JP2712975B2 - Ultrasound probe for body cavity - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe which is inserted into a body cavity or the like by being guided by an endoscope or the like and performs an ultrasonic inspection.

[0002]

2. Description of the Related Art In recent years, when examining the state of internal tissue using an ultrasonic probe, for example, an ultrasonic probe is used with a forceps channel or the like provided for inserting a treatment instrument such as a forceps in an endoscope as a guide. Into the body,
2. Description of the Related Art A body-insertable type that transmits and receives an ultrasonic signal directly from an inner wall of a body cavity is used. This kind of ultrasonic probe is
A distal end hard portion is connected to the distal end of a flexible cord that can be inserted into the forceps channel, and the ultrasonic vibrator is attached to the distal end hard portion. In this way, by transmitting and receiving ultrasonic waves directly from the inner wall of the body cavity, the ultrasonic transducer can be operated at a position very close to the site to be inspected, etc., and compared with those that transmit and receive ultrasonic signals from the body skin In addition, there is an advantage that the attenuation of an ultrasonic signal due to subcutaneous fat can be suppressed to a minimum, and the accuracy of ultrasonic diagnosis is improved.

[0003]

Here, the inside of the forceps channel in the endoscope is quite narrow, and when guided by the forceps channel of the endoscope, the ultrasonic probe must have an extremely small diameter. For this reason, the ultrasonic vibrator that can be mounted on the distal end hard portion is a single-plate vibrator and is limited to an extremely small one. However,
The vibration energy of the ultrasonic vibrator is proportional to the area thereof. Therefore, when the ultrasonic vibrator is miniaturized, the transmission signal and the reception signal are correspondingly weakened and the sensitivity is deteriorated.

[0004] Further, it is preferable that the beam pattern of the ultrasonic vibrator is circular. Therefore, the transmitting and receiving surfaces of the ultrasonic vibrator are generally formed in a circular shape. However, when a circular ultrasonic vibrator is used, there is a problem that a dead space is generated due to the relationship with the shape of the mounting portion of the ultrasonic vibrator at the hard end portion.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to increase the area of the transmitting / receiving surface of an ultrasonic vibrator mounted on a hard end portion by increasing the transmitting energy. Another object of the present invention is to provide an ultrasonic probe for a body cavity having high receiving sensitivity and high sensitivity.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a flexible cord having a small diameter and having a cross section at the tip thereof.
A substantially circular tip hard part is continuously provided, and a substantially semicircular
Cut out to form a flat part, and
Parallel to the plane of the part, the outer shape of which is approximately the same as the width of the flat part
An ultrasonic vibrator made of a rectangular single plate is mounted, and an acoustic lens having substantially the same outer shape as that of the ultrasonic vibrator is laminated on the transmitting / receiving surface side.

[0007]

In order to secure an area where the ultrasonic vibrator is attached to the distal end hard portion connected to the distal end of the flexible cord, the distal end hard portion is formed by converting a substantially cylindrical member into a substantially semicircular state. The flat portion is cut out, and the flat portion is used as a mounting portion of the ultrasonic vibrator. Therefore, in order to effectively use the flat portion, the ultrasonic transducer is formed in a square shape, and an acoustic lens having the same shape as the ultrasonic transducer is laminated. However, it is not preferable to simply form the square shape so as to fit the flat portion, since the beam pattern of the ultrasonic signal transmitted from the ultrasonic transducer becomes non-circular. Therefore, the shape of the ultrasonic transducer is formed to be substantially square. As a result, the ultrasonic beam does not necessarily converge in a circular shape, but is of a practically acceptable degree. In addition, the vibration energy is increased and the receiving sensitivity is improved by enlarging the area of the transmitting and receiving surfaces of the ultrasonic transducer. As a whole, the performance is improved. Here, the acoustic lens may be formed as a spherical surface, but if the acoustic lens has an aspherical shape, it is possible to correct the beam pattern so as to be almost completely circular.

Moreover, forming the ultrasonic transducer in a square shape in this way is extremely advantageous in terms of processing as compared with a circular shape. In particular, in the case of an ultrasonic probe for a body cavity inserted into a forceps channel of an endoscope, the external dimensions of the ultrasonic transducer are extremely small, such as about 2 mm square or less. Although it is extremely difficult to form a circle into a circle, it is relatively easy to work into a square.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 shows a cross-sectional structure of a distal end portion of the ultrasonic probe P for a body cavity. In FIG. 1, reference numeral 1 denotes a flexible cord, and a distal end hard portion 2 is provided at the tip of the flexible cord 1. The flexible cord 1 is constructed such that a double or triple contact coil spring 4 is provided inside a jacket tube 3 made of a tube member of a flexible member having a good sliding property such as a fluororesin. A signal cable 5 is inserted inside the coil spring 4.

A connecting pipe 6 is connected to the distal end hard portion 2, and a hard ring 7 made of metal or the like connected to the outer tube 3 of the flexible cord 1 is fitted to the connecting pipe 6. I have. The rigid ring 7 can be relatively rotated with respect to the connecting pipe 6 by bending the distal end thereof inward, and the two are not separated. Further, the close contact coil spring 4 is fixed to the inner surface of the connecting pipe 6 by means such as adhesion or brazing. If the close contact coil spring 4 is turned around an axis, the distal end hard portion 2 can be rotated.

Next, as is apparent from FIG. 2, the distal end hard portion 2 has a circular cross section at the distal end portion.
By cutting out from an intermediate position, a substantially semicircular cross section is obtained, and a flat portion 2a is formed in this portion. The flat portion 2a is a region where the ultrasonic transducer 8 is mounted. As shown in FIG. 3, the ultrasonic vibrator 8 has a square shape, and the length of each side is approximately the same as or slightly shorter than the width of the flat portion 2a. ing. On the ultrasonic vibrator 8, a concave acoustic lens 9 having the same outer shape as that of the ultrasonic vibrator 8 is laminated, and wirings 10 of the signal cable 5 are provided on both front and back surfaces at the corners of the ultrasonic vibrator 8. It is connected. Further, the wiring 10 is connected to the coil 11 mounted on the flat portion 2a, and the wiring in the signal cable 5 composed of a coaxial cable is connected to the coil 11.

As shown in FIG. 4, the ultrasonic probe P for a body cavity constructed as described above has a forceps channel C provided for inserting forceps and other treatment tools in an endoscope S. The ultrasonic wave signal can be transmitted and received directly from the inner wall of the body cavity by inserting the insertion portion I of the endoscope S into the body. That is, the insertion portion I of the endoscope S is guided to a site to be examined in the body, the ultrasonic probe P for a body cavity is inserted into the forceps channel C, and the distal end hard portion 2 is moved out of the forceps channel C to the outside. The ultrasonic pulse is directed toward the body by being derived and brought into contact with the body cavity wall, or facing the body cavity wall via the ultrasonic wave propagation medium. And get the reflected echo,
This signal is transmitted to the ultrasonic observation device T, and after performing predetermined signal processing, an ultrasonic image is displayed on the monitor device M.
Here, when the ultrasonic transducer is scanned over a predetermined range to acquire a B-mode ultrasonic image, the ultrasonic transducer 8 is mechanically moved in a linear direction or a radial direction. For this purpose, the base end of the flexible cord 1 in the ultrasonic probe P for a body cavity is connected to an operation unit U fixed to the endoscope S, and the ultrasonic probe P is pushed by the operation unit U. A pulling operation may be performed, or the close contact coil spring 4 in the flexible cord 1 may be rotated around an axis by a motor or the like. In addition, even when performing a linear scan, since it is necessary to point the ultrasonic transducer 8 in a desired direction, it is necessary to rotate the contact coil spring 4 to rotationally drive the distal end hard portion 2. Has become.

The ultrasonic inspection is performed in this manner,
Ultrasound examination is to receive an ultrasonic pulse from a site with a difference in acoustic impedance in the body, such as by entering an ultrasonic pulse into the body, etc., in order to raise the signal level of this reflected echo signal, In order to be able to receive a reflected echo from a deep part of the body, the ultrasonic signal transmitted from the ultrasonic transducer 8 must have its vibration energy as high as possible and a spot as small as possible. It must be focused to a diameter. Here, in order to improve the power of the ultrasonic vibrator 8, the area of the transmitting / receiving surface may be increased. On the other hand, the beam spot of the ultrasonic signal is focused at a predetermined depth position so as to have a circular or nearly circular shape. From the above, it is preferable that the ultrasonic transducer has a circular outer shape and has a transmitting and receiving surface as wide as possible. However, the ultrasonic probe P for a body cavity, which is inserted into the forceps channel C of the endoscope S, requires a very small diameter, so that the ultrasonic transducer 8 cannot be increased in size.

Here, looking at the shape of the flat surface 2a of the distal end hard portion 2 on which the ultrasonic vibrator 8 is mounted, the ultrasonic vibrator mounting space is square. Therefore, in order to effectively utilize the dead space in the mounting area of the ultrasonic vibrator so that no dead space is formed, the ultrasonic vibrator 8 is made square,
The length of each side is substantially the same as or slightly shorter than the width of the flat portion 2a, and the acoustic lens 9 having the same shape as the ultrasonic vibrator 8 is laminated on the transmitting / receiving surface. Almost the whole is used as a transmitting / receiving surface. As a result, the same flat surface 2
When it is mounted on a, the area of the transmitting and receiving surface obtained becomes considerably large. Moreover, since the connection portion of the wiring 10 is provided at the corner of the ultrasonic vibrator 8, almost the entire portion can be used as a transmission / reception surface.

When a rectangular ultrasonic transducer is used, there is a problem that the spot diameter of the ultrasonic beam cannot be focused in a circular shape. However, by making the ultrasonic transducer 8 a square and covering the entire ultrasonic transducer 8 with the acoustic lens 9, the ultrasonic transducer 8 is focused so as to have a shape close to a circle, so that there is no practical difference. .
Rather, even if the shape of the beam spot is somewhat irregular, increasing the vibration energy is more advantageous in terms of performance as an ultrasonic transducer. If the acoustic lens 9 has an aspherical shape, the spot of the ultrasonic beam can be corrected so as to be substantially circular.

Further, in forming an extremely small ultrasonic vibrator 8 (the outer dimension of which is limited to about 2 mm or less because it is regulated by the inner diameter of the forceps channel C of the endoscope S), Although it is relatively easy to form into a square shape, it is extremely difficult to work into a circular shape. Therefore, it is extremely advantageous to form the square from the viewpoint of processing the ultrasonic transducer.

Here, as the acoustic lens 9, it is general to use an epoxy resin as a material. In order to form an acoustic lens with the epoxy resin and converge the ultrasonic beam, it is necessary to use a concave lens. There is a need to.
When this concave lens is made square, projections 9a are formed at the four corners, and such projections 9a directly hit the body cavity wall.
Must not be . However, it is mounted on a flat portion 2a of the distal end hard portion 2, a bulging portion 2b is provided at a front position of the flat portion 2a, and an insertion portion 2c of the connecting pipe 6 is provided at a rear position thereof. The projection 9a of the acoustic lens 9 protrudes only to a position lower than these. Further, the molding of the acoustic lens 9 with the epoxy resin to the soft state, also possible to make to have a rounded and formed by press molding means in the portion of the protrusion 9a
It is .

[0018]

As described above, the present invention provides an ultrasonic
It will be almost semicircular on the hard part at the tip where the vibrator is mounted
An acoustic lens having the same outer shape as the ultrasonic vibrator is provided on the transmitting / receiving surface side of the ultrasonic vibrator with the notch provided, and the ultrasonic vibrator is mounted in a substantially square shape in parallel with the surface of the notch. So that the shape of the focused spot of the ultrasonic beam is suppressed to a non-circular shape that does not hinder practical use, and there is no dead space in the mounting part of the ultrasonic transducer at the hard end. By making effective use, it is possible to increase the area of the transmitting and receiving surfaces as much as possible, to increase ultrasonic vibration energy, and to greatly facilitate processing of ultrasonic vibrators. To play.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a distal end portion of a body cavity ultrasonic probe according to an embodiment of the present invention.

FIG. 2 is a plan view of a distal end hard portion of the ultrasonic probe.

FIG. 3 is an exploded perspective view of an assembly including an ultrasonic transducer and an acoustic lens.

FIG. 4 is an explanatory diagram showing an operation state of the ultrasonic probe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible cord 2 Tip hard part 2a Flat part 8 Ultrasonic transducer 9 Acoustic lens P Ultrasonic probe S Endoscope C Forceps channel

Continued on the front page (72) Inventor Shoichi Yamashita 6-22-1, Mure, Mitaka City, Tokyo Aloka Corporation (72) Inventor Keiji Kato 6-22-1, Mure, Mitaka City, Tokyo Aloka Corporation (72) Inventor Toshiyuki Matsunaka 6-22-1, Mure, Mitaka-shi, Tokyo Aloka Co., Ltd. (56) References JP-A-3-106351 (JP, A) JP-A-2-65852 (JP, A) JP-A-58-133224 (JP, A) JP-A-4-97742 (JP, A) JP-A-61-77009 (JP, U)

Claims (2)

(57) [Claims] 1. A cross section of a tip of a small-diameter flexible cord is substantially circular.
The rigid end of the shape is connected continuously, and the semi-circular shape is attached to this rigid end.
Notch to form a flat part, and the flat part
Substantially square, parallel to the surface, whose outer shape almost matches the width of the flat part
An ultrasonic probe for use in a body cavity, wherein an ultrasonic transducer made of a single plate is mounted and an acoustic lens having substantially the same outer shape as that of the ultrasonic transducer is laminated on the transmitting / receiving surface side. 2. The acoustic lens has an aspherical shape.
From the ultrasonic transducer by the aspherical acoustic lens
Correct the wave beam pattern so that it is almost perfectly circular
The body cavity according to claim 1, wherein
Ultrasonic probe.