JP3754113B2 - Ultrasonic therapy device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic therapy apparatus for focusing an ultrasonic wave and treating an affected part with its impact force or heating.
[0002]
[Prior art]
In recent years, improvement of quality of life (Quality Of Life: QOL) regarding patients after surgery has been desired. Under such circumstances, minimally invasive treatment (MIT) is attracting attention in the medical field.
[0003]
An example of MIT is the practical application of a stone crushing device that irradiates powerful stones from outside the body to crush only stones in a non-invasive manner, which has greatly changed the treatment of urinary stones. The source of intense ultrasonic waves used in this stone crushing device includes the underwater discharge method, electromagnetic induction method, micro-explosion method, piezo method, etc. The piezo method has the disadvantage that the pressure of the strong ultrasonic wave is small. However, there are excellent advantages such as small focus, no consumables, easy output control, and phase control of drive voltages applied to a plurality of piezo elements, so that the focal position can be arbitrarily controlled (Japanese Patent Laid-Open No. 60-145131). No. 4,526,168).
[0004]
In the field of cancer treatment, MIT is one keyword. Currently, many cancer treatments rely on surgical procedures. Therefore, there are many cases where the function and appearance of the organ to be treated are greatly impaired after the operation, and even if the life is prolonged, a heavy burden remains for the patient. Development of therapeutic devices is highly desired.
[0005]
In this trend, hyperthermia therapy has been attracting attention as one of the treatment techniques for malignant neoplasms, so-called cancer. This is a treatment method in which only the cancer cells are selectively killed by heating the affected area to 42.5 ° C. or higher using the difference in heat sensitivity between the tumor tissue and the normal tissue and maintaining it for a certain period of time. It is. As a heating method, a method using an electromagnetic wave such as a microwave precedes, but in this method, it is difficult to selectively warm a deep tumor due to the electrical characteristics of a living body, and the depth is 5 cm. A good therapeutic effect cannot be expected for these tumors. In view of this, for treatment of deep tumors, a method using ultrasonic energy that has good convergence and can reach a relatively deep part has been considered (Japanese Patent Laid-Open No. 61-13955).
[0006]
Further, there is a treatment method in which the above-mentioned heating treatment method is further advanced, the ultrasonic wave generated from the piezo element is sharply focused on the affected part, the tumor part is heated to 80 ° C. or more, and the tumor tissue is instantaneously heat-denatured necrotic. (G. Vallancien et.al .: Progress in Uro. 1991, 1,84-88 [EDAP paper], US Pat. No. 5,150,711).
[0007]
[Problems to be solved by the invention]
(1) In an ultrasonic therapy apparatus in which an ultrasonic probe for ultrasonic positioning is incorporated in an applicator, an extremely high-energy therapeutic ultrasonic wave is reflected from a living body surface or a strong reflector in the body such as a bone. Therefore, there is a possibility that the reflected wave of the therapeutic ultrasonic wave may destroy the image ultrasonic probe. In particular, in the case of treatment in which the temperature of the affected area is increased by continuous high-intensity ultrasound, the acoustic lens formed on the surface of the ultrasound probe absorbs the reflected ultrasound and is thermally destroyed. There was a thing.
[0008]
A first object of the present invention is to provide an ultrasonic therapy apparatus capable of preventing an image ultrasonic probe from being damaged by a reflected wave of therapeutic ultrasonic waves.
[0009]
(2) In the case of ultrasonic positioning, a hole for passing an ultrasonic probe has to be made in the center of an applicator that irradiates therapeutic ultrasonic waves, which reduces the area of the ultrasonic transducer and reduces the output. There was a problem of doing. On the other hand, in order to output the same output, there is a problem that the size of the treatment head becomes large.
[0010]
Further, the treatment applicator is large, and for example, when an MRI image is used for positioning or confirmation of treatment progress, it cannot be installed inside the gantry. The second object of the present invention is to provide a small and high output ultrasonic therapy apparatus.
[0011]
(3) Although the piezo element used for calculus crushing is driven with a high voltage of several kV, since the driving time for one time is several μs, there is no fear of heat generation. However, in the ultrasonic thermotherapy apparatus, the piezo element is continuously driven for a relatively long time, and the piezo element itself generates heat due to hysteresis loss, dielectric loss (tan δ), and mechanical loss (1 / Q). This heat generation deteriorates the backing material and the like, and eventually causes the apparatus to malfunction. In addition, since the conversion efficiency of the electrical signal / mechanical vibration of the piezo element has temperature dependence, energy loss occurs as the temperature rises, and the therapeutic effect decreases.
[0012]
A third object of the present invention is to provide an ultrasonic therapy apparatus capable of appropriately suppressing heat generation of a piezo element.
[0013]
(4) In the heat treatment method, unlike the conventional hyperthermia, very strong intensity in a limited area near the focal point, several hundred to several thousand W / cm ² The ultrasonic wave is input. For this reason, cavitation (bubbles) occurs, and a unique phenomenon occurs in which the affected part due to heat changes qualitatively. Due to this unique phenomenon, the acoustic characteristics are changed, and there is a concern that the therapeutic effect is reduced and the treatment time is prolonged.
[0014]
Since air is a strong reflector for ultrasonic waves, it is difficult for ultrasonic waves to reach deeper than the area where cavitation occurs.
[0015]
Further, in the region where cavitation occurs, the attenuation is apparently increased due to the scattering of ultrasonic waves, and heat generation is likely to occur. If irradiation with high-intensity ultrasonic waves was continued with cavitation occurring, an unexpected site fevered, which could cause side effects.
[0016]
Further, as described in Japanese Patent Application Laid-Open No. 60-145131 and US Pat. No. 4,658,828, intense ultrasonic waves are intermittently irradiated with the time required for the natural cavitation to decay as an interval. Is considered. However, this method has a problem that the treatment time is prolonged.
[0017]
Furthermore, it is considered to perform treatment while monitoring the progress and temperature of treatment by MRI. However, the magnetic susceptibility changes due to cavitation, and an error may occur.
[0018]
A fourth object of the present invention is to provide an ultrasonic therapy apparatus capable of forcibly collapsing cavitation.
[0019]
(5) When performing non-incision treatment such as puncture and catheterization using MRI as a monitoring device, the position of the puncture needle and catheter is recognized as a blackened portion on the image because they are non-signaled. Can do. However, if there is a non-signal portion such as an empty chamber such as the intestine or a bone near the puncture needle or catheter, the black-out portion of the puncture needle or catheter is buried and becomes indistinguishable. Further, it is conceivable to mark the tip of the puncture needle or catheter with a substance having a characteristic relaxation time, such as free water, but it is buried in an image of urine or the like and cannot be identified.
[0020]
Furthermore, in the case of treating with laser irradiation in a body cavity using flexible means such as an optical fiber, it is necessary not only to confirm the position of the tip but also to understand which direction the tip is facing. However, it was difficult only to see the MRI image.
[0021]
A fifth object of the present invention is to provide an insertion type treatment device such as a puncture needle, a catheter, and a laser optical fiber, the position and orientation of which can be confirmed on an MRI image.
[0022]
[Means for Solving the Problems]
(1) An ultrasonic therapy apparatus according to the present invention includes a therapeutic ultrasonic transducer that irradiates a therapeutic target in a subject with a therapeutic ultrasonic wave, and an ultrasonic image for obtaining an image in the subject. Based on an ultrasound probe for image scanning inside the subject, a receiving means for receiving a reflected wave of the therapeutic ultrasound wave via the ultrasound probe for image, and a reception signal by the receiving means Control means for controlling the intensity of the therapeutic ultrasound.
[0023]
The ultrasonic intensity for destroying the image ultrasonic probe or causing irreversible degradation to the ultrasonic probe is known in advance. Therefore, when the therapeutic ultrasonic wave is emitted by the ultrasonic probe while the therapeutic ultrasonic wave is emitted according to the first aspect of the invention, the intensity of the ultrasonic wave is increased as long as the ultrasonic ultrasonic probe receives the therapeutic ultrasonic wave. Since it is possible to measure whether the light is incident on the child, it is possible to detect a dangerous ultrasonic level and stop the therapeutic ultrasonic wave or reduce the intensity. For this reason, treatment can be performed without damaging the therapeutic ultrasound probe. In addition, this situation is often due to the positional relationship between the applicator and the living body, for example, the therapeutic ultrasound is reflected on the surface of the living body, and the position of the mirror image of the focal point coincides with the surface of the ultrasonic probe. In addition to simply controlling the intensity of the therapeutic ultrasound, it is also possible to issue an alarm prompting the operator to change the setting.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment of the first invention)
FIG. 1 shows the configuration of an ultrasonic therapy apparatus according to the first embodiment of the first invention. In an applicator (also referred to as a treatment head) 101, a concave treatment ultrasonic transducer 102 that emits a powerful treatment ultrasonic wave and an image ultrasonic probe 103 are provided in the center. Yes. The front surface of the applicator 101 is covered with an elastic film 105, and the inside is filled with a content liquid 104 for propagating ultrasonic waves into the patient. The therapeutic ultrasonic transducer 102 is driven by a drive circuit 107 based on a control signal from the control circuit 106, and irradiates a powerful ultrasonic wave toward a focal point 108 in the patient body. Here, in order to align the focus 108 and the position of the treatment target, an ultrasonic image obtained by the image ultrasonic probe 103 is used. This ultrasonic image is obtained by reconstructing an ultrasonic signal transmitted / received by the image ultrasonic probe 103 by the ultrasonic imaging apparatus 109 and displaying it on the CRT display 110.
[0041]
In this embodiment, the transmission / reception signal of the imaging ultrasonic probe 3 is guided to the detection circuit 111, and the intensity of the strong ultrasonic wave 112 reflected on the body surface of the patient and incident on the ultrasonic probe 103 is increased. Measuring. This measured value is sent to the control circuit 106, and if the measured value is equal to or greater than a predetermined value, the ultrasonic probe 103 is expected to be destroyed, so that the control circuit 106 reduces the power of the drive circuit 107, Alternatively, the drive is stopped. Further, an alarm is issued from the speaker 113 to change the relative position of the therapeutic ultrasonic transducer 102 and the image ultrasonic probe 103 to the operator. This alarm may be provided by visual means such as an indicator (not shown) attached to the control circuit 106.
[0042]
Next, the operation of the detection circuit 111 will be described in detail. The detection circuit 111 detects a transmission / reception signal of the image ultrasonic probe 103. This signal includes a drive waveform having a very high voltage and a weak reflected ultrasonic signal for an image, and further in the middle in terms of intensity. A therapeutic ultrasound reflected signal is included. The detection circuit 111 must separate only the reflected signal of the therapeutic ultrasound from the transmitted / received signal. For this purpose, a band pass filter (not shown) is incorporated in the first input stage of the detection circuit 111. This operation will be described with reference to FIG. Since the spectrum of the received signal is a continuous wave or a long burst wave with a center frequency of f1, a therapeutic ultrasound peak with a narrow band and a broad imaging ultrasound peak with a center frequency of f2 higher than f1 are obtained. . Specifically, f1 uses 1 to 2 MHz and f2 uses about 3 to 5 MHz. Therefore, it is possible to detect only the reflected signal intensity of the therapeutic ultrasonic wave by using a bandpass filter having a pass band with little image ultrasonic component mixed around f1. The intensity detection after passing through the bandpass filter can be performed by a known means such as peak value detection or energy detection.
[0043]
Next, a detection method that does not use a bandpass filter will be described. In this detection circuit 111, the drive timing of the image ultrasonic wave is captured from the ultrasonic image device 109 by the signal line indicated by the broken line 114 in FIG. Only the time width of the drive waveform 120 having a large amplitude can be erased from the RF signal shown in FIG. 3 taken into the detection circuit 111 by this timing signal. This is a method of applying a time window to the signal, and is a method known to those skilled in the art. By this operation, only the signal from which the pulse-like drive waveform for images is removed is obtained, so that subsequent intensity detection can be performed by a known means such as peak value detection or energy detection.
[0044]
(Second embodiment of the first invention)
FIG. 4 shows the configuration of an ultrasonic therapy apparatus according to the second embodiment of the first invention. In the present embodiment, a shutter 122 and a shutter control unit 123 are incorporated in the applicator 121. The elastic film and the content liquid are omitted because they are the same as in FIG. Here, when the operator presses the switch 124 for irradiating a strong ultrasonic wave, the control circuit 106 sends a signal for starting driving to the driving circuit 107, or at the same time, sends a signal to the shutter control unit 123 a little earlier. Then, the shutter 122 is operated and closed.
[0045]
FIG. 5 shows a view of the inside of the applicator 121 at this time as seen from the focal side. The shutter 122 is closed like a diaphragm of a camera and covers the front surface of the image ultrasonic probe 103. The shutter 122 is made of a material that does not easily transmit ultrasonic waves, and the ultrasonic wave is hardly incident on the image ultrasonic probe 103 and is protected while the therapeutic ultrasonic waves are being emitted.
[0046]
(Third embodiment of the first invention)
FIG. 6 shows a third embodiment according to the first invention. In the present embodiment, the portions of the shutter 122 and the shutter control means 122 in the embodiment of FIG. 4 are different. For this reason, drawings are omitted for portions that are not changed. The ultrasonic probe insertion hole at the center of the therapeutic ultrasonic transducer 102 is sealed with an elastic film 131. Since the space between the imaging ultrasound probe 103 and the therapeutic ultrasound transducer 102 is also sealed with the bellows 132, the tip of the imaging ultrasound probe 103 is inside the cavity 133 that does not contain the content liquid. Is located. Further, the image ultrasonic probe 103 is fixed to a moving mechanism 134, and the moving mechanism 134 moves the ultrasonic probe 103 back and forth by a signal from the control circuit 106. At this time, the position of the image ultrasonic probe 103 is measured by the moving mechanism 134 and fed back to the control circuit 106.
[0047]
Next, the operation of the present embodiment will be described. First, when an ultrasonic image is drawn, the moving mechanism 134 lowers the image ultrasonic probe 103 in accordance with an instruction from the control circuit 106 and fixes the tip so that the tip is completely in close contact with the elastic film 131. Accordingly, since the image ultrasonic wave does not have an air layer, it can be incident on the content liquid in the applicator, and conversely, a reflected wave can be received. However, when the operator gives an instruction to start treatment, a signal is sent from the control circuit 106 to the moving mechanism 134 to raise the ultrasound probe 103 for image. As a result, the tip of the ultrasonic probe 103 is away from the elastic film 131 and is in the air while the therapeutic powerful ultrasonic wave is being irradiated. Since air is a very strong ultrasonic reflector, therapeutic ultrasonic waves cannot pass through and the tip of the ultrasonic probe 3 is not damaged.
[0048]
The first invention can be variously modified as follows. For example, in the embodiment shown in FIG. 6, a protective air layer is provided at the tip by the vertical movement of the imaging ultrasonic probe 103, but by using means for injecting or discharging the internal solution into the cavity 133. The same effect can be obtained while keeping the distance between the tip of the ultrasonic probe 103 and the elastic film 131 constant. Alternatively, a means for reducing the pressure inside the cavity 133 is provided, and when the image is drawn, the cavity 133 is evacuated and the elastic film 131 is attracted to the surface of the ultrasonic probe 103. When therapeutic ultrasonic waves are irradiated, the atmospheric pressure is reversed. It is also possible to obtain the same effect as that of the above-described embodiment by opening the door.
[0049]
In the above embodiment, the concave ultrasonic fixed focus type is used as the therapeutic ultrasonic transducer. However, a phased array may be used as a matter of course. At this time, as described in the first embodiment, not only the drive power control but also the change of the focal position by the phase control is said to reduce the incident output of the therapeutic ultrasonic wave to the ultrasonic probe. The goal can be achieved.
[0050]
As described above, according to the first aspect of the present invention, even when a treatment is performed by irradiating a very strong ultrasonic wave, the image ultrasonic probe can be used without deteriorating.
[0051]
(First embodiment of the second invention)
FIG. 7 shows the configuration of the ultrasonic therapy apparatus according to the first embodiment of the second invention. In the present embodiment, an applicator 201 is attached to a stage 202 that can move in two directions of X and Y, and the whole is installed in a case 204 filled with an ultrasonic wave propagation solution 203.
[0052]
FIG. 9 shows details of the applicator 201. (A) is sectional drawing of the applicator 201. FIG. An image ultrasonic probe 222 made of a polymer piezoelectric film is adhered to the surface of a flat plate ultrasonic transducer 221. Here, as an electrode structure, an electrode 231 that is used in common on the bonding surface of both is formed on the entire surface, and is electrically used as a ground. FIG. 9B shows the electrode 232 viewed from below. The electrode 232 includes a plurality of concentric electrode groups, here, eight electrode groups, and forms an annular array. Usually, the area of each electrode 232 is constant. With this structure, it is possible to form the focus of the therapeutic ultrasound by adjusting the phase of the drive waveform to each electrode, and the focus position can be controlled in the depth direction by further changing the phase. is there.
[0053]
FIG. 9C shows a state where the electrode 233 is viewed from the focal side. In this way, the electrode 233 is configured in a two-dimensional array, for example, a total of 336 elements including 7 elements in the slice direction and 48 elements in the array direction. An ultrasonic tomographic image in the array direction can be obtained by transmitting and receiving these two-dimensional arrays at independent timings. By adopting such a flat plate structure, the applicator 201 can be manufactured very thinly, and therefore the entire case 204 can be configured to be thin.
[0054]
Although the applicator 201 is a flat plate here, it may be a concave surface. Although the therapeutic ultrasonic transducer 221 is configured as an annular array, the two-dimensional array as shown in FIG. 10A can control the focal position in the lateral direction. Coarse / fine adjustment is also possible. Also. The imaging ultrasonic probe 222 can scan not only a single slice plane but also a plurality of slice planes by using a completely isotropic two-dimensional array as shown in FIG. It becomes. Further, the image ultrasonic probe 222 may be a composite material of ceramics and polymer in addition to the polymer piezoelectric film.
[0055]
In addition, as shown in FIG. 10C, by providing two layers of the piezoelectric polymer film, it is possible to configure a coaxial biplane type ultrasonic probe for an image. In FIG. 10C, the array electrode 235 and the array electrode 236 are provided on both surfaces of the polymer piezoelectric film 224 so as to be orthogonal to each other. Further, a common electrode 234 is provided between the array electrode 235 and the therapeutic ultrasonic transducer 221.
[0056]
Here, the thicknesses of the polymer piezoelectric films 223 and 224 are made substantially the same, and the combined thickness is made almost ¼ of the wavelength determined by the therapeutic ultrasonic frequency. Then, a tomographic image parallel to the yz plane is obtained by short-circuiting the array electrode 235 and applying a drive pulse between the array electrode 235 and the short-circuited array electrode 235. Further, by applying a drive pulse between the array electrode 235 and the common electrode 234, a tomographic image parallel to the xz plane can be obtained. Note that the center frequency of these tomographic images is approximately 6 MHz when the therapeutic frequency is 2 MHz.
[0057]
FIG. 11 shows the structure of the applicator. The applicator 201, the stage 202, and the propagation solution 203 are as described above, and are covered with an elastic film 205 so that the front surface of the applicator 201 is watertight. Further, a support 206 is provided in the case 204 between the applicator 201 and the elastic film 205. The support 206 is, for example, a resin net, which can withstand the patient's pressure from above and does not directly touch the applicator 201 or the stage 202 on which the patient moves. However, since the support 206 is knitted with a very thin thread, it hardly interferes with the transmission of therapeutic ultrasonic waves and image ultrasonic waves irradiated from below. As a result, the entire applicator can be made very thin.
[0058]
FIG. 12 shows a state where the treatment apparatus of the present embodiment is incorporated in an MRI (magnetic resonance imaging) system. A normal MRI system is composed of a magnet 207, a top board 208 for inserting a patient into the magnet 207, a moving mechanism 209 for moving the top board 208, and a control device (not shown) for the entire system. ing. In the present embodiment, an applicator 261 composed of an applicator and a case is attached to the center of the top plate 208, and a cushion 210 that is adjusted to reduce the level difference is attached to the front and rear. When starting the treatment, the robot rides on the upper part of the applicator 261 and the cushion 210 and roughly adjusts so that the skin of the affected part exactly matches the position of the applicator 261, and then is fed into the magnet 207 to start the treatment.
[0059]
In FIG. 13, the block diagram of the treatment apparatus of this Embodiment is shown. The applicator 261 drives the internal applicator 201 to transmit power to the drive circuit 271 for irradiating therapeutic ultrasonic waves, the ultrasonic image device 272 for constructing an ultrasonic tomogram, and the stage 202 to position the applicator. The moving means 173 for changing and the propagation solution processing circuit 274 for controlling the amount, the degree of degassing and the temperature of the propagation solution 203 are coupled. These units are controlled by a control circuit 275. In addition, the control circuit 275 collects CRT 276 and MRI images for displaying image data and messages, and is also coupled to the MRI system 277 for controlling the position of the top board 208.
[0060]
Here, the means for transmitting the power from the moving means 273 to the stage 202 is not affected even within the MRI magnet and does not adversely affect the MRI image. Etc. are used. When this torque cable becomes long, backlash due to twisting occurs, so that sufficient position accuracy may not be obtained even if open loop control is performed on the moving means 273 side. In order to prevent this, if an optical encoder using a light source and a rotating slit is installed in the stage 202 of the applicator 261 and information is transmitted via an optical fiber, position control can be performed in a closed loop.
[0061]
(Second Embodiment of the Second Invention)
FIG. 14 shows an applicator structure according to a second embodiment of the second invention. The basic structure is the same as in FIG. 11 except that the applicator 201 is not a phased array but a concave fixed focus structure. For this reason, in order to change the depth of focus in the patient body, it is necessary to add a mechanism so that the applicator 201 can be moved up and down and to thicken the case 204. In contrast, in this embodiment, the amount of the propagation solution 203 inside the case 204 is controlled by the action of the propagation solution processing circuit 274, and the position is adjusted by changing the distance from the patient.
[0062]
As described above, according to the second aspect of the present invention, it is possible to provide an ultrasonic therapy apparatus that is very small and has a high output and that can obtain a good ultrasonic image. It is also possible to provide an applicator that can be used in situations such as in a very narrow MRI gantry.
[0063]
(First embodiment of the third invention)
FIG. 15 shows the configuration of the first embodiment according to the third invention. First, the ultrasonic treatment unit will be described. As shown in FIG. 15, the applicator 301 includes an ultrasonic transducer 302 that irradiates a powerful therapeutic ultrasonic wave, a coupling liquid 304 that guides the strong ultrasonic wave to the patient 303, and a water bag 305 that seals the coupling liquid 304. And a backing material 306 for storing them.
[0064]
As shown in FIG. 16, the applicator 301 has a shape obtained by dividing a circular flat plate ultrasonic transducer 302 into a radial direction and a circumferential direction. When treating, the applicator 301 is placed on the surface of the patient 303, and the water bag 305 is brought into contact with the skin of the patient 303 via an ultrasonic jelly 306 or the like. After the focal point 307 coincides with the tumor 308, the ultrasonic vibrator 302 is driven by the drive circuit group 309 to irradiate the powerful ultrasonic wave, and the treatment site coincident with the focal point 307 is heated to a high temperature to be treated.
[0065]
In this embodiment, a phased array is used as a powerful ultrasonic wave generation source. Therefore, by controlling the drive timing of the drive circuit group 309 by the phase control circuit group 310, it is possible to operate the focal position, the sound field, and the heating / heating region without moving the applicator 301. The drive circuit group 309 is divided into the number of channels of the divided ultrasonic transducers 302, and is driven by an independent timing signal delayed by the phase control circuit group 310 by a signal from the main control circuit 311. As a result, the ultrasonic focal points 307 and 307 'can be set at arbitrary positions in three dimensions. The operation of moving the focal position by this delay time control is described in detail in “USP-4526168”.
[0066]
Next, detection of heat generation of the ultrasonic transducer 302 and drive control of the ultrasonic transducer 302 will be described. In the present embodiment, a shape memory alloy member 313, for example, a shape memory alloy member having a transformation start temperature of high temperature (85 ° C.) such as Ti—Ni—Cu, which is a marmen alloy, is used, and its deformation is used to make a vibrator. The switch of the temperature control circuit 312 is turned on / off to control the vibrator temperature. Then, as shown in FIG. 17, a non-metallic pipe 316 is brought close to or in close contact with the ultrasonic transducer 302, and a cooling substance such as water is circulated therein using a cooling device 317.
[0067]
First, the shape memory alloy member 313 has a thin strip shape with a certain degree of strength, and the lower end has a heat-resistant property so that the metal temperature-sensitive portion does not directly contact the electrode surface of the ultrasonic transducer 302. It is mounted on the electrode surface through a polyimide resin thin film 314. The polyimide resin thin film 314 is extremely thin so as not to generate heat due to sound absorption by itself. The upper end of the shape memory alloy member 313 is connected to the vibrator temperature control circuit 312 as shown in FIG. 15, but at room temperature, it extends as shown in the state (a) in FIG. 15 and is heated to the transformation temperature. Then, as shown in the state (b), it is deformed into a “<” shape and touches the switch 315 provided in the vibrator temperature control circuit 312 to transmit abnormal heating. Here, the Curie point of the ultrasonic vibrator 302 is set to 300 ° C., the heat resistant temperature of the backing material 306 is set to 250 ° C., and the heat resistant temperature of an adhesive (not shown) for bonding the vibrator and the backing material is set to 250 ° C. Assume that the temperature was set at 200 ° C.
[0068]
First, assuming that heat of about 200 ° C. is generated in the ultrasonic vibrator 302 by continuous driving at a high voltage, this temperature is sensed by the shape memory alloy member 313. Here, considering the time difference in heat conduction from the ultrasonic transducer 302 to the shape memory alloy member 313, the transformation temperature of the shape memory alloy member 313 is selected to be lower than 200 ° C. The shape memory alloy member 313 is deformed by the heat generated by the ultrasonic transducer 302, and the heat generation information is sent to the transducer temperature control circuit 312. Next, the vibrator temperature control circuit 312 sends a signal to the main control circuit 311, and the main control circuit 311 stops driving by the drive circuit group 309. At this time, the vibrator temperature control device 312 controls the cooling device 317 to circulate the cooling substance through the non-metallic pipe 316 to lower the temperature of the ultrasonic vibrator 303. The cooling water may be circulated at any time or only when necessary. When the shape memory alloy member 313 expands again due to the temperature drop of the ultrasonic transducer 303 and returns to the state (a), a signal is sent to the drive circuit group 309 and the drive of the ultrasonic transducer 302 is resumed.
[0069]
Here, although a phased array is used for the ultrasonic transducer 302, this may be an annular array, or the applicator may be moved mechanically to move the focal point.
[0070]
Further, a thermocouple, a thermistor, or a radiation thermometer connected to the vibrator temperature control circuit 312 may be used for measuring the vibrator temperature.
[0071]
Further, as shown in FIG. 18, the ultrasonic vibration 302 has electrical properties in which impedance, capacitance, inductance, dielectric constant, and the like change depending on the temperature. Therefore, the temperature is monitored by measuring these changes. May be. An embodiment using this method will be described below.
[0072]
(Second embodiment according to the third invention)
FIG. 19 is a diagram showing the configuration of the second embodiment according to the third aspect of the invention. The electrical characteristic measurement circuit 318 always measures the electrical properties of the ultrasonic transducer 302, and the values are mainly measured in real time. This is sent to the control circuit 311. The main control circuit 311 calculates the energy for the loss caused by the change in the electrical characteristics of the ultrasonic transducer 302, and compensates the energy for the loss by controlling the drive circuit group 309 based on this data. Further, the reflection from the matching circuit 319 can be monitored by the electrical characteristic measuring device 318, and this reflection can be supplemented from the drive circuit group 309 by the control of the main control circuit 311.
[0073]
Also in these cases, when the main control circuit 311 determines that the electrical characteristics of the ultrasonic transducer 302 or the reflection change rate of the matching circuit 319 is large and cannot be controlled, the main control circuit 311. Controls the drive circuit group 309, stops the driving of the ultrasonic transducer 302, and simultaneously controls the cooling device 317 to cool the ultrasonic transducer 302. In the meantime, the electrical characteristic measurement circuit 318 is measuring the electrical characteristics of the ultrasonic transducer 302 or the reflection of the matching circuit 319. Based on this data, the main control circuit 311 determines whether the ultrasonic transducer 302 has been cooled. Judging. When the value of the data from the electrical characteristic measurement circuit 318 becomes a normal value and it is determined that the cooling of the ultrasonic transducer 302 has been completed, the main control circuit 311 controls the drive circuit group 309 to control the ultrasonic transducer 302. Resume driving. The resumption of driving may be automatically performed by the main control circuit 311 or may be manually performed by an operator with a signal from the main control circuit 311.
[0074]
(Third embodiment of the third invention)
Next, a third embodiment according to the third invention will be described with reference to FIG. In FIG. 20, the ultrasonic treatment unit is the same as in the previous embodiment. First, detection of heat generation of the ultrasonic transducer 302 and temperature control of the transducer 302 will be described. In this embodiment mode, a case where a thermocouple 320 and a cooling device 317 using liquid nitrogen are used will be described.
[0075]
First, the thermocouple 320 is attached to the electrode surface via a heat-resistant silicone-based coating material 321 so that the metal temperature measuring unit does not directly contact the electrode surface of the ultrasonic transducer 302. The silicone-based coating material 321 is applied very thinly so as not to generate heat due to sound absorption by itself. The thermocouple 324 is connected to the vibrator temperature control circuit 312, and the vibrator temperature control circuit 312 always measures the vibrator temperature. Here, the Curie point of the ultrasonic vibrator 302 is 300 ° C., the heat resistance temperature of the backing material 306 is −200 ° C. to 250 ° C., and the heat resistance of an adhesive (not shown) that bonds the ultrasonic vibrator 302 and the backing material 306. Assume that the temperature is set to -100 ° C to 250 ° C and the permitted temperature is set to -50 ° C to 200 ° C.
[0076]
First, assuming that 200 ° C. heat is generated in the ultrasonic vibrator 302 by continuous driving at a high voltage, this temperature is measured by the thermocouple 324 and sent to the vibrator temperature control circuit 312. Here, the vibrator temperature control circuit 312 calculates the temperature gradient of the rising temperature, and when it is determined that the vibrator temperature can be controlled based on the calculated temperature gradient data, the vibrator temperature control circuit 312 By controlling 317, a gas (air, nitrogen, etc.) 322 sufficiently cooled with liquid nitrogen is blown onto the ultrasonic vibrator 302 to lower the temperature. At this time, the vibrator temperature control circuit 312 monitors the temperature so that the temperature does not fall below −50 ° C. In addition, since the rapid temperature change causes damage due to the thermal stress of the vibrator, the vibrator temperature control circuit 312 also monitors the temperature gradient during cooling, and the amount of ejection and ejection of the cooled gas 322 to prevent rapid cooling. Control speed and interval. Further, it is desirable that the atmosphere around the vibrator is sufficiently dry so that condensation does not occur around the vibrator due to a decrease in temperature.
[0077]
On the other hand, when it is determined that control is impossible due to a rapid temperature rise, the vibrator temperature control circuit 312 sends a signal to the main control circuit 311, and the main control circuit 311 stops driving by the drive circuit group 309. At this time, the transducer temperature control device 312 reduces the transducer temperature with the cooled gas 322, and sends a signal to the drive circuit group 309 when the temperature seems to be appropriate, and resumes driving of the ultrasonic transducer 302. .
[0078]
Here, the ultrasonic transducer 302 may be cooled only by the coupling liquid 304 without using the cooling device 317. An embodiment in this case will be described below.
[0079]
(Fourth embodiment of the third invention)
FIG. 21 is a diagram showing a fourth embodiment according to the third invention. When a temperature of 200 ° C. is measured by a thermocouple 324 and this information is sent to the main control circuit 311, the main control circuit 311 is shown. Activates the coupling fluid circulation circuit 340. In the present embodiment, the applicator 301 includes a water inlet 341 and a drain outlet 342. There is a coupling liquid cooling device (not shown) in the coupling liquid circulation circuit 340, and the coupling liquid cooled here circulates through the water inlet 341 and the drain outlet 342 and generates heat. The ultrasonic transducer 302 is cooled.
[0080]
(Fifth embodiment of the third invention)
FIG. 22 shows the configuration of the fifth embodiment according to the third invention. The ultrasonic treatment unit is the same as that of the first embodiment, but here, it will be described as a type of treatment apparatus that uses imaging within a patient body using MRI.
[0081]
First, the positioning and MRI image imaging unit will be described. The patient 303 is set on the treatment table 323, and is controlled by the main control circuit 311 in an imaging gantry (not shown) in which the RF coil 324, the static magnetic field coil 325, and the gradient magnetic field coil 326 are incorporated. It is fed by the table moving device 327.
[0082]
Next, the main control circuit 311 activates the gradient magnetic field power source 328 and the transmission / reception circuit 329 according to a predetermined sequence (for example, T2-weighted imaging method) instructed from the console 330, and the three-dimensional image information in the body of the patient 303 is not illustrated. Store in memory.
[0083]
Here, it is possible to make a treatment plan in advance based on the MRI image in the body of the patient 303. The method of displaying the MRI image on the CRT and the method of treatment planning are described in “Japanese Patent Laid-Open No. 5-300910”.
[0084]
When the MRI image is obtained, the main control circuit 311 controls a mechanical arm (not shown), and the applicator 301 is attached to the patient 303. At this time, the position of the focus 307 of the powerful ultrasound for treatment in the body is a signal from an applicator position detection device (not shown) composed of a potentiometer (not shown) or the like attached to various parts of the mechanical arm. Then, the main control circuit 311 calculates from the information of the mounting positions of the MRI apparatus and the mechanical arm measured in advance and stores them. The focal position 307 is superimposed and displayed on the MRI image on the CRT display 331. Further, on the MRI image of the CRT display 331, not only the focal point 307 but also an ultrasonic incident path 332 can be displayed together.
[0085]
The coincidence state between the position of the focal point 307 stored in the main control circuit 311 and the position of the tumor 308 to be treated is checked. The main control circuit 311 instructs the drive circuit group 309 to start ultrasonic irradiation, and the treatment starts. Is done.
[0086]
Next, detection of heat generation of the ultrasonic ultrasonic transducer 302, control of the transducer driving state, and control of the transducer temperature will be described with reference to FIG. In this embodiment, a description will be given using a cooling device 317 using a radiation thermometer 333 and a cooling solid 334.
[0087]
First, the radiation thermometer 333 is connected to the vibrator temperature control circuit 312, and the vibrator temperature control circuit 312 always measures the vibrator temperature. Here, the Curie point of the ultrasonic vibrator 302 is 300 ° C., the heat resistance temperature of the backing material 306 is −200 ° C. to 250 ° C., and the heat resistance of an adhesive (not shown) that bonds the ultrasonic vibrator 302 and the backing material 306. Assume that the temperature is set to -100 ° C to 250 ° C and the permitted temperature is set to -50 ° C to 200 ° C.
[0088]
First, assuming that 200 ° C. heat is generated in the ultrasonic vibrator 302 by continuous driving at a high voltage, this temperature is measured by the radiation thermometer 333 and sent to the vibrator temperature control circuit 312. Here, the vibrator temperature control circuit 312 calculates the temperature gradient of the rising temperature, and when it is determined that the vibrator temperature can be controlled based on the calculated temperature gradient data, the vibrator temperature control circuit 312 performs the cooling device 317. The solid (for example, a metal whose surface is coated with a thin film of an insulator) 334 is pressed against the ultrasonic vibrator 302 and the temperature is lowered. On the other hand, when it is determined that control is impossible due to a rapid temperature rise, the vibrator temperature control circuit 312 sends a signal to the main control circuit 311, and the main control circuit 311 stops driving by the drive circuit group 309. At this time, the vibrator temperature control device 312 lowers the vibrator temperature by the cooling solid 334 and sends a signal to the drive circuit group 309 when the temperature seems to be appropriate, and restarts the driving of the ultrasonic vibrator 302. Here, the cooled solid 334 may be cooled in the cooling device 317 or may be a material in which a cooling substance is circulated.
[0089]
Next, a method for controlling the driving of the ultrasonic transducer 302 by changing the transducer temperature will be described. The temperature information of the ultrasonic transducer 302 by the radiation thermometer 333 is sent to the transducer temperature control circuit 312 and simultaneously to the main control circuit 311. Unless the oscillator temperature control circuit 312 sends a signal indicating that the oscillator temperature control is impossible, the main control circuit 311 first calculates a change in the electrical characteristics of the vibrator due to heat generation, and then calculates the electrical characteristics. The energy for the loss caused by the change is calculated, and the drive circuit group 309 is controlled based on this data to compensate for the energy for the loss.
[0090]
Ultrasound irradiation is stopped at the time when it seems to be in the middle or the end of the initial treatment plan, and the progress of treatment is observed. This is performed in the same manner as the above-described operation, and an MRI image around the tumor 308 is taken to examine a change in the living body. During this time, the applicator 301 remains attached to the patient 303. Here, when the T2-weighted image data stored in the memory before the treatment and the current data are subtracted, the heat-denatured region can be clearly confirmed, and the treatment has been sufficiently performed, or the treatment is insufficient and re-treatment. Can be determined. It is also possible to incorporate this into the treatment plan from the beginning and automatically capture images every predetermined treatment time.
[0091]
When it becomes possible to determine that the treatment has been sufficiently completed by judging the treatment effect by MRI, the operator ends the treatment. At this time, the main control circuit 311 can call a history of treatment conditions from the memory and output a treatment record from the CRT display 320.
[0092]
In addition, you may use a body cavity coil as RF coil for transmission / reception. In this embodiment, MRI is used as an imaging apparatus, but this may be an ultrasonic diagnostic apparatus, X-ray CT, or the like.
[0093]
As described above, according to the third invention, the heat generated by continuously driving the therapeutic ultrasonic transducer can be suppressed within an allowable range, and the ultrasonic transducer such as the ultrasonic transducer or the backing material is surrounded. This makes it possible to prevent accidents caused by deterioration of the material, and to perform safe treatment. In addition, since it is possible to prevent changes in the characteristics of the ultrasonic vibrator due to heat, energy loss can be reduced, and a stable ultrasonic intensity can be obtained.
[0094]
(First embodiment of the fourth invention)
FIG. 24 is a block diagram of the ultrasonic therapy apparatus according to the first embodiment of the fourth invention. The ultrasonic treatment apparatus is a thermotherapy apparatus that heats and treats the affected tissue by irradiating the affected area with therapeutic ultrasonic waves for a relatively long period of time.
[0095]
The applicator 401 includes an ultrasonic source 402 that generates therapeutic ultrasonic waves having a relatively high output level. The ultrasonic wave generation source 402 has a plurality of piezo elements. The plurality of piezo elements are arranged in a spherical shell shape so that therapeutic ultrasonic waves from each element are focused at the focal point 406.
[0096]
A water bag 405 is attached to the focal side of the ultrasonic wave generation source 402. The coupling liquid 404 is sealed in the water bag 405 so that the therapeutic ultrasound generated by the ultrasound generation source 402 is introduced into the subject 403 with little loss.
[0097]
The central portion of the ultrasonic wave generation source 402 is cut out, and an imaging ultrasonic probe 408 for confirming the position of the affected part 407 is inserted therein. The ultrasonic diagnostic imaging apparatus 409 scans the inside of the subject 403 with an ultrasonic beam via the imaging ultrasonic probe 408, and obtains an ultrasonic tomographic image (B mode image) near the focal point. The ultrasonic tomogram is visually displayed in gray on the CRT 415.
[0098]
The frequency phase modulation circuit 412 generates a drive signal that vibrates with a sine wave. The frequency phase modulation circuit 412 can modulate the frequency of the drive signal, and further can modulate the phase of the drive signal in a timely manner, for example, a sine wave oscillation circuit capable of frequency modulation and the sine wave. The phase modulation circuit is configured to be bypassable between the oscillation circuit and the output terminal. The drive circuit 411 serving as a voltage amplification circuit amplifies the drive signal output from the frequency phase modulation circuit 412 and is configured to be capable of amplitude modulation under the control of the system controller 413. The amplified drive signal is supplied to each piezo element of the ultrasonic wave generation source 402 via the impedance matching circuit 410. From each piezo element, therapeutic ultrasonic waves are generated at a frequency equivalent to the drive signal.
[0099]
A console 414 is connected to a system controller 413 as a control center of the entire apparatus. The console 414 is equipped with a switch for an operator to instruct start / end of treatment ultrasound irradiation (treatment), switches for setting various treatment conditions, and other switches.
[0100]
Next, the operation of this embodiment will be described. First, frequency modulation will be described. It is most preferable from the viewpoint of conversion efficiency of electric signal / mechanical vibration to drive the piezo element at the resonance frequency f0 inherent to the thickness of the piezo element and to generate therapeutic ultrasonic waves at the resonance frequency f0. However, it is known that cavitation (bubbles) gradually grow to a size depending on the wavelength by irradiating therapeutic ultrasonic waves continuously at a resonance frequency f0 for a relatively long period of time.
[0101]
The system controller 413 controls the frequency phase modulation circuit 412 so that the frequency fm of the drive signal is changed over time in the range of f0−Δf / 2 ≦ fm ≦ f0 + Δf / 2 with the resonance frequency f0 as the center. Change. The frequency of the drive signal and the frequency of the therapeutic ultrasonic wave generated from the ultrasonic wave generation source 402 are equivalent. Hereinafter, the “drive signal” will be read as “therapeutic ultrasonic wave” as necessary. I want to be. FIGS. 25 (a), 26 (a), 27 (a), and 28 (a) show time waveforms of various types of drive signals. FIGS. 25 (b), 26 (b), and 27 FIG. 28 (b) and FIG. 28 (b) show changes over time in the frequency of the corresponding drive signal. The operator may be selectable from a plurality of types, or any one type may be fixedly adopted. The drive signal shown in FIG. 25A is generated such that its frequency changes sinusoidally. The drive signal shown in FIG. 26A is generated such that its frequency changes stepwise. The drive signal shown in FIG. 27A is generated such that its frequency continuously changes with a constant gradient from a low frequency (f0-.DELTA.f / 2) to a high frequency (f0 + .DELTA.f / 2). The drive signal shown in FIG. 28A is generated such that a period in which the frequency is fixed at the resonance frequency f0 and a period in which the frequency changes sinusoidally occur alternately.
[0102]
Such a change in frequency with time, in other words, a change in wavelength with time suppresses the growth of cavitation, divides the grown cavitation, and causes cavitation in the growth process to decline. Therefore, any adverse therapeutic effects due to cavitation are eliminated.
[0103]
Next, amplitude modulation of the drive signal will be described. As shown in FIG. 29, the impedance on the piezo element side viewed from the drive circuit 411 shows a minimum at the resonance frequency f0 and becomes high at other frequencies. Further, the conversion efficiency of the electric signal / mechanical vibration of the piezo element is maximum at the resonance frequency f0 and decreases at other frequencies. Furthermore, the degree of attenuation of therapeutic ultrasound in vivo depends on the frequency. Therefore, the output energy of the therapeutic ultrasonic wave generated from the ultrasonic wave generation source 402 shows a maximum at the resonance frequency f0 and decreases at a frequency outside the resonance frequency f0. In the present embodiment, by modulating the amplitude of the drive signal according to the frequency of the drive signal, the output energy of the therapeutic ultrasonic wave is kept constant regardless of the change in frequency.
[0104]
The system controller 413 controls the gain of the drive circuit 411 according to the change of the frequency of the drive signal so that the output level of the therapeutic ultrasonic wave is maintained substantially constant regardless of the frequency, and inputs it to the ultrasonic wave generation source 402. The input power to be made constant. FIG. 30A shows the time waveform of the amplitude-modulated drive signal, and FIG. 30B shows the time of the output energy of the therapeutic ultrasound generated from the ultrasound generation source 402 by the amplitude-modulated drive signal. Shows the trend. The amplitude of the amplitude-modulated drive signal shows a minimum at the resonance frequency f0 and shows a maximum at f0 ± Δf / 2.
[0105]
The impedance may be measured by an impedance measurement circuit and feedback controlled by the value, or the actual input power may be measured by a wattmeter and the feedback control may be performed by the value.
[0106]
Further, as another method of correcting the output level, the values of the variable inductor and variable capacitor in the impedance matching circuit 410 with respect to the frequency of the drive signal are stored in the internal memory of the system controller 413, and the system controller according to the frequency. A method of controlling electrical matching by using 413 is also conceivable.
[0107]
As a method for reducing fluctuations in the output level of therapeutic ultrasonic waves, there are the following methods that are used instead of or in combination with amplitude modulation. In this method, an acoustic matching layer having a thickness of λ / 4 (λ = wavelength) is provided on the surface of the piezoelectric element, where λ is the wavelength of the ultrasonic wave at a frequency far away from the resonance frequency f 0, and the output band is broadened. This is to improve the output efficiency of ultrasonic waves having a frequency far away from the above.
[0108]
Next, phase modulation will be described. This phase modulation is used in combination with the above frequency modulation, or is independently performed on the drive signal fixed at the resonance frequency f0 without performing the above frequency modulation. As shown in FIG. 31, the system controller 413 controls the frequency phase modulation circuit 412 to intermittently shift the phase of the drive signal by 180 ° in the period T. By continuously irradiating therapeutic ultrasound, cavitation gradually grows. When the phase of the therapeutic ultrasound is reversed, the cavitation is subjected to a pressure opposite to that during the previous growth. Therefore, cavitation collapses.
[0109]
(Second embodiment of the fourth invention)
FIG. 32 is a configuration diagram of an ultrasonic therapy apparatus according to the second embodiment. Note that the same portions as those in FIG. 24 are denoted by the same reference numerals and description thereof is omitted. The fundamental frequency signal generation circuit 418 is a circuit that generates a drive signal at a resonance frequency f0 unique to the piezo element. The frequency modulation signal generation circuit 419 is a circuit that generates a drive signal whose frequency changes with time. The changeover switch 420 alternately connects the fundamental frequency signal generation circuit 418 and the frequency modulation signal generation circuit 419 to the drive circuit 411 under the control of the system controller 417. The drive signal generated by either the fundamental frequency signal generation circuit 418 or the frequency modulation signal generation circuit 419 is amplified by the drive circuit 411 via the changeover switch 420. The amplified drive signal is supplied to each piezo element of the ultrasonic wave generation source 402 via the impedance circuit 410.
[0110]
FIG. 33A shows a time waveform of the drive signal output from the drive circuit 411. FIG. 33B shows the time change of the frequency of the drive signal shown in FIG. The fundamental frequency signal generation circuit 418 and the frequency modulation signal generation circuit 419 are alternately connected to the drive circuit 411 by switching of the changeover switch 420. The fundamental frequency signal generation circuit 418 is continuously connected to the drive circuit 411 during the first period Tf0. The frequency modulation signal generation circuit 419 is continuously connected to the drive circuit 411 in the second period Tfm.
[0111]
In the first period Tf0, the ultrasonic wave generation source 402 is driven by a drive signal whose frequency is fixed to the resonance frequency f0, and therapeutic ultrasonic waves are constantly generated at the resonance frequency f0. In the second period Tfm, the ultrasonic wave generation source 402 is driven by a drive signal whose frequency changes over time, and therapeutic ultrasonic waves whose frequency changes over time are generated. Any of the types shown in FIGS. 25B, 26B, and 27B may be employed as the change in frequency over time. Here, the frequency fm changes linearly from the low frequency (f0−Δf / 2) to the high frequency (f0 + Δf / 2), and this change is repeated at a constant cycle time Tc, resulting in a sawtooth. It is assumed that the shape changes. Of course, the gradient of the frequency change may be reversed, that is, the frequency fm may change linearly from the high frequency (f0 + Δf / 2) toward the low frequency (f0−Δf / 2). Further, the cycle time Tc is not limited to be constant as long as it is within a specific range to be described later. As shown in FIGS. 34 (a), (b), and (c), the cycle time Tc May be gradually shortened, gradually lengthened, or irregularly changed in length.
[0112]
FIG. 35 shows the relationship between the cycle time Tc and the cavitation amount. As the cavitation amount, the cavitation amount generated when the continuous driving at the resonance frequency f0 and the driving at the frequency changing with time are alternately repeated as in the present embodiment. This is expressed as a relative value where the amount of cavitation generated by continuous driving at f0 is 1. The efficiency of decay of cavitation depends on the length of cycle time Tc when considering the rate of frequency change, that is, the constant frequency modulation width. In the present embodiment, cycle time Tc is set within a range of 500 μs to 50 ms.
[0113]
FIG. 36 shows the relationship between the second period Tfm and the cavitation amount. The time taken to collapse cavitation is longer than the time taken to produce it. In the present embodiment, the second period Tfm is set to a time that is three times or more of the first period Tf0 so that the cavitation sufficiently collapses. On the other hand, if the second period Tfm is too long, the first period Tf0 that is fixedly driven at the resonance frequency f0 is compressed and shortened, and the temporal efficiency of the sound output is reduced, and the treatment time is prolonged. It will make it. In the present embodiment, in consideration of this point, the upper limit of the second period Tfm is set to 10 times the first period Tf0.
[0114]
FIG. 37 shows the relationship between the ratio (Δf / f0) of the frequency change width Δf to the resonance frequency f0 and the cavitation amount. In the present embodiment, the frequency change width Δf is set to 20% or more with respect to the resonance frequency f0. Of course, the upper limit value of the frequency change width Δf is naturally determined to be a critical value at which the conversion efficiency of the electric signal / mechanical vibration of the piezo element maintains a predetermined level, but in consideration of a decrease in the conversion efficiency of the piezo element, f0 It is preferable to set it to 100% or less.
[0115]
In the first and second embodiments, the range of change of the frequency fm is centered on the resonance frequency f0 in consideration of the conversion efficiency of the piezoelectric element in which the frequency fm deviates from the resonance frequency f0.
f0-.DELTA.f / 2.ltoreq.fm.ltoreq.f0 + .DELTA.f / 2
However, the present invention is not limited to this. For example, as shown in FIG. 63 (a), when the range of change of the frequency fm is (f0 + .DELTA.f1 to f0-.DELTA.f2), .DELTA.f1 and .DELTA.f2 may not match. As shown in FIG. 63 (b), when the range of change of the frequency fm is (f0 + .DELTA.f1 to f0 + .DELTA.f2), f0 + .DELTA.f1> f0 and f0 + .DELTA.f2> f0. It may be.
[0116]
As described above, according to the present embodiment, it is possible to generate ultrasonic waves for treatment most efficiently from the viewpoint of collapse of cavitation and the speed of treatment.
[0117]
(Third embodiment of the fourth invention)
FIG. 38 is a configuration diagram of an ultrasonic therapy apparatus according to the third embodiment. Note that the same portions as those in FIG. 24 are denoted by the same reference numerals and description thereof is omitted. The therapeutic ultrasonic wave generation drive circuit 431 generates a fixed drive signal at a resonance frequency f 0 specific to the thickness of the piezoelectric element of the therapeutic ultrasonic wave generation source (first ultrasonic wave generation source) 402. This therapeutic drive signal is supplied to the therapeutic ultrasonic wave generation source 402 via the impedance matching circuit 410 in order to generate therapeutic ultrasonic waves. The cavitation decay drive circuit 432 generates a drive signal fixedly at a frequency f ′ that is higher than the resonance frequency f0. The drive signal for cavitation decay is generated separately from the therapeutic ultrasound generation source 402 via the second impedance matching circuit 433 in order to generate cavitation decay ultrasound. The ultrasonic wave is supplied to an ultrasonic wave generation source (second ultrasonic wave generation source) 434.
[0118]
The ultrasonic generation source 434 for cavitation collapse includes a plurality of piezo elements arranged in a spherical shell, and an area where cavitation is generated by therapeutic ultrasonic waves in order to collapse cavitation caused by therapeutic ultrasonic waves, that is, for therapeutic use It is installed at the position and direction where the ultrasonic wave for cavitation collapse is irradiated toward the ultrasonic propagation path.
[0119]
The therapeutic ultrasonic wave generation source 402 and the cavitation collapse ultrasonic wave generation source 434 may be provided separately as described above, or, as shown in FIG. May be arranged on the center side, and a relatively low frequency piezo element constituting the therapeutic ultrasonic wave generation source 434 may be arranged on the outside of the piezoelectric element so as to be shaped into a spherical shell as a whole. Also, as shown in FIG. 40 (b), a piezoelectric element having a resonance frequency f0 is bonded to two layers, and only one layer is driven, thereby generating therapeutic ultrasonic waves at the resonance frequency f0 and simultaneously driving the two layers. Thus, an ultrasonic wave for cavitation collapse having a high frequency f ′ may be generated.
[0120]
FIGS. 39A, 39B, and 39C are diagrams showing time waveforms of drive signals according to the present embodiment. In the example of FIG. 39 (a), therapeutic ultrasonic waves with a relatively low frequency f0 and ultrasonic waves for cavitation decay with a relatively high frequency f 'are irradiated alternately. In the example of FIG. 39 (b), the ultrasonic waves for cavitation collapse are intermittently superimposed on the therapeutic ultrasonic waves. In the example of FIG. 39 (c), “beat” is generated by continuously superimposing ultrasonic waves of slightly different frequencies (f0, f ′), and this is used to collapse cavitation. is there.
[0121]
As described above, according to the third embodiment, it is possible to forcibly collapse the cavitation that occurs with the irradiation of therapeutic ultrasonic waves. Therefore, the side effect to the unexpected site | part and the expansion of a heat denaturation area | region are suppressed, and heat denaturation can be induced correctly to the target site | part. Thereby, safe and reliable ultrasonic heating treatment can be realized. Further, by suppressing the occurrence of cavitation, it is possible to continuously input ultrasonic energy, so that the treatment time is reduced and the throughput of the patient is improved.
[0122]
(Fourth embodiment of the fourth invention)
In this embodiment, the amount of cavitation is monitored, and when the amount of cavitation reaches a certain amount, cavitation decay ultrasonic waves are generated irregularly. FIG. 41 is a configuration diagram of an ultrasonic therapy apparatus according to the fourth embodiment. Note that the same portions as those in FIG. 24 are denoted by the same reference numerals and description thereof is omitted. The ultrasonic image data generated by the ultrasonic diagnostic imaging apparatus 409 is also supplied to the difference circuit 416 together with the CRT 415.
[0123]
In the internal memory of the difference circuit 416, an ultrasonic image generated by the ultrasonic diagnostic imaging apparatus 415 as a mask image when no cavitation occurs or cavitation is very small as shown in FIG. Remembered. This mask image has no or very little cavitation image.
[0124]
FIG. 42B shows an ultrasonic image (real-time image) generated by the ultrasonic image diagnostic apparatus 415 after the start of irradiation of therapeutic ultrasonic waves. The therapeutic ultrasonic wave is intermittently irradiated as a burst wave, and the cross section near the focal point is scanned with the imaging ultrasonic beam at the interval of the therapeutic ultrasonic wave irradiation, and an ultrasonic image of the cross section is repeatedly generated. In the real-time image, the cavitation image gradually increases with an increase in the irradiation time of the therapeutic ultrasound.
[0125]
The real-time image is successively different from the mask image by the difference circuit 416, and difference images as shown in FIG. 42C are generated one after another. The difference image data is taken into the system controller 413. The system controller 413 obtains the sum of the pixel values of a plurality of pixels in the specific area of the difference image as the difference level. FIG. 43A shows the temporal transition of the difference level. The difference level depends on the amount of cavitation that has occurred. The specific area is set as a propagation area of therapeutic ultrasonic waves up to a focal point where cavitation is considered to occur.
[0126]
The system controller 413 compares the obtained difference level with a threshold value. When the difference level is lower than the threshold value, the system controller 413 generates a therapeutic ultrasonic wave at the resonance frequency f0 and proceeds with the heating treatment as shown in FIG. To control.
[0127]
The system controller 413 sets the frequency phase modulation circuit 412 so that the frequency fluctuates as shown in FIG. 43 (b) in order to actively collapse cavitation during the period when the difference level exceeds the threshold. Control.
[0128]
Further, when the difference level exceeds the threshold value, the system controller 413 adds to the frequency fluctuation or keeps the frequency fixed at the resonance frequency f0, as shown in FIG. 43 (c). The frequency phase modulation circuit 412 is controlled so that the phase of the ultrasonic wave is inverted.
[0129]
Thereby, cavitation can be destroyed in a timely manner, and a decrease in the speed of treatment can be suppressed.
[0130]
According to the present invention, it becomes possible to effectively suppress cavitation that occurs with the irradiation of therapeutic ultrasonic waves, so that side effects on unexpected sites and expansion of heat-denatured regions are more effective than conventional methods. The heat denaturation can be accurately induced at the targeted site. Thereby, safer and more reliable ultrasonic heating treatment can be realized. In addition, the total treatment time can be reduced, and the patient throughput is improved.
[0131]
(First Embodiment of Fifth Invention)
In FIG. 44, the ultrasonic applicator 571 is provided with a spherical shell-shaped ultrasonic transducer 572 made of a piezoelectric element capable of generating focused ultrasonic waves, and is attached to a subject 574 via a water bag 573. A drive circuit 575 is coupled to the piezo element. The drive circuit 575 determines the intensity based on the potential of a power source (not shown) and applies a voltage pulse to the piezo element. The MR locators 576, 577, and 578 are mounted at locations separated by an ultrasonic transducer so as not to be affected by the high-frequency magnetic field generated by the 572. The positions of the MR locators 576, 577, and 578 can be detected from the MR images obtained from these, and the position, axial direction, and circumferential posture of the ultrasonic applicator 571 can be known. Then, the position of the imaging plane of the ultrasonic probe 579 is detected, and this is superimposed on the image of the same slice imaged by MRI and displayed as shown in FIG.
[0132]
The MRI image used here may be an image obtained by imaging in advance and superposing information such as a treatment site, a real-time MR image such as a temperature distribution image measured during heating, or an image obtained by superimposing the two. Good. The image obtained in advance is three-dimensional, and a two-dimensional image that matches the imaging slice of the probe is reconstructed from the three-dimensional image.
[0133]
Although three position detection type MR locators 576, 577, and 578 are used here, a position / angle detection MR locator using an asymmetric coil is also possible. A schematic view of an ultrasonic applicator using this is shown in FIG. In FIG. 46, the configuration is almost the same as in FIG. 44, but the MR locator 591 is attached to the tip of the ultrasonic probe 579, and the reception signal is only one system. With this MR locator 591, the position and angle of the ultrasonic applicator can be obtained, and the MR image and the ultrasonic image can be superimposed and displayed as in FIG. Any device that can detect the position, the axis, and the angle in the circumferential direction (for example, two orthogonal rectangular coils) may be used. Further, since the geometric relationship between the coil and the central axis is known, it is not always necessary to install the MR locator on the central axis.
[0134]
In addition, although the case where an ultrasonic probe is used is described here, there are cases where this is not used, for example, when only MRI is used for the monitor. In this case, it is only necessary to detect the treatment position and direction using high-power ultrasonic waves. Only the direction of the axis needs to be detected. Therefore, for example, two position detection type MR locators or rectangular type MR locators may be used.
[0135]
(Second Embodiment of Fifth Invention)
FIG. 47 shows the configuration of an embodiment according to the fifth invention. In the figure, a static magnetic field magnet 501 is excited by an excitation power source 502 and applies a uniform static magnetic field in the z direction to a subject 503. The gradient magnetic field coil 504 is disposed in the static magnetic field magnet 510, is driven by the drive circuit 506 of the gradient magnetic field coil 504 controlled by the sequence controller 505, and is orthogonal to the subject 503 on the bed 507. Gradient magnetic fields Gx, Gy, Gz whose magnetic field strength changes linearly in the three directions are applied. The whole-body high-frequency coil 508 is a transmission / reception coil and is disposed in the gradient magnetic field coil 504. Under the control of the sequence controller 505, a high frequency signal from the transmission unit 509 is applied to the whole body high frequency coil 508 via the duplexer 510, and a high frequency magnetic field generated thereby is generated in the whole body high frequency coil 508 on the bed 507. Applied to the subject 503. The whole-body high-frequency coil 508 can generate a uniform high-frequency magnetic field in the region to be imaged of the subject 503. For example, a saddle type coil, a distributed constant type coil, or a quadrature transmission coil configured using these coils. used. However, when the treatment target is limited and a higher S / N ratio is desired, a surface coil may be used as the transmission / reception coil or the reception coil. When a surface coil is used for reception, a uniform coil is used for transmission.
[0136]
The whole body high frequency coil 508 receives a magnetic resonance signal from the subject 503, and the received signal is sent to the receiving unit 511 through the duplexer 510. The duplexer 510 is used to switch the whole body high frequency coil 508 between transmission and reception, and transmits a high frequency signal from the transmission unit 511 to the whole body high frequency coil 508 at the time of transmission, and at the time of reception, the whole body high frequency coil 508. It serves to guide the received signal from the receiver 511. The received signal is detected and band-limited by the low-pass filter, and then sent to the data collection unit 512 under the control of the sequence controller 505. The data collection unit 512 collects received signals and performs A / D conversion, and sends them to the electronic computer 513 as image reconstruction data.
[0137]
The electronic computer 513 is controlled by the console 514, performs image reconstruction processing including two-dimensional Fourier transform on the image reconstruction data input from the reception unit 511, and also controls the sequence controller 505. Image data obtained by the electronic computer 513 is supplied to the image display 515 and displayed as an image.
[0138]
The MR locator 520 is coupled to a medical device (not shown) such as a catheter or a puncture needle that is inserted into a subject to diagnose a site or treat an affected part without incision. At the time of reception, a magnetic resonance signal is received simultaneously.
[0139]
FIG. 48 is a schematic diagram of a small surface coil serving as an MR locator for position detection. This is a normal surface coil, and is tuned to the magnetic resonance frequency for observing the resonance frequency.
[0140]
FIG. 49 shows an example in which the MR locator 520 for position detection is attached to a puncture needle 522 that is one of medical instruments. That is, the MR locator 520 is mounted on the insulating film 521 at the tip of the puncture needle 522, and the cable is pulled out while being insulated from the needle. Note that a conductive film may be formed on the insulator of the puncture needle 522 by coating, and this may be etched to form a coil.
[0141]
FIG. 50 shows an imaging sequence in the present embodiment. Here, the same sequence as the normal two-dimensional spin echo sequence is used. Any sequence may be used, but at the time of data collection, the whole body high-frequency coil 508 and the MR locator 520 simultaneously receive magnetic resonance signals and collect data independently of each other. When there is a possibility that these are coupled, decoupling may be performed by Q dumping or the like as described in US Pat. No. 4,825,162 and Japanese Patent Application No. 2-047814. In addition, although two-dimensional imaging is used here for simplicity, it is desirable to perform three-dimensional imaging and three-dimensional position detection.
[0142]
The collected images are as shown in FIGS. 51 (a) to 51 (c), for example. FIG. 51A shows a head image obtained by the whole-body high-frequency coil 508, which is a normal morphological image. On the other hand, the signal intensity in the vicinity of the locator 520 is extremely high in the image of FIG. 51 (b) obtained by the MR locator 520 at the same time, and the signal in the distant part is hardly obtained. The position of the locator 520 is indicated. For the locator image obtained by the MR locator 520, the position of the locator 520 is calculated by performing processing such as obtaining the maximum point of the signal intensity or the center of an area exceeding a certain threshold value, and the like. The morphological image of (a) may be superimposed and displayed as shown in FIG. 51 (c), or may be superimposed and displayed by performing processing such as changing the color of the morphological image as it is.
[0143]
A procedure for performing treatment using this image for grasping the position of the tip of the puncture needle 522 will be described below. First, imaging by MRI for determining the treatment position is performed, and the puncture position and direction are determined. After entering the treatment, a morphological image by MRI and an image by the MR locator 520 are continuously obtained in real time by ultra high-speed imaging or the like. When the puncture is started, the position of the locator 520 can be determined from the image obtained by the MR locator 520, and the puncture is advanced while the operator observes the superimposed image.
[0144]
At this time, an image in which a treatment planned position is written on a fine image at the time of treatment planning may be superimposed and displayed while comparing the ultra-high speed form image and correcting the positional deviation. When it is confirmed that the puncture needle has reached the planned puncture site, for example, treatment such as cell collection and ethanol injection, and diagnostic action are performed. There is no problem if it is measured in 3 dimensions, but when imaging in 2 dimensions or less, multiple slices are set, multi-slice imaging is performed, the maximum intensity of each image is compared, and the slice position or signal including the maximum intensity When the slice position including the maximum point predicted from the intensity distribution is obtained, this becomes a slice including the MR locator 520, and the position can be grasped three-dimensionally.
[0145]
As shown in FIG. 52, even when the catheter 530 is used as a medical instrument, the coil 532 formed on the insulating film 531 at the distal end of the catheter 530 is only required to perform the therapeutic diagnosis at the distal end as described above. By attaching the, position detection is possible by the same means as puncture.
[0146]
However, when performing treatment energy irradiation in the forward axial direction such as a non-contact laser using a very flexible catheter, it is not sufficient to simply confirm the tip position. It is not possible to accurately grasp the area. Thus, when the directionality of a medical instrument is required, for example, as shown in FIG. 53, a rectangular coil can be used, and this major axis direction can be detected from an image to know the direction of the medical instrument. An example in which a rectangular coil is mounted on a catheter is shown in FIG. At this time, the image acquisition is the same as the method for position detection. An example of the obtained image is shown in FIGS. FIG. 55A shows a morphological image of a blood vessel part. FIG. 55B is an image obtained by the MR locator 520, and an image having a high-luminance portion shaped according to the magnetic field distribution of the rectangular coil is obtained. From this, the position of the locator is detected from the center of the high luminance region, and the direction is obtained from the long axis direction of the high luminance region. Then, the position, angle information, or the high-luminance region as it is is superimposed on the morphological image of FIG. 55A and displayed as shown in FIG. And display it with the direction. By making the rectangle trapezoidal, the front-rear direction can also be detected from the difference in the width of the high-frequency magnetic field distribution.
[0147]
Even if it is not a rectangular coil, you may mount | wear with two coils and each acquire an image independently. FIG. 56 shows the case where this is attached to the catheter. At this time, the processing may be the same as described above, but it is necessary to reconstruct three images by combining the morphological image and the images obtained by the MR locators 541 and 542. At this time, each position can be detected from the images obtained by the MR locators 541 and 542, and the direction can be obtained from the respective positional relationship.
[0148]
On the other hand, the direction of laser irradiation is not an axial direction but is deflected in a direction perpendicular to the catheter axis, and there are cases where the surroundings are cauterized while scanning in the circumferential direction. I need to know. In this case, when a coil having an asymmetric shape in the circumferential direction as shown in FIG. 57 is used, a circumferentially asymmetric high-frequency magnetic field distribution is obtained as shown in FIG. It can be obtained from an asymmetric high-frequency magnetic field distribution. FIG. 59 shows a case where this is attached to a laser catheter. As shown in FIG. 60, an asymmetric magnetic field distribution can be obtained in the same manner even when a coil having a slightly thicker long side is mounted along a cylindrical surface. Further, even with one rectangular coil and one small surface coil or three small surface coils, the position, axial direction, and circumferential direction can be obtained from the images obtained by the respective coils.
[0149]
In the rectangular coil and the small surface coil, for example, as shown in FIG. 61, they are arranged at positions orthogonal to each other. First, the position and direction are obtained by the rectangular coil 551, and the relative position to the position of the rectangular coil 551 is obtained by the small surface coil 552. Thus, the circumferential angle can be known. The same applies to two rectangular coils. Further, in the case of three small surface coils, one coil 561 is used as a reference as shown in FIG. 62, the other one coil 562 is shifted in the axial direction relative to this, and the remaining one is shifted in the circumferential direction. Two coils 563 are arranged respectively. The positions of the coils 561 to 563 are obtained from the images obtained by the coils 561 to 563, and the catheter position, axial direction, and circumferential angle are calculated from the positional relationship.
[0150]
As described above, according to the fifth invention, it is possible to provide a treatment apparatus capable of performing a treatment while accurately grasping the position and posture of a medical instrument inserted into a subject under MRI monitoring. it can.
[0151]
【The invention's effect】
(1) According to the first invention, it is possible to use an image ultrasonic probe without degrading it even when treatment is performed by irradiating a very strong ultrasonic wave.
[0152]
(2) According to the second aspect of the present invention, it is possible to provide an ultrasonic therapy apparatus that can obtain a good ultrasonic image with a high output even though it is very small. It is also possible to provide an applicator that can be used in situations such as in a very narrow MRI gantry.
[0153]
(3) According to the third invention, heat generated by continuously driving the therapeutic ultrasonic transducer can be suppressed within an allowable range, and materials around the ultrasonic transducer such as an ultrasonic transducer and a backing material are provided. It is possible to prevent accidents due to deterioration of the patient and to perform safe treatment. In addition, since it is possible to prevent changes in the characteristics of the ultrasonic vibrator due to heat, energy loss can be reduced, and a stable ultrasonic intensity can be obtained.
[0154]
(4) According to the fourth invention, the following effects can be realized. The frequency of the therapeutic ultrasound is changed over time. Due to this change in frequency, some cavitations are disrupted, and some cavitations are crushed and collapsed. Therefore, the side effect to the unexpected site | part and the expansion of a heat denaturation area | region are suppressed, and heat denaturation can be induced correctly to the target site | part. Thereby, safe and reliable ultrasonic heating treatment is realized. Also, since cavitation is actively disrupted, the total treatment time is reduced and patient throughput is improved rather than waiting for the cavitation to naturally decay.
[0155]
In addition, the phase of the therapeutic ultrasound is changed. This phase change causes the growing cavitation to be crushed and collapsed. Therefore, the side effect to the unexpected site | part and the expansion of a heat denaturation area | region are suppressed, and heat denaturation can be induced correctly to the target site | part. Thereby, safe and reliable ultrasonic heating treatment is realized. Also, since cavitation is actively disrupted, the total treatment time is reduced and patient throughput is improved rather than waiting for the cavitation to naturally decay.
[0156]
(5) According to the fifth invention, it is possible to provide a treatment instrument capable of performing a treatment action while accurately grasping the position / posture of the treatment device under MRI monitoring.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a first embodiment according to the first invention.
FIG. 2 is a spectrum of a signal detected from an ultrasonic probe.
FIG. 3 is a schematic diagram of a signal detected from an ultrasonic probe.
FIG. 4 is a configuration diagram of a second embodiment according to the first invention.
FIG. 5 is a diagram when the applicator in the embodiment is viewed from a focal side.
FIG. 6 is a configuration diagram of a third embodiment according to the first invention.
FIG. 7 is a block diagram showing an embodiment according to the second invention.
FIG. 8 is a schematic view showing a configuration of an applicator in the second invention.
FIG. 9 is a schematic view showing an applicator according to an embodiment of the second invention.
FIG. 10 is a schematic view showing an applicator according to another embodiment of the second invention.
FIG. 11 is a configuration diagram of an applicator according to a second invention.
FIG. 12 is a schematic diagram showing the configuration of the second invention.
FIG. 13 is a configuration diagram of another embodiment according to the second invention.
FIG. 14 is a configuration diagram of an applicator according to another embodiment of the second invention.
FIG. 15 is a configuration diagram of the first embodiment according to the third invention.
FIG. 16 is a schematic diagram of an ultrasonic transducer in the embodiment.
FIG. 17 is a schematic diagram of ultrasonic transducer cooling means in the same embodiment.
FIG. 18: Temperature characteristics of dielectric constant of ultrasonic transducer
FIG. 19 is a block diagram of a second embodiment according to the third invention.
FIG. 20 is a configuration diagram of a third embodiment according to the third invention.
FIG. 21 is a configuration diagram of a fourth embodiment according to the third invention.
FIG. 22 is a block diagram of a fifth embodiment according to the third invention.
FIG. 23 is an enlarged view of an applicator portion in the same embodiment.
FIG. 24 is a block diagram showing the configuration of the first embodiment according to the fourth invention.
FIG. 25 is a diagram showing a time waveform of a frequency-modulated drive signal and a change with time in frequency.
FIG. 26 is a diagram showing another time waveform of a frequency-modulated drive signal and a change with time in frequency.
FIG. 27 is a diagram showing still another time waveform of a frequency-modulated drive signal and a change over time in frequency.
FIG. 28 is a diagram showing still another time waveform of a frequency-modulated drive signal and a change with time in frequency.
FIG. 29 is a diagram showing the relationship between frequency and impedance.
FIG. 30 is a diagram illustrating a time change of an amplitude-modulated drive signal and a time change of output energy of an ultrasonic wave.
FIG. 31 is a diagram showing a time waveform of a phase-modulated drive signal.
FIG. 32 is a block diagram showing a configuration of a second embodiment according to the fourth invention.
FIG. 33 is a diagram showing a time waveform of a frequency-modulated drive signal and a change with time in frequency.
FIG. 34 is a diagram showing another change over time in the frequency of the drive signal.
FIG. 35 is a diagram showing a relationship between a cycle time Tc and a residual cavitation amount.
FIG. 36 is a diagram showing a relationship between a frequency modulation period Tfm and a residual cavitation amount.
FIG. 37 is a diagram showing a relationship between a frequency modulation width and a residual cavitation amount.
FIG. 38 is a block diagram showing the configuration of the third embodiment according to the fourth invention.
FIG. 39 shows a time waveform of a drive signal time-divided for treatment and cavitation decay, a time waveform of a drive signal in which a cavitation decay drive signal and a treatment drive signal are superimposed, and a cavitation decay drive signal and treatment. The figure which shows the other time waveform of the drive signal on which the drive signal for superimposition was superimposed.
FIG. 40 is a cross-sectional view of an ultrasonic wave generation source showing an arrangement relationship between two types of piezoelectric elements having different resonance frequencies.
FIG. 41 is a block diagram showing the configuration of the fourth embodiment according to the fourth invention.
FIG. 42 is a schematic diagram of a mask image before ultrasonic irradiation, a real-time image during ultrasonic irradiation, and a difference image between the mask image and the real-time image.
FIG. 43 is a diagram showing timing for applying frequency modulation and timing for applying phase modulation in response to a change in the difference level over time.
FIG. 44 is a schematic diagram showing an example of application of the hand probe type ultrasonic applicator according to the fifth invention to a position, axial direction, and circumferential direction detecting three-coil MR locator.
FIG. 45 is a schematic diagram showing an example of superposition display of MR images and ultrasonic images according to the fifth invention.
FIG. 46 is a schematic diagram showing an example of application of the hand probe type ultrasonic applicator according to the fifth invention to an asymmetric coil type MR locator for detecting the position, axial direction, and circumferential direction;
FIG. 47 is a block diagram of an embodiment according to the fifth invention.
FIG. 48 is a schematic diagram of a position detection type MR locator according to a fifth invention.
FIG. 49 is a schematic diagram showing an example when the position detection type MR locator according to the fifth invention is attached to the puncture needle.
FIG. 50 is a diagram showing a normal two-dimensional spin echo sequence as an example of an imaging pulse sequence when performing MR locator position measurement according to the fifth invention. )
FIG. 51 is a diagram showing an example of each captured image in the case of position detection according to the fifth invention.
FIG. 52 is a schematic view showing an example when the position detection type MR locator according to the fifth invention is attached to the catheter tip.
FIG. 53 is a schematic diagram of a rectangular MR locator for position and axial direction detection according to the fifth invention.
FIG. 54 is a schematic diagram showing an example when the position and axial direction detecting rectangular MR locator according to the fifth invention is attached to the catheter tip;
FIG. 55 is a view showing each image captured when the position and the axial direction are detected (using a rectangular shape) and a display example thereof according to the fifth invention.
FIG. 56 is a view showing an application example of the MR locator using two coils for position and axial direction detection according to the fifth invention to a catheter;
FIG. 57 is a schematic diagram showing the shape of an asymmetric coil type MR locator for detecting position, axial direction, and circumferential direction according to the fifth invention.
FIG. 58 is a schematic view showing a magnetic field distribution in the circumferential direction of the asymmetric coil according to the fifth invention.
FIG. 59 is a schematic view showing a case where the asymmetric coil according to the fifth invention is attached to a catheter.
FIG. 60 is a schematic view showing a case where the asymmetric coil according to the fifth invention is deformed so as to be in close contact with a cylindrical shape and is attached to a catheter.
61 is an arrangement view of MR locators for detecting position, axial direction and circumferential direction by a rectangular coil and a small surface coil according to the fifth invention at the distal end of the catheter. FIG.
FIG. 62 is an arrangement view of the position, axial direction, and circumferential direction detection type MR locator on the catheter tip by three small surface coils according to the fifth invention.
FIG. 63 is a diagram showing a change over time in the frequency of the drive signal.
[Explanation of symbols]
101 ... applicator,
102 ... an ultrasonic transducer,
103 ... Ultrasonic probe,
104 ... coupling liquid,
105. Elastic membrane,
106: control circuit,
107 ... Drive circuit,
109 ... Ultrasonic imaging device,
110 ... CRT display,
111... Detection circuit,
121 ... applicator,
122... Shutter
123. Shutter control unit,
124 ... moving mechanism,
131: elastic membrane,
201 ... applicator,
222 ... Ultrasonic probe for images,
202 ... stage,
231 to 233 ... electrodes,
203 ... propagation solution,
261 ... applicator,
204 ... Case,
271 ... Drive circuit,
205 ... elastic membrane,
272 ... ultrasonic diagnostic imaging apparatus,
206 ... support,
273 ... moving means,
207 ... Magnet,
274: Propagation solution processing circuit
208 ... top plate,
275 ... Control circuit,
209 ... a moving mechanism,
276 ... CRT display,
210 ... Cushion,
277 ... MRI system,
221 ... ultrasonic transducer,
301 ... applicator,
302 ... ultrasonic transducer,
303 ... Patient, 304 ... Coupling fluid
305 ... Water bag,
306 ... backing material
307: Focus,
308 ... Tumor,
309 ... Drive circuit group,
310 ... Phase control circuit group,
311 ... Control circuit,
312 ... vibrator temperature control circuit,
313 ... Shape memory alloy member,
314: polyimide resin film,
315 ... switch,
316 ... pipe,
317 ... cooling device,
318 ... Electrical characteristic control circuit,
319 ... matching circuit group,
320 ... thermocouple,
321 ... Silicon coating material,
322 ... cooling gas,
323 ... Treatment table,
324 ... RF coil,
325 ... static magnetic field coil,
326 ... gradient magnetic field coil,
327 ... Table moving device,
328: Gradient magnetic field power supply,
329 ... transmission / reception circuit,
330 ... console,
331 ... CRT display,
332: Ultrasonic incident path,
333 ... radiation thermometer,
334 ... Cooling solid,
340 ... Coupling fluid circulation circuit,
341 ... water inlet,
342 ... Drain port,
401 ... applicator,
402: Piezo element (group),
403 ... Subject,
404 ... coupling solution,
405 ... Coupling membrane,
406 ... therapeutic ultrasound focus,
407 ... affected area (tumor),
408 ... ultrasonic probe,
409 ... ultrasonic diagnostic imaging apparatus,
410 ... impedance matching circuit,
411 ... Drive circuit (amplifier),
412 ... frequency / phase modulation circuit,
413 ... System controller,
414 ... console,
415 ... CRT display,
417 ... System controller,
418 ... fundamental frequency signal generation circuit,
419 ... frequency modulation signal generation circuit,
420 ... changeover switch,
431 ... therapeutic ultrasonic wave generation drive circuit,
432 ... Cavitation collapse drive circuit,
433 ... a second impedance matching circuit,
434 ... an ultrasonic source for cavitation collapse,
501: Static magnetic field magnet,
502 ... Excitation power source,
504 ... gradient magnetic field coil,
506 ... gradient magnetic field coil drive circuit,
509 ... Transmitter,
510 ... Duplexer,
508 ... high frequency coil,
511 ... the receiving unit,
503: Subject,
505 ... Sequence controller,
507 ... Sleeper,
512 ... data collection unit,
513 ... an electronic computer,
514 ... Console,
515: Image display,
516 ... ultrasonic applicator,
517 ... Driving circuit group,
518 ... Phase control circuit group,
519 ... Power supply (for pulse generation),
520 ... Position detection type MR locator,
521. Insulating film,
522 ... a puncture needle,
530 ... catheter tip,
531,532 ... Coil,
541, 542 ... Position / axis direction detection type MR locator,
551 ... rectangular coil,
552 ... Small surface coil,
561-563 ... Small surface coil,
571. Hand probe type ultrasonic applicator,
572 ... an ultrasonic transducer,
573 ... water bag,
574: Subject,
575 ... a drive circuit,
576 to 578 ... position detection type MR locator,
579 ... ultrasonic probe,
591: Asymmetrical coil type position / circumferential / axial angle detection type MR locator.

Claims (1)

A therapeutic ultrasound transducer for irradiating a treatment target in a subject with therapeutic ultrasound;
An ultrasound probe for images that scans within the subject with ultrasound for images to obtain an image in the subject;
Receiving means for receiving a reflected wave of the therapeutic ultrasonic wave via the image ultrasonic probe;
An ultrasonic treatment apparatus comprising: control means for controlling the intensity of the therapeutic ultrasonic wave based on a signal received by the receiving means.

Images