GB1578093A

GB1578093A - Ultrasonic diagnostic apparatus for inspection of a living body

Info

Publication number: GB1578093A
Application number: GB658278A
Authority: GB
Original assignee: Tokyo Shibaura Electric Co Ltd
Current assignee: Toshiba Corp
Priority date: 1977-02-18
Filing date: 1978-02-20
Publication date: 1980-10-29
Also published as: JPS53101880A; FR2418472A1; DE2806686A1

Description

(54) ULTRASONIC DIAGNOSTIC APPARATUS FOR INSPECTION OF A LIVING BODY (71) We, TOKYO SHIBAURA ELECTRIC COMPANY LIMITED, a Japanese corporation, of 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Japan, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to an ultrasonic diagnostic apparatus for diagnosing the internal organs of a living body.

There have been proposed diverse diagnostic apparatuses in which ultrasonic waves are transmitted into a living body such as a human body and the information obtained by detecting the reflecting ultrasonic waves reflected from the internal organs of the living body are used for the diagnosis. The ultrasonic diagnostic apparatuses thus far developed and currently used are classified into two categories. One of them is ultrasonic wave tomography in which ultrasonic wave pulses are transmitted into the the living body e.g.

the heart and a picture corresponding to a cross-section of the living body is visualized through detection of the ultrasonic wave pulses reflected from the internal organs.

Such an apparatus is disclosed in U.S.

Patent No. 3,789,833, for example. The other is to detect the movement, e.g. blood flow, in the living body. In this type of apparatus, ultrasonic waves are transmitted into the living body and the change of the frequency of the reflecting ultrasonic wave arising from the movement in the living body is detected. That is, the Doppler effect appearing on the reflecting ultrasonic wave pulses is used for the diagnosis, and thus this type apparatus is called an ultrasonic Doppler apparatus. Such an apparatus is disclosed, for example, in "Pulsed Ultrasonic Doppler Blood-Flow Sensing" by Donald W. Baker in "IEEE Transactions On Sonics And Ultrasonics" Vol. SU-17, No. 3, July 1970.

Generally, ultrasonic waves are less hazardous to the living body than X-rays.

For this reason, the ultrasonic wave diagnostic apparatuses have been widely used in certain fields in which X-rays are undesirable, for example, obstetrics. The low level hazard of ultrasonic waves is one of the most important merits for such use.

However, it is also understood that an excessive irradiation of ultrasonic waves into the living body is dangerous. It is unknown at present what amount of ultrasonic irradiation is dangerous to the living body. The safety limit of ultrasonic irradiation will be found empirically in the years to come. Because the safety limit of ultrasonic irradiation is unknown. it is conventional to maintain the power level of irradiating ultrasonic waves as low as possible. Nevertheless, there has been no ultrasonic diagnostic apparatus with an ability to monitor the total amount of ultrasonic energy irradiated into the living body.

The total amount of the ultrasonic wave transmitted into the living body corresponds to the result of the integration of the ultrasonic wave output with respect to the emission time. Therefore, the power level of the ultrasonic wave and the irradiation time of it to the living body as well are important factors, as a safety view point. In ultrasonic diagnosis, therefore, this necessitates measurement and display of these factors. It is desirable to provide an alarm to make an operator aware of danger when the ultrasonic irradiation time exceeds a safety limit obtained by experience. Automatic operation of the indication and the alarm is also desirable for such an apparatus.

Accordingly, an obiect of the present invention is to provide an ultrasonic diagnostic apparatus capable of automatically indicating and/or recording the power level of ultrasonic waves as well as the irradiation time in order to inform an operator of the amount of energy of ultrasonic wave energy irradiated into th living body, and further capable of giving an alarm to the operator, if necessary.

According to the present invention, there is provided an ultrasonic diagnostic apparatus for inspection of a living body, comprising transmitting and receiving means for transmitting an ultrasonic wave into the living body and for receiving the ultrasonic wave reflected by internal organs of the living body; signal providing means for providing a signal representative of the period during which ultrasonic waves are transmitted into the living body in dependence on signals delivered from said ultrasonic transmitting and receiving means; display means for displaying an image of the internal organs of the living body in dependence on signals derived from said transmitting and receiving means; and indicating means connected to receive the signal provided by the signal providing means for indicating the total amount of ultrasonic energy transmitted into the living body.

Such an ultrasonic diagnostic apparatus can be arranged to simultaneously and automatically indicate, display and/or record an image of the internal organs of the living body, and the power level and the total emission time of the ultrasonic wave transmitted into the living body. Further, the indicating means may be provided with an alarming means to issue an alarm when the total amount of ultrasonic energy transmitted into the living body exceeds a safety limit.

Embodiments of the present invention will now be described with reference to the accompanying drawings, in which: Figs. la to Id schematically illustrate the principle of the ultrasonic diagnosis; Fig. 2 shows a block diagram of an ultrasonic diagnostic apparatus according to the present invention Figs. 3a to 3i show a set of wave forms useful in explaining the operation of the apparatus shown in Fig. 2; Fig. 4 shows a block diagram of another ultrasonic diagnostic apparatus according to the present invention; Figs. Sa and Si to Sm show a set of wave forms useful in explaining the operation of the apparatus shown in Fig. 4; and Fig. 6 shows a circuit diagram of a part of the apparatus shown in Fig. 4.

An ultrasonic diagnostic apparatus of the invention is designed as to detect the ultrasonic wave pulses having been transmitted into a living body, which pulses are reflected by the internal organs thereof at time intervals dependent upon the kind of the living body. The diagnostic apparatus, upon detection of the reflected wave, checks whether the ultrasonic wave is transmitted into the living body or not.

That is, when it fails to detect the reflected wave, it is decided that no ultrasonic wave is emitted into the living body. On the other hand, when it is detected, the ultrasonic diagnostic apparatus immediately starts to measure the emission time of the ultrasonic wave presently being irradiated into the living body. Accordingly, the diagnostic apparatus is able to indicate and/or record the emission time of the ultrasonic wave, in addition to its power level which is displayed as in conventional ultrasonic diagnostic apparatus. The illustrated diagnostic apparatus according to the invention has an additional function to issue an alarm when the ultrasonic wave emission time exceeds a predetermined one, in order that the emission time does not exceed a safety limit for the living body, that is to say, the living body is protected from being injured by the ultrasonic waves.

In the explanation given below, the same numerals or signs are used to denote the same parts or sections.

The principle of the ultrasonic diagnostic apparatus will be briefly given with reference to Figures la to Id. As shown in Figure la, a transducer 10 projects an ultrasonic wave pulse 12 into a living body 14 and the transmitted wave pulse 12 passes through internal organs 16. The transmitted pulse is partly reflected at the boundary between the organs 16 and the other organs in the living body 14 and the reflected pulse is received by the transducer 10. The transducer 10 has the functions of both emission and reception of the ultrasonic wave, and a piezoelectric element is commonly used for such a transducer. The reflected wave pulse from the inside of the living body 14 is always progressively more delayed in the returning to the transducer 10; i.e. the farther the reflection point in the living body 14 is distanced from the transducer 10. The reflected wave pulse received by the transducer 10 is amplified, detected and displayed by a receiver included in the ultrasonic diagnostic apparatus, taking wave forms as shown in Fig. Ib. Such wave forms may readily be observed by an oscilloscope and generally called "A Scan". In the same living body, the propagation velocity of ultrasonic wave is substantially constant, i.e. approximately 1,500 m/sec. When a signal pulse of ultrasonic wave is transmitted into the living body 14, internal organs reflect some of this energy back to the transducer 10. The time delays of the reflecting pulses substantially correspond to the distances from the transducer 10 to the reflecting objects of organs, respectively. Therefore, the time intervals of delays indicate the locations of the internal organs of the living body 14, respectively.

If the beam of a cathode ray tube (CRY) of an oscilloscope is intensity-modulated by the wave forms 18, or the reflecting pulses, as shown in Fig. Ib, each pulse reflection may form a series of reflection points 20 arranged on a horizontal sweep line of the CRT, as shown in Fig. Ic. The reflection points 20 displayed on the CRT screen has meaning that the interval between adjacent reflection points 20 indicates the location of the corresponding organ in the living body such as the organs 16, and the intensity of the reflection points 20 indicates the amplitude of the reflecting pulse.

When the transducer 10 is moved along the human body 14 in the direction of an arrow, as shown in Fig. Ia, the position and intensity of the reflection points 20 on each horizontal sweep line change in dependence on the shape and tissue of the organs 16.

The transducer 10 is moved on the body 14 normal to the emitting direction of ultrasonic beam while the positions on the horizontal scanning line are correspondingly shifted with respect to a vertical axis, that is to say, the vertical beam scanning is carried out. In this case, a dotted image representing a sectional view of the body 14 is displayed on the CRT screen, as shown in Fig. Id. Generally, the mode giving such an image is called "B-Scan".

When the vertical beam scanning is performed by manual operation and by using a single transducer, it is preferable to use an oscilloscope using a CRT with a long afterglow time or a storage type oscilloscope for display. Although not shown, there is another method of obtaining a "B-Scan" in which the transducer 10 is positioned fixedly in relation the body 14 and the direction of emission and reception is electrically moved vertically. In the B-Scan, change of a part of the organs 16 located along the pulse emitting direction is displayed by the CRT.

The above-mentioned "B-Scan" are all derived from the "A-Scan" signal as shown in Fig. Ib. Accordingly, the information obtained from the reflecting ultrasonic pulses are substantially represented by the "A Scan" signal. The "A Scan" signal observed includes a large amplitude pulse 181 called an "initial pulse" and reflecting pulses 182 to 184 following the initial pulse 18,, as shown in Fig. Ib. In actual fact, a living body includes various kinds of organs intricately arranged so that the reflecting pulses displayed are more complicatedly and continuously arranged than those in Figure Ib.

Figure 2 shows a block diagram of an ultrasonic diagnostic apparatus according to the invention and Figures 3a to 3i are a set of wave forms at major portions of the apparatus in Figure 2. In Figure 2, a rate pulse generator 22 generates rate pulses a as shown in Figure 3a. A pulse width of about 0.25 cL sec and a pulse interval of about 0.25 m sec are used for the rate pulses a. The rate pulses a are amplified up to a driving pulse having a signal level enough to drive a transducer 10 by a transmitter 24. A piezoelectric element, for example, is used for the transducer 10. Upon receipt of the rate pulses a, the transducer 10 transmits ultrasonic pulses b into a living body 14 such as a human body, when the transducer 10 is acoustically coupled with the body 14. A wave pulse irradiated onto the living body in response to a rate pulse a1 is reflected by the organs in the body 14 and returns to the transducer 10. The signal representing the reflecting wave pulse caused by the wave pulse b1 detected by the transducer 10 is subjected to a signal procession such as amplification, detection, etc. The signal representing the reflecting wave pulses detected by the transducer 10 takes the wave forms as shown in Figure 3c, when observed by an oscilloscope. The wave forms shown in Figure 3c, however, also includes the wave forms obtained from the driving pulses supplied to the transducer 10.

The amplitude of the wave forms obtained from the driving pulses is much larger than the amplitude of the reflecting wave forms.

Therefore, the amplitude of the driving pulses is limited by a limiting circuit included in a receiver 26 as described later.

The reflecting pulse as shown in Fig. 3c, i.e.

the reflecting signal c, is amplified and amplitude-detected by the receiver 26. That is, the envelope of positive or negative going signal of the reflecting wave signal c is transformed into a demodulated signal d as shown in Fig. 3d which in turn is derived from the receiver 26. As described above, the receiver 26 has signal limiting, amplifying and detecting functions. The signal derived from the receiver 26 may be used for indicating a power level of the ultrasonic wave irradiated into the living body by using a digital volt meter.

The demodulated signal d derived from the receiver 26 is transformed into a sampled pulse e as shown in Fig. 3e by a comparator 28. In comparator, noise or low level signals unnecessary for diagnosis are selectively pulled out from the signal d and are discarded. As a result, only the signal components essentially necessary for diagnosis are picked up. More specifically, the comparator 28 compares a reference voltage level corresponding to the minimum level for the pick-up with the signal d level to pick up only the signal d level higher than the reference level to provide the sampled pulse signal e.

The rate pulse a generated by the rate pulse generator 22 is also applied to a delay circuit 30. The delay circuit 30 is used to avoid the influence of the driving pulses supplied from the transmitter 24 to the receiver 26. The circuit 30 provides a delaying pulse f1 which is the rate pulse a, delayed by a time td (for example, 20y sec) enough to damp the driving pulses. The delaying pulse fr triggers a monostable multivibrator (MM) 32. The MM 32 provides selecting pulses g as shown in Fig.

3g to produce a pulse train of the sampled pulses e at a proper time interval t,. The time interval t; is a proper time length from the generation of the delayed pulse fit due to the first rate pulse a, to the generation of the second rate pulse a2. Assume now that the pulse interval of the rate pulse a and the time interval t; are set up for the living body.

Under this assumption, when the ultrasonic wave pulse is transmitted into the living body, the diagnostic apparatus surely detects the pulse train of the sampled pulse e in the time interval t,.

The sampled pulse e and the selecting pulse g are transformed into the AND-pulse h by an AND gate 34. In other words, the pulse h corresponds to the sampled pulse e selectively extracted in the time interval t.

The pulse h is applied as a setting pulse to a flip-flop circuit (F/F) 36. A resetting pulse with the same period as that of the rate pulse a is applied to a reset input terminal of the F/F 36. A clock pulse i which is an output signal of the F/F 36 becomes "HIGH" level in response to the first pulse h1 in the time interval t and becomes "LOW" level in response to the second rate pulse a2.

The clock pulse i is applied as a counting input to a counter 38. During a time that the diagnostic apparatus transmits the ultrasonic wave pulse, therefore, the counter 38 continues counting the clock pulse with the generating period of the rate pulse a, only if it detects the reflecting pulse i.e. the ultrasonic wave pulse is being transmitted into the living body. The count of the counter 38 represents a net time of transmission of the ultrasonic wave pulses into the living body. The count of the counter 38 progressively increases in proportion to the emission time of the ultrasonic wave, unless the counter 38 is reset. The net time of the ultrasonic emission is expressed by N/fr where N is the count of the counter 38 and fr the oscillation frequency of the generator 22. Therefore, if the count of the counter 38 is properly used, it is possible to indicate the emission time of the ultrasound or to give an alarm on the cautionary amount of ultrasonic emission.

The output of the counter 38 is applied to a display indicator 40, a recorder 42 and an alarm device 44 where the information of the ultrasonic emission are displayed, indicated and/or recorded.

A designator 46 to designate the kind of the living body being diagnosed at that time is additionally connected to the devices 40 and 42. With the use of the designator 46, the kind of the living body currently undergoing diagnosis and other information such as patient number are displayed, indicated and/or recorded, together with the ultrasonic emission time. In addition to such functions, the designator 46 has a function to reset the counter 38. That is, every time that the living body changes, the designator 46 resets the counter 38 to be "0" in its contents in preparation for the next diagnosis for another patient. The modulated signal d also is applied from the receiver 26 to the devices 40 and 42. The signal d is recorded in the device 42 and displayed by the device 40 as the crosssectional image of the living body of the "B Scan Turning now to Fig. 4, there is shown another ultrasonic diagnostic apparatus according to the present invention. The operation of the Fig. 4 embodiment is schematically illustrated in Figs. Sa to 51. In the explanation of Fig. 4 to follow, the explanatory portion common to that in Fig.

2 will be omitted.

In Fig. 4, for example, a CRT is used for the device 40. Accordingly connected to the device 40 is a scan signal generator 48 for scanning an electron beam in the vertical and horizontal directions on the CRT screen. The horizontal scanning of the generator 48 is synchronized with the rate pulse fed from the generator 22 while the vertical scanning is synchronized with the frame pulse fed from a frame synchronous generator 50. The generator 50 has a function to frequency-divide the rate pulse fed from the generator 22 by necessary number. For example, to form one frame of the CRT screen by m horizontal scanning lines, the frequency of the frame pulse j must be l/m of the rate pulse frequency. In this case, the generator 50 is an oscillator to oscillate a signal with the frequency of l/m rate pulse frequency or a l/m frequency divider. In Figs. Sa and Sj, the frequency dividing ratio, i.e. "m", is 8 for ease of explanation; however, it is generally selected to be a larger value. For example, when the frequency fr of the generator 22 is 1 KHz, the m selected is in the order of 128.

Since the F/F 36 is reset by the frame pulse A the ultrasonic emission time is measured for every one frame.

The output signal of the F/F 36, i.e. the clock signal i, is applied as a trigger pulse to a second monstable multivibrator (MM) 52.

The delay time td of the pulse ito the pulse corresponds to the time interval to avoid the effect of the driving pulses supplied to the receiver 26, as previously mentioned. The MM 52 triggered by the pulse i, provides an integrating pulse k with a width of the time interval for integration tint, as shown in Fig.

5k. The pulse k is applied to an integrator 54 where it is integrated during the time interval tint. The integrating operation is performed for each pulse k so that the wave form of the output signal I of the integrator 54 is as shown in Fig. 51. That is, the voltage level of the signal I is proportional to the ultrasonic emission time.

Assume now that Vk designates the voltage of the pulse k, Tc the integrating time constant of the integrator 54 and V, the voltage level of the signal I. In integration during N frames, the voltage Vk is constant so that the signal I is given Vk V,=N tint 'Te The ultrasonic emission time TE of N frames is m N, fr with notation that fr designates the oscillation frequency of the generator 22 and m the frequency dividing ratio of the generator 50. From the above mentioned two formulas, it will be understood that Vk fr Vl= tint TE.

Tc m Since the ultrasonic total emission time may be expressed by integer, the voltage V1, i.e.

the voltage level of the signal I, is proportion to the ultrasonic total emission time. The integrating operation of the integrator 54 is not performed in the absence of the pulse i, that is to say, when the diagnostic apparatus does not transmit the ultrasonic wave into the living body. Accordingly, the voltage level V, of the signal I is proportional to the ultrasonic emission time.

The signal I is applied to a second comparator 56 as well as the devices 40 and 42. The comparator 56 having a fixed voltage level EA provides an alarm signal m to the device 44 when the voltage level of the signal I reaches the level EA. If the level EA is set up at the level representing the cautionary amount of the ultrasonic emission, the alarm may be given since the comparator 56 provides the signal m as shown in Fig. 5m. The cross-sectional image of the living body displayed on the CRT screen may be photographically recorded.

A buzzer or lamp may be used for the alarming operation. The alarm may be stepwisely performed. Assuming now that three steps are employed for the alarm.

In this operation, the first step announces the fact that the stop of the ultrasonic transmission onto the living body approaches. The second step announces the fact that the time the ultrasonic emission is to be stopped is imminent. The final step permits the diagnostic apparatus to automatically stop the transmission of the ultrasonic wave. Such an automatic stopping operation may be executed by applying, for example, the signal for final step execution to the transmitter 24 or the generator 22 thereby to stop its transmitting or its generating operation.

Fig. 6 shows a circuit diagram of the integrator 54, the comparator 56 and the device 44 shown in Fig. 4. The integrator 54 is a Miller type integrator and is comprised of an operational amplifier 54, used in inverting connection mode, a resistor R1, a capacitor C1, and a resetting transistor 542 connected across the capacitor C,. The resistor R2 is used for offset-balancing of the amplifier 54,. The time constant Tc of the integrator 54 is C,R,, i.e. Tc=C,R,. The output level of the integrator 54 is reset every frame by a reset pulse from the designator 46 to the gate electrode of the transistor 542, thereby to be zero. An input signal k from the MM 52 to the integrator 54 is transferred to the inverted input terminal of the amplifier 54,, through the resistor R,.

The integrated output signal I of the integrator 54 is taken out from the output terminal of the amplifier 54,. The signal I is applied to the inverted input terminal of a comparing amplifier 56, of the comparator 56. Applied to the non-inverted input terminal of the amplifier 56, is the reference voltageEA for comparison. Accordingly, when the voltage level of the signal I exceeds YEAS the output signal m of the amplifier 561 is at the minimum level. When the signal I drops to coincide with the EA, the output signal m of the amplifier 561 instantaneously increases up to the maximum level. Then, a light emission diode 44, serving as an alarming element in the device 44 starts to emit light rays.

The embodiments thus far described relate to non-Doppler type diagnostic apparatus. It should be understood that the present invention may be applied to Doppler blood-flow sensing. It will be apparent to those skilled in the art that the present invention is applicable to the diagnostic apparatus using an ordinary ultrasonic wave reflection which is not of pulse wave, in the detection and indicate of the total time of ultrasonic emission or the total energy of it which is essential to the invention.

Other suitable measuring means such as a digital clock may be used for measuring the ultrasonic emission time.

Proper combination of the constructions shown in Figs. 2, 4 and 6 will produce many other embodiments than the disclosed ones.

As described above, in the diagnostic apparatuses of the invention, the total amount of ultrasonic energy transmitted into the living body may be automatically indicated and/or displayed in real time fashion. For this, an operator may properly adjust the ultrasonic power level while observing the CRT screen. For this reason, excessive ultrasonic emission into the living body may be avoided. Additionally, the total amount of ultrasonic energy or the total time of ultrasonic emission may be recorded. Therefore, the operator may readily know the information concerning the cautionary amount of ultrasonic wave emission to the living body. Particular!y, in the diagnostic apparatus shown in Figs. 2 and 4, even if there is a time that no crosssectional image of the living body is displayed on the CRT device, the total time of the ultrasonic wave emission is correctly measured unless ultrasonic wave is not emitted onto the living body. Additionally, provision of the alarm ensures avoidance of adverse effect of the ultrasonic transmission upon the living body.

In construction of the diagnostic apparatus according to the invention, there is no need of specially designed transducer and devices for detecting the ultrasonic emission time. Therefore, its construction may be easily made without any trouble.

The present invention also is applicable for checking whether the reflecting wave is surely detected or not. It is as a matter of course that the present invention is applicable to diagnostic apparatus with a plurality of transducers.

WHAT WE CLAIM IS:- / 1. An ultrasonic diagnostic apparatus for inspection of a living body, comprising transmitting and receiving means for transmitting an ultrasonic wave into the living body and for receiving the ultrasonic wave reflected by internal organs of the living body; signal providing means for providing a signal representative of the period during which the ultrasonic waves are transmitted into the living body in dependence on signals delivered from said ultrasonic transmitting and receiving means; display means for displaying an image of the internal organs of the living body in dependence on signals derived from said transmitting and receiving means; and indicating means connected to receive the signal provided by the signal providing means for indicating the total amount of ultrasonic energy transmitted in to the living body.

2. An ultrasonic diagnostic apparatus according to claim 1, in which said indicating means includes an indicating device for indicating the power level of the ultrasonic wave irradiated into the living body and its total transmission time.

3. An ultrasonic diagnostic apparatus according to claim 1 or claim 2, in which said indicating means includes a recording device for recording the indication.

4. An ultrasonic diagnostic apparatus according to any of claims I to 3, in which said transmitting and receiving means is arranged to transmit ultrasonic waves in pulses and comprises a delay circuit for providing a delayed pulse delayed in relation to each transmitted pulse of ultrasonic waves, a gate pulse generating circuit which is triggered by the delayed pulse to produce a gate pulse having a gate time corresponding to the time interval from the generation of a first delayed pulse due to a first transmitted pulse to the generation of a second transmitted pulse; a comparing circuit for producing a sampled pulse from a signal supplied from said transmitting and receiving means from the ultras

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Other suitable measuring means such as a digital clock may be used for measuring the ultrasonic emission time.

Proper combination of the constructions shown in Figs. 2, 4 and 6 will produce many other embodiments than the disclosed ones.

As described above, in the diagnostic apparatuses of the invention, the total amount of ultrasonic energy transmitted into the living body may be automatically indicated and/or displayed in real time fashion. For this, an operator may properly adjust the ultrasonic power level while observing the CRT screen. For this reason, excessive ultrasonic emission into the living body may be avoided. Additionally, the total amount of ultrasonic energy or the total time of ultrasonic emission may be recorded. Therefore, the operator may readily know the information concerning the cautionary amount of ultrasonic wave emission to the living body. Particular!y, in the diagnostic apparatus shown in Figs. 2 and 4, even if there is a time that no crosssectional image of the living body is displayed on the CRT device, the total time of the ultrasonic wave emission is correctly measured unless ultrasonic wave is not emitted onto the living body. Additionally, provision of the alarm ensures avoidance of adverse effect of the ultrasonic transmission upon the living body.

In construction of the diagnostic apparatus according to the invention, there is no need of specially designed transducer and devices for detecting the ultrasonic emission time. Therefore, its construction may be easily made without any trouble.

The present invention also is applicable for checking whether the reflecting wave is surely detected or not. It is as a matter of course that the present invention is applicable to diagnostic apparatus with a plurality of transducers.

WHAT WE CLAIM IS:- / 1. An ultrasonic diagnostic apparatus for inspection of a living body, comprising transmitting and receiving means for transmitting an ultrasonic wave into the living body and for receiving the ultrasonic wave reflected by internal organs of the living body; signal providing means for providing a signal representative of the period during which the ultrasonic waves are transmitted into the living body in dependence on signals delivered from said ultrasonic transmitting and receiving means; display means for displaying an image of the internal organs of the living body in dependence on signals derived from said transmitting and receiving means; and indicating means connected to receive the signal provided by the signal providing means for indicating the total amount of ultrasonic energy transmitted in to the living body.
2. An ultrasonic diagnostic apparatus according to claim 1, in which said indicating means includes an indicating device for indicating the power level of the ultrasonic wave irradiated into the living body and its total transmission time.
3. An ultrasonic diagnostic apparatus according to claim 1 or claim 2, in which said indicating means includes a recording device for recording the indication.
4. An ultrasonic diagnostic apparatus according to any of claims I to 3, in which said transmitting and receiving means is arranged to transmit ultrasonic waves in pulses and comprises a delay circuit for providing a delayed pulse delayed in relation to each transmitted pulse of ultrasonic waves, a gate pulse generating circuit which is triggered by the delayed pulse to produce a gate pulse having a gate time corresponding to the time interval from the generation of a first delayed pulse due to a first transmitted pulse to the generation of a second transmitted pulse; a comparing circuit for producing a sampled pulse from a signal supplied from said transmitting and receiving means from the ultrasonic pulse reflected from the internal organs in the living body; an AND gate circuit for producing a set pulse from the sample pulse and the gate pulse; a flip-flop circuit for producing a clock pulse which is set by the set pulse due to the first transmitted pulse and reset by the second transmitted pulse; and a counting circuit for counting the clock pulses for providing a signal representative to the total transmission time to said indicating means.
5. An ultrasonic diagnostic apparatus according to claim 4, in which said indicating means includes an alarm device in which the count of said counting circuit is compared with a preset value, and wherein when the preset value is equalled or exceeded, an alarm is issued.
6. An ultrasonic diagnostic apparatus according to any of claims I to 3, in which said transmitting and receiving means is arranged to transmit ultrasonic waves in pulses and comprises a delay circuit for providing a delayed pulse delayed in relation to each transmitted pulse of ultrasonic waves, a gate pulse generating circuit which is triggered by the delayed pulse to produce a gate pulse having a gate time corresponding to the time interval from the generation of a first delayed pulse due to a first transmitted pulse to the generation of a second transmitted pulse; a comparing circuit for producing a sampled pulse from a signal supplied from said transmitting and receiving means from the ultrasonic pulse reflected from the internal

organs in the living body; an AND gate circuit for producing a set pulse from the sample pulse and the gate pulse; a flip-flop circuit for producing a clock pulse which is set by the set pulse due to the first transmitted pulse and reset by the second transmitted pulse; an analogue integrating circuit for integrating the clock pulses, in order to provide a signal representative the total transmission time to said indicating means.
7. An ultrasonic diagnostic apparatus according to claim 6, in which said analogue integrating circuit includes a monostable multivibrator for generating a signal for integration with a time interval corresponding to that from the generation of a first clock pulse due to a first transmitted pulse to the generation of a second transmitted pulse, said monostable multivibrator being triggered by the clock pulse; and a Miller integrating circuit for integrating the signal for integration.
8. An ultrasonic diagnostic apparatus according to claim 6, in which said indicating means includes a comparator in which the output level of said analog integrating circuit is compared with a preset level and wherein when the levels are coincident, an alarm signal is issued and alarm means for giving an alarm in response to the alarm signal.
9. An ultrasonic diagnostic apparatus according to any of claims I to 3, in which said display means comprises a cathode ray tube, and the transmitting and receiving means comprises a scan signal generator for generating a horizontal scan signal and a vertical scan signal for scanning an electron beam of the cathode ray tube; and a frame synchronous signal generator which is synchronized with a rate pulse used to form a transmitted ultrasonic wave pulse for providing synchronous signals for the horizontal and vertical scan signals to said scan signal generator.
10. An ultrasonic diagnostic apparatus according to any of claims I to 3, in which said transmitting and receiving means includes a rate pulse generator for generating a rate pulse used to form a transmitted ultrasonic wave pulse; and a counting device for counting the rate pulses when the reflected ultrasonic waves are received from the living body.
11. An ultrasonic diagnostic apparatus according to any of claims 1 to 3, in which said transmitting and receiving means includes a frame synchronous signal generator as for generating a frame pulse which is synchronized with a rate pulse used to form a transmitted ultrasonic wave pulse and is employed by a cathode ray tube display of said display means; and a counting device for counting the frame pulse when reflected ultrasonic waves are received from the living body.
12. An ultrasonic diagnostic apparatus for inspection of a living body, substantially as hereinbefore described with reference to the accompanying drawings.