JPH07236641A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To control a focus position arbitrarily by constituting an acoustic lens part filled with an ultrasonic transmitting medium which has an acoustic impedance different from an ultrasonic transmitting medium in a cap on a part facing to an ultrasonic transducer on the cap. CONSTITUTION:An ultrasonic probe is provided with a cap 13 composed of an member with excellent acoustic characteristic on the tip part of its insertion part 10 and encloses an ultrasonic transmitting medium as well as accommodates an ultrasonic transducer 14 in its inner part. And a ring-shaped recessed part 17 is formed on the inside face of the surrounding body of the cap 13 so as to give a focusing function to an ultrasonic beam to be transmitted and the ultrasonic transmitting medium having a higher acoustic impedance than that of the ultrasonic transmitting medium is filled in a chamber 16a partitioned by a flexible membrane 18 attached to the recessed part 17 to be made a acoustic lens part 16. Thus, the adjustment of a swelling degree of the flexible membrane 18 facilitates the adjustment of the focus position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus in which an ultrasonic transducer is provided at the tip of an insertion portion to be inserted into the body of a patient.

[0002]

2. Description of the Related Art Among ultrasonic diagnostic apparatuses, a body-insertion type having an insertion portion to be inserted into a patient's body is conventionally known. This body-insertion type ultrasonic diagnostic device
An insertion section made of a flexible member is connected to the operation section of the main body, and an ultrasonic transducer is attached to the distal end of this insertion section. By transmitting a pulse, receiving an echo reflected from a tomographic part of a body tissue, and processing the received signal, information about the state of the body tissue is acquired in the form of an ultrasonic image. Then, while moving the ultrasonic transducer in a linear direction (linear scanning) or a rotational direction (radial or convex scanning), ultrasonic pulses are transmitted at predetermined distances or angular intervals and reflected echoes are received. The so-called B-mode scanning is performed to obtain an ultrasonic image in a predetermined range inside the body.

Generally, as a sound source, an ultrasonic beam transmitted from a transmitting / receiving surface of an ultrasonic transducer diverges while advancing through internal tissues, so that the directivity of the ultrasonic beam is improved and the lateral resolution is improved. To improve, it is necessary to focus the ultrasonic beam. A structure in which an acoustic lens is attached to the transmitting and receiving surface side of the ultrasonic transducer in order to provide this focusing function has been conventionally used. Here, the acoustic lens utilizes the difference in the acoustic impedance between the material and the body to narrow the ultrasonic beam, and when using a material having a sound velocity faster than that of the living body,
When the acoustic lens has a concave curved surface shape and a material whose sound velocity is slower than that of a living body is used, it has a convex curved surface shape.

[0004]

By the way, in obtaining information about body tissues, there are cases where it is necessary to more closely examine a position close to the inner wall of the body, and where there is a need to obtain precise information in deep areas. There is. In the former case,
The resolution of the region to be inspected / diagnosed is higher when the focus position where the ultrasonic beam is most narrowed by the acoustic lens is closer, that is, when the focal length of the acoustic lens is shorter. The longer the focal length, the better the resolution. In this way, depending on the site to be diagnosed,
It is preferable that the focal length can be changed. However, in the above-mentioned conventional technique, since the acoustic lens is fixedly provided on the transmission / reception surface side of the ultrasonic transducer, the focus position of the acoustic lens cannot be changed.

The present invention has been made in view of the above points, and an object thereof is to be able to control the focus position of an ultrasonic beam by an acoustic lens.

[0006]

In order to achieve the above-mentioned object, the present invention provides a cap at the tip of the insertion portion,
An ultrasonic transducer is provided in this cap, an ultrasonic transmission medium is enclosed, and an ultrasonic signal is transmitted from this ultrasonic transducer through the cap. A part of the cap facing the ultrasonic transducer. Is characterized in that an acoustic lens portion formed by filling an ultrasonic transmission medium having an acoustic impedance different from that of the ultrasonic transmission medium enclosed in the cap is provided.

Another aspect of the present invention is to provide a through hole in a portion of the cap facing the ultrasonic transducer, and attach a flexible film to the through hole so that the cap has an acoustic impedance different from that of a living body. It is also characterized in that the ultrasonic wave transmission medium is provided with an acoustic lens portion formed by deforming the flexible film into a spherical shape.

[0008]

When the ultrasonic transducer is rotated at the time of attaching the ultrasonic transducer to the insertion portion to be inserted into the body, when performing radial scanning, in order to prevent the body wall from being entangled, this radial transducer is also used. Scanning and other scanning methods, for example, even when performing a linear scanning, protect the ultrasonic transducer, stains and adheres body fluids, when performing cleaning and disinfection,
In order to prevent the disinfectant solution from adhering to the cap, a cap is provided at the tip of the insertion part, and the ultrasonic transducer is accommodated in the cap. And, in order to suppress the attenuation of the ultrasonic signal as much as possible in the cap,
A medium having a good acoustic transmission characteristic, that is, an ultrasonic transmission medium is enclosed.

Therefore, an acoustic lens portion is formed by filling the inner surface side of the cap with an ultrasonic transmission medium having an acoustic impedance different from that of the ultrasonic transmission medium enclosed in the cap. As a result, a function as an acoustic lens can be exerted between both ultrasonic transmission media. When the impedance of the ultrasonic transmission medium in the cap is lower, the acoustic lens part is bulged toward the inside of the cap to make the acoustic lens part a convex curved surface, and the acoustic lens part has a higher impedance. In this case, the acoustic lens portion may be formed into a concave curved surface.

On the other hand, by utilizing the difference in acoustic impedance between the ultrasonic transmission medium and the living body, the function as an acoustic lens can be exhibited. In this case, a through hole is provided in the cap, a flexible film is provided in the through hole, and an ultrasonic transmission medium having a volume equal to or larger than the inner volume of the cap is supplied, or the ultrasonic transmission medium is made smaller than or equal to the inner volume of the cap. To do. As a result, the flexible film is deformed into a convex or concave spherical shape, and thus an acoustic lens having a concave spherical shape or a convex spherical shape is formed by the ultrasonic transmission medium having an acoustic impedance different from that of the living body.

As described above, by forming the acoustic lens portion filled with the ultrasonic transmission medium, the curvature of the lens is changed by changing the amount of the ultrasonic transmission medium supplied to the acoustic lens portion. The position where the acoustic beam is focused can be changed. Further, the acoustic lens characteristics can be similarly changed by filling the acoustic lens portion with ultrasonic transmission media having different compositions. Therefore, if the amount or type of the ultrasonic transmission medium is changed according to the site or the like to be inspected, the ultrasonic beam can be focused on the site requiring the most information.

If the supply amount of the ultrasonic transmission medium to the acoustic lens portion can be controlled by remote control on the side of the main body operating portion connected to the insertion portion, the ultrasonic beam is inserted in the body. The focus position of can be adjusted appropriately. Therefore, when scrutinizing the shallow part in the body, by setting the focus position to be close to the ultrasonic transducer, the resolution of this part is improved, and when scrutinizing the deep part, Set to focus at a position far from the ultrasonic transducer. As a result, it is possible to easily improve the resolution of a necessary part, and it is possible to perform more accurate diagnosis.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows the overall configuration of the ultrasonic diagnostic apparatus. In the figure, 1 is an ultrasonic probe, and 2 is an ultrasonic observation device. The ultrasonic probe 1 includes an insertion section 10 made of a flexible member to be inserted into the body, a main body operation section 11 in which a proximal end portion of the insertion section 10 is connected, and an ultrasonic observation apparatus 2.
A cord 12 connected to the. On the other hand, the ultrasonic observation apparatus 2 controls the transmission / reception of ultrasonic waves, processes the received signal and generates an ultrasonic image signal, and based on the signal from the signal processing unit 20. The monitor 21 is configured to display an ultrasonic image.

FIG. 2 shows a cross section of the distal end portion of the insertion portion 10. As is clear from this figure, a cap 13 made of a member having excellent acoustic characteristics is attached to the tip of the insertion portion 10 made of a flexible member, and the ultrasonic transducer 14 is housed in the cap 13. ing. The ultrasonic transducer 14 is adapted to perform radial scanning, and for this purpose, the tip of a control cable 15 is connected to the ultrasonic transducer 14. The control cable 15 is composed of a flexible shaft 15a formed by winding a metal wire rod in a close contact coil shape, and a flexible tube 15b covering the flexible shaft 15a. Both ends of the flexible tube 15b are fixedly held, the distal end of the flexible shaft 15a is connected to the ultrasonic transducer 15, and the proximal end portion thereof extends into the main body operating portion 11, and this main body operating portion is The ultrasonic transducer 14 connected to the tip of the motor 11 is rotated by rotationally driving the motor built in 11. The signal cable connected to the ultrasonic transducer 14 is inserted into the flexible shaft 15a.

The flexible shaft 15a constituting the control cable 15 is remotely operated to rotationally drive the ultrasonic transducer 14, while transmitting ultrasonic pulses at a predetermined angle and receiving reflected echoes from the inside of the body. However, in order to suppress the attenuation of the ultrasonic transmission / reception signal as much as possible, the inside of the cap 13 has a hermetically sealed structure, and the ultrasonic transmission medium is enclosed therein.

Here, it is necessary to narrow down the ultrasonic beam transmitted from the ultrasonic transducer 14 to enhance its directivity and thereby improve the directional resolution. Therefore, the acoustic lens portion 16 is formed on the inner surface of the cap 13. This acoustic lens unit 16
An annular concave portion 17 is formed on the inner surface of a portion where ultrasonic pulses are transmitted from the ultrasonic transducer 14 in the peripheral body portion of the cap 13 and reflected echoes from the body are received, and the concave portion 17 is flexible so as to be closed. The membrane 18 is attached. Thus, the recess 1 closed by the flexible film 18
The chamber 16a formed by 7 is filled with an ultrasonic wave transmission medium, and the flexible film 18 is swollen inward, so that an acoustic lens effect is provided. Therefore, a supply tube 19 for supplying the ultrasonic transmission medium is connected to the chamber 16a, and the ultrasonic transmission medium supplied from the supply tube 19 is the ultrasonic transmission medium enclosed in the cap 13. A higher acoustic impedance is used.

By the way, in order to function as an acoustic lens, the flexible film 18 must bulge in an arc shape. Generally, when the ultrasonic transmission medium is supplied into the chamber 16a, the flexible film 18 bulges in a substantially arc shape, but in order to more accurately bulge in an arc shape, for example, as shown in FIG. As the cross-sectional shape of the flexible film 18, it is preferable to use the flexible film 18 having the thinnest portion in the middle portion and the thickness continuously increasing toward both ends. The flexible film 18 is
It goes without saying that it is necessary to use a material having excellent elasticity and acoustic characteristics.

As described above, the acoustic lens function is exerted by supplying the ultrasonic transmission medium into the chamber 16a constituting the acoustic lens portion 16 via the tube 19, but the ultrasonic transmission medium is supplied. By controlling the amount, the degree of bulging of the flexible film 18 can be changed to change the characteristics of the acoustic lens. In order to control the supply amount of the ultrasonic transmission medium, as shown in FIG. 4, the proximal end portion of the supply tube 19 is extended into the main body operation portion 11, and this main body operation portion is extended. It is connected to a cylinder 30 provided inside 11. A piston 31 is slidably inserted in the cylinder 30. By slidingly displacing the piston 31 along the cylinder 30, the ultrasonic transmission medium is transferred to the chamber 16.
It can be fed into a. In order to operate the piston 31, a feed screw 32 is provided on the piston 31 so as to be relatively rotatable. The feed screw 32 is screwed into a female screw member 34 fixedly provided on the inner surface of the casing 11 a of the main body operation unit 11, and when the base end side of the feed screw 32 is rotated, the feed screw 32 is screwed into and out of the female screw member 34. I will move in the axial direction,
The piston 31 is slidably displaced along the cylinder 30.

In order to drive the feed screw 32 to rotate, a drive shaft 35 is rotatably supported by a pair of bearing members 36, 36 fixedly provided on the casing 11a of the main body operating portion 11. The tip of the drive shaft 35 has a forked portion 35.
a, and the base end portion of the feed screw 32 becomes a chamfered connecting portion 32a, and the connecting portion 32a becomes the drive shaft 3.
5 is inserted into the bifurcated portion 35a and constitutes a joint portion between the feed screw 32 and the drive shaft 35. Therefore, when the drive shaft 35 is rotated, the feed screw 32 rotates following the rotation of the drive shaft 35. However, the feed screw 32
Moves in the axial direction by its rotation, but the drive shaft 35
Is not affected by the axial movement of the feed screw 32. A worm gear transmission mechanism is used to drive the drive shaft 35 to rotate. That is, the worm wheel 37 is provided at a portion of the drive shaft 35 between the bearing members 36, 36.
The worm wheel 37 is fixedly installed.
A worm 38 is meshed with the worm 38, and the rotary shaft 39 connected to the worm 38 is connected to the casing 11 of the main body operation unit 11.
It is led out to the outside from a, and the tip part thereof is the operation knob 39.
It is a. Other than this, as the ultrasonic transmission medium supply amount control mechanism, for example, a syringe or the like can be used.

Therefore, when the operating knob 39a is rotated by a finger, the drive shaft 35 rotates via the worm gear transmission mechanism, and the feed screw 32 connected to the drive shaft 35 via the joint portion rotates following. At the same time, since it moves in the axial direction, the piston 31 moves to the cylinder 3
The ultrasonic transmission medium is supplied to and discharged from the acoustic lens portion 16 by sliding displacement in 0. When the ultrasonic wave transmission medium is supplied into the chamber 16a that constitutes the acoustic lens unit 16 and the flexible film 18 bulges inward, the ultrasonic wave transmission medium in the cap 13 is pushed away, so that this excess It is necessary to have the function of an accumulator that absorbs the ultrasonic transmission medium. For this purpose, the cap 13 is thinned to form the expansion / contraction portion 13a, and when the flexible film 18 swells, the expansion / contraction portion 13a has a distal end as shown by an imaginary line in FIG. It swells to the side. In addition, as shown in FIG. 5, a communication pipe 40 is provided that connects the inside of the cap 13 and the flexible portion of the insertion portion 10, and a flexible bag 41 is provided on the proximal end side of the communication pipe 40. It is also possible to deal with the volume change in the cap 13 by connecting and disconnecting and expanding and contracting the flexible bag 41 according to the supply amount of the ultrasonic transmission medium to the acoustic lens portion 16.

As described above, by supplying the ultrasonic wave transmitting medium into the acoustic lens portion 16, the flexible film 18 is swollen inward and the function as an acoustic lens is exerted, but stable lens characteristics are obtained. In order to have the shape, it is necessary to improve the shape retention of the swollen flexible film 18. Therefore, as a matter of course, the ultrasonic transmission medium supplied to the acoustic lens unit 16 must have an acoustic impedance different from that of the ultrasonic transmission medium enclosed in the cap 13, and in addition to this, By using a medium having a viscosity as high as possible, the medium is not easily deformed even when an external force is applied, and is kept in a stable shape. Since the ultrasonic transmission medium having such a high viscosity is used, a considerably high pressure is applied when the ultrasonic wave is supplied into the acoustic lens unit 16, so that the supply tube 19 has good pressure resistance.

The present embodiment is constructed as described above, and the ultrasonic probe 1 constituting this ultrasonic diagnostic apparatus is inserted into the body of a patient to inspect the state of the internal tissues. You can

Then, while operating the main body operation unit 11, the insertion unit 10 is inserted into the patient's body, and the distal end portion thereof is guided to the inspection target portion inside the digestive tract or the like. Then, activate the control cable 15,
The ultrasonic transducer 14 is rotationally driven, and ultrasonic pulses are transmitted toward the body at every predetermined angle during this period. A part of the ultrasonic beam transmitted by the tomographic portion of the internal tissue will be reflected, and the reflected echo is received by the ultrasonic transducer 14. Then, this received signal is transmitted to the ultrasonic observation apparatus 2 via the code 12, and at the same time, the signal of the angular position of the ultrasonic transducer 14 detected by the encoder or the like is taken into the ultrasonic observation apparatus 2 and these An ultrasonic image is displayed on the monitor 21 by the signal processing unit 20 performing a predetermined process on the signal. When performing the radial scan, if the entire circumference of the cap 13 at the tip of the insertion portion 10 does not adhere to the inner wall of the body, a well-known balloon is attached and the balloon is filled with the ultrasonic transmission medium. To do.

By the way, when the ultrasonic beam is transmitted from the ultrasonic transducer 14 which is a sound source, the ultrasonic beam diverges as it is, the directivity deteriorates, and a sufficient directional resolution cannot be obtained. Therefore, the ultrasonic beam is focused by using an acoustic lens. The focus position of this acoustic lens changes according to the curvature of the acoustic lens. Thus, in the present invention, the function as an acoustic lens is exerted by supplying the ultrasonic transmission medium to the acoustic lens portion 16. Then, the focus characteristic can be changed by controlling the supply amount of the ultrasonic transmission medium supplied to the acoustic lens unit 16.

Now, as shown in FIG. 6, the acoustic lens unit 1
By supplying a predetermined amount of ultrasound transmission medium into the chamber 16a constituting the 6, the flexible membrane 18 radius of curvature R ₁
Suppose that it is bulged and deformed so that This chamber 16
Since the ultrasonic transmission medium supplied in a has a higher acoustic impedance than the ultrasonic transmission medium in the cap 13, the acoustic lens function is exerted in accordance with the difference in acoustic impedance between the two ultrasonic transmission mediums. Sound wave transducer 1
The ultrasonic beam transmitted from No. 4 has a focus position F
_The beam diameter is narrowed until it reaches ₁ , and the beam tends to diverge after passing the focus position F ₁ . That is, the focal length of the acoustic lens at this time is the distance D ₁ from the transmitting / receiving surface of the ultrasonic transducer 14 to the focus position F ₁ . Then, the ultrasonic image of the region between the region V ₁ before and after the region including the focus position F ₁ has high resolution.

On the other hand, when the operation knob 39a is operated to return a certain amount of the ultrasonic transmission medium in the chamber 16a of the acoustic lens section 16 into the cylinder 30, as shown in FIG. The amount of swelling will decrease, and the radius of curvature will increase to R ₂ . As a result, the aperture angle of the ultrasonic beam transmitted from the ultrasonic transducer 14 becomes small, and the focus position becomes far from F ₂ ,
The focal length becomes as long as D ₂ . As a result, the site where high resolution is obtained changes to V ₂ .

From the above, when the region to be inspected is a shallow region close to the inner wall of the body, the acoustic lens unit 16 is not in the state shown in FIG. 6, and in the case of deep region inspection, The acoustic lens 16 may be in the state shown in FIG.
Moreover, with the insertion portion 10 still inserted into the body, it is possible to focus on the most inspected part only by performing the extremely simple operation of rotating the operation knob 39a, so that it is possible to obtain a clear image with high resolution. Ultrasonic images can be acquired, and the accuracy of inspection / diagnosis is significantly improved.

Although the ultrasonic transmission medium supplied to the acoustic lens unit 16 has a higher acoustic impedance than the ultrasonic transmission medium enclosed in the cap 13, the acoustic lens unit 16 has the same structure. When the ultrasonic transmission medium having a lower acoustic impedance is used, the flexible film 18 has a concave curved surface shape as shown by a virtual line in FIG. Then, by changing the curvature of the concave curved surface of the flexible film 18, the focus position can be changed as described above. Further, even if the radius of curvature of the flexible film in the acoustic lens portion 16 is the same, by changing the type of the ultrasonic transmission medium supplied inside or the ultrasonic transmission medium enclosed in the cap 13, both ultrasonic transmission members are changed. If the difference in the acoustic impedance of is changed, the focus position can be changed.

Next, FIGS. 8 and 9 show a second embodiment of the present invention. In this embodiment, the ultrasonic transducer 50 is configured to perform mechanical linear scanning. This ultrasonic transducer 50 is also provided in a cap 52 provided at the tip of the insertion portion 51, and an ultrasonic transmission medium is enclosed in the cap 52, which is the same as in the first embodiment described above. . However, the ultrasonic transducer 50 is fixedly arranged in the cap 52, and while the insertion portion 51 is moved along the inner wall of the body, ultrasonic pulses are transmitted at a predetermined distance interval and the reflection echo thereof is transmitted. Is received, the mechanical linear scanning is performed.

On the outer peripheral surface of the cap 52, a through hole 52a is formed at a portion facing the ultrasonic transducer 50, that is, at a position where the ultrasonic beam passes, and this through hole 52a has excellent acoustic characteristics. A flexible film 53 made of an elastic film is attached. Further, in the cap 52, a supply tube 54 for supplying an ultrasonic transmission medium is provided.
Are connected. Then, the supply tube 54 is extended to the main body operation part and connected to the same ultrasonic transmission medium supply amount control mechanism as shown in FIG. 4, for example. As a result, the ultrasonic transmission medium having a volume equal to or larger than the inner volume of the cap 52 is supplied from the supply tube 54 to bulge the flexible film 53 outward in a convex spherical shape. Here, the acoustic impedance of the ultrasonic transmission medium supplied into the cap 52 is lower than that of the living body. Further, in order to make the flexible film 53 spherical more accurately, it is preferable that the central part of the flexible film 53 be thin and that the thickness be continuously increased toward the peripheral part.

Even with this configuration, the function as an acoustic lens can be exerted by swelling the flexible film 53 by a predetermined amount, and the ultrasonic transducer 50 can be realized.
It becomes possible to narrow down the ultrasonic beam transmitted from. Moreover, by the ultrasonic transmission medium supply amount control mechanism,
By adjusting the amount of bulging of the flexible film 53, the focus position can be controlled to an arbitrary position.

The acoustic impedance of the ultrasonic transmission medium supplied into the cap 52 may be higher than the acoustic impedance of the living body. In this case, the amount of the ultrasonic transmission medium in the cap 52 may be adjusted so that the flexible film 53 has a concave curved surface shape so as to be drawn into the cap 52.

[0033]

As described above, according to the present invention, the portion of the cap facing the ultrasonic transducer is filled with the ultrasonic transmission medium having an acoustic impedance different from that of the ultrasonic transmission medium enclosed in the cap. Or an ultrasonic transmission medium having an acoustic impedance different from that of the living body is used to provide a flexible film on the cap, and the ultrasonic transmission medium is supplied into the cap to form a flexible film. By deforming, there is an effect that the focus position by the acoustic lens unit can be arbitrarily adjusted.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an ultrasonic diagnostic apparatus showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a tip portion of an ultrasonic probe.

FIG. 3 is an enlarged cross-sectional view of a flexible film.

FIG. 4 is a sectional view showing a configuration of an ultrasonic transmission medium supply amount control mechanism.

FIG. 5 is an explanatory diagram showing a configuration of an accumulator that absorbs a surplus ultrasonic wave transmission medium.

FIG. 6 is an operation explanatory view showing an example of an aperture state of an ultrasonic beam of an acoustic lens unit.

FIG. 7 is an operation explanatory view showing another example of the diaphragm state of the ultrasonic beam of the acoustic lens unit.

FIG. 8 is a cross-sectional view of a tip portion of an ultrasonic probe showing a second embodiment of the present invention.

9 is a sectional view taken along line XX of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Ultrasonic observation device 10,50 Insertion part 11 Main body operation part 13,52 Cap 14,50 Ultrasonic transducer 16 Acoustic lens part 16a Chamber 17 Recessed part 18,53 Flexible film 19,54 Supply tube 30 Cylinder 31 Piston 39a Operation knob

Claims (5)

[Claims] 1. A device comprising a cap provided at a tip of an insertion portion, an ultrasonic transducer provided in the cap, an ultrasonic transmission medium enclosed therein, and an ultrasonic signal transmitted / received from the ultrasonic transducer through the cap. In the portion of the cap facing the ultrasonic transducer, an acoustic lens portion is provided which is filled with an ultrasonic transmission medium having an acoustic impedance different from that of the ultrasonic transmission medium enclosed in the cap. Characteristic ultrasonic diagnostic equipment. 2. A device comprising a cap provided at the tip of an insertion portion, an ultrasonic transducer provided in the cap, an ultrasonic transmission medium enclosed therein, and an ultrasonic signal transmitted / received from the ultrasonic transducer through the cap. , A through hole is provided in a portion of the cap facing the ultrasonic transducer, and a flexible film is attached to the through hole, and the cap serves as an ultrasonic wave transmission medium having an acoustic impedance different from that of a living body, An ultrasonic diagnostic apparatus having a configuration in which an acoustic lens portion formed by deforming a spherical shape is provided. 3. The acoustic lens unit is configured by providing a flexible film that bulges and deforms by enclosing an ultrasonic transmission medium on the inner surface of the cap. 2. The ultrasonic diagnostic apparatus according to 2. 4. The acoustic lens unit is configured to make a focus position of an ultrasonic beam variable by controlling a supply amount of an ultrasonic transmission medium to be enclosed. The ultrasonic diagnostic apparatus according to claim 2. 5. A supply tube having one end connected to the acoustic lens and the other end of the supply tube disposed on the main body operation section side in order to control the supply amount of the ultrasonic transmission medium to the acoustic lens section. 5. A structure comprising a cylinder, a piston for changing the volume in the cylinder, and an operating means for operating the piston.
The ultrasonic diagnostic apparatus described.