JPH10248851A - Ultrasonic endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic endoscope which can provide good ultrasonic images by preventing noises that may be produced by the irregular reflections of ultrasonic waves radiated toward an end part main body. SOLUTION: This ultrasonic endoscope causes ultrasonic wave radiated from an ultrasonic piezoelectric transducer 16 to reach an end part main body 4 when the acoustic axis 16a of the ultrasonic piezoelectric transducer 16 reaches near the boundary face between an end cap 10 and the end part main body 4. Then most of the ultrasonic waves radiated from the ultrasonic piezoelectric transducer 16 undergo total reflections, so that a reflected echo significantly greater than a reflected echo signal reflected by the end cap 10 returns. From this, the acoustic axis of the ultrasonic piezoelectric transducer 16 is determined to pass over the end part main body 4, during which the radiation of the ultrasonic waves from the ultrasonic piezoelectric transducer 16 is stopped temporarily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to an ultrasonic endoscope in which ultrasonic waves are mechanically scanned.

[0002]

2. Description of the Related Art By inserting an elongated insertion portion into a body cavity, an internal organ or the like in the body cavity can be observed, and if necessary, various treatments can be performed using a treatment tool inserted into a treatment tool channel. Mirrors are widely used. Also, the endoscope
Observation of objects in pipes of boilers, machines, chemical plants, etc.
It is used for inspection. Further, various types of electronic endoscopes using a solid-state imaging device such as a charge-coupled device (CCD) as an imaging means at the distal end of the endoscope insertion portion are also used.

[0003] In an endoscope having a treatment tool insertion channel, for example, an ultrasonic probe is inserted through the treatment instrument insertion channel to perform ultrasonic diagnosis.
When performing an ultrasonic diagnosis, an ultrasonic probe is guided to a target site via a treatment tool insertion channel, and an ultrasonic beam is oscillated to perform an ultrasonic diagnosis.

Further, an ultrasonic transducer is provided at the distal end of an endoscope insertion portion which can be inserted into a body cavity so that an ultrasonic tomographic image can be obtained by the ultrasonic transducer and a treatment instrument is inserted into the insertion portion. An ultrasonic endoscope has been put into practical use, which is provided with an insertion channel and allows a treatment tool to protrude from an outlet provided at a distal end of the treatment tool insertion channel to perform a treatment such as collecting a diseased tissue. ing.

[0005] An ultrasonic probe and an ultrasonic endoscope are designed to obtain an ultrasonic tomographic image in a lateral direction by directing an ultrasonic wave transmitting / receiving surface in a direction orthogonal to an insertion axis direction, The ultrasonic tomographic image in the forward direction is obtained with the ultrasonic wave transmitting / receiving surface facing forward.

For example, in Japanese Patent Application Laid-Open No. Hei 8-229045, a rotating shaft is provided at the distal end of an insertion portion in a direction perpendicular to the direction of the insertion axis, and an ultrasonic vibrator is supported on the rotation shaft, so that the front of the insertion direction is superposed. An ultrasonic inspection apparatus capable of ultrasonic scanning is shown.

[0007]

However, when scanning is performed by rotating the ultrasonic vibrator disclosed in the ultrasonic inspection apparatus disclosed in Japanese Patent Application Laid-Open No. Hei 8-229045, the surface of the ultrasonic vibrator (the vibrator When the sound axis is directed toward the ultrasonic endoscope main body, the ultrasonic wave is being emitted. For this reason, as a result of the ultrasonic wave being reflected by the distal end main body, a part of the reflected wave (also referred to as a reflected echo) is received by the ultrasonic vibrator in the diagnostic area, and noise such as ghost is generated in the ultrasonic image. Was causing it.

The present invention has been made in view of the above circumstances, and when performing ultrasonic scanning around a rotation axis orthogonal to the insertion axis direction, irregular reflection of ultrasonic waves radiated toward the distal end body is performed. An object of the present invention is to provide an ultrasonic endoscope capable of preventing noise and obtaining a good ultrasonic image.

[0009]

According to the ultrasonic endoscope of the present invention, a distal end cap for transmitting an ultrasonic wave is provided on a distal end main body of an insertion portion which can be inserted into a body cavity, and an insertion axial direction is provided in the distal end cap. An ultrasonic endoscope that rotationally scans an ultrasonic wave around a rotation axis perpendicular to the ultrasonic endoscope, wherein a reflected echo of the ultrasonic wave scanned around the rotation axis causes a boundary between the tip cap and the tip body to be moved. The transmission of the ultrasonic wave is interrupted for a certain time after the detection and the detection of the tip main body.

[0010] According to this configuration, the ultrasonic wave is emitted around the rotation axis that rotates in one direction, and is transmitted through the distal end cap and into the living body. Then, when the ultrasonic wave is irradiated toward the distal end main body, the ultrasonic wave is reflected by the distal end main body and a reflected echo is received. As a result, the boundary between the tip cap and the tip body is detected.

When the boundary between the tip cap and the tip body is detected, the driving of the ultrasonic transducer is interrupted for a certain time based on the detection. Then, since the ultrasonic wave is no longer irradiated, there is no reflected wave from the distal end body.

Then, a certain time elapses. Then, the ultrasonic vibrator is driven again to emit ultrasonic waves. At this time, the ultrasonic waves emitted from the rotating body pass through the distal end cap at the boundary between the distal end main body and the distal end cap and propagate into the living body.

When the ultrasonic wave is again irradiated toward the distal end main body and the boundary between the distal end cap and the distal end main body is detected, the driving of the ultrasonic vibrator is interrupted for a predetermined time.

By repeating the above operation, an ultrasonic image free of noise generated by the reflection of the ultrasonic wave on the distal end body is obtained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 7 relate to an embodiment of the present invention, FIG. 1 is an explanatory diagram showing a schematic configuration of an ultrasonic endoscope, FIG. 2 is a cross-sectional view showing a configuration of a distal end portion of the ultrasonic endoscope,
FIG. 3 is a block diagram illustrating the configuration of the ultrasonic endoscope system, FIG. 4 is a diagram illustrating a state in which the sound axis of the ultrasonic transducer is moving on the distal end cap, and FIG. FIG. 6 is a diagram showing the waveform of the reflected echo signal returned by
FIG. 7 shows a state when the sound axis of the ultrasonic transducer reaches the boundary surface between the tip cap and the tip body, and FIG. 7 shows a waveform of a reflected echo signal reflected back to the tip body. It is.

As shown in FIG. 1, an ultrasonic endoscope 1 constituting an ultrasonic endoscope system according to the present embodiment has an operation section 2 also serving as a grip section, and extends to the distal end side of the operation section 2. An insertion portion 3 which is elongated and inserted into a body cavity.

The insertion portion 3 includes a distal end body 4 formed of a hard member in order from the distal end side, a bending portion 5 which can be bent up and down and left and right, and a soft tube formed of a flexible tube member having flexibility. The unit 6 is provided in series.

The distal end main body 4 has an illumination window 7 for illuminating the inside of the body cavity, an observation window 8 in which an observation optical system for observing the inside of the body cavity under illumination is provided, and suction of body fluids and introduction into the body cavity. An outlet 9 for a treatment tool insertion channel for guiding the treatment tool is provided. A distal end cap 10 formed of a material having excellent ultrasonic permeability is provided on the distal end side of the distal end body 4.
Are arranged.

A universal cord 11 having a bifurcation branching from the side of the operation unit 2 at the base end thereof is extended. One of the branched cords is a light source cord 11a connected to a light source device for an endoscope (not shown), and a light source connector 1 detachably attached to the light source device at a base end.
2 are provided. The other branching cord is an ultrasonic cord 11 b connected to the ultrasonic drive unit 13, and an ultrasonic connector 14 detachable from the ultrasonic drive unit 13 is provided at the base end. The ultrasonic driving device 13 is connected to an ultrasonic observation device 15 described later, and relays ultrasonic signals to the ultrasonic endoscope 1 and supplies power for scanning the ultrasonic signals. Is going.

Reference numeral 2a denotes a bending operation knob for bending the bending portion 5, and reference numeral 2b denotes an eyepiece for observing an optical image of a portion to be inspected acquired by the observation optical system through the observation window 8. Department. Reference numeral 2c denotes a treatment instrument insertion port for guiding the treatment instrument to the treatment instrument insertion channel.

As shown in FIG. 2, a housing 17 having an ultrasonic vibrator 16 is rotatably supported with respect to the distal end body 4 inside a distal end cap 10 disposed on the distal end body 4. The rotating shaft 18 is integrally provided. The center axis 18a of the rotating shaft 18 is
Is orthogonal to the direction of the insertion shaft 1a.

At one end of the rotating shaft 18, a rotation transmitting shaft 19 for transmitting a rotational driving force from the ultrasonic driving device 13 constituted by a flexible member such as a flexible shaft is provided.
Are connected at one end. The rotation transmission shaft 19
A signal cable 20 through which an ultrasonic driving signal from the ultrasonic driving device 13, an electric signal received and converted by the ultrasonic vibrator 16, and the like are transmitted. One end is connected to the ultrasonic vibrator 16.

The other end of the rotation transmitting shaft 19 into which the signal cable 20 is inserted is passed through the distal end main body 4, the bending section 5, the flexible section 6, the operating section 2, the universal cord 11, and the ultrasonic cord 11b. It extends to the ultrasonic connector 14.

As shown in FIG. 3, the ultrasonic observation device 15
A transmitting circuit 21 for transmitting a high-voltage pulse for generating an ultrasonic wave in the ultrasonic vibrator 16; a receiving circuit 22 to which a reflected echo signal received by the ultrasonic vibrator 16 is input; A comparison processing circuit 23 for detecting whether or not the magnitude of the reflected echo signal sent from the vibrator is greater than a preset value; and writing / reading digital data converted according to the strength of the reflected echo signal An address generator 24 for generating an address signal so as to perform a coordinate conversion of a signal sent from the ultrasonic transducer 16 and an interpolating process between pixels to generate a video signal. 25,
It mainly includes a TV monitor 26 for displaying an ultrasonic tomographic image of the observation site. The ultrasonic driving device 13 includes:
A drive motor 27 for generating a rotational drive force for rotating the rotary shaft 18 to which the housing 17 is fixed, and a position detector 28 for detecting the rotational position of the drive motor 27
And a rotation signal detector 29 composed of a slip ring or the like.

In the comparison processing circuit 23, the reflection intensity of the reflected echo signal of the ultrasonic wave radiated from the ultrasonic transducer 16 to the diagnostic area is compared with a preset value.
When the comparison processing circuit 23 detects an ultrasonic echo whose reflection intensity is larger than a preset value, the transmission circuit 21
And outputs a command to interrupt the transmission of the high-voltage pulse to the ultrasonic vibrator 16 for a predetermined time.

The value set in advance for comparison in the comparison processing circuit 23 is larger than the value of the reflected echo signal due to the reflected echo at the tip cap 10 and the reflected echo signal due to the reflected echo at the tip body 4. A value smaller than the signal value is set.

That is, when the reflection intensity of the reflected echo signal input to the comparison processing circuit 23 is larger than the value of the reflected echo signal due to the reflected echo at the tip cap 10, the transmission circuit 21 sends a high voltage pulse to the ultrasonic vibrator 16. The command to interrupt the transmission of the message for a certain time is output. Further, the certain time during which the transmission is interrupted is at least during the time when the sound axis of the ultrasonic transducer 16 is moving on the distal end body 4.

That is, when the sound axis of the ultrasonic vibrator 16 is moving on the tip cap 10, ultrasonic waves are emitted from the ultrasonic vibrator, and the sound axis of the ultrasonic vibrator 16 is After moving on the boundary surface with the main body 4, it moves on the front end main body 4 to move the front end main body 4 and the front end cap 1.
A high-voltage pulse is transmitted from the transmission circuit 21 to the ultrasonic vibrator 16 so that the emission of the ultrasonic wave is interrupted until reaching the boundary with zero. The tip cap 10 is filled with an acoustic medium such as water.

The operation of the ultrasonic endoscope system configured as described above will be described. The surgeon inserts the ultrasonic endoscope 1 into a target site while observing the inside of the body cavity by looking into the eyepiece 2b. Then, when the distal end cap 10 of the ultrasonic endoscope 1 reaches the target site, the drive motor 27 of the ultrasonic observation device 15 is driven in order to perform rotational scanning, and the ultrasonic vibrator 16 is transmitted from the transmission circuit 21. Send high voltage pulse to

Then, as shown in FIG. 4, the rotating shaft 18 starts rotating in the direction indicated by the arrow, and the ultrasonic vibrator 16 is excited by the high voltage pulse sent from the transmitting circuit 21 so that the ultrasonic wave is emitted. The light passes through the cap 10 and is propagated into the living body to start the rotational scan.

Then, as shown in FIG.
When the sound axis 16a of No. 6 moves on the tip cap 10, a waveform of the reflected echo signal value as shown in FIG. 5 is obtained. Initially prominent echo signal V1 shown in FIG.
Is a reflection echo signal from the tip cap 10, transmitted to the rotation signal detector 29 of the ultrasonic driving device 13 via the signal cable 20, transmitted to a non-rotating signal line, and then transmitted to the ultrasonic observation device. The comparison processing circuit 23 in 15
Is input to

When a reflected echo signal larger than the echo signal V1, which is a reflected echo signal value reflected by the front end cap 10, returns first to the comparison processing circuit 23, the ultrasonic oscillator 16 A command is issued to suspend the transmission of the high voltage pulse to

For this reason, if the first returned echo signal is the echo signal V1, after processing the magnitude relationship of one end signal, this reflected echo signal is compared with the comparison processing circuit 2.
After passing through the receiving circuit 22, the digital signal is normally processed by the digital scan converter 25 via the receiving circuit 22, and is displayed on the TV monitor 26 as an ultrasonic image.

On the other hand, as shown in FIG. 6, the rotating shaft 18 rotates, and the sound axis 16a of the ultrasonic vibrator 16 is
When reaching the vicinity of the boundary surface between the zero and the tip body 4, the ultrasonic waves radiated from the ultrasonic transducer 16 hit the tip body 4. Then, a waveform of the reflected echo signal value as shown in FIG. 7 is obtained. The tip main body 4 is an ultrasonic transducer 1
Ultrasonic waves radiated from 6 are almost totally reflected. For this reason,
The first reflected echo signal V2 that returns to the tip main body 4 has a considerably larger value than the reflected echo signal V1.

The reflected echo signal V2 is supplied to the comparison processing circuit 2
3, the comparison processing circuit 23 recognizes that a signal larger than the reflected echo V1 has been input. At this time, the comparison processing circuit 23 outputs an instruction to the transmission circuit 21 to stop transmission of the high-voltage pulse to the ultrasonic vibrator 16 for a predetermined time.

While the transmission from the transmission circuit 21 is stopped, other functions are operating. For this reason, while the transmission from the transmission circuit 21 is stopped, a non-echo state is eventually displayed on the TV monitor 26. That is,
The ultrasonic wave radiated from the ultrasonic vibrator 16 is applied to the tip main body 4.
The transmission from the transmission circuit 21 to the ultrasonic vibrator 16 is interrupted during the time of direct contact with the
The irregular reflection due to the reflected echo reflected on the surface is eliminated.

As described above, when the signal value of the reflected echo input to the comparison processing circuit is larger than the reflection echo signal value when reflected by the tip cap set in advance in the comparison processing circuit, the signal is reflected by the tip body. The direction of the ultrasonic wave radiated from the ultrasonic transducer is recognized by comparing whether or not the range is smaller than the reflected echo signal value of the ultrasonic transducer. The voltage pulse can be controlled. As a result, while the sound axis of the ultrasonic vibrator passes over the distal end main body, no ultrasonic radiation is emitted from the ultrasonic vibrator, so that reflected echo or irregularly reflected echo reflected on the distal end main body is generated. Can be suppressed. In addition, since unnecessary reflected echoes from the distal end body do not enter the ultrasonic transducer, a good ultrasonic image is displayed on the monitor screen.

Japanese Patent Application Laid-Open No. 4-319342 discloses that the direction of the rotation axis is changed by a set of bevel gears, and a camshaft attached to one bevel gear and a cam attached to an ultrasonic vibrator are used. An ultrasonic diagnostic apparatus provided with a mechanism for swinging an ultrasonic transducer to perform ultrasonic scanning in a fan shape in the front in the insertion direction is shown. In the ultrasonic diagnostic apparatus disclosed in Japanese Unexamined Patent Publication No. 4-319342, the direction of the rotation axis is changed by a set of bevel gears, and a swing scan is performed in a fan shape without rotating the ultrasonic vibrator by a cam shaft and a cam. Therefore, the problem caused by the noise caused by the reflection of the ultrasonic waves radiated from the ultrasonic vibrator to the tip main body as in the ultrasonic inspection apparatus disclosed in JP-A-8-229045 is eliminated.

However, in order to realize a wide range of ultrasonic scanning, the swing angle must be increased, and in order to secure a large swing angle, it is necessary to increase the rotation radius of the cam shaft. In this case, there is a possibility that the length of the main body of the distal end portion becomes longer, which may be a factor that deteriorates the insertability.

For this reason, there has been a demand for an ultrasonic probe which has a short length of the distal end portion body and has a good insertability and which can swing and scan the front of the insertion direction.

FIGS. 8 to 10 relate to an ultrasonic probe which oscillates an ultrasonic vibrator and ultrasonically scans the front in the insertion direction. FIG. 8 is a cross-sectional view for explaining the configuration of the distal end portion of the ultrasonic endoscope. 9 is an explanatory diagram showing the positional relationship between one drive bevel gear and two driven bevel gears when FIG. 8 is viewed from the direction of the arrow, and FIG. 10 illustrates another configuration of the distal end portion of the ultrasonic endoscope. It is sectional drawing.

As shown in FIG. 8, in the present embodiment, a housing 33 provided with an ultrasonic vibrator 32 is provided inside a distal end cap 31 provided on a distal end body 30 in the direction of the insertion axis 30a of the ultrasonic probe. It is integrally attached to a rotating shaft 34 which is rotatably supported in a direction orthogonal to the direction.

A rotation transmission shaft 35 for transmitting a rotational driving force from an ultrasonic driving device (not shown) is inserted through substantially the center of the distal end body 30. The distal end of the rotation transmission shaft 35 is connected to the distal end body 30. Are held rotatably. One drive bevel gear 36 is provided at the tip of the rotation transmission shaft 35.

As shown in FIG. 9, the drive bevel gear 36 has
It is formed in a substantially sector shape, and (a) and (b) of FIG.
As shown in (c), the rotation is made about the rotation transmission shaft 35. A signal cable for transmitting an ultrasonic driving signal from the ultrasonic driving device 13 or an electric signal received and converted by the ultrasonic vibrator 16 is inserted into the rotation transmission shaft 35.

As shown in FIG. 8 and FIG. 9, a pair of driven bevel gears 37, 37 is provided on both side surfaces of the housing 33 disposed in a direction perpendicular to the direction of the insertion axis 30a of the ultrasonic probe. 37 are provided facing each other. The driven bevel gears 37, 37 are disposed equidistant from the rotation center of the drive bevel gear 36.

The housing 33 or at least one of the pair of driven bevel gears 37 has the housing 3
A swing restraining member 38 is provided to prevent the swing of the wheel 3 when no load is applied. Further, a rotation position detector 39 is provided on the rotation shaft 34 so as to transmit position information to an ultrasonic observation device (not shown).

The movement of the ultrasonic vibrator 32 by the plurality of bevel gears 36 and 37 will be described. As shown in FIG. 9A, the rotation of the rotation transmission shaft 35 causes the drive bevel gear 36 to rotate in the direction of arrow a. When the drive bevel gear 36 rotates in the direction of arrow a, the driven bevel gear 37 meshing with the drive bevel gear 36 and located on the right side in the figure rotates in the direction of arrow b. As a result, the driven bevel gear 3
The housing 33 to which is mounted 7 rotates in the direction of the arrow b similarly to the driven bevel gear 37. As a result, the ultrasonic transducer 32 fixed to the housing 33 swings downward in the figure.

As the drive bevel gear 36 continuously rotates in the direction of arrow a, the drive bevel gear 36 is driven by one of the pair of driven bevel gears 37, 37 as shown in FIG. Move to a position where it does not mesh with. Then, since the rotation from the drive bevel gear 36 is not transmitted to the housing 33, the housing 33 is in a no-load state. At this time, the housing 33 is held at the position shown in the drawing without idling by the repulsive force of the pressing member 38 acting on the driven bevel gear 37.

Subsequently, when the drive bevel gear 36 continuously rotates in the direction of the arrow a, the drive bevel gear 36 meshes with the driven bevel gear 37 located on the left side in the figure as shown in FIG. Then, the driven bevel gear 37 rotates in the direction of arrow c. When the driven bevel gear 37 rotates in the direction of arrow c, the housing 33 to which the driven bevel gear 37 is attached also rotates in the direction of arrow c, similarly to the driven bevel gear 37. As a result, the ultrasonic vibrator 32 fixed to the housing 33 swings upward in the drawing opposite to the above-mentioned drawing (a).

Thus, for one drive bevel gear,
By providing two driven bevel gears, the swing direction of the ultrasonic transducer fixed to the housing can be switched between rotation in one direction and rotation in the other direction without reversing the rotation of the rotation transmission shaft. . As a result, the swing scanning of the ultrasonic transducer can be performed only by rotating the rotation transmission shaft in one direction without using the crank mechanism, so that the length of the distal end body can be shortened and the motor drive control can be simplified. I can do it.

As shown in FIG. 10, the drive bevel gear 36 is replaced with a sector-shaped drive friction plate 41 and the pair of driven bevel gears 37 is replaced with a pair of disk-shaped driven friction plates 4.
The same operation and effect as in the above-described embodiment can be obtained by substituting 2
The effect can be obtained.

Incidentally, as one application example of diagnostic ultrasonic waves in the medical field, there is a demand for performing a puncture under observation of an ultrasonic image and collecting a living tissue to make a definite diagnosis of a lesion.

On the other hand, US Pat. No. 5,090,414 discloses a configuration of a mechanical scanning type ultrasonic probe for performing puncture under observation of an ultrasonic image. In the ultrasonic probe of the present invention, a living body is formed by a combination of an ultrasonic probe that can perform a sector scan in the forward direction of the probe axis, a puncture needle guide provided so that the puncture needle can advance and retreat in the ultrasonic scan plane, and a puncture needle. Tissue sampling has been achieved. However, the ultrasonic probe with this puncture needle guide is allowed to have a diameter of about 20 mm as the ultrasonic probe diameter, and is intended for use in application sites such as prostate scanning from the rectum and uterine scanning from the vagina. Was designed to.

For this reason, for a part inside a body cavity observation, such as a digestive tract, where it is difficult to insert an ultrasonic probe provided with a puncture needle guide, a body cavity disclosed in JP-A-1-148248 is used. There is an ultrasound diagnostic device. In this intracavity ultrasonic diagnostic apparatus, an ultrasonic transducer is installed at the distal end of an endoscope, and a puncture needle is inserted into a target site through a treatment instrument insertion channel provided in the endoscope. As the method of the ultrasonic vibrator, there are a method using a convex type vibrator and a method using mechanical scanning.

The application site of the ultrasonic endoscope of the present embodiment is as follows.
It is in the body cavity for the digestive tract and its surrounding organs, and the diameter of the insertion portion is preferably as small as possible. For this reason, it is difficult to use the method in which the puncture needle guide is provided in addition to the ultrasonic probe due to a problem in external dimensions.

On the other hand, under observation of an ultrasonic image obtained by ultrasonic waves radiated laterally or obliquely forward from the linear or convex transducer to the submucosa with a puncture needle protruding from a channel of the endoscope. When performing a tissue biopsy, a puncture needle is pressed against a living tissue using a forceps raising device. However, there has been a problem that it is difficult to perform puncture reliably because the distal end of the insertion portion warps due to the reaction when the puncture needle is pressed against the living tissue, and the distal end of the endoscope is shaken.

The ultrasonic endoscope of the linear type vibrator has a disadvantage that the length of the hard portion at the end of the endoscope becomes long and the insertability is deteriorated, and the ultrasonic endoscope of the convex type vibrator is disadvantageous. However, there is a disadvantage that the distal end diameter becomes large and the burden on the patient during insertion is large.

For this reason, in the mechanical forward scanning type ultrasonic probe, a method in which the puncture needle is projected through the treatment instrument channel is considered. However, the puncture needle can be projected in parallel to the insertion axis direction. When the channel opening is formed, the outer diameter of the probe tip becomes large, which adversely affects the insertability.

An apparatus capable of performing puncture using a mechanical scanning ultrasonic probe is disclosed in US Pat.
No. 1292 proposes an ultrasonic probe in which a ring-type vibrator is sector-scanned and a needle is projected from a center hole to enable puncture.

However, in the ultrasonic probe disclosed in US Pat. No. 4,671,292, the scanning angle is limited by the diameter of a hole provided at the center of the transducer. For this reason, in order to obtain an ultrasonic image with a sufficient scanning angle and sensitivity, there is a disadvantage that the transducer itself becomes large and miniaturization becomes very difficult.

Therefore, it is possible to reliably and easily puncture the target site without increasing the outer diameter of the distal end of the insertion portion or to shake the distal end of the probe at the time of puncturing, and to perform a suction biopsy. There has been a need for a mechanically forward-scanning ultrasound probe that reduces reflected echoes due to channels in the acoustic window.

For this reason, the ultrasonic endoscope is provided with a rotating power generating mechanism provided in an operation unit located near the hand, a flexible shaft for transmitting the rotating power to the distal end, and a rotating shaft transmitted to the flexible shaft. A conversion mechanism that converts the rotation direction of the power into a direction orthogonal to the probe insertion axis direction, and an ultrasonic mirror that rotates in the rotation axis direction converted by the conversion mechanism is provided in the acoustic room. A channel through which a puncture needle can be inserted is provided. The channel is provided at a position where the puncture needle which advances and retreats in the channel moves along the ultrasonic scanning surface. Also, the cross-sectional shape makes it difficult for the ultrasonic waves reflected on the channel to enter the ultrasonic transducer.

Hereinafter, details of the ultrasonic endoscope according to the present embodiment will be described with reference to FIGS. As shown in FIG. 11, the ultrasonic endoscope 70 includes an operation unit 71 also serving as a gripping unit that is gripped by an operator, and an insertion unit 72 that is inserted into a body cavity of a patient.
, A sub-operation unit 73 having a built-in rotation power generation mechanism, an ultrasonic cable 74 and an observation light guide cable 75 extending from the operation unit 71. A distal end body 77 and a curved portion 7 are provided at the distal end side of the insertion portion 74.
6 are provided.

As shown in FIG.
A hemispherical acoustic window 61 is provided on the front side. A flexible shaft 66 that transmits the rotational power from the rotational power generation mechanism to the distal end portion is provided in an acoustic chamber 61a inside the acoustic window 61.
6 is provided with a bevel gear mechanism 67 which is a conversion mechanism for converting the rotation direction of the rotational power transmitted to 6 into a direction orthogonal to the endoscope insertion axis direction.

The bevel gear mechanism 67 includes a drive bevel gear 67 fixedly mounted at the tip of the flexible shaft 66.
a, and a driven bevel gear 67b meshing at right angles with the drive bevel gear 67a.
An ultrasonic mirror 65 formed by inclining a mirror surface 65a at 45 degrees is provided on a rotation shaft 68 of 7b.

An ultrasonic vibrator 63 is disposed in front of the rotary shaft 68. Ultrasonic waves emitted from the ultrasonic vibrator 63 are reflected by a reflecting surface 65a of a rotating ultrasonic mirror 65. Then, the light is emitted in the direction of the arrow to rotationally scan the inside of the body cavity. That is, with the above-described configuration, it is possible to perform ultrasonic scanning on a cross section in the endoscope insertion axis direction.

The rotation of the flexible shaft 66, which is rotated by a driving unit (not shown) inside the sub-operation unit 73, is transmitted from the driving bevel gear 67a to the driven bevel gear 67b, and is transmitted to the ultrasonic mirror 65. Rotate. An acoustic medium such as water is sealed in the acoustic chamber 61a, so that the acoustic medium sealed by the acoustic window seal portion 62 does not leak into the body cavity. Further, in the ultrasonic endoscope 70 of the present embodiment, the optical system 64 is provided because the ultrasonic endoscope is an ultrasonic endoscope.

As shown in FIG. 12 (b), a channel 69 having an opening 69a at its tip is disposed so as to pass through the acoustic chamber 61a and be located within the scanning plane of the reflection mirror 65. A puncture needle (not shown) is inserted through the channel 69, and the puncture needle is inserted into the opening 69a.
When the puncture needle is protruded from the puncture needle, the puncture needle is unconditionally arranged in the ultrasonic scanning plane. As a result, the puncture needle is extracted as a line of high luminance (high echo) in the ultrasonic image.

As shown in FIG. 13, a ridge 69b is formed on the side of the channel 69 facing the ultrasonic mirror 65. For this reason, when the ultrasonic wave is propagated from the direction of the arrow shown in FIG. For this reason, when the ultrasonic wave radiated from the ultrasonic mirror 65 is reflected by the channel 69, the amount of ultrasonic energy scattered becomes larger than when the cross-sectional shape of the channel 69 is, for example, a circular cross-section.
The appearance of unnecessary reflected echoes on the ultrasonic image is suppressed.

Since the channel 69 and the acoustic window 61 are joined by ultrasonic welding, the acoustic medium does not leak from this joint. Also, this channel 69
Of the acoustic window 61 in order to secure the bonding strength.
It is desirable that the same member be used. In addition, channel 6
In the case where a channel having a circular cross section in which the ridge 69b is not formed in the cross section of No. 9 is used, the same operation and effect can be expected by providing an ultrasonic absorbing layer formed of an ultrasonic absorbing material on the outer peripheral surface of the channel. As the ultrasonic absorbing material, a resin member having a high ultrasonic attenuation effect, such as Teflon, or an ultrasonic absorbing rubber is suitable.

As described above, the flexible shaft for transmitting the rotational power from the rotational power generating mechanism, the bevel gear mechanism for converting the rotational direction of the rotational power transmitted to the flexible shaft, the ultrasonic mirror, the ultrasonic vibrator, and the like are included. By providing a channel for inserting a puncture needle in the installed acoustic window in the same direction as the insertion axis direction, puncture performance can be significantly improved, and the space in the acoustic room can be effectively used. Thus, the distal end portion of the ultrasonic endoscope and the distal end portion main body can be reduced in size without increasing in size, and the insertability can be improved.

Further, by arranging the channel so as to be positioned within the scanning plane of the reflection mirror, the puncture needle in the channel and the puncture needle protruding from the opening can be extracted as a high-luminance line in the ultrasonic image. Can be.

Further, by providing a ridge line in a channel arranged in the scanning plane of the reflecting mirror to increase the amount of scattered ultrasonic energy and to suppress unnecessary reflected echo from appearing on the ultrasonic image, Observation performance can be improved.

Another configuration of the distal end portion of the ultrasonic endoscope will be described with reference to FIG. In this embodiment, FIGS.
The purpose of the present invention is to make it possible to perform puncture and aspiration cytology more reliably by shortening the path through which the ultrasonic wave propagates in the acoustic medium than the embodiment shown in FIG. I have.

As shown in FIGS. 14A and 14B, in the present embodiment, the rotation of the flexible shaft 66 is transmitted to the rotating shaft 68 via the bevel gear mechanism 67 as in the above-described embodiment. An ultrasonic vibrator 78 is directly connected to the rotating shaft 68. Therefore, the ultrasonic vibrator 78 rotates in synchronization with the rotation of the flexible shaft 66.

The signal cable 74a extending from the ultrasonic vibrator 78 is connected to an ultrasonic drive circuit (not shown) via a pipe 79, through an inside of a flexible shaft 66, and via an operation unit 71 located on the hand side. In this configuration, since the rotation direction of the flexible shaft 66 matches the rotation direction of the signal cable, the signal cable 74
a is not twisted.

In this embodiment, as in the embodiment shown in FIGS. 12 and 13, the channel 69 is inserted into the acoustic chamber 61a, and the opening 69a of the channel 69 is provided on the surface of the acoustic chamber 61a. . In addition, the observation optical system 81
The illumination optical system 82 is provided on the surface of the acoustic window 61. The observation optical system 81 is an image guide for image transmission, and the illumination optical system 82 has a built-in light guide for illumination. As a substitute for the image guide, a charge coupled device may be provided at the tip of the optical system to convert an optical image into an electric signal and transmit the electric signal.

In this embodiment, the ultrasonic wave is transmitted to the ultrasonic mirror 6.
Since the light is radiated from the ultrasonic vibrator 78 directly connected to the rotation shaft 68 without passing through the path 5, the path through which the ultrasonic wave propagates can be shortened. As a result, the attenuation of the ultrasonic wave caused by the longer propagation path which causes the decrease in the sensitivity of the ultrasonic image is reduced, and the resolution is improved.

Further, since two optical systems 81 and 82 for the endoscope are provided in the inevitable unnecessary space 83 in the acoustic chamber 61a as in the case of the channel 69, the diameter of the end portion can be increased without increasing the diameter of the end portion. It becomes an ultrasonic endoscope.

Further, since the positions of the optical systems 81 and 82 in FIG. 14 are located on the distal end side as compared with the position of the optical system 64 in FIG. 12, the length of the distal end body which is an important element of the insertability is reduced. Has become.

As described above, in the case of the ultrasonic probe of the present embodiment, the puncture can be performed while confirming the puncture site with both the optical image and the high-sensitivity ultrasonic image, so that the treatment can be performed more reliably. .

Further, since the length of the distal end body is short, the burden on the patient during insertion can be further reduced.

The surface roughness of an ultrasonic mirror (hereinafter also referred to as a mirror) is described in
“Using a reflection mirror having a mirror-finished reflection surface” is specified in “Method of measuring sensitivity of ultrasonic transducer by reflection method” in the IAJ) standard. That is, it is desirable that the surface that reflects the ultrasonic waves be as smooth as possible. It has also been found that the surface roughness of the ultrasonic mirror is related to the generation of multiple echoes, and that no multiple echoes will be generated if mirror processing is performed.

However, mirror polishing requires a polishing step after machining, which complicates the processing step, and all ultrasonic mirrors to be used may have been processed through a polishing step such as mirror finishing. This raises the cost and the price of the product, and has been a factor that hinders the spread of ultrasonic probes. In addition, in order to suppress the product cost and provide an inexpensive ultrasonic probe, it is desirable that grinding be the last step.

However, in the case of the ultrasonic mirror in which the grinding process is the final step, if the surface of the mirror is large, irregular reflection in a direction different from a preset direction increases.

When designing an ultrasonic probe, the ultrasonic vibrator and the mirror are arranged so as to reflect a sound wave at the same reflection angle as the angle of incidence on the mirror. When bending the mirror, the mirror is arranged at an angle of 45 degrees with respect to the incident direction of the sound wave. At this time, if the mirror has a large surface roughness and is irregularly reflected,
Among the reflection components in various directions, there are reflection components that return in the incident direction.

If the signal level of the reflected component returning from the mirror in the direction of incidence becomes higher than the signal level displayed on the monitor, it appears as an artifact on the monitor, which is a great obstacle to diagnosis. . Therefore, there is a demand for a method of manufacturing a reflecting mirror for an ultrasonic probe that can reduce artifacts that hinder diagnosis, improve image quality near the ultrasonic probe, and can be manufactured at low cost.

As shown in FIG. 11, the ultrasonic mirror 65 is arranged so as to deflect the ultrasonic wave radiated from the ultrasonic transducer 63 by 90 degrees. The ultrasonic mirror 65 is rotated by a flexible shaft 66 that transmits power of a rotation drive unit (not shown).

When the surface of the ultrasonic mirror 65 is finished by grinding, the surface roughness of the mirror changes depending on the grinding conditions at the time of grinding. That is, it depends on the precision of the grinding tool (granularity of the grinding wheel), the cutting amount of the grinding tool, the moving speed of the grinding tool, and the viscosity of the grinding oil. In the case of a non-planar mirror, the cutting is performed by an NC processing machine, but it has been found that the cutting speed greatly affects the roughness. The surface roughness of the mirror can be appropriately set by shaving in consideration of these conditions.

More specifically, in the present embodiment, comparison was made between ultrasonic images obtained using mirrors whose mirror surfaces were finished to Rmax 12.1S, Rmax 8.8S, and Rmax 1.5S. The gain and the contrast level of the ultrasonic diagnostic apparatus are the same.

FIG. 15A shows that the mirror surface roughness is Rmax1.
It is an ultrasonic image 90a using a mirror finished to 2.1S.
1 is clearly shown.

FIG. 11B shows that the mirror surface roughness is Rmax8.8.
This is an ultrasonic image 90b using a mirror finished in S, in which the artifact 91 clearly projected in the upper part of the screen in FIG.

FIG. 9C shows that the mirror surface roughness is Rmax1.5.
This is an ultrasonic image using a mirror finished in S, and the artifact 91 shown in the upper part of the screen in FIGS.

From the results, although there is no significant difference between FIGS. (A) and (b), a clear significant difference was confirmed between FIGS. (B) and (c). From this,
By setting the mirror surface roughness to at least 8.8 s or less in Rmax value, it is possible to suppress multiple reflection and obtain a good ultrasonic image.

As described above, by grinding the surface of the ultrasonic mirror to have a surface roughness of Rmax 8.8S or less, the component reflected in the same direction as the incident ultrasonic wave is reduced to a level below the level displayed as an ultrasonic image. Thus, multiple echoes can be eliminated from an ultrasonic image.

By the way, in the mechanical scanning type ultrasonic probe, the emitted ultrasonic waves reach the living body through a flowing medium (acoustic medium) such as water and an acoustic window. However, at the interface of the propagation path from the flowing medium to the acoustic window and from the acoustic window to the living body, the greater the difference between the acoustic impedances of the opposing materials, the higher the ratio of ultrasonic waves reflected. Particularly, in the diagnosis using an ultrasonic probe, the presence of the reflection of the ultrasonic wave as described above causes an artifact to be generated, which greatly impairs the diagnostic ability. Therefore, it has been desired to reduce the reflection ratio of ultrasonic waves as much as possible.

This embodiment provides a mechanical scanning type ultrasonic probe in which an artifact caused by an acoustic window is prevented.

For this reason, a casing or a casing provided with an ultrasonic vibrator and an ultrasonic reflecting mirror for reflecting and scanning the ultrasonic vibrator or the ultrasonic waves radiated from the ultrasonic vibrator are provided. The acoustic window is made of a resin (for example, Dainippon Plastics Co., Ltd.) having a ring-shaped structure (IPN structure) in which polymer molecules of a saturated type thermoplastic elastomer forming an agglomeration region and a polyolefin-based polymer are penetrated. (MK resin).

That is, a casing or an acoustic window is formed by cutting out a rod or a thick plate of the IPN structural resin. By using an IPN structural resin having high fluidity, it is also possible to mold using mold molding.

The MK resin has a specific gravity of 0.9, a measured value of a sound velocity at room temperature (25 ° C.) of 1728 m / s,
The calculated acoustic impedance is 1.55. The acoustic impedance of other materials is 1.
8. Polymethylpentene is a material much closer to water than 1.7.

As described above, by forming the casing and the acoustic window with a material whose acoustic impedance is close to that of water,
The interface reflection is small, and artifacts such as multiple echoes on an ultrasonic image can be greatly reduced.

In general, a resin material having a low density is too flexible to be cut by a lathe or the like because of its too high flexibility. However, since this material has an intermediate elastic modulus and flexibility between the elastomer and the olefin resin, cutting can be performed while maintaining the flexibility.

Further, the acoustic window is a portion that is in direct contact with the living body, and is made of a biologically harmless and stable material, and may be subject to an impact during washing or the like. No. This material is excellent in electrical insulation, rigidity stability due to temperature change, polar solvent resistance to acids, alkalis, water, etc., excellent biological safety, and is required as an external member of an ultrasonic probe as a medical device All conditions are met.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the invention.

[Appendix] According to the above-described embodiment of the present invention as described in detail above, the following configuration can be obtained.

(1) A distal end cap for transmitting ultrasonic waves is provided on the distal end body of the insertion portion that can be inserted into the body cavity, and the ultrasonic waves are rotated in the distal end cap around a rotation axis orthogonal to the insertion axis direction. In the scanning ultrasonic endoscope, by the reflected echo of the ultrasonic wave scanned around the rotation axis, the boundary portion between the tip cap and the tip body is detected, and after detecting the tip body, a predetermined time, An ultrasonic endoscope that interrupts the transmission of sound waves.

(2) An end portion of the rotation transmitting shaft disposed in the ultrasonic-transparent tip cap, a fan-shaped rotation transmitting member provided integrally with the rotation transmitting shaft, and a right angle to the rotation transmitting shaft. A rotation shaft integrally provided with a housing arranged in a direction to be rotated, and a rotation switching member attached to both side surfaces of the housing to switch the swing direction of the ultrasonic transducer by transmitting the rotation of the rotation transmitting member. An ultrasonic probe comprising:

(3) The ultrasonic probe according to attachment 2, wherein the rotation transmitting member and the rotation switching member are bevel gears.

(4) The ultrasonic probe according to attachment 2, wherein the rotation transmitting member and the rotation switching member are friction plates.

(5) A rotary power generation mechanism provided on the operation unit located near the hand, a flexible shaft for transmitting the rotary power of the rotary power generation mechanism to the distal end, and a rotary power transmitted to the flexible shaft. A conversion mechanism that converts the rotation direction to a direction orthogonal to the probe insertion axis direction, and an ultrasonic mirror that rotates in the rotation axis direction converted by the conversion mechanism in an acoustic room, and punctures the acoustic room. An ultrasonic endoscope provided with a channel through which a needle can be inserted.

(6) The ultrasonic endoscope according to appendix 5, wherein the channel is provided at a position where a puncture needle which advances and retreats in the channel moves along an ultrasonic scanning surface.

(7) The mirror surface roughness of the ultrasonic mirror is R
A method of manufacturing an ultrasonic mirror for an ultrasonic probe, which is finished by grinding so as to have a maximum of 8.8S or less.

(8) A casing provided with an acoustic window containing an ultrasonic transducer and an ultrasonic reflecting mirror for reflecting and scanning the ultrasonic transducer or the ultrasonic wave radiated from the ultrasonic transducer, and this casing An ultrasonic probe having an acoustic medium filled therein, wherein at least one of the casing and the acoustic window is formed of a resin in which a saturated thermoplastic elastomer and a polyolefin-based polymer are blended.

[0114]

As described above, according to the present invention, when ultrasonic scanning is performed around a rotation axis orthogonal to the insertion axis direction, noise due to irregular reflection of ultrasonic waves radiated toward the distal end body is obtained. Is prevented, and an ultrasonic endoscope that can obtain a good ultrasonic image can be provided.

[Brief description of the drawings]

1 to 7 relate to one embodiment of the present invention,
FIG. 1 is an explanatory diagram showing a schematic configuration of an ultrasonic endoscope.

FIG. 2 is a cross-sectional view showing a configuration of a distal end portion of the ultrasonic endoscope.

FIG. 3 is a block diagram illustrating a configuration of an ultrasonic endoscope system.

FIG. 4 is a diagram showing a state in which the sound axis of the ultrasonic transducer is moving on the tip cap.

FIG. 5 is a diagram showing a waveform of a reflected echo signal reflected back from the tip cap.

FIG. 6 is a diagram showing a state in which the sound axis of the ultrasonic transducer reaches a boundary surface between the tip cap and the tip body.

FIG. 7 is a diagram showing a waveform of a reflected echo signal reflected back to the tip main body.

FIGS. 8 to 10 relate to an ultrasonic probe that scans the front in the insertion direction by oscillating an ultrasonic transducer,
Sectional view for explaining the configuration of the end portion of the ultrasonic endoscope

FIG. 9 is an explanatory diagram showing the positional relationship between one drive bevel gear and two driven bevel gears when FIG. 8 is viewed from the direction of the arrow;

FIG. 10 is a cross-sectional view illustrating another configuration of the distal end portion of the ultrasonic endoscope.

FIG. 11 is an explanatory diagram showing a schematic configuration of an ultrasonic endoscope having another configuration.

FIG. 12 is an explanatory diagram showing a configuration of an acoustic room of the ultrasonic endoscope in FIG. 11;

FIG. 13 is a cross-sectional view illustrating a cross-sectional shape of a channel through which a puncture needle is inserted.

FIG. 14 is an explanatory diagram showing another configuration of the acoustic room of the ultrasonic endoscope.

FIG. 15 is a view for explaining a relationship between mirror surface roughness and an ultrasonic image.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ultrasonic endoscope 4 ... Tip main body 16 ... Ultrasonic transducer 17 ... Housing 18 ... Rotation axis

Claims (1)

[Claims] 1. A tip cap for transmitting an ultrasonic wave is provided on a tip end body of an insertion portion that can be inserted into a body cavity, and the ultrasonic wave is rotationally scanned around a rotation axis orthogonal to an insertion axis direction in the tip cap. In the ultrasonic endoscope, the boundary between the tip cap and the tip main body is detected by the reflected echo of the ultrasound scanned around the rotation axis, and the ultrasonic wave is applied for a predetermined time after the detection of the tip main body. An ultrasonic endoscope, which interrupts transmission of a sound.