JPS6099238A - Endoscopic ultrasound diagnostic equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Field of application of the invention] TECHNICAL FIELD The present invention relates to a congratulatory ultrasound diagnostic apparatus.

[Background of the invention]

Conventionally, most ultrasonic diagnostic apparatuses emit ultrasonic pulses from the body surface into the body and receive the reflected waves to obtain in-vivo information. In recent years, another type of ultrasound diagnostic method has been used, in which an ultrasound probe is inserted into a body cavity and ultrasound pulses are transmitted and received from near living organs. According to this method, since there is little attenuation of sound waves due to the subcutaneous fat layer etc. interposed between the objects, it is possible to achieve high resolution using high frequencies, and highly accurate biological information can be obtained.

As an example of the endoscopic ultrasonic diagnostic apparatus (abbreviated as an ultrasonic endoscope), FIG. 1 is a sectional view showing the configuration of a distal end portion 11 inserted into a body cavity. An ultrasonic endoscope is generally used in conjunction with an endoscope as a means for optical observation, and its configuration will be explained below with reference to FIG.

The tip 11 is of a side-viewing type, and is an image guide using an optical imaging system consisting of a right-angle prism 13 and an imaging lens 14 arranged adjacent to the output end of a light guide 12 that transmits and emits illumination light. The image is formed on the end face of 15. The image is transmitted through the image guide 15, and an intracorporeal surface image is obtained by an observation optical system outside the body (not explained here).

The ultrasonic transducer 2 is installed so that the sound wave transmitting/receiving surface is perpendicular to the rotation axis 2o. Transmit and receive ultrasonic waves in the direction of A. The ultrasonic transducer 2 and the sound wave absorbing damper material 17 attached to the rotating shaft 2o are rotated around Z@ by the rotation of a motor placed outside the body via the flexible shaft 16, and are rotated perpendicularly to the Z axis. Obtain an in-plane tomographic image. The rotating shaft 20 is supported by a bearing 22, and the bearing 22 is supported and fixed by a bearing support base 21 whose periphery is fixed to the inner wall of the tip portion 11. The signal from the vibrator 2 is sent to the slip ring 2 that is in contact with the rotating shaft 20.
5, from the rotating side signal #1I23 to the fixed side signal line 2
4, and is connected to a signal processing circuit system (not shown) through a cable 10 to obtain an image of a cross section perpendicular to the Z axis.

In the conventional ultrasound endoscope configured as described above,
For example, as shown in FIG. 2, when inserting the distal end 11 of the endoscope into the duodenum 30 and diagnosing the pancreas 31, etc., a single transducer is rotated and scanned, so if the distal end 11 is fixed, the cross section Only B can be imaged. Different cross sections of the pancreas 31 (
For example, in order to image n/), it is necessary to move the distal end 11 in the duodenum 30 in the direction of the arrow. In addition, in Fig. 2, cross sections B and B' are assumed to be perpendicular to the page, but when observing blood vessels, etc., information on cross sections tilted to the page is required, and in that case, the duodenal It is necessary to bend the tip 11 inside the tube. However, it is very difficult to manipulate the tip within a narrow tube and take images of different cross sections.

Furthermore, even if the tip fi511 is moved and information on different planes is obtained, the amount of movement (the position of the tip fi511)
It is not possible to measure three-dimensional information (such as the height of the affected area) of the subject unless the

[Purpose of the invention]

The present invention was made in order to solve the problems of conventional ultrasound endoscopes, and it is an electronic sector scanning system that can scan an ultrasound beam in any direction in the arrangement direction of transducer elements. By combining this method with the mechanical radial scanning (or sector scanning) used in conventional ultrasound endoscopes, the beam deflection angle is changed in synchronization with the rotation angle of the probe. The present invention is characterized in that it is possible to gtL any cross section of the affected area while fixing the section near the affected area, and that the relative position of each cross section can be clearly set.

[Summary of the invention]

Before describing the details of the present invention, the conventional electronic sector system used in the present invention will be briefly explained.

FIG. 3 illustrates a method of deflecting a supersonant beam. As shown in FIG. 3, small oscillators 32a to 32n, which can be regarded as point sources, are arranged in a fixed line with an interval d, and each of these oscillators is controlled by a control drive unit 33 to have a delay time expressed by the following equation. Drive with pulses 34a to 34n of t1.

d Layer for tI=-sinθ...(1) ■ ■ is the speed of sound in the medium.

The composite wave of the spherical waves emitted from each vibrator propagates in the direction of the direction angle θ due to the interference of the four waves. Gakatsu C1
This delay time 1. each vibrator 328 to 320 by changing
When driving, the deflection angle θ can be set arbitrarily.

Directivity of received waves can also be controlled in a similar manner.

The basic configuration of an electronic sector scanning device using the beam deflection method described above is shown in FIG. n digitally controlled transmission triggers generated by a digital variable delay circuit 42 based on a signal from a control signal generator 44 are connected to a transmission pulse generator 41. The number of transmission pulse generators 41 equal to the number of transducers is installed, and the number of transmission pulse generators 41 is equal to the number of transducers.
transmits ultrasonic waves with a time difference ti expressed by equation (1).

The echoes reflected from within the body are received by the n transducers 4o, delayed by the time t1 shown in equation (1) by the analog variable delay circuit 43, and the received signal of rllllil is added. This output is connected to a receiving amplifier 45, and produces a brightness modulation output depending on the magnitude of the signal. On the other hand, the sweep signal generator 46 generates sweep signals for indicating the direction of the ultrasonic beam, and these signals are transmitted to the Braun tube display device 47.
A raster corresponding to a single ultrasonic beam is created and displayed with brightness modulation. Since the control signal generator 44 sequentially generates control signals that slightly deflect the ultrasonic beam and the two stars, the tomographic images are successively completed.

Even if the electronic sector scanning probe is built into an ultrasonic endoscope, it is not possible to image a cross section parallel to the direction in which the transducers are arranged.

Therefore, in the present invention, the electronic sector probe is built into an ultrasonic endoscope, and the electronic sector probe is rotated and scanned, and the beam deflection angle θ is sequentially adjusted in accordance with the rotation angle β. By changing the angle ↓, it is possible to obtain a cross-sectional image in which the rotating shaft 2 is arbitrarily cut.

The details of the method of the present invention will be explained below.

Figure 5(a) shows the coordinate system x − fixed at the tip of the endoscope.
FIG. 3 is a diagram showing the relationship between the J-plane section at y-z and the beam deflection angle. The rotation axes of the probe are two axes, and the plane perpendicular to them is the xy plane. Now, consider a case where an image is captured in a plane where the angle between the tomographic plane and the X-y plane is 00. The X-axis is the transmitting direction O8 with a deflection angle of 0°, and the relationship between the direction angle θ of the transmitting direction OR and the display angle α on the Frikun tube with respect to the probe rotation angle β from the X-axis is given by the following formula. It will be done.

α=jan-'(=Nara Both...(3) Therefore, if the rotation angle β is known, the deflection angle θ and the display angle α with respect to the inclination θ0 of the tomographic plane are equalized.

By setting θθ arbitrarily, as shown in Fig. 5(b), it is possible to image cross sections A' and A'' tilted with respect to the Z axis up to '1 where the tip 11 is fixed. .Also,
Coordinate system x / y / rotated by β0 around the Z axis
If we assume a fault plane based on z, that is, β′−β
Substituting 1β0 into equation (2) and finding the deflection angle θ(b), we get
In FIG. 5(b), it is possible to capture an image on a plane that is inclined to the plane of the paper.

[Embodiments of the invention]

Next, an embodiment of the present invention using the above method will be described using the basic configuration diagram shown in FIG. In the figure, 40 is a sector scanning probe, 41 is a transmission pulse generator, 42 is a digital variable delay circuit, 43 is an analog delay circuit, 44 is a control signal generator, 45 is a receiving amplifier, 46 is a sweep signal generator, 4
Reference numeral 7 denotes a cathode ray tube display device, and the operations of the above-mentioned components are similar to those described in the explanation of FIG. However, in the present invention, the probe 40 is rotated by the motor 51 via the rotation transmission flexible shaft 52. Probe 4
The rotation angle β of 0 is the transmission angle interval Δβ−360°/M(M
is measured by the rotation angle detector 48 for each Lascou number) and inputted to the control signal generator 44 manually. The tomographic plane determination parameters 00 and β0 are input manually (for example, from a keyboard) into the calculator 50, (2), (3
), θ(βJ
)l α(βj) is calculated and stored in the memory 49.

However, βj=j x Δβ (j=1~M) ・・・・・・(4
). The control signal generator 44 reads the deflection angle θ (βJ) from the memory 49 in response to the rotation angle β5 inputted from the rotation detector 48, and calculates the M extension time 1. The control signal that generates the digital I! Send to extension A 11i642.

At the same time, two stars are read from the memory 49 in the display direction α (β
j) and sends a control signal to the sweep signal generator 46 in order to generate a sweep signal such that the display angle of the display device 47 becomes α(βI). According to the above configuration, a control signal is generated so that the ultrasonic beam and the two stars are deflected little by little according to the rotation angle βj, so that one image of an arbitrary cross-sectional no plane (θ0.β0) is performed.

Next, the configuration of the distal end portion 11 of the ultrasonic endoscope according to the present invention will be explained with reference to FIG. The sector-scanning ultrasonic transducer 3 is mounted so that its all-wave transmitting and receiving surface is perpendicular to the rotating shaft 20, and the one-sound case 18 is used for acoustic coupling between an ultrasonic transmission medium 19 such as olive oil and a living body. , ultrasonic waves are transmitted and received in a direction A' that is deflected by θ0 from the vertical direction A by delayed transmission pulses applied to each element of the vibrator. Rotating shaft 20
Sector vibrator 3 and damper material 17 attached to
is the rotation of a motor placed outside the body via the flexible shaft 16! ,! Rotate 9 times around the DZ axis to obtain a cross-sectional J-image of a plane that cuts the Z axis at an inclination of 90°-00.

The rotating shaft 20 is supported by a bearing 22, and the bearing 22 is attached to the tip end 1.
It is supported and fixed by a bearing support stand 21 whose periphery is fixed to the inner wall of 1. The main signal line 23 from each element of the sector vibrator 3 passes through the inside of the hollow rotating shaft 41I1120 and the hollow flexible shaft 16, and is connected to a zero-pole slip ring (not shown) on the motor side located outside the body. It is connected to the signal processing circuit system via. The disk-shaped reflector 27 is printed with a reflection pattern divided into M equal parts at equal angles.
The reflective photosensor 28 is mounted perpendicularly to the rotating shaft 20 and generates a rotation angle detection signal of the vibrator 3 by detecting its reflection pattern. By sequentially changing the deflection angle of the ultrasonic beam and the display direction of the raster in synchronization with this rotation angle detection signal using the signal processing circuit shown in FIG. 6, an arbitrary tomographic image can be obtained as described above. It will be done.

In the above embodiment, the mechanical scanning of the sector vibrator 3 is performed by rotating the Z-axis through 360 degrees using a flexible shaft.
Although rotating radial scanning has been described, it is also possible to perform arbitrary cross-sectional imaging by combining mechanical lamp scanning and electronic radial scanning with the rotation of the transducer 3t-Z axis without reciprocating rotation. , can be implemented using exactly the same configuration.

[Effects of the Invention] As explained above, according to the present invention, by combining electronic sector scanning and mechanical radial scanning and changing the beam deflection angle in synchronization with the rotation angle of the probe, Imaging of any cross section can be performed while the tip of the sonic endoscope is fixed inside the body. In addition, since the relative position of each cross section can be clearly set, a set of tomographic images can be
It can be used as dimensional information.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view showing the outline of the tip configuration of a conventional ultrasound endoscope, Figure 2 is a diagram showing the imaging position of the pancreas by a conventional ultrasound endoscope, and Figure 3 is an electronic sector scanning diagram. 4 is a block diagram showing the basic signal processing configuration of the electronic sector scanning device. FIG. 5(a) is a diagram showing the tomographic plane and beam in the coordinate system of the tip of the endoscope. FIG. 5(b) is a diagram showing the imaging position by the ultrasound endoscope of the present invention, FIG. 6 is a block diagram showing an embodiment of the present invention, and FIG. 7 is a diagram showing the relationship between deflection angles. 1 is a vertical cross-sectional view schematically showing the configuration of a distal end portion of an ultrasonic endoscope according to the invention. Figure 1 %z Figure 1 Figure 3 Figure 4 ((L) χ (b) Figure 6 θ, β. Person who corrects the ultrasound diagnostic device +1i'l and σ) III fee Patent applicant name L, +
+0+Stock Co., Ltd. 11]

Claims (1)

[Claims] By combining electronic sector scanning and mechanical radial (or sector) scanning, and by synchronizing the deflection angle of the ultrasound beam and the rotation angle of the probe, it is possible to image any cross section of the object. Ultrasound diagnostic equipment.