close

Вход

Забыли?

вход по аккаунту

?

DESCRIPTION JPH0646495

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH0646495
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
probe used in an ultrasonic imaging apparatus, and more particularly to transmitting ultrasonic
waves from an ultrasonic probe into an object through an ultrasonic wave propagation medium.
The present invention relates to an ultrasonic probe that is designed to
[0002]
2. Description of the Related Art In an ultrasonic imaging apparatus, an ultrasonic probe is
brought into contact with an object to transmit ultrasonic waves to the inside of the object, and
reflections at interfaces with different acoustic impedances in the object, the object, It is to image
the frequency deviation of the ultrasonic wave by the moving object inside. In order to transmit
ultrasonic waves into a subject, the difference between the acoustic impedances of the
transmission surface of the ultrasound probe and the subject must not be large. Therefore, for
example, an ultrasound diagnostic apparatus for medical diagnosis For example, an acoustic
matching layer may be provided on the front of the transducer of the ultrasonic probe, or at the
time of diagnosis of a portion where the probe is not in close contact with the living body,
degassing between the ultrasonic probe and the living body Ultrasonic waves are transmitted to
the living body via an acoustic coupler in which an ultrasonic wave propagation medium such as
water is enclosed in a bag.
[0003]
13-04-2019
1
The above-mentioned acoustic couplers cope with the problem that ultrasonic waves are
reflected between propagation media if the difference in acoustic impedance is large and
propagation becomes impossible. There were still other problems to be improved. That is, it is a
problem of the occurrence of artifacts due to side lobes. As shown in FIG. 2, when the ultrasonic
transducer 11 is excited, an ultrasonic wave is emitted from the transducer 11. This is because
the main lobe 12 of the large energy radiated to the front of the transducer 11 and the
transducer It consists of what is called a small energy side lobe 13 radiated diagonally forward.
The material of the ultrasonic wave propagation medium sealing material of the conventional
acoustic coupler is determined in consideration of the fact that the ultrasonic wave emitted from
the ultrasonic transducer is made to enter the object, and the acoustic impedance is determined.
However, the acoustic coupler does not contact the subject in the entire closed space in front of
the ultrasonic probe, but a part thereof is in contact with the subject and the remaining part is
surrounded by air. .
[0004]
The portion of the acoustic coupler in contact with air is normally used in the side lobe radial
direction. As shown in FIG. 3, when ultrasonic waves are emitted from the probe in such a use
state, the main lobe and side lobes related to the side lobes are reflected by the air contact
surface (side wall) of the acoustic coupler. Then, it is incident on the object through the
propagation medium and the seal together with the ultrasonic beam relating to the main lobe.
Since the reflected ultrasound on the side wall due to the side lobe and the ultrasound due to the
main lobe have a difference in the propagation distance to the organ 20 present in the imaging
region in the subject, the received signal of the ultrasound due to the side lobe is an artifact As
shown in FIG. 4, in addition to the real image 21 of the organ 20, an artifact 22 is displayed on
the screen of the display device.
[0005]
This artefact 22 is that the reflected ultrasound at the side wall due to the side lobe appears at a
distance of 1/2 distance (depth) of the propagation distance from the emission to the reception,
and the doctor interferes with the diagnosis by the doctor. It was An object of the present
invention is to solve the above-mentioned problems and to provide an ultrasonic probe with an
acoustic coupler capable of obtaining an excellent image.
13-04-2019
2
[0006]
[Means for Solving the Problems] In order to achieve the above object, the present invention has
a probe main body incorporating an ultrasonic transducer, and is easy to transmit ultrasonic
waves to a subject attached to the probe main body. To an ultrasonic probe comprising a
propagation medium such as deaerated water and an acoustic coupler comprising a container for
enclosing the medium, to the portion of the propagation medium enclosure which is not in
contact with the object. It is characterized by having provided.
[0007]
As described above, even if the ultrasonic absorber is provided on the portion of the acoustic
coupler not to be in contact with the subject, the generation of the side lobe can not be prevented
when the vibrator is excited.
However, if an ultrasonic absorbing material is provided on a portion of the propagation medium
enclosing container not in contact with the subject, that is, the side wall of the container, the side
lobe absorbs the energy and is attenuated by the ultrasonic absorbing material. It becomes
difficult to move in the direction of the observation site. And if it goes on, its energy level will be
significantly reduced. Therefore, the artifacts are substantially less likely to appear.
[0008]
Embodiments of the present invention will be described hereinbelow with reference to the
drawings. FIG. 1 shows a schematic configuration of an ultrasonic probe according to an
embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a housing case of an
ultrasonic probe, and a known ultrasonic transducer unit including an ultrasonic transducer, a
backing material, an acoustic matching unit, an acoustic lens and the like inside the housing case
1 2 is built in and supported. A probe cable 3 supplies a high voltage pulse to the vibrator, and
sends an echo signal received by the vibrator to an ultrasonic diagnostic apparatus main body
(not shown). An acoustic coupler 4 comprises an ultrasonic wave propagation medium 5 such as
deaerated water and the like, and an enclosed container 6 which encloses and holds the
propagation medium 5 in a state of being filled with the housing case 1.
[0009]
13-04-2019
3
A member 7 for absorbing ultrasonic waves is attached to the side wall of the enclosed container
6, that is, the inside of the portion not in contact with the subject 10. As the ultrasonic absorbing
member 7, a sheet of a mixture of silicon resin and tungsten powder is used. This material has an
acoustic impedance close to that of the material used as an acoustic coupler, and the attenuation
of ultrasonic waves is large. Even if it is formed into a thin film like a sheet, the object of the
present invention is achieved.
[0010]
Next, the operation of the present embodiment will be described, but before entering into the
present discussion, the cause of the side lobe artifact will be described in more detail. In the
ultrasonic diagnostic apparatus, the ultrasonic wave transmitted from the ultrasonic transducer is
reflected in the object, and the reflected wave (echo) is half of the ultrasonic wave propagation
distance until it is received by the ultrasonic transducer. Perform signal processing assuming that
there is a reflection source at the place. Therefore, as shown in FIG. 3, with respect to the main
lobe direction emitted from the ultrasonic transducer, there is a reflecting tissue 20 at a distance
l1 from the transducer transmission wavefront, and the point B on the reflecting tissue 20 is
taken as the reflecting point Also, there is a reflective surface of the acoustic coupler in the
propagation path of the side lobes, and in the path after the side lobes are reflected by the
acoustic coupler 20 (the reflective tissue is not necessarily the same as the reflective tissue of the
main lobe). , And the echo reflected by the reflection tissue 20 is assumed to be received by the
ultrasonic transducer. Assuming that the transmission position of the ultrasonic transducer is A,
the reflection position of the acoustic coupler is C, and AC = l2, BC = l3, BA = l4 (= l1), the
following relationship is satisfied: . Assuming that the propagation velocity of the ultrasonic wave
in the subject is V, 2 1 1 <1 2 + 1 3 1 + 1 1 1 <1 2 (1 2 + 1 3 + 1 4). Receive and then receive the
echo due to the side lobe after (l2 + l3 + l4) / V time. Of course, these echo signals are imageprocessed and displayed as signals from the main lobe direction, and it is an ultrasonic device.
Thus, the reflective tissue 20 is displayed as if it were also at a depth of (l 2 + l 3 + l 4) / 2 in the
main lobe direction. これがアーチファクトである。
[0011]
Next, the operation of the present invention will be described with reference to FIG. The
ultrasound probe is brought into contact with the subject 10 so that transmission and reception
of ultrasound can be performed toward a diagnosis site in the subject. The acoustic coupler 4 of
13-04-2019
4
the ultrasound probe is pressed against the subject 10, and when the subject 10 and the acoustic
coupler 4 are in close contact with each other, the ultrasound apparatus main body is operated to
transmit ultrasound from the ultrasound probe. It is transmitted toward the subject 10. From the
transducer unit 2 of the ultrasonic probe, an ultrasonic beam is transmitted in the direction of
the main lobe shown in the drawing and at the same time a side lobe is output. They travel
through the acoustic propagation medium 5 over time. Then, the ultrasonic waves due to the side
lobes traveling from the point A to the point C 'reach the surface of the ultrasonic absorbing
material 7 attached to the inside of the acoustic coupler 6 after 12' / V 2 time. The ultrasonic
wave that has reached the ultrasonic wave absorbing material 7 is absorbed and attenuated by
the ultrasonic wave absorbing material 7. Therefore, the ultrasonic waves due to the side lobes
from the point A to the point C ′ are not incident on the object 10 reflected by the acoustic
coupler 6 as in the conventional device. Even if reflection occurs, the energy level of the reflected
ultrasonic wave is significantly reduced, so that it does not substantially appear in the image as
an artifact.
[0012]
On the other hand, the ultrasonic wave which has traveled in the direction of the main lobe is
reflected at point B of the reflection tissue 20 after l1 / V time, received by the ultrasonic
transducer, and processed as an echo signal. In the ultrasonic diagnostic apparatus, transmission
and reception of ultrasonic waves are repeated at a predetermined cycle, and signals obtained
thereby are displayed as an image on the display screen of the display device.
[0013]
As mentioned above, although one Example of this invention was described based on drawing,
this invention is not limited to the said Example, A modification is considered in the range which
does not deviate from the summary. For example, in the above embodiment, the ultrasonic wave
absorbing material 7 is attached to the inside of the ultrasonic wave propagation medium
enclosing container 6 of the acoustic coupler 4. In addition, as shown in FIG. A product obtained
by integrating a cylindrical portion 7a made of a sound absorbing material and a container
portion 6a made of a material having an acoustic impedance that facilitates the propagation of
ultrasonic waves from the propagation medium 5 to the subject 10 by adhesion or the like Even
if it uses, the same effect is acquired.
[0014]
13-04-2019
5
As described above, according to the present invention, since the ultrasonic wave absorbing
material is provided on the portion of the acoustic coupler which is not in contact with the object,
the ultrasonic waves due to the side lobes are absorbed and not reflected. It is possible to prevent
the occurrence of artifacts due to reflection at the side lobe acoustic coupler. Thereby, the image
quality improvement of the ultrasound image is achieved.
13-04-2019
6
Документ
Категория
Без категории
Просмотров
0
Размер файла
15 Кб
Теги
description, jph0646495
1/--страниц
Пожаловаться на содержимое документа