 81, correction capacitors C5 and C6 for correcting the capacity generated due to the mechanism of the noise filter 3 when the noise filter 3 is configured are connected. I have to.
[0054]
Accordingly, if such a noise filter 3 is provided between the surgical device main body 2 and the microwave surgical electrode 5 of the microwave surgical device 1, the noise filter 3 is supplied from the surgical device main body 2 via the connector 82. Among the high-frequency signals, the microwave signal necessary for the operation has a high frequency, so that it can be supplied from the connector 83 to the microwave operation electrode 5 through the capacitors C1 and C2.
[0055]
On the other hand, a high-frequency signal (hereinafter referred to as “noise component signal”) that impairs the MRI image has a low frequency, and therefore cannot pass through the capacitors C1 and C2, and the series circuit of the coil L1-capacitor C3, In addition, the screw terminal 86 of the shield case 81 is led to the ground via the series circuit of the coil L2 and the capacitor C4. Thereby, the ratio of the noise component signal that is equivalent to the MR imaging frequency supplied to the microwave surgical electrode 5 can be significantly reduced.
[0056]
As described above, in the microwave surgical apparatus 1 according to the present embodiment, the noise filter 3 for removing only the noise component resonating with the MR imaging frequency from the continuity noise generated in the magnetron by introducing it to the external ground is provided. Therefore, even when the operation is performed by combining the microwave surgical apparatus 1 and the MRI apparatus 6, it is possible to remove and reduce the obstacles to the MR image of the MRI apparatus 6.
[0057]
4-2 Filter characteristics
An example of the filter characteristics of the noise filter described above is shown in FIGS.
Here, a filter characteristic of a noise filter for enabling the microwave surgical apparatus 1 of the present embodiment to be used simultaneously with the MRI apparatus 6 having a magnetic field strength of 0.5T is taken as an example.
FIG. 8 is a diagram showing filter characteristics in the entire band of the noise filter 3.
The insertion loss characteristic in the entire band (0 to 3000 MHz) of the noise filter 3 of the present embodiment is shown as shown in FIG. Further, the return loss in the entire band of the noise filter 3 is shown as in FIG.
Further, the insertion loss characteristic in the stop band (21.28 MHz ± 100 kHz) of the noise filter 3 is shown as in FIG. 9A, and the return loss is shown as in FIG. 9B.
Further, the insertion loss characteristic in the pass band (2200 MHz to 2500 MHz) of the noise filter 3 is shown as in FIG. 10A, and the return loss is shown as in FIG. 10B.
[0058]
From the characteristic data shown in FIGS. 8 to 10, the noise filter 3 indicates that the frequency component in the vicinity of 21.28 MHz that interferes with the MRI image is attenuated by 50 dB or more in the MRI apparatus 6 having a magnetic field strength of 0.5 T. I understand. It can also be seen that the frequency components of 2300 MHz to 2500 MHz necessary for the microwave surgical apparatus are transmitted with a slight loss of about 0.4 dB.
[0059]
That is, according to the noise filter 3, a noise filter capable of sufficiently attenuating only a frequency component in the vicinity of 21.28 MHz that impairs the MRI image without substantially attenuating the frequency components of 2300 MHz to 2500 MHz necessary for the operation. Can be formed.
[0060]
FIG. 11 is a diagram showing a state of an MR image when the microwave surgical apparatus 1 and the MRI apparatus of the present embodiment are operated simultaneously.
An MR image when the microwave surgical apparatus 1 and the MRI apparatus of the present embodiment are operated simultaneously is shown as in FIG. FIG. 11B shows an MR image obtained when the conventional microwave surgical apparatus and the MRI apparatus are simultaneously operated, that is, an MR image obtained when the microwave surgical apparatus not provided with the noise filter and the MRI apparatus are simultaneously operated. As shown. Therefore, as can be seen by comparing FIGS. 11A and 11B, if the noise filter 3 is provided as in the microwave surgical apparatus 1 of the present embodiment, noise in the MR image can be prevented. Proven.
[0061]
As a result, it is possible to perform microsurgery while displaying a real-time image with higher resolution than the nuclear magnetic resonance imaging apparatus. Therefore, it is possible to confirm the therapeutic effects such as the coagulation change and coagulation range of the living tissue while observing the temperature distribution of the diseased tissue site during microwave irradiation.
[0062]
In the present embodiment, the noise filter 3 when the imaging frequency f of the MRI apparatus 6 is 21.28 MHz, that is, the static magnetic field strength is 0.5 T has been described as an example, but this is only an example. Yes, for example, even when the imaging frequency f of the MRI apparatus 6 is 42.56 MHz, 12.768 MHz, 8.512 MHz, etc., the frequency components of 2300 MHz to 2500 MHz necessary for the surgery are hardly attenuated, and the imaging frequency of the MRI image If the noise filter 3 capable of sufficiently attenuating only the frequency component in the vicinity of f is formed, the noise of the MR image can be prevented even if the microwave surgical apparatus 1 and the MRI apparatus are used simultaneously. Nor.
[0063]
【The invention's effect】
As described above, according to the microwave surgical apparatus of the present invention, the noise filter means is provided between the microwave oscillating means and the surgical electrode, and the continuous wave included in the microwave signal output from the microwave oscillating means. Since only noise components that resonate with the imaging frequency of tomographic images are guided to the external ground and removed from the characteristic noise, a microwave that does not affect the MR image even when a high magnetic field MRI apparatus is used A surgical device can be realized.
As a result, it becomes possible to display a high-resolution image of the lesioned tissue site and an image of the temperature distribution in real time by the MRI apparatus, so that it is possible to easily confirm the therapeutic effect such as the coagulation change and coagulation range of the living tissue. it can.
[0064]
In addition, an electrical insulator that cuts off direct current is provided in the output circuit of the microwave oscillating means, and a tuning circuit is formed by a capacitor and an inductor between the transmission line of the noise filter means and the external ground, and the noise filter means is connected to the direct current. When the microwave operation device and other treatment equipment, or a biological monitoring device are used in combination, the abnormality may occur in the ground circuit of any of these devices for some reason. However, it is possible to configure the surgeon and patient so that they do not receive an electric shock from the leakage current.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a surgical system using a microwave surgical apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing an external configuration of a microwave surgical apparatus according to the present embodiment.
FIG. 3 is a diagram showing an external configuration of a microwave surgical apparatus according to the present embodiment.
FIG. 4 is a block diagram showing an internal configuration of the microwave surgical apparatus according to the present embodiment.
FIG. 5 is a view showing an example of the structure of a microwave surgical electrode.
FIG. 6 is a diagram illustrating an external structure of a noise filter.
FIG. 7 is a diagram illustrating a circuit configuration of a noise filter.
FIG. 8 is a diagram illustrating characteristics of a noise filter.
FIG. 9 is a diagram illustrating characteristics of a noise filter.
FIG. 10 is a diagram illustrating characteristics of a noise filter.
FIG. 11 is a diagram showing a state of an MR image
[Explanation of symbols]
1 Microwave surgical device, 2 Surgical device body, 3 Noise filter, 4 High-frequency coaxial cable, 5 Microwave surgical electrode, 6 MRI device, 7 Patient, 8 Foot cable, 9 Foot switch, 10 Base, 11 Main control panel , 12 Sub-operation panel section, 13 Alarm area, 14 Mode area, 15 Coagulation area, 16 Dissociation area, 17 Memory area, 21 Lamp, 22 Mode change switch, 23 Repeat count display section, 24 25 Microwave output setting switch, 26 27 changeover switch, 28 coagulation confirmation lamp, 29 output indicator, 30 coagulation time indicator, 31 coagulation time unit confirmation lamp, 32 dissociation confirmation lamp, 33 dissociation time indicator, 34 dissociation time setting switch, 35 dissociation current indicator, 36 Dissociation current setting switch, 37 Memory switch, 38 Simultaneous energization switch , 39 switch, 40 41 output connector, 42 foot switch connector, 43 main power switch, 44 handle, 45 volume control knob, 46 fuse holder, 47 vent hole, 48 equipotential terminal, 51 fuse, 52 earth leakage breaker, 53 Setting output stabilization device, 54 output setting device, 55 output control device, 56 high voltage power supply, 57 microwave oscillator, 58 microwave transmission unit, 59 coaxial relay, 61 contact checker, 62 low voltage power supply circuit, 63 output time setting device, 64 Magnetron forced cooling device, 65 audio output device, 66 speaker, 67 earth detection circuit, 69 tissue dissociation device, 71 connector body, 72 external electrode, 73 insulator, 74 center electrode, 75 center conductor, 81 shield case, 82 83 connector 84 Internal transmission line, 85 External transmission line 86 screw terminals

Claims (3)

A microwave surgical apparatus that can be used in a state where a tomographic image is being captured by a nuclear magnetic resonance imaging apparatus,
A microwave oscillating means configured by a magnetron and provided with an electrical insulator that cuts off direct current in an output circuit that oscillates and outputs a microwave signal having a frequency of 2300 MHz to 2500 MHz;
A surgical electrode configured to be able to irradiate a lesion tissue site with the microwave signal;
Only a noise component that is provided between the microwave oscillating means and the surgical electrode and resonates with the imaging frequency of the tomographic image from continuity noise included in the microwave signal output from the microwave oscillating means. Noise filter means for removing by guiding to an external ground;
Equipped with a,
The noise filter means includes
A first capacitor is inserted into the pair of transmission lines for transmitting the microwave signal from the microwave oscillating means to the surgical electrode, and is formed by a capacitor so as to pass the microwave signal having a frequency of 2300 MHz to 2500 MHz. A bandpass circuit of
A capacitor and an inductor are connected in series so that only a noise component having a frequency that resonates with the imaging frequency of the tomographic image among the continuity noise generated by the magnetron is inserted between the transmission line and the external ground. microwave surgical device according to claim Rukoto a and a second band pass circuit formed by the tuning circuit formed by connecting the correction capacitor. The noise filter means includes
By removing a noise component that affects the tomographic image taken by the nuclear magnetic resonance imaging apparatus, the nuclear magnetic resonance imaging apparatus can display the temperature distribution of the lesion tissue site in real time. The microwave surgical apparatus according to claim 1.   The microwave surgical apparatus according to claim 1, wherein the noise component removed by the noise filter means is determined by a magnetic field intensity of the nuclear magnetic resonance imaging apparatus.

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