JPS6139815B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diagnostic apparatus in which an endoscope is equipped with an ultrasonic transducer, and images of various organs inside the body are created from within the body cavity.

In recent years, diagnosis using ultrasound tomographic images using the pulse echo method has become widely used in the medical field. This is usually done by pressing an ultrasonic transducer probe against the patient's body surface, scanning the probe mechanically or electrically, and simultaneously displaying reflected pulses from internal organs on a cathode ray tube. Such ultrasonic diagnostic methods have advantages over diagnostic methods using X-rays, such as being able to image soft tissue without using a contrast agent and being non-invasive. However, when obtaining ultrasonic tomographic images of internal organs from the body surface, there are physical limitations to the images obtained. In other words, in order to improve the resolution of reconstructed images, it is necessary to use high-frequency ultrasound, but increasing the frequency increases absorption in living tissues, making deep contrast imaging difficult and making it difficult to obtain images of the target organ. I can't. In addition, there are non-uniform tissue layers such as fat thickness near the body surface, which causes deterioration of image quality. Furthermore, the reflection and absorption of ultrasound waves by bones in the living body is large.
It was difficult to contrast the organs located behind the bones.

Ultrasonic diagnosis from within the body cavity has been proposed as a method for improving the drawbacks of ultrasound diagnosis from the body surface. Diagnostic methods from inside the body cavity include, for example, a method in which a tube with an ultrasonic transducer attached to the tip is inserted into the rectum and the prostate is diagnosed by radar scanning (SSD-62 manufactured by Aloka), or a method using the German patent No. As seen in the specification of No. 2305501 and Japanese Patent Application Laid-Open No. 53-85982, there is a method in which one or more ultrasonic transducers are attached to the longitudinal direction of the side surface of the insertion tube and scanning is performed manually or electrically. However, none of these ultrasound diagnostic devices are equipped with a means to optically observe the inside of the body cavity, so it is difficult to know where in the body cavity the ultrasound transducer is located and in what direction it is facing. However, the diagnosis area was limited to shallow areas within the body cavity.

On the other hand, endoscopes are widely known as devices that can optically observe the inside of a body cavity. Therefore, it is expected to provide an ultrasonic diagnostic apparatus that eliminates the above-mentioned drawbacks by incorporating an ultrasonic transducer into the tip of an endoscope having such an optical observation means. However, endoscopes are limited in their thickness; for example, for endoscopes that pass through the oral cavity to observe the stomach or duodenum, the diameter that can be inserted without causing great pain to the patient is the maximum diameter.
It is 13-14mm. The smallest transducer for electronic sector scanning currently available is 10 x 13 x 16 mm.
Therefore, a single transducer is more practical to incorporate into an endoscope. When using a single transducer, some kind of mechanical scanning method is required to obtain a two-dimensional tomographic image. One method is to connect the ultrasonic transducer attached to the tip of the endoscope and the endoscope operation part with a flexible shaft, and rotate the ultrasonic transducer from outside the body manually or by power means. It is conceivable to perform sector scanning by moving the endoscope, but as an alternative method, for example, Japanese Patent Application Laid-Open No. 1984-1984 places an ultra-small motor near the ultrasonic transducer at the tip of the endoscope. An example is described in which scanning is performed by rotating a sonic vibrator. However, for a motor used in such an application, for example, a 5 mmφ x 7 mm pulse motor has a maximum torque of about 100 mg cm, and even if a reduction gear head with a gear ratio of 200:1 and a transmission efficiency of 50% is used, the output will be low. Torque is only 10gcm. on the other hand,
Since high-frequency ultrasound waves used for diagnosis hardly propagate through gas, it is necessary to place an ultrasound transducer in an ultrasound propagation medium such as degassed water. It is necessary to seal the gap airtightly against the ultrasonic propagation medium. As a method of sealing against such liquids, it is usually known to use a ring-shaped or sheet-shaped elastic member such as rubber.
Since these sealing materials directly contact the output shaft of the motor or gear head, friction is large, and mechanical loss is large, making it unsuitable especially when using an ultra-small motor with a small output torque as in this example.

An object of the present invention is to be able to optically observe the inside of a body cavity not only during insertion into a body cavity but also after insertion, thereby avoiding dangers during insertion, and allowing an ultrasonic transducer to move into a body cavity. The purpose of the present invention is to provide an ultrasonic diagnostic device that can obtain more accurate information inside a body cavity by knowing which part of the body is facing in which direction, and furthermore, an ultrasonic diagnostic device that can be assembled to the tip of an endoscope. An object of the present invention is to provide a means for sealing between a built-in ultrasonic transducer and an output shaft of an ultra-small motor using a method with little mechanical loss.

In the intrabody cavity ultrasound diagnostic apparatus according to the present invention, an opening is formed in the outer barrel of the endoscope in the vicinity of the observation section of the endoscope having an observation optical system and an illumination optical system, and this opening is covered. an enclosure is provided, and a cavity communicating with the enclosure is formed within the endoscope,
An ultrasonic transducer is swingably disposed in a chamber defined by the cavity and the enclosure, and an ultrasonic propagation medium can be supplied and discharged to this chamber. A motor having a speed reduction mechanism is disposed outside the chamber, and the output shaft of the speed reduction mechanism projects into the chamber and is mechanically coupled to the ultrasonic transducer, wherein the output shaft of the speed reduction mechanism and the chamber are connected to each other. A magnetic circuit arranged to generate a magnetic flux passing through or along the output shaft is provided at the boundary, and a magnetic fluid is filled between the output shaft and the magnetic circuit to generate ultrasonic electricity in the room. This device is characterized in that it seals the carrier medium.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a sectional view showing a distal end observation section of an embodiment of the intracorporeal ultrasound diagnostic apparatus of the present invention, and FIG. 2 is a perspective view showing details of a part thereof. This example shows a side-viewing endoscope, in which a light guide 2 for guiding illumination light and an image guide 3 for transmitting images are extended within a flexible outer tube 1. The tip of the light guide 2 is bent approximately 90 degrees to face the glass window 4 fitted in the outer cylinder 1. The light passing through the light guide 2 and exiting from the glass window 4 is reflected by the body cavity wall S, and the light is emitted from the glass window 4.
After being introduced into the endoscope through the prism 6 and reflected by the prism 6, the image is formed on the end surface of the image guide 3 by the lens system 7, and is led out through the image guide 3. In this way, the body cavity wall S can be optically observed.

In the present invention, an opening 1A is formed in the vicinity of the observation section of the outer tube 1 of the endoscope, and an enclosure made of a flexible material that can be expanded and contracted, such as a rubber bag, is provided to cover the opening 1A. Install 8. A space 1B communicating with the enclosure 8 is defined in the outer cylinder 1 by yoke members 15, 16 made of soft magnetic material and a partition wall 1C.
A partition wall 1C is formed between this space 1B and optical systems such as the light guide 2 and the image guide 3. In order to supply and drain an ultrasonic propagation medium such as degassed water into the space defined by the storage part 1B and the enclosure 8, a tube 9 is extended into the outer cylinder 1 of the endoscope through the partition wall 1C. , the other end of the tube 9 is led out. In this example, the ultrasonic transducer 10 is placed in the space 1B, and the ultrasonic wave is transmitted to the output shaft 13 of the deceleration mechanism 12 connected to the motor 11 placed adjacent to the ultrasonic vibrator 10 at the tip of the endoscope. The vibrator 10 is connected. As shown in detail in FIG. 2, a magnetic circuit is provided around the output shaft 13 so as to generate magnetic flux through the output shaft 13. This magnetic circuit is constituted by an annular magnet 14 magnetized in the axial direction, and annular yoke members 15 and 16 made of a soft magnetic material and arranged to sandwich the magnet 14. The output shaft 13 is preferably made of a soft magnetic material, and the magnet 14 is preferably made of a material with a large maximum energy product, such as a samarium cobalt magnet. A magnetic gap formed between the inner peripheral portions of the yoke members 15 and 16 and the output shaft 13 of the reduction mechanism 12 is filled with a magnetic fluid 17. Magnetic fluid is made by dispersing magnetic fine powder such as Fe ₃ O ₄ of about 100 Å in a solvent such as diester so as not to condense. It has been known. When the ultrasonic propagation medium is water, a hydrophobic solvent is used for the magnetic fluid 17. Note that 18 and 19 are lead wires of the ultrasonic transducer 10 and the motor 11, respectively, through the inside of the outer cylinder 1 and led out to the outside.

The outer peripheries of the yoke materials 15 and 16 are sealed with the outer cylinder 1, and a magnetic fluid 17 is held by magnetic force in a magnetic gap between the inner peripheries of the yoke materials 15 and 16 and the output shaft 13 of the reduction mechanism 12. Therefore, the motor 11 and the speed reduction mechanism 12 are sealed from the ultrasonic propagation medium filling the space defined by the cavity 1B and the enclosure 8. In addition, the sealing material does not come into direct contact with the output shaft 13 like normal rubber packing materials, and the only resistance when the output shaft 13 rotates is the viscous resistance of the magnetic fluid 17, so the output torque is reduced to almost nothing. Rotation can be transmitted to the ultrasonic transducer 10 without damage. This is a great advantage when using an ultra-small motor with a small output torque, and especially when a pulse motor is used as the motor 11, it has the advantage of reducing accidents such as miss pulses due to increased load torque.

FIG. 3 is a diagram showing a second embodiment of the intrabody cavity diagnostic apparatus of the present invention. Two magnets 14a and 14b having recesses corresponding to the cross-sectional shape of the output shaft 13 are arranged on both sides of the output shaft 13 of the speed reduction mechanism 12 so that their opposite polarities face each other. magnet 1
Both side surfaces and outer peripheries of 4a and 14b are molded with a non-magnetic material 20 such as plastic material, as shown by the hatched area surrounded by broken lines in the figure, except for the vicinity of the output shaft 13. In addition, the magnets 14a, 14b and the output shaft 1
The gap surrounded by 3 is filled with magnetic fluid 17.
By adopting such a structure, the same waterproof sealing effect as explained in the first embodiment can be obtained. Also, compared to the first embodiment, the yoke material 15,1
6 is not required, it is expected that the thickness in the axial direction can be reduced.

As described above, according to the present invention, in an intrabody cavity ultrasound diagnostic apparatus in which an ultrasonic transducer, a motor for rotating the transducer, and a deceleration mechanism are installed near an endoscope tip observation system, the motor deceleration mechanism By sealing the output shaft of the motor using a magnetic fluid, the motor section can be sealed from the ultrasonic propagation medium with almost no loss in output torque.

The present invention is not limited to the above-mentioned examples, and can be modified and modified in many ways. For example, in the example described above, the output shaft 13 was made of magnetic material,
It can also be made of non-magnetic material, in which case the magnetic circuit can be configured so that a magnetic flux is created along the output axis. In addition, the magnetic circuit is connected to the output shaft 13.
It is also possible to install multiple units in the direction of . Further, in the above example, the present invention is applied to a side-viewing endoscope, but it is of course possible to apply the present invention to a direct-viewing endoscope. Furthermore, the output shaft 13 can be made of a magnetic material and can be magnetized.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the distal end observation part of an embodiment of the intracorporeal ultrasound diagnostic device of the present invention, FIG. 2 is a perspective view showing details of a part of FIG. 1, and FIG. 3 is the device of the present invention. FIG. 3 is a sectional view showing a second embodiment of the present invention. 1... Outer tube of endoscope, 1A... Opening, 1B...
...Vacancy, 1C...Bulkhead, 2...Light guide, 3
...Image guide, 4, 5...Glass window, 6...
...prism, 7...lens, 8...envelope, 9...
...Tube, 10...Ultrasonic transducer, 11...Motor, 12...Deceleration mechanism, 13...Output shaft, 1
4, 14a, 14b... Magnet, 15, 16... Yoke material of soft magnetic material, 17... Magnetic fluid, 18,
19...Conducting wire, 20...Mold of non-magnetic material.

Claims (1)

[Claims] 1. An opening is formed in the outer barrel of the endoscope in the vicinity of the observation section of the endoscope having an observation optical system and an illumination optical system, and an enclosure is provided to cover this opening. A cavity communicating with the enclosure is formed inside the chamber, and an ultrasonic transducer is swingably disposed in the chamber defined by this cavity and the enclosure, and an ultrasonic propagation medium is supplied and discharged to and from this chamber. A motor having a deceleration mechanism is further disposed inside the endoscope outer cylinder outside the chamber, and the output shaft of the deceleration mechanism protrudes into the chamber so as to be mechanically connected to the ultrasonic transducer. In the combined structure, a magnetic circuit is provided at the boundary between the output shaft of the speed reduction mechanism and the chamber, and the magnetic circuit is arranged to generate a magnetic flux passing through or along the output shaft, and the output shaft and the magnetic circuit are connected to each other. 1. An intrabody cavity ultrasonic diagnostic apparatus, characterized in that a magnetic fluid is filled between the spaces to seal against an ultrasonic propagation medium in the room.