JP5963158B2 - Self-propelled capsule endoscope - Google Patents

Description

  The present invention relates to a self-propelled capsule endoscope, and more particularly to a propulsion drive mechanism for a capsule endoscope.

  Endoscopes are widely used in the field of medicine and the like for observing a site that cannot be directly observed, such as in a lumen. Such an endoscope is generally configured with an elongated insertion portion, and is inserted into a subject by a user's procedure.

  In general-purpose tube endoscopes, the imaging range is limited to the esophagus, stomach, duodenum, large intestine, etc., and it is difficult to diagnose and treat diseases in the small intestine located inside. The current situation is. For this reason, imaging methods and specific endoscopic methods are mainly used as small intestine inspection methods currently being implemented.

  Among the imaging methods, the small intestine fluoroscopy method based on contrast examination using barium has a drawback in that there is a considerable individual difference in the distribution of barium throughout the small intestine, and it takes a long examination time. CT and MRI tomography can sufficiently confirm large lesions such as the presence of tumors and the extent of intestinal obstruction, but small intestinal mucosal lesions (such as ulcers or injuries that damage the intestinal lining, or vascular lesions with bleeding) Etc.) are said to be difficult to detect.

  As for the endoscopic method, the double balloon method (see Non-Patent Document 1) and the capsule method (see Non-Patent Document 2) have been widely used at present. In the double balloon method, when the entire small intestine is examined, it is generally performed in two steps, oral and transanal, and the detected lesion is biopsied and endoscopically as necessary. It is characteristic that endoscopic procedures such as polypectomy or balloon dilation for intestinal stenosis are possible.

  The other capsule method is attracting attention as a non-invasive examination method that is less burdensome and less painful for the subject because the capsule endoscope is small in size. Recently, the development of a system that swallows a tablet-like capsule equipped with a small camera and transmits imaging throughout the small intestine by wireless communication outside the body has been promoted. Full-scale introduction of endoscopes has begun.

  However, many capsule endoscopes currently used cannot be self-propelled, and in the digestive tract, the capsule body moves by retinal movement of the intestinal wall of the same organ as food and peristaltic movement of the intestine. Therefore, observation and control from an arbitrary position and direction are difficult, and as a result, there are problems in the reliability of diagnosis, such as oversight of lesions due to unclear images or oversight due to inability to observe lesions. There is.

  Furthermore, when the motility function of the digestive tract itself has deteriorated, the moving speed that progresses decreases, and the entire small intestine cannot be examined or imaged due to time constraints on the battery performance, or the digestive tract due to lesions such as the diverticulum on the inner wall of the digestive tract In some cases, capsules stay in bent or narrowed areas of the tube, and the reliability of diagnosis and treatment of diseases is not sufficient.

  On the other hand, the self-propelled capsule endoscope was announced in Japan in July 2009, but it can swim underwater previously swallowed in the stomach with a conductive soft actuator fin attached to the conventional capsule (full length). 48 mm), and there are many problems to be solved for application to the intestinal environment (see Non-Patent Document 3).

  Therefore, the capsule method is often used separately for screening, and the double tube method is often used for close inspection. However, in the capsule method, if it is possible to provide the reliability of the image data taken by the camera, the safety and controllability of traveling, and the functionality to avoid stagnation, the reliability of the capsule endoscopy can be improved. Increasing demand for capsule endoscopes is expected to increase.

  In order to solve these problems, the present inventors presented “Development of a self-propelled capsule endoscope having a DDS function” at the Japan Society of Mechanical Engineers Welfare Engineering Symposium 2008. Fig. 4 shows the self-propelled capsule endoscope presented at the symposium. Its features are as follows: (1) Since the power supply is performed from outside the body, the main unit battery is unnecessary, and the free space is used for transporting therapeutic drugs and sampling equipment. (2) Self-propelled drive system can use rotation / vibration and linear propulsion, (3) Function to escape from falling or staying in diverticulum or stenosis To improve safety and reliability.

  However, in the self-propelled capsule endoscope presented at the symposium, as shown in FIG. 4, a magnet is inserted into a single electromagnetic coil arranged along the inside of the cylindrical capsule, and the electromagnetic coil is energized. Although it has a structure that drives the magnet in the coil to obtain propulsive force, the propulsion direction is the same as the movement direction of the magnet in the electromagnetic coil, that is, the longitudinal movement of the self-propelled capsule endoscope moves back and forth. It was only possible, and it was not possible to change the direction up and down, left and right, etc., and it was insufficient as a function to escape from dropping or staying in a diverticulum or stenosis.

  In addition, the self-propelled capsule endoscope announced above is a method in which the direction can be changed by the magnetic force generated by the magnetic field generator provided outside the body, in order to change the direction of the self-propelled capsule endoscope in the body. There is a problem that it is necessary to generate a large magnetic field, and the influence of a strong magnetic field on the human body cannot be ignored.

  Furthermore, in order to realize the function to apply the medicine mounted on the capsule endoscope to the diseased part and the function to image the diseased part from various angles, the movement to the imaging location before and after the affected part or the capsule stops It is necessary to change the angle in small increments. Therefore, the capsule endoscope needs a direction changing function for moving to the imaging region by rotation, but the announced self-propelled capsule endoscope does not have the function.

Tajiri, H.M. What do we see in the endorsement world in 10 years' time? . Digestive Endoscopy. 2007, Vol. 19 (suppl.1), p. 174-179. de Francis, R.D. Rondonotti, E .; Villa, F .; Capsule endoscopy-state of the art. Dig Dis. 2007, Vol. 25, no. 3, p. 249-251. Eijiro Morita, Naotake Otsuka, Yasunori Endo et al., “A trial of making a self-propelled capsule endoscope controlled by a magnetic field”, Gastroenterology, 2009, Vol. 48, No2, p. 177-183

  As a result of diligent research, the inventors changed to a linear propulsion structure in which a magnet is arranged in a single electromagnetic coil provided along the inside of a conventional cylindrical capsule, and inside the cylindrical capsule, By providing a linear propulsion structure in which a rod-shaped coil is provided and a drive unit is disposed outside the rod-shaped coil, the capsule endoscope is provided with a direction changing function, and further, a plurality of rod-shaped coils are provided. A drive unit is placed in between, and the energization of multiple rod-shaped coils is controlled to give the capsule endoscope a forward and backward propulsion function and a direction change function in various directions. I found it. The present invention has been made based on the new knowledge.

  That is, an object of the present invention is to sufficiently escape from a drop or stay in a small intestinal diverticulum or stenosis by enabling rotation in various directions in a self-propelled capsule endoscope having a linear propulsion mechanism. It is to provide a self-propelled capsule endoscope having a function capable of being performed. Another object of the present invention is to provide a self-propelled capsule endoscope having a direction changing function for applying a drug to a diseased part around the affected part and photographing the affected part from various angles. is there.

  The present invention relates to a self-propelled capsule endoscope described below.

(1) In a self-propelled capsule endoscope having a linear propulsion mechanism including a rod-shaped coil portion and a drive portion inside,
A plurality of the rod-shaped coil portions are provided inside the capsule,
The drive unit is provided in a capsule outside the rod-shaped coil unit, and
The drive unit is provided so that the center side of the capsule can be moved along the plurality of bar-shaped coil units from the plurality of bar-shaped coil units,
A self-propelled capsule endoscope characterized by providing a capsule endoscope with a propulsion function in the front-rear direction and a direction changing function in various directions by controlling energization of the plurality of rod-shaped coil portions .

(2) The self-propelled capsule endoscope according to (1), wherein the rod-like coil portions are provided in an odd number of 3 or more and at equal intervals.

(3) The self-propelled capsule endoscope according to (1) or (2), wherein the number of the rod-shaped coil portions is three.

  In the present invention, a linear propulsion mechanism having a rod-shaped coil and a drive unit disposed outside the rod-shaped coil enables (1) rotating the capsule endoscope in small increments, (2) applying a drug to the diseased part, 3) The diseased part can be imaged and examined from various angles. Also, by providing a plurality of bar-shaped coils, disposing a drive unit between the plurality of bar-shaped coils and energizing all of the plurality of bar-shaped coils or energizing only a part thereof, the capsule endoscope can be operated in the front-rear direction and the vertical and horizontal directions Can be controlled more reliably, and can be reliably escaped from dropping or staying in the diverticulum or stenosis of the small intestine.

  Further, since the forward and backward propulsive force and the direction changing function of the capsule endoscope can be obtained only by controlling the energization of the rod-shaped coil, no external magnetic field is required, and the influence on the human body can be reduced. And since a rod-shaped coil part is provided in the inside of a capsule at intervals, it becomes easy to design a DDS function.

FIG. 1 is a schematic view showing an example of a self-propelled capsule endoscope having the linear propulsion mechanism of the present invention. FIG. 2 shows the propulsion drive principle of the self-propelled capsule endoscope of the present invention. FIG. 3 shows the principle of direction change of the self-propelled capsule endoscope of the present invention. FIG. 4 shows an outline of a conventional self-propelled capsule endoscope.

  Hereinafter, an example of a self-propelled capsule endoscope having the linear propulsion mechanism of the present invention will be described with reference to the drawings. FIG. 1 shows an overall schematic configuration of a self-propelled capsule endoscope 10. The self-propelled capsule endoscope of the present invention has a configuration for imaging the inside of the digestive tract, a capsule endoscope. Includes a configuration for propelling and changing the direction, and a configuration for transmitting imaging data.

  A configuration for imaging the inside of the digestive tract includes an optical dome 11 provided at one end of a self-propelled capsule endoscope, a camera unit 12 provided in the optical dome 11, a power receiving coil unit 13, and a storage capacitor unit 14. And an illumination unit such as an LED (not shown). The camera unit 12 is not particularly limited as long as it can capture a digital image, such as a CCD image sensor, and is a combination of a focus adjustment function using a reaction caused by a magnetic force and brightness of LEDs arranged on the left and right (not shown). This makes it possible to create a stereoscopic image even with a single eye. In addition, since it is equipped with a self-propelled function, an image sensor-assisted image stabilization function of the same method as the optical method can be applied. If the imaging time by the camera is limited, the imaging of the in-vivo image is affected. Therefore, it is desirable to secure the power source from outside the body. For example, the power receiving coil unit 13 for adopting wireless power transmission is provided. Has been placed. The magnetized power is stored in the storage capacitor unit 14 and supplied for generating propulsive force and changing the direction of the self-propelled capsule endoscope in addition to imaging in the digestive tract. In many capsule endoscopes that are currently widely used, a battery for imaging is mounted in the capsule, but the capacity of the capsule main body is still large although it is considerably downsized. If an external power transmission system is adopted, a large free space can be secured inside the capsule, and it can be used as a compartment 15 for storing precision examinations, therapeutic drugs, sensors, etc., and further use of the capsule endoscope Expansion can also be expected. Of course, if the battery is miniaturized to such an extent that the function of the self-propelled capsule endoscope of the present invention can be sufficiently achieved, the battery can be used as a drive source for the self-propelled capsule endoscope.

  The capsule endoscope of the present invention can be propelled and changed in direction by a linear propulsion mechanism having a coil portion 16 and a driving portion 17 disposed outside the coil portion 16. The coil section 16 is a thin rod coil in which a thin wire with excellent conductivity such as enamel or copper is wound in a hollow shape, or a thin wire with excellent conductivity such as enamel or copper is wound around a core rod such as iron or magnet. It is made of a thin rod-like coil that is attached, and is made so that electricity supplied by remote supply from an internal battery or an external magnetic field is energized.

  The drive unit 17 is a member driven by a magnetic field generated by energizing the coil unit 16 and is not particularly limited as long as it is an iron core or a magnet having a high magnetic flux density. For example, the drive unit 17 is made of a magnet such as neodymium.

  The configuration for transmitting the imaging data includes a microwave video transmitter unit 18, transmits image data captured by the camera unit 12 of the self-propelled capsule endoscope to a host computer (not shown), and analyzes the data. Enable diagnosis.

  The linear propulsion mechanism is controlled by a microcomputer (not shown), and the drive signal can be transmitted to the capsule endoscope wirelessly.

  Next, the principle of linear propulsion drive according to the present invention will be described. FIG. 2 is a cross-sectional view of the self-propelled capsule endoscope of FIG. 1, and is a view for explaining the propulsion principle in the front-rear direction when four coil portions 16 are provided at equal intervals of 90 degrees. When all the coil portions 16 are energized, the drive portion 17 is in a state of floating at the center of the capsule of the endoscope as shown in FIG. Next, as shown in (2), the drive unit 17 is given an acceleration toward the center of the self-propelled capsule endoscope. At this time, the self-propelled capsule endoscope is given a propulsive force that slides to the right by the reaction force. When the drive unit 17 passes through the central portion of the moving space, a current in the reverse direction is passed through the coil unit 16 (3). At this time, the speed of the drive unit 17 is set so that the friction force between the self-propelled capsule endoscope and the external environment is greater than the force to move the self-propelled capsule endoscope by the reaction force of the movable magnet. Control is performed so as to be slower than in the cases (1) to (2). Specifically, in PWM (Pulse Width Modulation) control by the microcomputer, the duty ratio (on-off time ratio) is controlled to be low. If the above operation is repeated as one cycle, the self-propelled capsule endoscope can be driven in the right direction of the drawing (hereinafter, this method may be referred to as “slide running”).

  On the other hand, as shown in FIG. 2 (4), it is possible to make the drive unit 17 collide with the right end of the self-propelled capsule endoscope and move the self-propelled capsule endoscope with the collision force. In this case, first, the drive unit 17 is gently moved from the state (1) to the position (3) by passing a current with a reduced duty ratio through the coil unit 16. Next, when a reverse current is passed through the coil unit 16 without suppressing the duty ratio, the driving unit 17 continues to accelerate until it collides with the right end, and the self-propelled capsule endoscope moves to the right by the impact force. . At this time, in the acceleration process of (4), the self-propelled capsule endoscope moves to the left by the reaction force, but the movement by the impact force wins, so by repeating the above operation, the aircraft moves to the right A net amount of movement in the direction can be obtained (hereinafter, this method may be referred to as “knock traveling”).

  The above description is a driving method in the case of propelling the self-propelled capsule endoscope in the right direction, but the moving direction and the energizing direction of the driving unit 17 in (1) to (4) in FIG. 2 are reversed. Thus, it is possible to push the self-propelled capsule endoscope in the left direction based on the same principle as described above.

  Next, direction change using the linear propulsion mechanism of the present invention will be described. 3A and 3B are vertical sectional views in the moving direction of the drive unit 17 of the self-propelled capsule endoscope, and FIG. 3A is a drive unit 17 when all the coil units 16a to 16d are energized. Indicates the position. Since the center of the drive unit 17 coincides with the center of the capsule of the self-propelled capsule endoscope, as shown in FIG. 2, a propelling force to the left and right is applied to the self-propelled capsule endoscope.

  On the other hand, for example, as shown in FIG. 3 (2), when only a part of the coil part (16a and 16d in FIG. 3 (2)) is energized, the drive part 17 moves in the coil parts 16a and 16d direction. Moving. As shown in (3), when the drive unit 17 collides with the right end in a state of being decentered from the center of the capsule of the self-propelled capsule endoscope, the self-propelled capsule endoscope rotates in the direction of the arrow. Is given. Of course, in addition to the knocking traveling method, a rotating force can be applied even in the sliding traveling method as long as it is in an eccentric state. And it is possible to give the force which rotates to a self-propelled capsule endoscope to various directions by changing suitably the direction change rotor coil part 16 which supplies electricity, and controlling an electricity supply direction.

  As described above, when a plurality of coil units 16 are provided, the drive unit 17 is controlled relatively easily. However, if at least one coil unit 16 is provided, the drive unit 17 can be driven. Since the capsule endoscope is rotated by the friction of the intestinal wall when it travels and passes by the peristaltic motion etc. in the intestine, the coil portion 16 provided near the inner side surface of the capsule of the capsule endoscope is In the intestine, the capsule endoscope can take various positions such as up, down, left and right. Further, since the drive unit 17 is also affected by the weight, the drive unit 17 is driven in various positional relationships depending on the position of the coil unit 16 and the acceleration speed. As a result, the capsule endoscope is moved in the front-rear direction. Various movements such as rotation to the left and right are possible.

  However, as described above, the present invention can be implemented with one or more coil portions 16, but it is desirable that the control as shown in FIGS. 3 (1) and (2) is possible. It is preferable that the number 16 is three or more, and the current supplied to the coil portion 16 is appropriately adjusted to one, two, or all.

  Furthermore, it is preferable that the coil part 16 is arrange | positioned asymmetrically. For example, in the case where three coil parts 16 are arranged at equal intervals, when the capsule endoscope is rotated as described above, the coil part 16 may be in an equilateral triangle state in which two are located at the bottom. Only one will be in the shape of an inverted triangle located at the bottom. If it does so, it will become easy to move the drive part 17 from the coil part 16 by the effect | action of a weight, or it will be in a contact state, and the exercise | movement performance of a self-propelled capsule endoscope will improve.

  On the other hand, in the case of propulsion control in the front-rear direction, it is preferable to energize all the coil parts 16. However, if the number of the coil parts 16 is too large, the power consumption increases, and the compartment 15 in which a therapeutic drug or the like is mounted. Less space is not desirable.

  Therefore, considering the driving force to the capsule endoscope, the direction change, and the space of the compartment 15, it is most preferable that the number of the coil portions 16 is three and they are arranged at equal intervals.

  The drive unit 17 may be of any shape, such as a sphere, a cylinder, a cube, a rectangular parallelepiped, etc., as long as it can move smoothly in the moving space. From the viewpoint of effectively giving to the wall surface, a cylindrical shape is preferable. If the drive unit 17 occupies the moving space is too small, sufficient driving force cannot be obtained, and if it is too large, the degree of eccentricity becomes small, and the direction change of the capsule endoscope becomes insufficient.

An apparatus for testing a self-propelled capsule endoscope of the present invention was produced as follows. Three hollow rod-like coils having an outer diameter of φ8, in which enamel wires were wound at a linear density of 2.5 wires / mm, were provided at equal intervals inside a thin cylindrical cylinder made of transparent PVC (vinyl chloride) of φ32 × 120 ^L. A movable magnet (made of neodymium having a magnetic flux density of 400 mT, φ15 × 10 ^L ) was provided between the three rod-shaped coils. In the running test, a voltage of 6 V and a current of 2.1 A were supplied, and a magnetic flux density of 5.5 mT was generated.

  The self-propelled capsule endoscope was installed on an intestinal model and an experiment was conducted. The outline of the intestinal tract model used in this example is a vertically divided acrylic cylinder having an inner diameter of 50 mm, an outer diameter of 60 mm, and a length of 500 mm, and the inner surface has a height of about 10 mm. A 20 mm silicon crease was adhered, and the entire inner surface was coated with an ultra-soft urethane resin having a friction coefficient similar to that of human skin. The urethane resin contains a main agent (polyol blend) and a curing agent (isocyanate) vol. The mixture was mixed and cured at a ratio of 3: 1, and the surface of the silicon fold was coated with a thickness of 4 to 8 mm. The friction characteristics between the self-propelled capsule endoscope and the test course surface were measured, and the static friction coefficient was 0.25 and the dynamic friction coefficient was 0.018.

  When all the coil parts 16 were energized, it was confirmed that the capsule endoscope was driven back and forth in both the sliding traveling and knock traveling systems. Further, when the drive unit 17 is driven by energizing only a part of the coil unit 16, the self-propelled capsule endoscope rotates in various directions in both the slide traveling and knock traveling methods, and in particular, the intestinal tract. When energizing only a part of the coil portion 16 in contact with the silicon fold of the inner model, it was confirmed that the self-propelled capsule endoscope jumped and turned over in the reverse direction.

Claims (3)

In a self-propelled capsule endoscope having a linear propulsion mechanism including a rod-shaped coil unit and a drive unit inside,
A plurality of the rod-shaped coil portions are provided inside the capsule,
The drive unit is provided in a capsule outside the rod-shaped coil unit, and
The drive unit is provided so that the center side of the capsule can be moved along the plurality of bar-shaped coil units from the plurality of bar-shaped coil units,
A self-propelled capsule endoscope characterized by providing a capsule endoscope with a propulsion function in the front-rear direction and a direction changing function in various directions by controlling energization of the plurality of rod-shaped coil portions . 2. The self-propelled capsule endoscope according to claim 1, wherein the rod-like coil portions are provided in an odd number of 3 or more and at equal intervals. The self-propelled capsule endoscope according to claim 1 or 2, wherein the number of the bar-shaped coil portions is three.

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