JPS6230014B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic diagnostic apparatus including a tip component in which an ultrasonic transmitting/receiving surface or the like is provided with a cushioning material for suppressing generation of unnecessary ultrasonic echo waves.

Generally, the ultrasonic waves emitted from an ultrasonic transducer are
The ultrasonic wave enters the object, and a portion of it is reflected as an ultrasonic echo wave at the interface where the acoustic impedance differs. This ultrasonic wave is scanned, and as mentioned above, the echo waves from the boundary surfaces with different acoustic impedances are received again and displayed on a display device (monitor device) configured with a cathode ray tube, etc., to form an ultrasonic tomographic image. It is something that makes you

By the way, the tip component of an ultrasonic diagnostic apparatus is housed by fitting a cylindrical cover over a support member that constitutes a housing chamber in which an ultrasonic transducer and a mirror that reflects ultrasonic waves are installed. The chamber is closed, an ultrasonic transmitting/receiving surface for emitting ultrasonic waves is provided in a part of the chamber, and an ultrasonic transmission liquid is filled in the chamber. For this reason, the cover that fits this storage chamber needs to be made of a material with a certain degree of mechanical strength. Generally, such materials (for example, polyethylene, etc.) often have a different acoustic impedance from the transmission fluid, and if this material is used as is for the cover, reflected echo waves will occur at the interface between the transmission fluid and the cover, causing damage to the cover. This has the disadvantage that it interferes with reflected echo waves as tomographic image signals from the specimen. When the reflected echo wave of the interference wave is received by the display device, it is displayed as a concentric band from the oscillation source in the tomographic image,
This significantly interfered with diagnosis using tomographic images. Furthermore, since the mirror rotates, the ultrasonic waves may be reflected in unnecessary directions, resulting in repeated diffuse reflections within the storage chamber, which also interferes with the original tomographic image.

This invention was made based on the above circumstances, and the acoustic impedance of the cover that fits the tip component and the acoustic impedance of the transmission fluid are determined at least on the ultrasonic transmitting and receiving surface of the tip component of the ultrasonic diagnostic device. An object of the present invention is to provide an ultrasonic diagnostic device which is provided with a buffer material having an acoustic impedance between 1 and 2, and which eliminates reflections at boundary surfaces such as a cover and reduces interference to a display device.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the state in which the invention is used, FIG. 2 shows an enlarged cross section of the distal end component, and FIG. 3 is shown to explain the principle of the invention. In the figure, reference numeral 1 indicates a rigid scope used for abdominal examinations, etc., as an example of an endoscope. The insertion section 2 of this endoscope 1 has two inner tubes inserted inside an outer tube 3, an observation optical system light guiding member is accommodated in one of the inner tubes, and a processing instrument insertion hole is inserted into the other inner tube. It has come to be used as 4. Further, the gap between the outer tube 3 and the two inner tubes is filled with an illumination optical system light guide member to transmit illumination light from a light source device (not shown).
On the other hand, the observation optical system light guiding member is guided to the eyepiece section 5.

The ultrasonic diagnostic device 6 according to the present invention is inserted into the treatment instrument insertion hole 4. This ultrasonic diagnostic device 6 includes an elongated ultrasonic diagnostic element 7 that is inserted into the body through an endoscope 1, and a drive operation section 8 that is configured separately from the diagnostic element 7. The diagnostic element 7 has an elongated rod-shaped insertion section 9 that is movably inserted into the treatment instrument insertion hole 4, and a distal end component 10 located at the distal end of the insertion section 9.

The tip component 10 is composed of three parts: a probe part 10a that houses the ultrasonic transducer 11, a curved part 10b, and a rear end part 10c. 12 is an ultrasonic transmitting and receiving surface that transmits and receives ultrasonic waves, and this transmitting and receiving surface 12
The vibrator 1 is placed in a housing chamber 50 formed inside the vibrator 1.
A mirror 14 for directing the transmission/reception direction of 1 toward the transmission/reception surface 12 is rotatably provided. The storage chamber 50 is filled with an ultrasonic transmission liquid 14 such as oil to prevent ultrasonic waves from attenuating, and is kept liquid-tight by oil seals 15, 16 and a cover 17.

Further, on the inner peripheral surface of the ultrasonic transmitting and receiving surface 12,
A buffer material 18 is provided which is made of two or more materials having different acoustic impedances, and which has an acoustic impedance between the acoustic impedances of the transmission fluid 14 and the cover 17. The feature of the present invention is that the cushioning material 18 is provided at least on the inner peripheral surface of the ultrasonic wave transmitting/receiving surface 12 in this manner.

The curved portion 10b is as shown in FIG.
It is designed so that it can be freely bent only on the opposite side of the ultrasonic transmitting/receiving surface 12 at a maximum curvature angle of 90 degrees.

Further, the tip of a flexible rotation transmission shaft 19 such as a tightly wound coil is connected to the rotation shaft of the mirror 13 via a tip rotation shaft 13 a supported by a bearing 20 . On the other hand, the rear end portion of the rotation transmission shaft 19 is connected to the drive operation section 8 .

Further, 21 is a signal cable of the ultrasonic transducer 11, and this signal cable 21 is connected to a socket (not shown) of the drive operation section 8 via a plug (not shown). This drive operation section 8 has a built-in drive section and a circuit section.

Note that 22 is a cord connected to a display device 23. In FIG. 1, a guide tube 25 such as a trocar is punctured into the abdominal wall 24 of a subject.
The tip component 10 is pressed against a reservoir 26 as a subject. Further, 27 is a support member that constitutes the storage chamber 50.

In the above configuration, there are two substances, for example, the transmission fluid 14 and the cover 17, which are referred to as first and second substances, respectively. Then, if the density of the first substance is ρ ₁ , the speed of sound propagating in this is C ₁ , the density of the second substance is ρ ₂ , and the speed of sound propagating in C ₂ , then the reflectance R is R =ρ ₁ C ₁ −ρ ₂ C ₂ /ρ ₁ C ₁ +ρ ₂ C ₂ )
² ……(1) is given. Here, it can be understood that when the acoustic impedance of the two substances is large, the reflectance R also becomes large.

Here, the material currently used for the cover 17 has an acoustic impedance that is considerably different from that of a living body. For example, the acoustic impedance of the cover 17 is ρC=0.965×252000=243000 [g/cm ²
sec], the acoustic impedance of the human body as the subject (for example, the liver) is ρC = (1.03 ~ 1.05) × 157000
= 162000 to 165000 [g/cm ² ·sec].

If the acoustic impedances differ in this way, a reflected echo wave will be generated at this boundary surface as described above, and an echo image will be displayed on the display device 23. Therefore, in this invention, a material whose acoustic impedance is between the values of the acoustic impedances of the two materials is interposed between the two materials to eliminate reflected echo waves at this interface. .

This will be explained in more detail with reference to FIG. 3. In the figure, 14 is an ultrasonic transmission liquid whose acoustic impedance is ρ ₁ C ₁ , and 18 is a buffer material whose acoustic impedance is ρ 1 C 1 . ₂ C ₂ and 1
7 is a cover whose acoustic impedance is ρ ₃ C ₃ , the interface between the transmission liquid 14 and the buffer material 18 is P ₁ , the interface between the buffer material 18 and the cover 17 is P ₂ , and The reflectance of these interfaces P ₁ and P ₂ is
R ₁ and R ₂ , the reflectance R ₁ and R ₂ is R ₁ = (ρ ₁ C ₁ − _{ρ 2} C ₂ /ρ ₁ C ₁ +ρ ₂ C ₂
) ² ...(2) R ₂ = (ρ ₂ C ₂ −ρ ₃ C ₃ /ρ ₂ C ₂ +ρ ₃ C ₃
) ² ...(3) is given.

Therefore, the reflectances R ₁ and R ₂ are approximately 1/4 of the reflectance when the transfer liquid 14 and the cover 17 are simply brought into contact without providing the buffer material 18.

Further, due to the thickness of the buffer material 18, the echo image due to the boundary surface _P1 and the echo image due to the boundary surface _R2 are displayed on the display device 23 at different positions.

As mentioned above, the echo intensity decreases due to the difference in reflectance, and the display position or location shifts.
The disturbance will be smaller.

Additionally, dividing the cushioning material 18 into multiple layers of acoustic impedance further reduces disturbances.

In addition, in FIG. 1, the cushioning material 18 is provided only on the inner peripheral surface of the ultrasonic transmitting and receiving surface 12, but if it is provided so as to cover the entire inner peripheral surface of the storage chamber 50, it may be provided only in the observation direction. Compared to this, the radiation of sound waves outside the observation range is attenuated and less likely to disturb the echo image of the observation region.

Also, although this example was written for medical use,
Due to the structure of the probe of this embodiment, it is not limited to medical use, but can be applied to all uses in which the inside of an object is searched using ultrasonic waves.

As described above, according to the present invention, at least the inner peripheral surface of the ultrasonic transmitting and receiving surface of the tip component of the ultrasonic diagnostic apparatus has a buffer having an acoustic impedance intermediate between the acoustic impedance of the ultrasonic transmission liquid and the cover. Since it is provided with a material, there is an effect that reflection is reduced and diagnosis becomes more reliable.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view of the overall configuration showing an example of the use of the present invention, FIG. 2 is a sectional view showing an enlarged tip structure of the invention, and FIG. 3 is an explanatory view showing the principle of the invention. 10...Tip component, 11...Ultrasonic transducer, 13
...Mirror, 17...Cover, 12...Ultrasonic transmission/reception surface, 14...Ultrasonic transmission liquid, 18...Buffer material, 27...
Support member, 50...accommodation chamber.

Claims (1)

[Scope of Claims] 1. A cylindrical cover is fitted onto a supporting member constituting a storage chamber in which an ultrasonic transducer and a mirror that reflects ultrasonic waves are installed, thereby closing the storage chamber and In an ultrasonic diagnostic apparatus, the ultrasonic diagnostic apparatus has an ultrasonic transmitting/receiving surface for emitting and receiving ultrasonic waves on at least a part of the cover, and has a distal end component in which an ultrasonic transmission liquid is filled inside the storage chamber. An ultrasonic diagnostic apparatus characterized in that a cushioning material having an acoustic impedance between the acoustic impedance of the cover and the acoustic impedance of the cover is provided on at least the circumferential surface of the housing chamber of the ultrasonic transmitting/receiving surface of the cover. 2. The ultrasonic diagnostic apparatus according to claim 1, wherein the cushioning material is provided over the entire inner peripheral surface of the storage chamber.