JPH04176443A - Medical capsule - Google Patents

Abstract

PURPOSE:To enable arrival accurately at a desired part of an organism by making a compact medical capsule using a traveling actuator utilizing an inertial force of an inertial body caused by a quick deformation of a piezoelectric element and an friction force with the organism. CONSTITUTION:A piston 4 in an internal space 3 of a capsule body 2 is airtightly provided slidable in a longitudinal direction and chemicals or the like 6 are held in a storage chamber 5. A piezoelectric element 12 is set in the rear of the piston 4 expandable in a direction of the movement of the piston 4 and the front end of the piezoelectric element 12 is fastened t the rear end of the piston 4 and the rear end thereof 12 on an inertial body 13. Behind the inertial body 13, a power source 11 for supplying current to an electrode of the piezoelectric element 2 and a control circuit 15 for controlling an applied voltage thereof are provided, and a telemeter circuit is attached to the control circuit 15 to issue an operation command receiving a radio wave from outside. The control circuit 15 controls a drive applied voltage to the piezoelectric element 12 so that the traveling of the capsule body 2 is controlled utilizing an inertial force of the inertial body 13 caused by the expansion of the piezoelectric element 12 in the axial direction and a friction force with an organism subject to the capsule body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a medical capsule for releasing a medicinal solution or collecting a body fluid in a living body.

[Prior Art] A medical capsule of the type that releases a medical solution or the like in a living body has been proposed in Japanese Patent Application Laid-Open No. 2-19140. This medical capsule moves by the spiral movement of the body cavity and cannot move by itself.

[Problems to be Solved by the Invention] Conventional medical capsules move by the spiral movement of the body cavity, and cannot move by themselves.

Therefore, it takes a considerable amount of time to reach the target site.

Moreover, if it goes too far, it cannot be returned to a predetermined position. Furthermore, since a spiral movement is used, it is difficult to accurately reach a desired location. Furthermore, there were other problems such as the inability to introduce a medical capsule into a site where there is no helical movement.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a medical capsule that can quickly travel within a living body and reliably reach a desired site. .

[Means and effects for solving the problem] In order to solve the above problem, the first invention provides a medical capsule to be administered into a living body, in which a capsule body that also serves as a moving body includes:
A piezoelectric element that is arranged in an axial direction along the direction in which the capsule body is to be moved and is expandable and contractible in the axial direction is provided, one end of the piezoelectric element in the axial direction is substantially fixed to the capsule body, and the piezoelectric element An inertial body is attached to the other end in the axial direction of the capsule, and a battery is provided in the capsule body for applying a driving voltage to the piezoelectric element, and the driving voltage is controlled so that the piezoelectric element moves in the axial direction. The device has a built-in control means for controlling the running operation of moving the capsule body using the inertia force of the inertial body when expanding and contracting and the frictional force between the capsule body and the living body.

Further, the second invention is a medical capsule to be administered into a living body, which includes a movable leg part that performs a self-propelled displacement operation in contact with a body cavity wall, and a giant magnetostrictive element that is displaced in an axial direction by an applied magnetic field. and a displacement transmission mechanism that transmits the displacement of the giant magnetostrictive element to the movable leg section to cause the movable leg section to perform a traveling motion.

[Embodiment] FIGS. 1 to 9 show a first embodiment of the present invention.

As shown in FIG. 1, a medical capsule 1 has a hollow capsule body 2 made of a material harmless to living organisms. The capsule body 2 has a front end wall portion and a rear end wall portion each having a spherical shape, and an intermediate portion having a cylindrical shape. A piston 4 is provided in the internal space 3 of the capsule body 2 so as to be able to slide in an axial direction along the front and back in an airtight manner. and,
The front end wall of the capsule body 2 and the piston 4 partition an internal space 3 of the capsule body 2 to form a storage chamber 5.

This storage chamber 5 is adapted to store a medicinal solution 6 to be administered into a living body. An opening 7 is formed in the front end wall of the capsule body 2 to communicate the storage chamber 5 to the outside. The front inner wall of the storage chamber 5 and the front wall of the piston 4 are formed into spherical shapes of corresponding size.

Two circumferential grooves 9 are formed on the outer periphery of the maximum diameter portion of the piston 4, into which a piston ring 8 is fitted. As shown in FIG. 2, each piston ring 8 is mounted with its notch portions facing each other. Furthermore, the piston ring 8 is made of a bidirectional shape memory material, such as a shape memory alloy or a shape memory resin, and when heated, it recovers its shape and increases its diameter as shown in FIG. There is. When the diameter of the piston ring 8 is increased in this way, it presses against the wall surface of the internal space 3 of the capsule body 2 and fixes the piston 4 to the capsule body 2. Note that the means for heating the piston ring 8 include electrical heating from a power source (battery) 11, which will be described later, inside the capsule body 2;
There are heating methods such as external ultrasonic waves.

A laminated piezoelectric element (PZT) 12 that expands and contracts in the moving direction of the piston 4 is installed behind the piston 4, and the front end of the piezoelectric element 12 is fixed to the rear end of the piston 4.

An inertial body 13 is fixed to the rear end of the piezoelectric element 12. The mass of this inertial body 13 is larger than the mass of the piston 4, which functions as a moving body, as will be described later. Of course, the combined mass of the capsule body 2 and the piston 4, which are integrated and function as a moving body, is also larger than the mass of the inertial body 13.

In the internal space 3 of the capsule body 2, the inertial body 13
Behind the piezoelectric element 12, a power source 11 for energizing the electrodes of the piezoelectric element 12 and a control circuit (control means) 15 for controlling the applied voltage are fixedly installed. A telemeter circuit (not shown) is attached to the control circuit 15 for receiving radio waves from the outside and issuing operation commands.

By applying a predetermined drive voltage to the piezoelectric element 12, the piezoelectric element 12 expands and contracts in its axial direction, and the piston 4 as a moving body or the capsule body 2 that is integrated with the piston 4
This is designed to be moved as a moving object.

This movement principle is conceptually illustrated in FIGS. 4 and 5.

As shown in FIG.
P is the laminated piezoelectric element 12 that connects the moving body M and the inertial body m.
It will be explained as follows.

Then, by applying a drive voltage having a waveform as shown in FIG. 5 to the laminated piezoelectric element P, the entire device moves forward or backward.

First, the operation when moving forward, that is, moving to the left will be explained. As shown in the diagram on the left side of FIG. 4, before the start of operation, the movable body M is placed on the base B and held by static friction, and the piezoelectric element P is in a contracted state. For this reason,
The inertial body m is attracted by the moving body M in front and is on standby.

From this state, when a high driving voltage is instantaneously applied to the piezoelectric element P to rapidly extend the piezoelectric element P, the moving body M and the inertial body m
or move in opposite directions at the same time.

At this time, the moving body M moves forward by a distance Δm while receiving dynamic frictional force.

Next, the voltage applied to the piezoelectric element P is reduced relatively slowly, the piezoelectric element P is contracted, and the inertial body m is moved toward the moving body M.
is pulled back with a constant acceleration. At this time, the applied voltage is adjusted so that the inertial force caused by the acceleration is smaller than the frictional force so that the movable body M is held stationary by the static frictional force with the base B.

When the piezoelectric element P has sufficiently shrunk, the current supply is abruptly stopped to abruptly stop the movement of the inertial body m. In other words, the pull-back operation is abruptly stopped. Then, the inertial body m collides with the moving body M, and as a result, the entire self-propelled device overcomes the frictional force and starts moving forward, moving until the kinetic energy is lost by the kinetic frictional force of the moving body M. and stop. This movement moves the robot forward a distance of 6m2.

Therefore, it is possible to move forward (coarse movement) by a distance of (Δml+Δm2) in this one cycle operation.

By repeating this slight forward motion, it is possible to make a large advance.

On the other hand, when moving backward, that is, moving to the right, the operation pattern is reversed. That is, as shown in the diagram on the right side of FIG. 4, the moving body M
is placed on the base B and held by frictional force, and the piezoelectric element P
is in an extended state.

Therefore, the inertial body m is separated from the moving body M in front.

When the application of high voltage to the piezoelectric element P is instantly removed from this state and the piezoelectric element P is rapidly reduced, the inertial force of the inertial body m becomes relatively large compared to the frictional force of the moving body M.
The moving body M and the inertial body m move simultaneously in opposite directions.

At this time, the moving body M moves backward by a distance of 6 m1.

Next, the voltage applied to the piezoelectric element P is gradually increased to extend the piezoelectric element P, and the inertial body m is retreated from the movable body M side at a constant acceleration. At this time, the moving body M is based on the base B
In order to be held stationary by the frictional force with the object, the inertial force caused by the acceleration must be smaller than the frictional force.

When the piezoelectric element P has fully expanded, the movement of the inertial body m is suddenly stopped. As a result, a large inertial force is generated, and the entire self-propelled device overcomes the frictional force and begins to move backward, moves until the kinetic energy of the entire self-propelled device is lost by the kinetic frictional force of the moving body M, and then stops. This movement moves the robot a distance of 6m2 backwards.

Therefore, in this one cycle operation (Δml +6m2)
can be retreated a distance of By repeating this slight movement backward, it is possible to make a large backward movement.

In addition, by outputting the voltage twice to perform the movement movement as a single cycle, and by raising the voltage immediately after lowering it, the energy generated during rapid deformation is added to the movement during the next rapid deformation. It is possible to obtain a larger amount of momentum.

Based on this principle, the piston 4, or the piston 4 and the capsule body 2, can be moved forward or backward.

When only the piston 4 is to be moved as shown in FIGS. 6 and 7, the piston ring 8 is not heated so that the piston 4 can slide inside the capsule body 2. Then, by controlling the application of the drive voltage to the piezoelectric element 12 as described above, the piston 4 is moved to the sixth position.
It can be moved forward as shown or retracted as shown in FIG. FIG. 6 shows a situation in which the piston 4 is advanced and the medicinal solution 6 in the storage chamber 5 is administered into the body from the mouth portion 7. Further, FIG. 7 shows a situation in which the piston 4 is retracted and body fluid or the like is collected from the mouth portion 7 into the storage chamber 5. Of course, when injecting the chemical solution 6 into the storage chamber 5, the piston 4 is moved backward as shown in FIG.

On the other hand, when moving the capsule body 2 forward or backward, the piston ring 8 is heated and expanded as described above, and is pressed and locked against the inner wall of the capsule body 2, thereby fixing the piston 4 to the capsule body 2. .

In other words, the capsule body 2 and the piston 4 are integrated into a single moving body. Then, the outer circumferential surface of the capsule body 2 is subjected to frictional force by contact with the lumen 16 of the living body, and moves by performing the above-described operation.

FIG. 8 shows a situation in which the capsule body moves forward, and FIG.
By stopping the heating of the piston ring 8 and applying the driving voltage to the piezoelectric element 12 again, the chemical liquid, etc.
It shows the situation in which the drug is administered. Of course, it is also possible to collect body fluids at this location.

Incidentally, FIG. 10 shows an example of a water jet scalpel using the above-described traveling principle. In this case, a moving body 22 that slides in airtight contact with the inner surface of a cylinder 21 is a piston, and the moving body 2
2, an inertial body 24 is attached to the rear end of the body 2 via a piezoelectric element 23 as described above. cylinder 21
A supply tube 28 that passes through a tank 27 is connected to the intake port 25 of the tank 27 via a check valve 26 . cylinder 21
There are two jet nozzles on the front of the machine. Therefore, if the traveling mechanism consisting of the moving body 22, the piezoelectric element 23, and the inertial body 24 is driven as described above to cause reciprocating motion,
A moving body 22 serving as a piston can be slid within the cylinder 21.

By moving it forward, water can be jetted from the jet nozzle 29 and water can be taken in from the tank 27.

Further, FIG. 11 shows an example of an indwelling type administration device that administers a drug solution or the like using the above-mentioned traveling principle. That is,
This is the movable body 3 that slides into airtight contact with the inner surface of the cylinder 31.
2 is a piston, and an inertial body 34 is attached to the rear end of the movable body 32 via the piezoelectric element 33 as described above. A supply tube 37 communicating with a blood vessel 36 such as the liver is connected to the supply port 35 of the cylinder 21 . Therefore, if the traveling mechanism consisting of the moving body 32, the piezoelectric element 33, and the inertial body 34 is driven to perform reciprocating motion as described above, the moving body 32 as a piston can be slid within the cylinder 31. can. Then, by moving it forward, drugs such as anticancer drugs can be administered to the living body through the supply tube 37. In addition, 38 in the figure is a chemical liquid injection control device having a battery, a drive voltage control circuit, and the like.

Furthermore, in this configuration, since the piezoelectric element 33 emits ultrasonic waves when the moving voltage is applied, the cylinder 3
The piezoelectric element 33 detects the ultrasonic pulse wave reflected by the rear wall surface of 1, and the position from the wall surface can be measured based on the time from transmission to reception. Thereby, the amount of drug solution to be administered can be determined from the amount of movement of the moving body 32.

Therefore, it is possible to control the operation of the traveling mechanism and accurately adjust the injection amount of the chemical solution. In addition, if an alternating voltage for position detection is applied to the piezoelectric element 33 instead of a voltage for movement, more efficient position detection can be performed.

12 to 15 show a second embodiment of the present invention. The medical capsule 40 of this embodiment has a capsule main body 41 and a traveling mechanism 42 for driving the capsule main body 41. This traveling machine 1l 142 has a giant magnetostrictive element 43 that expands and contracts in the axial direction by a magnetic field, and converts the displacement of this giant magnetostrictive element 43 into movement of a plurality of short traveling legs 44 via a displacement magnifying mechanism 45. . Giant magnetostrictive element 43
has one axial end fixed to the rear end of the capsule body 41, and the other axial end of the giant magnetostrictive element 43 connected to the input end of the displacement magnifying mechanism 45. The running legs 44 are giant magnetostrictive elements 43
The shafts 4 are arranged at equal intervals along the traveling direction on the upper, lower, left, and right sides around the
7, respectively. Furthermore, the middle of the rotating side of each traveling leg 44 is connected to an operating rod 48 along the traveling direction. By moving the operating rod 48 of the displacement amplifying mechanism 45, which also serves as a displacement transmission mechanism, in the running direction, each running leg 44 can be rotated in the front-rear direction. One end of the operating rod 48 is connected to the giant magnetostrictive element 43 via an extension of the rearmost leg 44.

A midway portion of the extension portion of the leg 44 is pivotally connected to a shaft 49 provided at a fixed portion (not shown).

The capsule body 41 has a storage chamber 51 therein for storing a medicinal solution 50, and a piston 52 in the storage chamber 51.
Or is provided. The piston 52 is biased by a coil spring 53 made of a shape memory alloy. In other words, the coil spring 53 is heated by ultrasonic waves, energization, etc., and expands to move the piston 52 forward, so that the medicinal solution 50 in the storage chamber 51 is administered into the body from the mouth portion 54.

Therefore, when the medical capsule 40 is operated to travel, it is performed as follows. That is, as shown in FIG. 12, an alternating magnetic field is generated by an electromagnetic coil 56 installed outside the body, aiming at the medical capsule 40 in the lumen 55 of the living body, and a magnetic field is applied to the medical capsule 40 within the magnetic field. Try to give.

In this case, when no DC bias magnetic field is applied, the 13th
As shown in the figure, the giant magnetostrictive element 43 is in a contracted state, and the tip side of the running leg 44 maintains a state in which it is tilted backward. When an alternating magnetic field is applied in this state, the giant magnetostrictive element 43 expands and contracts finely in the axial direction, and this expanding and contracting movement is transmitted to each traveling leg 44 via the operating rod 48 in an expanded manner.
Rotate 4 back and forth. Since each traveling leg 44 vibrates finely around its rearward tilted position, the lumen 5
It moves forward by the movement of the tips of its respective running legs 44 that touch the wall surface of 5.

When a large DC bias magnetic field is applied, the giant magnetostrictive element 43 expands greatly, as shown in FIG.
The tip side of the tip will be tilted forward and this state will be maintained. When an alternating magnetic field is applied in this state, each traveling leg 44 vibrates finely centering on the forward tilted state, so that the tip of each traveling leg 44 touches the wall surface of the lumen 55 and moves backward.

Note that if the DC bias magnetic field is applied at an intermediate value, the 15th
As shown in the figure, the traveling legs 44 are at right angles, and even if an alternating magnetic field is applied in this state, no traveling operation is performed.

FIG. 16 shows a third embodiment of the present invention. The medical capsule 40 of this embodiment is provided with running mechanisms 42 for moving the capsule body 41 in four directions around the capsule body 41, respectively.

For this reason, a plurality of drive giant magnetostrictive elements 43 are provided laterally,
Correspondingly, the displacement magnifying mechanism 45 and the traveling leg group 44
were set up separately. The rest of the configuration of the traveling mechanism 42 is the same as that of the previous embodiment, and its traveling operation is also the same.

Further, a so-called mechanical substance 58 is used as a means for moving the piston 52 within the capsule body 41, and the piston 52 is moved forward by expansion thereof.

FIG. 17 shows a fourth embodiment of the present invention. In the medical capsule 60 of this embodiment, the traveling mechanism 62 for causing the capsule body 61 to travel is constructed in the same manner as in the second embodiment, but the internal configuration of the capsule body 61 is different. This includes an ultrasonic observation means built into the capsule body 61. That is, an ultrasonic transducer 63 is rotatably installed in an observation chamber 64 filled with liquid paraffin 63a, and an ultrasonic motor 65 for rotationally driving the ultrasonic transducer 63 is provided. Further, inside the capsule body 61, a transmitting circuit 66, a communication circuit 67, an antenna 68, a battery 69, etc. are incorporated. Observation operations can be performed in response to commands from outside using wireless communication.

Thus, the medical capsule 60 can move the capsule body 61 to a desired site and observe that site using ultrasound.

FIG. 18 shows a fifth embodiment of the present invention. The medical capsule 70 of this embodiment has a traveling mechanism 72 attached to the side surface of the capsule body 71. Further, the giant magnetostrictive element 73 of the traveling mechanism 72 is located inside the capsule body 71. Further, one end of the giant magnetostrictive element 73 is connected to the capsule body 7.
The other end of the giant magnetostrictive element 73 is connected to a movable plate 75 arranged on the side surface of the capsule body 71. And a plurality of traveling legs 7 tilted in advance.
6 is connected to the movable plate 75 thereof.

Therefore, by applying an alternating magnetic field, the giant magnetostrictive element 73
The traveling leg 44 can be vibrated by expanding and contracting to allow the vehicle to travel as described above.

Note that the configuration of the means for administering the drug is substantially the same as that of the second embodiment. If the intermediate portion of the running leg 76 is configured to be pivoted, the traveling direction can be selected as described above depending on the magnitude of the DC bias magnetic field.

FIG. 19 shows a sixth embodiment of the present invention. The medical capsule 80 of this embodiment is a modification of the fifth embodiment, and has a giant magnetostrictive element 7 inside the capsule body 81.
This device incorporates a mechanism to increase the amount of extension in step 3. That is, one end of the giant magnetostrictive element 73 is fixed to the fixing plate 82. Further, the other end of the giant magnetostrictive element 73 is connected to the tip of the short end of the lever lever 83. Further, the tip of the long end of the lever lever 83 is connected to the operation moving plate 75.

Note that the fulcrum of each lever 83 is supported by a fixed plate 85 by a support rod 84. Note that the configuration of the means for administering the drug is also substantially the same as that of the second embodiment.

Therefore, in this embodiment, the movement of the giant magnetostrictive element 73 is magnified via the lever 83 and transmitted to the operation moving plate 75.

FIG. 20 shows the configuration shown in FIG. 19 in which the movable plate 75 is replaced with a flexible rod-shaped stopper 91.

The distal end portion of the stopper 91 can vertically protrude and retract from the side surface portion of the capsule body 81.

Then, by applying a direct current magnetic field and elongating the giant magnetostrictive element 73,
This amount of expansion is magnified by the lever lever 83 and transmitted to the stopper 9, so that the capsule is projected from the side surface of the capsule body 81. By protruding the stopper 91 from the side surface of the capsule body 81 in this manner, the tip of the stopper 91 is brought into contact with the wall surface of the lumen 55 to hold the capsule body 81.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications are possible.

[Effects of the Invention] As explained above, according to the present invention, a compact medical capsule can be constructed by using a traveling actuator that utilizes the inertial force of an inertial body due to rapid deformation of a piezoelectric element and the frictional force between the body and the living body. At the same time, it is possible to reliably reach the desired site within the living body.

[Brief explanation of the drawing]

1 to 9 show a first embodiment of the present invention, FIG. 1 is a sectional view of a medical capsule thereof, FIG. 2 is a perspective view of a piston ring, and FIG. 3 is a deformation of the piston ring. FIG. 4 is an explanatory diagram of the driving principle, FIG. 5 is a waveform diagram of the driving voltage applied to the piezoelectric element, and FIGS. 6 and 7 are cross-sectional views showing the operating state of the medical capsule. , FIG. 8 is an explanatory diagram of the running state of the medical capsule, and FIG. 9 is an explanatory diagram of the medicinal solution administration state of the medical capsule. No.'10
The figure is an explanatory diagram of the schematic configuration of the water jet, No. 11.
The figure is a perspective view of an indwelling medical solution administration device. FIGS. 12 to 15 show a second embodiment of the present invention, and FIG.
The figures are cross-sectional views of the medical capsule, Figures 13 to 1.
FIG. 5 is an explanatory diagram of the principle of operation in different operating states. FIG. 16 is a sectional view of a medical capsule showing a third embodiment of the invention, FIG. 17 is a sectional view of a medical capsule showing a fourth embodiment of the invention, and FIG. 18 is a sectional view of a medical capsule showing a fourth embodiment of the invention. 5
FIG. 19 is a sectional view of a medical capsule showing a sixth embodiment of the present invention, and FIG. 20 is a sectional view of another medical capsule. M... moving body, m... inertial body, P... piezoelectric element,
B... Base, 1... Capsule, 2... Capsule body, 12... Piezoelectric element, 13... Inertial body, 15...
Control means, 40... Capsule, 42 - Traveling mechanism, 4
3... Giant magnetostrictive element, 44... Leg, 45... Displacement magnification mechanism, 48... Operation rod. Applicant's agent Patent attorney Atsushi Tsuboi 1rA Jl12 Figure 3tlA Figure 4 W & 5 Figure 6 #711! J Figure 8 JII9 Figure 110 Figure 11n Figure 121A Figure 13 Figure 14 Figure 1S Figure 16 Figure 18

Claims (2)

[Claims] (1) In a medical capsule that is administered into a living body, a piezoelectric element that is axially arranged along the direction in which the capsule body is to be moved and that can be expanded and contracted in the axial direction is provided in the capsule body that also serves as a moving body. , one end of the piezoelectric element in the axial direction is substantially fixed to the capsule body, an inertial body is attached to the other end of the piezoelectric element in the axial direction, and further, the piezoelectric element is provided within the capsule body. The capsule body uses the inertial force of the inertial body when the piezoelectric element expands and contracts in its axial direction by controlling the battery that applies a driving voltage and the driving voltage, and the frictional force between the capsule body and the living body. A medical capsule characterized by having a built-in control means for controlling the traveling motion of moving the capsule. (2) In a medical capsule to be administered into a living body, a movable leg part that performs a self-propelled displacement operation in contact with a body cavity wall, a giant magnetostrictive element that is displaced in the axial direction by an applied magnetic field, and this giant magnetostrictive element A medical capsule comprising: a displacement transmission mechanism that transmits the displacement of the movable leg portion to the movable leg portion to cause the movable leg portion to perform a traveling motion.