JPS60185537A - Ultrasonic probe - 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] The present invention relates to an ultrasonic probe used in an ultrasonic tomography apparatus and having a liquid tank in an ultrasonic transmitting/receiving section.

[Background of the invention]

In an ultrasonic tomography device, tomographic images are taken of tissue that is shallow from the body surface of the subject, such as the foramen line or thyroid gland, and where the body surface to which the probe is applied is curved. When desired, the probe is generally used with a liquid tank, such as a water tank, added to the ultrasonic transmitting/receiving part at its tip in order to improve contact with the subject and resolution. In this case, especially in the case of electronic scanning ultrasound probes, there are limits to the shape and weight of the water tank due to the small size of the probe itself and to avoid deteriorating operability. 10 to 50 rnrl+, the opening was set to be somewhat larger than the outer shape of the probe.

However, the above-mentioned size was not sufficient in terms of the ultrasonic emission range, and unnecessary echoes and false echoes were generated that caused resolution deterioration. That is, the ultrasonic waves emitted from the probe enter the subject and propagate mainly through the contact surface between the water tank and the subject, but they also enter the vicinity of the contact surface and the inner surface of the water tank around it. . This incident wave causes diffuse reflection and becomes an acoustic air load especially on the inner surface of the tank other than the contact surface with the test object, so tl becomes total reflection υ, generating unnecessary echoes and false echoes, and S/N The resolution was degraded by lowering the ratio.

[Purpose of the invention]

The present invention was made in view of the above-mentioned circumstances, and reduces unnecessary echoes and false echoes in the liquid tank, and improves the S/N.
An object of the present invention is to provide an ultrasonic probe that can improve the ratio and achieve high resolution.

[Summary of the invention]

The present invention provides an ultrasonic probe with a liquid tank, in which the liquid tank is configured to include an inner tank and an outer tank, each of which is changeable in shape,
In addition, the outer tank is made more flexible than the inner tank, the inner and outer tanks are each filled with an ultrasonic medium, and the outer tank filling medium is selected to have a high ultrasonic absorption rate.

[Embodiments of the invention]

The present invention will be described in detail below with reference to FIGS. 1 to 4. FIG. 1 is a partially cutaway view of an embodiment of the ultrasonic probe according to the present invention, and FIG. 2 is a right side view of FIG. 1. In both figures, 1 is made of plastic, for example. A probe case 2 is an ultrasonic transmitter/receiver section housed on the tip side of the case 1. The transmitter/receiver section 2 includes a piezoelectric element 2a, a matching layer 2b on the front side thereof, an acoustic lens 2C, a backing material 2d on the back side, and the like.

Reference numeral 3 denotes a shape-changeable inner tank made of, for example, soft silicone rubber or plastic film, which is hermetically attached to the distal end of the case 1 using a band 4 or the like while covering the transmitting/receiving section 2 . 5 is an outer tank formed to cover the inner tank 3, and is made of a membrane body that is more flexible than the inner tank 6. The outer tank 5 is hermetically attached, for example, by pasting its opening edge to the outer periphery of the inner tank 3 on the opening side.

6 is an ultrasonic medium filled in the inner tank 3 (inner tank filling medium)
, 7 are ultrasonic media filled in the outer tank 5 (outer tank filling medium), and the outer tank filling medium 7 is selected to have a high ultrasonic absorption rate. For example, the outer tank filling medium 7 is made of silicone resin with low viscosity mixed with tungsten powder with high specific gravity, and has an ultrasonic absorption rate of 60 dB/. Acoustic impedance is 1.54
10 kg/ze.

The following characteristics were obtained. Note that 8 is a medium to which ultrasonic waves are radiated, such as a subject.

Next, the operation of the above-mentioned probe of the present invention will be explained.

First, when a drive signal is sent to the ultrasonic transmitter/receiver 2, ultrasonic waves are emitted from the transmitter/receiver 2. The emitted ultrasonic waves are transmitted through the inner tank filling medium 6 → inner tank 3 → outer tank filling medium 7 → outer tank 5
The radiation propagates along the path and is incident on the radiation target medium 8. Now, when making the ultrasonic wave enter a desired part of the radiation target medium 8,
When the outer tank 5 is applied to that part, the inner and outer tanks 3, 5 change shape to conform to the shape of the desired part of the radiated medium 8, as shown in FIGS. 5 and 4, for example, due to their shape changeability. transform. At the same time, the outer tank filling medium 7 is pushed out to the periphery of the outer tank 5 due to the pressure upon contact with the radiated medium 8, and the inner tank 3 and the outer tank 5 and the outer tank 5 and the radiated medium 8 are in close contact with each other. becomes. In other words, the outer tank filling medium 7 has a large liquid layer in areas other than the contact area between the inner and outer tanks 3 and 5, and absorbs a large amount of ultrasonic waves.
The closer the liquid layer gets to the contact area, the smaller the liquid layer becomes, and the ultrasonic absorption decreases, and the ultrasonic absorption becomes minimum at the contact area.

In other words, the ultrasonic waves from the transmitting/receiving section 2 are emitted toward the desired portion of the radiation target medium 8 without being absorbed, and are largely absorbed in other directions.
The reflected echo from w5 is also largely absorbed by the external structure filling medium 7. Therefore, unnecessary echoes and false echoes mainly caused by diffused reflection of reflected echoes are also greatly reduced. Note that the inner tank filling medium 6 is placed between the acoustic lens 2C surface, which is the ultrasonic radiation surface of the transmitter/receiver 2, and the inner tank 3.
The one that acoustically matches these two is selected, and the generation of unnecessary echoes within the inner tank 3 is reduced.

[Effects of the Invention] As described above, the present invention provides an ultrasonic probe with a liquid tank, in which the liquid tank is configured to include an inner tank and an outer structure, each of which has a shape changeable structure, and an outer tank. The inner tank is made flexible and each of these inner and outer tanks is filled with an ultrasonic medium. At this time, the outer tank filling medium is selected to have a high ultrasonic absorption rate, so unnecessary echoes and false echoes are avoided in the liquid tank. Significantly reduced, S/
This has the effect of improving the N ratio and achieving higher resolution.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway view of an embodiment of the ultrasonic probe according to the present invention, FIG. 2 is a right side view of the same, and FIG. 6 is a diagram showing the probe of the present invention shown in FIG. FIG. 4, which shows the state of use, is a right side view of the same. 2... Ultrasonic transmitting and receiving unit, 6... Inner tank, 4... Band, 5... Outer tank, 6... Inner tank filling medium, 7... Exterior filling medium, 8...・Ultrasonic radiation target medium (subject). Patent Applicant Hitachi Medico Co., Ltd. Agent Patent Attorney Masaru Akimoto Minoru Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In an ultrasonic probe equipped with a liquid tank in the ultrasonic transmitting/receiving part, each of the liquid tanks consists of an inner tank and an outer tank, each of which can change its shape, and the outer tank is formed to be flexible as well as the inner tank. An ultrasonic probe characterized in that the inner and outer tanks are each filled with an ultrasonic medium, and the outer tank filling medium is made of a material having a high ultrasonic absorption rate.