JP2562890Y2 - Ultrasound diagnostic equipment - 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 diagnostic apparatus, and more particularly, to an ultrasonic diagnostic apparatus for preventing or suppressing heat generated by irradiation ultrasonic waves on the surface of a bone when the bone is present before and after a site to be observed. About.

[0002]

2. Description of the Related Art When irradiating a human body with ultrasonic energy for diagnosis, heat generation due to the ultrasonic energy may cause a problem in biological action or biological safety. In particular, it is likely to cause a problem in Doppler observation in which transmission energy is concentrated and irradiated at one point. In addition, especially at the interface between bone and soft tissue, both transmission and reflection tend to be problematic due to large loss. In the human body, generally, regardless of the heat source, the heating means or the heating mechanism, it can be said that it is completely harmless up to a temperature rise of 1.5 ° C. from body temperature, but when the temperature rise exceeds about 42 ° C. as a result. In any case, it is considered harmful.

[0003] Since there is a bone at the focal point of the transmitted ultrasonic beam or at a farther place, the situation where the transmitted ultrasonic beam causes the bone to generate heat may occur in an adult in which the depth of the pelvic cavity is probed on the abdominal wall. This can be considered when observing from a tentacle. However, when the propagation distance is long as described above, the attenuation in the living tissue serving as the propagation medium becomes large. Therefore, even if the focusing effect is included, heat generation at the focal point or a far destination hardly causes a problem. Rather, when focusing on a shallow place and observing a bone near or near the shallow place, such heat generation may cause a problem. Such a problem is generally likely to occur in the observation of a fetus, particularly in the case of a thin pregnant woman, and also in the case of observing a blood vessel near the surface of a bone, not limited to a pregnant woman or a fetus. Can also occur. Also, despite the presence of ribs, if one tries to inadvertently look into the gap through the gap, some bones may transmit the transmitted beam directly below the acoustic aperture of the probe that generates the transmitted beam. An obstruction situation may occur, and such a problem may also occur locally.

[0004]

However, in the conventional ultrasonic diagnostic apparatus, in the operation mode of Doppler observation, in particular, means and method for preventing, reducing, and suppressing the temperature rise on the surface of the bone. Was not taken. One reason is that the irradiation output of the apparatus was not so large that such a heat generation problem on the surface of the bone became apparent, but also because the need for such safety management was not sufficiently educated. However, recent diagnostic needs are coming to a stage that requires awareness of these safety controls and usage precautions.

The present invention has been made to solve such a problem, and an object of the present invention is to provide an ultrasonic diagnostic apparatus that prevents or suppresses heat generation in a subject due to ultrasonic irradiation.

[0006]

According to a first aspect of the present invention, there is provided an ultrasonic probe for transmitting and receiving a plurality of ultrasonic beams, and an ultrasonic probe for transmitting and receiving a plurality of ultrasonic beams based on signals received from the ultrasonic probe. Means for determining a predetermined ultrasonic beam that generates heat.

In a second aspect, the invention is characterized in that the reception signal is a signal processed based on a range gate signal in Doppler processing and a signal processed to form a B-mode image. Device.

In a third aspect, the present invention is an ultrasonic diagnostic apparatus, wherein the Doppler processing is a Doppler processing in a pulse Doppler mode or a CW Doppler mode.

[0009]

The interface with the bone can be determined by returning a much stronger echo than normal tissue from the interface.
It is also possible to supplementarily determine that an echo in a previous section cannot be received substantially from the interface.

[0010]

FIG. 1 is a block diagram showing a preferred embodiment of the present invention. In the figure, 1 is an array probe, 2 is a transmitting / receiving section, 3 is a B-mode section, 4 is a pulse Doppler section,
5 is a transmission / reception timing controller, 7 is a range gate generation circuit, 8 is a focal zone gate generation circuit, 9 is a heat generation evaluation section extraction gate, 10 is a comparator, 11 is an adaptation control circuit, and 6 is a system controller. is there.

FIG. 2 is a diagram showing an outline of a scanned sound field showing that the ultrasonic diagnostic apparatus of FIG. 1 can avoid heat generation at a bone interface. As a typical example, a case where the array probe 1 is applied to a foot 22 of a subject via a water bag 21 and Doppler observation of blood flow of an artery 24 running near the bone 23 is shown. Here, A to N are transmitting and receiving elements (or sub-apertures, or partial arrays in such an array) each large enough to form a beam by itself (hereinafter simply referred to as "elements"). This is abbreviated.)

FIG. 3 is a waveform diagram for explaining the echo signals obtained by the elements A to N. In this figure, 3
Reference numerals 1 and 32 denote signals including echoes from bones, and reference numeral 33 denotes a signal not including echoes from bones.

FIG. 4 shows an example of the timing relationship between transmission / reception, a range gate and a focal zone gate. In this, Ttr is a transmission trigger, RG is a range gate,
FG indicates a focal zone gate, Vref indicates a reference voltage, and LogVideo indicates the amplitude of a rectified signal obtained by logarithmically compressing a high frequency signal of an echo in a B mode system, that is, a logarithmically compressed A mode image (or a signal thereof).

In the following, characteristic matters relating to the operation of the ultrasonic diagnostic apparatus of FIG. 1 will be described in detail.

Under the control of the system controller 6, the transmission / reception unit 2 first drives or transmits / receives some or all of the elements A to N so as to obtain a B-mode image of the entire observation area. Next, in the obtained B-mode image, a portion where Doppler observation is to be performed is automatically or manually determined. Next, a predetermined element is selected from A to N, transmission control is set so that the beam is directed from the element to the site where the Doppler observation is to be performed, and the beam is focused, and the corresponding distance is small. A range gate (RG) is set for the section. Here, first, test transmission / reception is started for the selected predetermined element.

The focal zone gate generation circuit 8 generates a focal zone gate (FG) that is coordinated with the time of the range gate (RG) output from the range gate generation circuit 7 under the control of the system controller 6. I do. In the section where the focal zone gate (FG) occurs, the transmission beam in the actual measurement (that is, the measurement for actually diagnosing the subject) is sufficiently focused (closed) in this section. If the ultrasonic beam encounters the interface with the bone in this section, it means a section where there is a risk of generating harmful heat at that location.

The heat generation section extraction gate 9 receives the focal zone gate (FG) and extracts a LogVideo evaluation section output from the B-mode system section 3. The signal in the extracted section is compared with the comparison reference voltage Vref in the comparator 10, and a signal in a portion exceeding the reference voltage Vref is compared with the section L.
It is extracted as ogVideo (and binarized if necessary). Here, the comparison reference voltage Vref is
Such a comparison is set empirically or in consideration of various parameters inside the apparatus so that the strong echoes 31 and 32 at the interface with the bone can be captured and discriminated.

The adaptation control circuit 11 receives a section LogVideo (or a binary signal indicating the section) exceeding the comparison reference voltage Vref, and determines whether or not this is an echo at a bone interface, mainly based on its duration. to decide. or,
In the determination, the amplitude or its integral value can be additionally considered. By transmitting the determination result to the system controller 6, the system controller 6 can know without delay whether the selected element has a bone in the section in addition to the current transmission / reception setting state.

Such test transmission / reception is performed by the elements A to N
Are sequentially repeated, the system controller 6 can determine which element from which Doppler measurement is dangerous by test transmission.
For example, in Doppler measurement using an ultrasonic beam that reaches the target artery 24 using the element A or B as a launch point shown in FIG. 2, bone is located near the target artery (back or front) on the path of the ultrasonic beam. ) Can be determined to be dangerous. On the other hand, in Doppler measurement from N elements, it can be determined to be safe because no bone exists on the path.

Thereafter, in the continuous repetitive transmission / reception in the Doppler measurement for diagnosis, a dangerous element beam (ultrasonic beam from the element) is eliminated so as to avoid irradiation to the interface with the bone, and only a safe element beam is selected. Then, alone or in combination, it is possible to determine the incident angle or azimuth of the ultrasonic beam, and the launch point or the partial area on the aperture surface to be adopted for transmission, and perform the measurement. it can.

The selection of the elements based on the judgment as to whether it is thermally dangerous or safe contributes to an improvement in the overall S / N ratio, particularly when the bone is in front of the beam and blocks the transmission beam. . In such a case, the corresponding element cannot obtain a Doppler signal of the target blood flow at all, and falls into a state of simply adding noise to the system output.

It is an example of a preferable idea to issue an alarm and notify when an interface with bone is found by such test transmission / reception.

The present invention is also applicable to CW Doppler. In the case of CW Doppler, it is not possible to determine the mixture of bone echoes at the stage of the time axis waveform of the echo. However, if the bone has a certain size, it can be determined from an increase in the clutter level. Here, clutter is a generic term for the result of accumulation of echoes from an echo source showing little or no Doppler shift, that is, little or no motion,
The demodulation result is a DC or very low frequency component. Therefore, if the DC or very low frequency component is higher than the set discrimination criterion level in the demodulation result, it can be determined that the transmission condition may include an interface with bone in the path of the transmission beam. In such a CW operation, the transmitting element and the receiving element are provided adjacent to each other, and the transmitting and receiving beams intersect at the destination point.
This can be realized by keeping the G and focal zone gates FG open at all times.

[0023]

As described above, according to the present invention, heat generation in a subject due to ultrasonic irradiation can be prevented or suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram of the ultrasonic diagnostic apparatus of the present invention.

FIG. 2 is a cross-sectional view when the probe 1 is applied to a subject's foot.

FIG. 3 is a waveform diagram illustrating echoes from elements A to N.

FIG. 4 is a diagram showing transmission / reception, range gate, and focal zone timing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Probe 2 Transmission / reception part 3 B-mode system part 4 Pulse Doppler system part 5 Transmission / reception timing controller 6 System controller 7 Range gate generation circuit 8 Focal zone generation circuit 9 Gate 10 Comparator 11 Adaptation circuit

Claims (2)

(57) [Scope of request for utility model registration] 1. A plurality of the ultrasonic probe for transmitting and receiving an ultrasonic beam, a predetermined ultrasound beam to generate heat in a test sample based on the received signal from the ultrasound probe ultrasound bi
An ultrasonic diagnostic apparatus comprising: means for discriminating one unit of a room. 2. An ultrasonic sound transmitting and receiving a plurality of ultrasonic beams.
Based on the signals received from the wave probe and the ultrasonic probe
Signals and Dopples Processed to Form B-Mode Images
A range gate signal is generated in the
Signal processed to form a Doppler image and Doppler processing
Heat in the subject based on the range gate signal at
Means for determining a predetermined ultrasonic beam to be generated
An ultrasonic diagnostic apparatus characterized by the above-mentioned.