JPH02185238A - Ultrasonic diagnostic device - Google Patents

Abstract

PURPOSE:To hold the S/N of a received signal high with a simple constitution, to increase an operability and to match a device main body to respective kinds of probes by sharing signal transmission and reception between the device main body and the probe, and a voltage supply from the device main body to a preamplifier with a single cable. CONSTITUTION:A device 10 main body is equipped with a transmitter 16 and a receiver 18, and a driving pulse from the transmitter is sent through a connection cable 12 into an ultrasonic probe 14. The ultrasonic probe is equipped with a vibrator 20 to convert the driving pulse into an ultrasonic wave and a preamplifier 22. Since, the signal is transmitted and received with the single cable between the main body and the ultrasonic probe, a diode 24 for blocking a driving pulse and a diode 26 for blocking an echo signal are interveningly inserted between the cable and preamplifier and between the cable and vibrator, respectively, and a diode 28 for blocking a driving pulse is arranged in the front stage of the receiver. Thereby, all pulses from the main body side are used for a vibrator exciting work, the echo signal reflected from a subject is inputted to the receiver in the main body, the voltage supply to the preamplifier is executed by a power source at the main body side, and it is supplied by the single connection cable.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic diagnostic device, and particularly to a signal transmission path of an ultrasonic diagnostic device in which a probe with a built-in preamplifier is connected to the main body of the device via a connecting cable. Regarding improvements.

[Prior Art] Ultrasonic diagnostic equipment that transmits an ultrasound beam into a subject and forms a tomographic image using reflected echoes obtained from differences in acoustic impedance of tissues within the subject is well known, and is known to cause harmful effects on tissues. It has the advantage of allowing internal observation without causing
It plays a very important role as a means of diagnosing affected tissue in the human body.

By the way, the S of the received signal is an important condition for obtaining clear and high-quality tomographic images in such ultrasonic diagnostic equipment.
An example of this is to maintain a sufficiently high /N ratio.

To this end, various devices have been used in the past, but one particularly effective method is to provide a preamplifier within the ultrasound probe, and after amplifying the received signal within the ultrasound probe, it is sent to the main body of the device via a connecting cable. A method has been developed to send it to the other side.

According to this method, particularly high frequency components of the received signal are attenuated due to the capacitance of the connection cable between the ultrasound probe and the main body of the device, and the S/N ratio is degraded due to the pickup of external noise. Prevention is possible.

[Problems to be Solved by the Invention] However, when such a method of incorporating a preamplifier in the probe is adopted, while it is possible to prevent deterioration of the S/N ratio, the following disadvantages occur.

First, the preamplifier, which is an active element, requires a dedicated power supply, so when such a configuration is adopted, there is a conductor for power supply and a conductor for signal transmission and reception, that is, for applying drive pulses to the vibrator. At least three types of conducting wires must be provided, including a conducting wire for transmitting the received signal amplified by the preamplifier to the main body of the device.

This inevitably leads to an increase in the diameter of the connection cable that connects the device and the probe, especially when using an array type transducer in which multiple vibrating elements are arranged, and the cable is extremely thick and rugged. It became,
This results in a significant loss of operability, which is one of the important factors that determines the performance of an ultrasonic diagnostic apparatus.

As a countermeasure to these problems, it has been considered to provide a dedicated battery for powering the preamplifier inside the ultrasound probe, but this would directly lead to an increase in the size of the ultrasound probe itself and shorten the life of the battery. The inconvenience of reduced reliability cannot be avoided. Although this eliminates the need for conductors for power supply, separate conductors for transmitting and receiving are still required, so it does not contribute much to reducing the diameter of the connecting cable and does not significantly improve operability. do not have.

In addition, with the conventional device configuration as described above, a preamplifier is installed inside the probe, which has some effect when it is desired to improve the S/N ratio of the received signal and give priority to image clarity. It will be done. However, in ultrasonic diagnosis, it is often necessary to prioritize the miniaturization of the probe over the reception characteristics itself depending on the region or situation to be diagnosed, and in such cases, the configuration inside the probe must be Therefore, the preamplifier must be placed in the main body of the device. However, conventional device configurations do not take this situation into account, and the device main body is designed only for probes with built-in preamplifiers, so a dedicated device main body must be provided for each type of probe. First, there was a problem in that the versatility of the device itself was extremely low.

Purpose of the Invention The present invention was made in view of the above-mentioned conventional problems, and its purpose is to reduce the number of cables between the ultrasound probe and the main body of the device while ensuring a sufficiently high S/N ratio of the received signal with a simple configuration. It is an object of the present invention to provide an ultrasonic diagnostic apparatus which has improved operability by reducing the number of noises, and whose main body is compatible with both types of probes, including those with a built-in preamplifier and those without a built-in preamplifier.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a system in which a device body having a transceiver and connected to a power source, and a probe having a built-in vibrator and preamplifier are connected to each other by a connecting cable. In an ultrasonic diagnostic apparatus that displays a tomographic image of a desired biological tissue by transmitting and receiving driving pulses and ultrasonic echo signals through A drive pulse blocking diode is inserted between the connection cable and the preamplifier to block the ultrasonic echo signal and supply it only to the transducer side, and a drive pulse blocking diode is connected to allow the ultrasonic echo signal to flow only into the preamplifier side. an echo signal blocking diode inserted between the cable and the vibrator; An amplifier is installed to receive the voltage-to-current converted received signal sent through the probe, and a single connection cable can be used for signal exchange between the device body and the probe, as well as voltage supply from the device body to the preamplifier. It is characterized by being configured as follows.

[Function] According to the present invention configured as described above, the transducer drive pulse output from the device main body side is built into the probe by a drive pulse blocking diode inserted between the connecting cable preamplifier. All of this is used for the vibrator excitation action without going around to the preamplifier side.

The ultrasonic echo signal reflected from the tissue inside the subject is prevented from flowing backward through the drive pulse supply line to the main body by an echo signal blocking diode inserted between the connection cable and the transducer, and is always routed to the preamplifier. After being subjected to a predetermined amplification effect, the signal is input to a receiver in the main body of the device via a connecting cable.

Then, during reception, voltage is supplied to the preamplifier built in the probe by the power supply on the device main body side via the connection cable and the drive pulse blocking diode.

As a result, the transmission and reception of drive pulses and ultrasonic echo signals between the device main body and the probe, and the voltage supply from the device main body to the preamplifier are all covered by a single connection cable. It becomes possible to obtain a sonic diagnostic device.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

In the figure, the same reference numerals are given to the same components as those of the conventional device, and the explanation thereof will be omitted.

FIG. 1 shows an example of the circuit configuration of an ultrasonic diagnostic apparatus according to the present invention.

In the figure, the entire ultrasonic diagnostic apparatus is shown roughly divided into three parts with dashed lines at the apparatus main body, connection cable, and ultrasonic probe, and the boundaries of elements included in each part are made clear.

A characteristic feature of the device of the present invention is that a single connection cable is used to transmit and receive transducer drive pulses and ultrasound echo signals between the device main body and the ultrasound probe, and to supply voltage to the preamplifier built into the ultrasound probe. This allows for a high S/N ratio of the received signal by incorporating a preamplifier on the probe side, and sufficient flexibility by minimizing the diameter of the connecting cable. This makes it possible to obtain an ultrasonic diagnostic apparatus that has both reception performance and operability.

The apparatus main body 10 includes a transmitter 16 and a receiver 18, and sends a driving pulse output from the transmitter 16 into the ultrasound probe 14 via a connection cable 12.

The ultrasonic probe 14 includes a transducer 20 for converting the sent drive pulse into ultrasonic waves, and an ultrasonic echo signal from within the living body inputted via the transducer 20 to the apparatus main body 1.
A preamplifier 22 is provided for amplifying the signal in advance to ensure a high S/N ratio before sending it to the 0 side. As described above, the action of the preamplifier 22 effectively prevents the ultrasonic echo signal reflected from the living body from being attenuated during the transmission path and from reducing its S/N ratio due to noise contamination. .

The ultrasonic echo signal that has entered the apparatus main body lo side via the connection cable 12 is input to the receiver 18, subjected to a predetermined amplification effect, and then output to the subsequent image display processing section.

Further, in the present invention, the apparatus main body 10 and the ultrasound probe 14 having a built-in preamplifier 22 are connected by a single connection cable 12.
A driving pulse blocking diode 24 and an echo signal blocking diode 26, which play a major role in this purpose as will be described later, are connected between the connecting cable 12 and the preamplifier 22, respectively. and is inserted between the connection cable 12 and the vibrator 20,
Further, a drive pulse blocking diode 28 is disposed upstream of the receiver 18 to block the drive pulse from flowing into the receiver 18 during transmission.

Next, the operation will be explained.

First, at the time of transmission, the transmitting amplifier 30 in the transmitter 16
When the transmission trigger pulse Tp is applied to the transmission amplifier 30, a high voltage drive pulse, in the illustrated example, a falling pulse, is generated in the transmission amplifier 30.

A capacitance 32 is inserted after the transmitting amplifier 30 to remove the DC part from its output, and as a result, as shown in the graph of FIG. 2, point A in the diagram is 110
It will be drawn into a negative potential exceeding 0V.

At this time, point A is maintained by the voltage supply of about ten or more volts from the power supply VCC, and the drive pulse blocking diodes 24 and 2, which had been in the energized state,
8 becomes momentarily de-energized. It will be appreciated that this blocks the flow of drive pulses to preamplifier 22 and receiver 18, and protects transistors 34 and 36 from negative high voltages.

On the other hand, only the echo signal blocking diode 26 becomes forward biased and energized at the same time as the potential at point A suddenly decreases, and as a result, the driving pulse from the transmitting amplifier 30 is transmitted to the cable 12 and the echo signal blocking diode 26. It is applied to the electrode of the vibrator 20 through the oscillator 20, and is converted into an ultrasonic pulse beam by the excitation action of the piezoelectric material and radiated into the living body.

Note that in the illustrated example, only a configuration corresponding to a single vibrator is extracted and drawn for convenience of explanation.

Therefore, in the case of an array type transducer including a plurality of vibrating elements, it is sufficient to connect circuits having the same configuration in parallel for each element.

When the vibrator 20 is excited, the voltage of the vibrator 20 is applied to the gate of the transistor 34 via the resistor R1, but the forward voltage (for example, about 0.7 V) is applied to the gate of the transistor 34 by the diodes 40 and 42. Since the transistor 34 is clamped, the driving pulse will not destroy the transistor 34.

The transmission operation is performed by the action of each element, and the drive pulse is transmitted to the vibrator 20 which is the input target.
It is understood that the device only performs an excitation action, and faithfully performs its original function without adversely affecting other elements.

Next, the reception operation will be explained.

Basically, in this embodiment, after the power is turned on, it is considered to be in the receiving state at all times except for the above-mentioned drive pulse transmission, and at this time, the resistor R4 A bias current is supplied through the connecting cable 12 and the drive pulse blocking diode 24. Similarly, the transistor 36 of the receiver 1B includes a resistor R4 and a driving pulse blocking diode 2.
Bias current is supplied via 8.

As described above, in this receiving state, point A is maintained at a positive DC potential of around several volts, and the echo signal blocking diode 26 is biased in the reverse direction and is in an off state.

Here, the ultrasonic echo signal from the reflecting object in the living body undergoes voltage conversion by the transducer 20, but the received ultrasonic echo signal voltage exceeds the point A potential of about several volts and turns off. The level is not high enough to energize a certain echo signal blocking diode 26.

Therefore, the echo signal blocking diode 26 remains off even during this echo signal voltage conversion, and the received signal voltage V
s is directly applied to the gate of the transistor 34 via the resistor R1.

As a result, a signal current expressed by the following equation flows through the drain of the transistor 34, and this current flows into the point A of the device main body 10 through the connection cable 12.

m is≠ ・Vs
... (1) 1+gm-R3 (where g, m: mutual conductance of transistor 34) The ultrasonic echo signal will be input from point A to the emitter of transistor 36, which functions as a grounded base, but at this time If the input impedance of the transistor 36 including the series on-resistance component of the drive pulse blocking diode 28 is Z1tr2, the following relationship exists.

I ZItr21 <(R4-(2)) Here, it is assumed that the transmitting amplifier 30 maintains a high impedance state except during the transmitting period and does not affect reception.

If this relationship holds, then the signal type? 1ytis is considered to all flow into the emitter of transistor 36.

The transistor 36 plays a role as a kind of current-voltage converter, and when the current amplification factor is sufficiently large, the emitter current and the collector current become almost equal, and as a result, the signal voltage VO appearing at the collector terminal becomes Voyols. :R7In-R7--Vs1+g1R3...(3) It is expressed as follows.

Here, if VQ/Vs is defined as the voltage amplification factor Av of the preamplifier, it becomes gffl-R7v-1+gffl6R3...(4). Furthermore, under the condition of 1<<gm-R3, it can be expressed by the simple formula Av 1 R3 (5).

In this way, according to the present embodiment, the drive pulse during transmission is reverse-flowed to the transistor 34 in the preamplifier 22 by the drive pulse blocking diode 24 inserted between the connection cable 12 and the preamplifier 22. The ultrasonic echo signal from the living body is applied only to the vibrator 20, which is the desired supply target, without causing destruction due to the inflow, and the ultrasonic echo signal from the living body is transmitted through an echo signal blocking diode interposed between the connecting cable 12 and the vibrator 20. 26, the voltage is always sent to the device main body 10 side via the preamplifier 22, and furthermore, during the reception period, the voltage is supplied to the preamplifier 22 from the power supply VCC of the device main body 10 side via the connection cable 12 without any problems. will be held. Furthermore, a driving pulse blocking diode 2
8, the inflow of drive pulses into the transistor 36 of the receiver 18 during transmission can be reliably avoided, and a single connection cable 12 can be connected (1) from the transmitter 16 to the transducer 20.
(2) Supplying driving pulses from the transducer 20 to the receiver 18
Transmission of ultrasonic echo signals to (3) ultrasonic probe 1
It is possible to share the three functional purposes of supplying voltage from the power [Vcc] of the device main body 10 to the preamplifier 22 in the preamplifier 22 in the device 4.

As a result, by arranging the preamplifier 22 in the ultrasonic probe 14, a high level of S/N ratio of the received signal is ensured, and by using a single connection cable 12, the probe 14
It is possible to realize an ultrasonic diagnostic apparatus that can effectively satisfy the conventionally conflicting conditions of improved operability.

Next, the second embodiment of the ultrasonic diagnostic apparatus according to the present invention will be described in a third embodiment.
This will be explained with reference to the figures. This embodiment shows a state in which an apparatus main body 10 having the same configuration as the first embodiment is connected to an ultrasound probe without a built-in preamplifier. As already mentioned, in cases where an ultrasound probe must be inserted into a body cavity or used to monitor an affected area during surgery, it is important to downsize the physical scale of the probe itself, regardless of its reception performance. This is the first condition. Under such circumstances, the components within the probe will naturally be reduced to the necessary minimum, so the preamplifier will be removed from the probe.

Conventionally, when a preamplifier is embedded in a probe, the device main body must have a dedicated circuit configuration, making it difficult to compatibility with an ultrasound probe without a built-in preamplifier. The reality is that there is no compatibility, and each probe requires a large and expensive device.

The second embodiment solves these problems and achieves versatility for both probes with and without a built-in preamplifier in the same device body.

Therefore, in the apparatus shown in FIG. 3, the circuit on the apparatus main body 10 side is the same as that in FIG. 1, and only the internal structure of the ultrasonic probe 14 is different.

As a result, since the operation at the time of transmission is the same as that shown in FIG. 1, only the operation at the time of reception will be described.

Impedance Z of transistor 36 whose base is common
If Itr2 and the iso-image signal source impedance Ztd of the vibrator 20 have a relationship such that l Ztd l >> l Z 1tr2, the received signal from the vibrator 20 has a current is
It is all O-shaped and flows into point A. At this time, transistor 36
The voltage VD appearing at the collector terminal of can be expressed as VO-i 5-R7-(6). The voltage amplification factor Av in this case is Av l I... (7) d .

Therefore, from the above equations (5) and (7), R3 and Zdl
If R3 in FIG. 1 is selected so as to be l, the signal amplification factor can be maintained constant for both types of probes, those with a built-in preamplifier and those without a built-in preamplifier.

FIG. 4 shows a third embodiment of the device of the present invention.

The characteristic feature of this embodiment is that Ci is used instead of the resistor R1 in FIG.
This is because the power of the drive pulse is sufficiently large, especially during transmission, and a relatively large resistance is inserted between the vibrator 20 and the transistor 34 as shown in FIG. Vibrator 20 without
It is effective in terms of reception performance when sufficient excitation is possible.

FIG. 5 shows a fourth embodiment of the device of the present invention.

A feature of this embodiment is that a capacitor C3 is interposed between the connection cable 12 and the receiver 18 to provide AC coupling, which allows the bias current flowing through the transistor 34 in the amplifier to It becomes possible to independently select the DC operating points of the transistors 36 in the side receivers, which facilitates circuit design.

FIG. 6 shows a fifth embodiment of the device of the present invention.

This embodiment is characterized in that the vibrator 20 is excited by a positive drive pulse, and the basic circuit configuration is the same as that of the device shown in FIG. 1 above. Therefore, the operation and effect are the same as in the first embodiment.

[Effects of the Invention] As explained above, according to the present invention, transmission and reception of transmission and reception signals between the preamplifier built-in ultrasound probe and the device main body and the device main body can be performed using a single connection cable with a relatively simple configuration. It is possible to realize a voltage supply to the preamplifier in the probe from the above, and it is possible to receive an ultrasonic echo signal with a high S/N ratio without impairing operability, and it is possible to obtain a high-quality image.

In addition, the same device main body can be applied to both types of ultrasound probes, one with a built-in preamplifier and one without a built-in preamplifier.
Excellent versatility can be obtained at the same time.

[Brief explanation of the drawing]

Fig. 1 is a circuit (1) diagram showing a first embodiment of the device of the present invention, Fig. 2 is a graph showing the time change of the transmitting/receiving signal voltage in the device of the present invention, and Fig. 3 is a diagram of the second embodiment of the device of the present invention. FIG. 4 is a circuit diagram showing a third embodiment of the device of the present invention; FIG. 5 is a circuit diagram showing a fourth embodiment of the device of the present invention (1'4 diagram; The figure is a circuit configuration diagram showing a fifth embodiment of the device of the present invention. 10...Device body work 2...Connection cable 14...Ultrasonic probe 16...Transmitter 18...Receiver 20... Vibrator 22... Preamplifier 24... Driving pulse blocking diode 26/Eco signal blocking diode.

Claims (1)

[Claims] (1) The main body of the device, which has a transceiver and is connected to a power source, and the probe, which has a built-in transducer and preamplifier, send and receive drive pulses and ultrasonic echo signals via a connecting cable, and target the desired living body. In an ultrasonic diagnostic device that displays tomographic images of tissues, the probe is connected to a connection cable in order to prevent drive pulses transmitted from the device main body during transmission from flowing into the preamplifier side and supply them only to the transducer side. A driving pulse blocking diode inserted between the preamplifier and an echo signal blocking diode inserted between the connection cable and the transducer to allow the ultrasonic echo signal to flow only into the preamplifier side. a diode, and the receiver in the device main body is provided with an amplifier connected to the preamplifier in a parallel cascade manner and receiving a voltage-to-current converted received signal sent via a connecting cable. An ultrasonic diagnostic apparatus characterized in that a single connection cable can be used for signal exchange between the apparatus main body and the probe and for voltage supply from the apparatus main body to the preamplifier.