JPS6215214B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic scanning ultrasound diagnostic device, and particularly to an ultrasound diagnostic device that can scan a wide range with a small probe, that is, enlarge the diagnostic field of view, and can obtain high-quality images with good resolution. It is something.

In electronic scanning ultrasound diagnostic apparatuses, there are a linear scanning method (FIG. 1) in which ultrasound beams are scanned in parallel, and a sector scanning method (FIG. 2) in which ultrasound beams are scanned in a fan shape.

The former linear scanning method applies high-frequency pulses by sequentially switching over time a plurality of transducers arranged on a plane at equal intervals. The switching is performed electronically using an analog switch or the like. In FIGS. 1 and 2, R is a probe, 1 is a transducer constituting the probe, P is a subject, and P' is the body surface of the subject P.

In this case, generally in order to improve the directivity of the ultrasonic beam from the transducers, a plurality of transducers are driven simultaneously, for example, high-frequency pulses are applied to m transducers 1 to m. Next, a high frequency pulse is applied to the m transducers while shifting them one transducer at a time from 2 to m+1, and the ultrasonic beam is moved one transducer at a time to perform linear scanning. are doing.

Therefore, in this case, the ultrasonic beam has a directivity characteristic that is directed from the center of the m transducers to which high-frequency pulses are applied in a direction perpendicular to the transducer array plane.

In addition, the latter sector scanning method delays the high-frequency pulse applied to each transducer arranged at equal intervals in a plane, and the relative delay time of the high-frequency pulse applied to each transducer is This is done by electronic control.

That is, the first
From the th transducer (i-1)d/c×
When a high-frequency pulse delayed by sinθ (where d is the transducer interval and c is the sound speed) is applied, the ultrasonic beam is deflected by θ from the direction perpendicular to the transducer array plane, and this delay time is electronically controlled. By doing so, the direction of the ultrasonic beam changes and is scanned in a sector.

However, in the former case, if the scanning range is to be increased, it is necessary to arrange a large number of transducers to obtain a desired field of view, and the probe becomes larger. As a result, a gap forms between the probe and the patient's body surface, especially in the surrounding area, making it difficult to make close contact with the patient's body surface. In addition to not being able to obtain images, it also gives the patient a feeling of pressure. In addition, when diagnosing heart disease, etc. by emitting an ultrasound beam into the subject's body from between the bones, the probe cannot be made large, resulting in a small field of view. ) part becomes a blind spot.

In the latter case, as is clear from Fig. 2, the field of view is particularly narrow near the body surface, and when the deflection angle θ of the ultrasound beam is increased in order to enlarge the diagnostic field of view, the field of view becomes narrower as it moves away from the transducer array plane. ,
That is, the ultrasonic beam becomes coarser as it goes deeper from the body surface, and the resolution is significantly lowered. The deflection angle θ of the ultrasonic beam is determined by controlling the relative delay time of each transducer, but it is technically difficult to set it to 90° or more. Additionally, although this method is effective for emitting an ultrasound beam into the subject from between the bones,
The field of view near (shallow) the body surface was narrow, and this area became a blind spot, making it impossible to make effective diagnoses from areas close to the body surface to areas far away.

Therefore, in this type of field, it would be beneficial if the scanning range could be expanded with a small probe and the diagnostic field of view could be enlarged. There is a strong desire for an ultrasonic diagnostic device that can provide high-quality images.

In view of the above, it is an object of the present invention to provide an ultrasonic diagnostic apparatus in which the probe is miniaturized, the scanning range is enlarged, the diagnostic field of view is enlarged, and high-quality images with good resolution can be obtained. This is the purpose.

In order to achieve this purpose, a configuration is adopted in which high-frequency pulses can be sequentially applied to each transducer of the transducer group that constitutes the transducer group arranged in parallel in a plane, and a predetermined pulse is applied to each transducer at the end of the transducer group. The system is configured to apply high-frequency pulses with electronically controlled relative delay times to each transducer, and allows linear scanning and sector scanning to be used together to enlarge the scanning range and improve the diagnostic field of view. At the same time, a predetermined number of transducers at both ends of the transducer group are connected to delay elements, such as delay lines, each having a predetermined delay time set to give a focusing effect to the ultrasonic beam. By applying a high-frequency pulse whose delay time is electronically controlled to each transducer via the delay element, the ultrasonic beam becomes thicker as it moves away from the transducer array surface during sector scanning. It is designed to prevent this.

The present invention will be explained below with reference to embodiments shown in the drawings. FIG. 3 is a schematic diagram for explaining the principle of the scanning method of the present invention, where R is a large number of transducers 1 ₁ to 1 _o
are probes arranged at equal intervals on the same plane. In the embodiment, by applying a high frequency pulse whose relative delay time is electronically controlled to a predetermined number of transducers at the left end of the probe R, the ultrasonic beam B is further shifted by θ sector in the direction of arrow a. When the beam B reaches the position , high-frequency pulses are sequentially applied to each transducer of the probe R, so that the ultrasonic beam B is linearly scanned in the direction of arrow b along the transducer array surface. When the ultrasonic beam B reaches the position of It is configured such that sector scanning is performed up to the position θ in the direction of arrow c. This state is shown in FIG. 3a.

At this time, each of the predetermined transducers used for sector scanning at least at both ends of the probe R is connected to a delay line having a delay time set to focus the ultrasound beam as described above. The high-frequency pulses with controlled relative delay times for sector scanning are delayed by these delay lines and applied to each transducer. It is focused at point F at distance D from the surface.

That is, each predetermined number of transducers 1 ₁ to
It is assumed that the relative delay time of 1 _n is controlled and the ultrasonic beam B is directed in the direction θ from the direction perpendicular to the row surface.
A wavefront W ₁ is formed.

Here, each of the transducers 1 ₁ to 1 _n is provided with a delay line 3 ₁ to 3 _n for focusing the ultrasonic beam, and each delay line forms a focused wavefront of W ₂ in the figure. Each delay time of delay line 3 is
From 3 ₁ to 3 _n , it is set to have a parabolic delay time that is maximum at the center and minimum at both ends of 3 ₁ and 3 _n , so the result is
Since both wavefronts W ₁ and W ₂ are superimposed, the ultrasonic beam from each transducer is deflected as shown in the figure and travels toward F at a distance D from the transducer array surface, reaching point F. focus on.

The dotted line in the figure shows the case where the relative delay time of each transducer 1 ₁ to 1 _n is controlled and the ultrasonic beam B is directed in the direction θ ₁ from the direction perpendicular to the row plane. Also each transducer 1
Since a high frequency pulse is applied through each delay line ₃₁ to _3n having a parabolic delay time of ₁ to _1n , the ultrasonic beam from each transducer is transmitted at a distance D from the transducer array surface. Focus on the focus point F ₁ .

Therefore, if the relative delay time of each transducer is electronically controlled and sector scanning is performed in the directions of arrows a and c in Fig. 3a, the ultrasonic beam will pass through the transducer as shown in Fig. 3C. Distance D from row surface
F, F ₁ , F ₂ ... on the line d.
and will be moved. Therefore, even in areas far from the transducer array plane, that is, areas deeper than the body surface, the ultrasound beam does not travel straight as shown by the dotted line in the figure, and due to the action of the focusing delay line, the distance D is increased as shown by the thin line. It will not be focused on line d and become thicker, but will be sector scanned.

Furthermore, as shown in FIG. 3d, the ultrasonic beam emitted from the transducer diverges as it moves away from the transducer array surface as shown by the dotted line in the figure. As shown by the thin line in the figure, a narrow ultrasonic beam is obtained from the transducer array surface to a distance D, and the ultrasonic wave Coupled with the fact that the beam does not become coarse, it becomes possible to perform dense scanning with a narrow beam.

Furthermore, the focusing distance of the ultrasonic beam from the transducer array surface, that is, the focal length D, is determined by the delay time of the focusing delay lines 3 ₁ to 3 _n connected to each transducer 1 ₁ to 1 _n. It can be arbitrarily changed by adjusting and changing the shape of the wavefront W ₂ of FIG. 3b formed thereby.

In addition, in this example, a focusing delay line is also connected to all transducers constituting the probe, and during linear scanning, in which high-frequency pulses are sequentially applied electronically to the transducers from one end. As shown in Fig. 3e, a delay time is given to form a wavefront W ₂ that is the same as the wavefront W ₂ in Fig. 3b, and it is moved in the scanning direction (direction of arrow b) by a shift register, that is, the wavefront W ₂ ' is W ₂ ′→
W ₂ '' to focus the ultrasonic beam at a distance D from the transducer array surface, enabling linear scanning with a narrow ultrasonic beam.

FIG. 4 is a block diagram of an embodiment for realizing the scanning method described in FIG. 3.

In the figure, R is a probe, and a large number of transducers 1 ₁ to 1 _o are arranged on the same plane at equal intervals. For convenience of explanation below, transducers 1 ₁ to 1 _n and 1 _K+1 to 1 at both ends of the probe R are used.
_phased array transducer
PT ₁ , PT ₂ , central transducer 1 _n+1 ~ 1
_K is called Linear Aire Transducer LT. Furthermore, the phased air transducers PT ₁ and PT ₂ each include, for example, 32 transducers, and the linear air transducer LT includes, for example, 32 transducers.

Reference numeral 3 denotes a delay line group for ultrasonic beam focusing connected to each transducer 1 ₁ to 1 _o , and during sector scanning, a phased air transducer is used to form the wavefront W ₂ explained in FIG. A parabolic delay time is given from delay line 3 ₁ to 3 _n connected to user PT ₁ such that it is maximum at the center and minimum at both ends of 3 ₁ and 3 _n (phased air transducer PT The delay lines _{3k +1} to _3o connected to the wavefront W2 are also given the same parabolic delay time to form the wavefront _W2 ). During linear scanning, m transducers are connected to each other by a shift register (described later). The delay line connected to is given a parabolic delay time similar to that in the sector scanning described above to form the wavefront W ₂ in FIG. 3e, and the wavefront W ₂ ', as explained in FIG.
It is moved (shifted) to form W ₂ ″.

4 is a phased air transducer
A delay line group for sector scanning that provides a predetermined relative delay time to each transducer 1 of PT ₁ and PT ₂ .
Each transducer 1 ₁ to 1 _n , 1 _K of PT ₁ and PT ₂
The delay lines 3 ₁ to 3 _n , 3 _K+ connected to ₊₁ to 1 _o
1 and ₃ are connected in series.

Reference numeral 5 denotes a sector scanning control circuit for controlling the delay time of the delay line group 4, which is a counting circuit composed of a counter and a decoder, which is controlled by a command signal _P2 from the control circuit 6 and counts it.

7 is a linear scanning control circuit consisting of a shift register 8 and a decoder 9;
is an n-digit register in which the parabolic delay time given to the focusing delay line group 3 is set so as to form the wavefront W ₂ explained in FIGS. 3b and 3e, and the command signal from the control circuit 6 is P ₂ shifts the contents to the right, and the contents of the shift register 8 are applied to each delay line 3 ₁ to 3 _o of the focusing delay line group 3 via a decoder 9, and the corresponding n A parabolic delay time set for each delay line is given.

Reference numeral 10 denotes a receiving circuit that receives the ultrasonic echoes received by the transducer 1 and converted into electrical signals.This circuit 10 includes the same delay line group 3 for focusing and the delay line group 4 for sector scanning. Delay line groups 3', 4' are provided, and said delay line groups 3, 4
Similarly, the control signals β, γ from the shift register 8 and sector scanning control circuit 5, respectively
The delay time is controlled by , and the same delay time as that of the delay line groups 3 and 4 is provided.

Therefore, the ultrasonic echo is guided to the receiving circuit 10 and received through the delay line group 3', 4', which has the same delay time as the time of transmission, so it has the same directional characteristics as the emitted ultrasonic wave. F explained in Figure 3
The maximum sensitivity will be at a point at a distance D from the transducer array surface.

The output signal of the receiving circuit 10 is guided to a display mechanism 11 such as a CRT. The display mechanism 11 further includes a sector scanning control circuit 5 and a linear scanning control circuit 7 that display the ultrasonic beam direction (angle signal) during sector scanning and the beam position (scanning position signal) during linear scanning.
Control signals β and γ from the control circuits 5 and 7 are guided to the display mechanism 11, and this display mechanism 11 receives the control signals β and γ from the control circuits 5 and 7 and the output signal from the receiving circuit 10 to display an ultrasonic scanning image during diagnosis. put out

In addition, 2 in the figure indicates each transducer 1 ₁ to 1 _o
and the focusing delay lines 3 ₁ to 3 _o .

FIG. 5 shows a delay line 4 and its control circuit 5 suitable for sector scanning in FIG.
This is an example.

In the figure, the delay line ₄₁ consists of two tap-type variable delay lines l _1-1 and l _1-2 . Delay line l _1-2
has a delay time in which the total delay time of delay line l _1-1 is equal to the delay time between one tap. For example, if the total delay time of delay line l _1-1 is 10 ns, delay line l _1-2
The delay time between the taps is 10 ns, and if both delay lines have 9 taps, the delay time can be selected every 1 ns from 0 to 99 ns when switching both taps.

Reference numeral 5 denotes a sector scanning control circuit for controlling tap switching of delay lines l _1-1 and l _1-2 , and is composed of a corresponding counter and decoder.

51 and 52 are BCD counters, counter 51
is the ultrasonic echo reception completion signal P ₂ from the control circuit 6
This counter counts pulse P ₂ by 9
When another pulse P ₂ comes in, a rising pulse P ₅ is sent to the counter 52. The counter 52 also counts up to 9 in the same way as the counter 51, and is reset to 0 by the pulse _P2 from the other counter 51, and outputs a count-up signal _P3 . This count-up signal _P3 is supplied to the control circuit 6.

Decoders 53 and 54 decode the 4-bit output from each BCD counter 51 and 52 from BCD to decimal, and the output is used for each delay line l _1-1 ,
l Analog switch S ₁ to switch taps _1-2
-1 and S _1-2 are controlled, and a delay time corresponding to the count value is given.

Although FIG. 5 only shows the delay line ₄₁ that provides the delay time to the transducer ₁₁ ,
The other delay lines 4 ₂ to 4 _n have the same configuration, and their taps are simultaneously switched to tap positions that give the same delay time by the outputs of the decoders 53 and 54 by analog switches S ₁ to _{S n} . .

In the above configuration, when the trigger pulse P ₁ is generated by the control circuit 6 to generate a pulsed ultrasonic wave, the pulse P ₁ is delayed by the time given to the delay line 4 ₁ and then sent to the high frequency pulse generator 2. supplied,
Transducer ₁ with a higher frequency pulse than that
is driven and an ultrasonic beam is emitted. The ultrasonic echo is received by the transducer ₁₁ , and when the reception is completed, the control circuit 6 issues a reception completion signal _P2 . This signal _P2 is counted by the counter 51, and its 4-bit output (0001) is sent to the decoder 53.
is decoded to decimal 1 by , and each analog switch _S1-
1 ...S _n-1 is switched to the tap position giving a delay time of 1 ns.

As a result, a delay time of 1 ns is given to each delay line _{4 1 to} 4 _n of each transducer 1 1 to 1 _n , and the relative delay time of each delay line is 1 ns. At this time, the signal β from the control circuit 5 causes the receiving circuit 10 in FIG.
Each delay line 4 is also given a relative delay time of 1 ns. In this state, when a new trigger pulse _P1 is generated from the control circuit 6 to generate the next pulsed ultrasonic wave, this trigger pulse _P1 is relatively delayed by the 1 ns time given above. The signal is supplied to a high frequency pulse generator 2, and its output drives each transducer ₁₁ to _1n .

As a result, the ultrasonic beam is swung from a direction perpendicular to the transducer row plane by 0.266° determined by a relative delay time of 1 ns for each transducer.

The reflected echoes of this pulsed ultrasonic wave are received by each transducer 1 ₁ to 1 _n with the same delay time, so they have the same directivity characteristics as the emitted ultrasonic waves.
0.266 perpendicular to the transducer plane
It has maximum sensitivity at °.

Note that, in reality, the trigger pulse P ₁ is supplied to each high-frequency pulse generator 2 through the delay line group 3 for focusing in series with the delay line group 4. Focus on point F in figure B,
In addition, since the receiving circuit 10 passes the delay line groups 3' and 4' given the same delay time as the delay line groups 3 and 4, the reflected echo has the same directional characteristics as the emitted ultrasonic wave, and The maximum sensitivity is at point F in Figure 3b. When the reception of the ultrasonic echo is completed, the control circuit 6 again issues a reception completion signal P ₂ and supplies it to the counter 51 . This signal _P2 causes the BCD counter 51 to count up by one and output a 4-bit output (0010). This output is decoder 53
is decoded to decimal 2, and each analog switch _S1-
1 ...S _n-1 is switched all at once to the tap position that provides a delay time of 2 ns. (Note that since the BCD counter 52 naturally does not receive the rising pulse _P5 from the counter 51, its contents remain unchanged and the decoder 54
also remains unchanged, and the delay lines l _1-2 to _{l n-2} have zero delay time. ) Therefore, the delay time of all delay lines is 2ns
Therefore, the ultrasonic beam is deflected by approximately 0.553° with respect to the direction perpendicular to the transducer array plane.

In this way, a pulsed ultrasonic wave is emitted by the trigger pulse _P1 from the control circuit 6, and the counter 51 is counted up as soon as the reception completion signal _P2 of the emitted echo is supplied from the control circuit 6. 52 is also counted up once every 10 times, and the outputs of decoders 53 and 54, which convert BCD to decimal, change one by one from 0 to 9 based on these 4-bit outputs.

As a result, two tap-type variable delay lines l _1-1 ~
The delay time of l _n-1 , l _1-2 to l _n-2 is from 0 to 99 ns.
The delay time changes every 1 ns, and the ultrasonic beam is deflected at an angle of 0° to 27.41° with respect to the direction perpendicular to the transducer row plane, that is, sector-scanned.

When the contents of both counters 51 and 52 reach 9 and the next reception completion signal _P2 is supplied from the control circuit 6, the counter 52 outputs a count-up signal _P3 , and this signal _P3 is sent to the control circuit 6. supplied to
After receiving this signal, the control circuit 6 sends a reception completion signal P ₂
is sent to the system register 8 and switched to linear scanning.

In this way, sector scanning is performed with 100 scanning lines and a scanning angle of 27.41°, and a sector scanning image is obtained on the display mechanism.

Next, the operation of the configuration shown in FIG. 4 will be explained. In the figure, sector scanning delay lines 4 ₁ to 4 _n connected to phased air transducer PT ₁
is at the tap position that gives the maximum deflection angle θ to the ultrasonic beam and the maximum delay time, and the focusing delay lines 3 ₁ to 3 _n are connected to the third position by the shift register 8.
A parabolic delay time that forms the wavefront W ₂ in Figure b and a delay time that compensates for the time delay of each switching element are given, and the focusing delay line 3 _n+1 ~
3 _o is turned off so as not to pass the trigger pulse P ₁ to the high frequency pulse generator 2 .

When a trigger pulse P ₁ is supplied from the control circuit 6 in this state, the pulse P ₁ is transmitted to both delay lines 4 ₁ to 4.
A predetermined relative delay time determined by _n , 3 ₁ to 3 _n is given, and each high frequency pulse generator 2 ₁ to 2
_n is triggered, and each transducer 1 ₁ to 1 _n is driven. Therefore, the ultrasonic beam is directed in the direction of the angle θ determined by the relative delay time given to the sector scanning delay lines 4 ₁ to 4 _n from the direction perpendicular to the plane of the row of ultrasonic beam transducers (see FIG. 3a). position) and is narrow enough to be focused at a position a distance D from the transducer array plane determined by the delay times of the focusing delay lines 3 ₁ to 3 _n . The ultrasound echoes of this ultrasound beam are received by each transducer of the same faced air transducer PT ₁ , converted into electrical signals, and delayed to give the same delay time as delay line groups 3 and 4. The ultrasonic echoes are guided to a receiving circuit 10 having line groups 3' and 4', and are received through delay line groups 3' and 4', thereby reaching point F at a distance D from the transducer array surface. It will have maximum sensitivity.

When the reception is completed, the control circuit 6 sends a reception completion signal.
_P2 is supplied to the sector scan control circuit 5, the relative delay time of each transducer of the phased array transducer _PF1 is controlled, and the ultrasonic beam is deflected by a predetermined angle in the direction of arrow a,
The focusing delay lines 3 ₁ to 3 _n focus the light at a distance D from the transducer array surface.

In this way, each time the control circuit 6 issues the reception completion signal _P2 , the relative delay time of each transducer is electronically controlled, and the ultrasonic beam is deflected by a predetermined angle θ (for example, 45 degrees) in the direction of arrow a. Sector scanning is performed by

During this sector scanning at a predetermined angle θ, the focusing delay lines 3 _{1 to} 3 _n connected to the transducers 1 1 to 1 _n have a delay time determined by the delay time data set in the shift register 8, that is, The delay time is set to form the wavefront W ₂ in FIG. 3b, which is not changed during the deflection of the ultrasound beam in the direction of arrow a, so that the ultrasound beam
As shown in , the light is focused on a line d at a distance D from the transducer array surface.

The reception completion pulse _P2 from the control circuit 6 is counted (counted down) by the sector scanning control circuit 5.
When the number of pulses by which the ultrasonic beam is deflected from the predetermined angle θ to 0° is counted, the sector scanning control circuit 5 generates a sector scanning end signal P ₃ and this signal P ₃ is supplied to the control circuit 6. be done.

By supplying the signal P ₃ to the control circuit 6,
The reception completion signal _P2 from the circuit 6 is not supplied to the sector scanning control circuit 5, but is supplied to the shift register 8 of the linear scanning control circuit 7.

_Incidentally , when the signal _P3 is generated, _the ultrasonic beam is at the _position shown in FIG _.
4 _o is switched to the tap 0 position in FIG. 5, making the delay time zero.

Therefore, when the reception completion signal _P2 is supplied from the control circuit 6 to the shift register 8, its contents are shifted to the right, and the leftmost delay line ₃₁ of the focusing delay lines 3 receives the trigger pulse P. ₁ is not passed, and 3 ₂ to 3 _n+1 are given the delay time set in the shift register 8, that is, the delay time to form the wavefront W ₂ of FIG. 3e.

When the next reception completion signal P ₂ is supplied to the shift register 8, the contents of the shift register 8 are further shifted to the right, the delay lines 3 ₁ and 3 ₂ are turned off, and the 3
₃ to 3 _n+2 are given a delay time to form a wavefront W ₂ , and the wavefront W ₂ is moved one transducer to the right to the position W ₂ ' shown in FIG. 3e.

In this way, if the contents of the shift register 8 are shifted n-1 times with the reception completion signal P ₂ from the control circuit 6, the ultrasonic beam is sequentially shifted at the transducer interval S.
Next, the process moves in the direction of the transducer array (direction of arrow b), and linear scanning between - in FIG. 3a is performed. During this linear scanning, only the wavefront _W2 shown in Fig. 3 is maintained, so that it is focused at a position at a distance D from the transducer row surface, and as shown in Fig. 3 e, as in the previous linear scanning. As shown in Figure 2, linear scanning is performed using a narrow beam without the ultrasonic beam diverging.

The ultrasonic echoes of the ultrasonic beams at this time are received by each transducer, converted into electrical signals, and guided to a receiving circuit 10 having a delay line group 3' given the same delay time as the delay line 3. As a result, a linear scanning image is obtained on the display mechanism 11.

When the linear scanning is completed, a linear scanning completion signal _P4 is supplied from the shift register 8 to the control circuit 6.

By supplying this signal P ₄ to the control circuit 6, the reception completion signal P ₂ from the circuit 6 is no longer supplied to the linear scanning control circuit 7.
Furthermore, from this signal _P4 , the delay time data of the shift _{register 8} , that is, the wavefront _W2 of FIG _. Given the parabolic delay time given, the fuzed array transducer PT ₁ , the linear array transducer LT
The delay lines 3 ₁ to 3 _K are turned off so as not to pass the trigger pulse P ₁ from the control circuit 6.

As a result, as described above, each time the reception completion signal _P2 from the control circuit 6 is supplied to the sector scanning control circuit 5, it is counted, and
The relative delay time is electronically controlled, and the ultrasonic beam is sector-scanned at a predetermined angle θ (for example, 45°) in the direction of arrow c, so that a sector-scanned image is obtained on the display mechanism 11.

As described above, according to the above configuration, the field of view A is obtained by sector scanning by the phased array transducer PT ₁ , and the field of view B is obtained by linear scanning by the linear array transducer LT. A field of view C can be obtained by sector scanning by the phased array transducer PT ₂ , and by combining the information of ultrasonic echoes from each scanning in the receiving circuit 11, an image of the field of view A+B+C is obtained, which is displayed on the display mechanism 13. can be displayed on top.

For example, if the deflection angle of the phased array transducers PT ₁ and PT ₂ is 45 degrees, the same field of view can be obtained with a transducer half the size of diagnosis using linear scanning alone; Conversely, with a probe that can obtain field of view B by linear scanning, a field of view that is approximately twice as large can be obtained.

In addition, each transducer is provided with a delay line for focusing, and is given a delay time to form a focused wavefront _W2 , so that, especially during sector scanning, the transducer array surface, that is, the area deeper than the body surface, is The ultrasonic beam does not become coarse even in
In addition, it becomes possible to perform scanning with a narrow, focused beam, and in combination with the compactness of the probe that allows close contact with the patient's body surface, an image with good resolution can be obtained.

Especially phased array transducers
In the sector scanning area by PT ₁ and PT ₂ ,
By controlling the relative delay time of each transducer, the number of ultrasound beams, ie, the number of scanning lines, within a desired deflection angle can be increased, resulting in a higher quality image with better resolution.

In the above embodiment, each transducer is provided with a high frequency pulse generator 2, and its trigger pulse is
Although P ₁ is directly delayed through the delay line, it is also possible to delay the high frequency pulse from the high frequency pulse generator through the delay line and apply it to each transducer.

In this case, only one high-frequency pulse generator is required;
There is no need to bypass the high frequency pulse generator connected to each transducer as shown in Figure 4,
Since the ultrasonic echo can be extracted from point Z in the figure, the receiving circuit can be significantly simplified.

In addition, in the embodiment, the ultrasonic echo reception completion signal P ₂
However, it was configured to control the sector scanning circuit and the linear scanning circuit.
It is not limited to the reception completion signal.

Furthermore, in the embodiment, the tap-type delay line shown in FIG. 5 is used as a delay element for sector scanning and a delay element for focusing, so that they can be controlled digitally, but other delay elements, such as an analog voltage It may also be a delay circuit controlled by.

Furthermore, in the embodiment, the scanning method is performed in the following order: sector scanning by phased array transducer PT ₁ → linear scanning by linear array transducer LT → sector scanning by phased array transducer PT ₂ Although this is done in the above example, a combination such as the reverse order or the order of LT→PT ₁ → PT ₂ may be used. In addition, in the embodiment, both ends of the probe R are connected to phased array transducers.
Although PT ₁ and PT ₂ are used, it is also possible to use only one of them, and it is also possible to perform the linear scanning method and the sector scanning method independently.

As described above, according to the present invention, a high-frequency pulse can be sequentially applied to each transducer of a transducer group arranged in parallel in a plane, and a predetermined number of transducers at both ends of the transducer group are arranged. The ducer is configured to be able to apply a high-frequency pulse whose relative delay time is electronically controlled, and performs linear scanning at the center and sector scanning at both ends. Means is provided for electronically focusing the ultrasound beam onto a predetermined number of each transducer at the one end to be controlled. Therefore, by taking advantage of the features of both linear and sector scanning methods,
In particular, by performing sector scanning at both ends of the transducer group, the probe can be made smaller, and the diagnostic field of view can be enlarged with a smaller probe, eliminating blind spots. Due to the miniaturization of the patient's body surface, and the electronic focusing means of the ultrasound beam, it is possible to perform dense scanning with a narrow beam without the ultrasound beam diverging, especially during sector scanning. It is an object of the present invention to provide an ultrasonic diagnostic device that is capable of obtaining high-quality images with good resolution and no blind spots to deeper parts, and that is particularly effective in diagnosing heart diseases, etc., in which an ultrasonic beam is emitted into a subject from between the bones. can.

Furthermore, the ultrasonic beam is focused at a desired distance D from the transducer row surface by electronic focusing means, that is, the focusing distance D can be set arbitrarily, so that high resolution can be obtained in the target area of the affected area. I can do it. In this case, according to the configuration of the embodiment, the focal length can be freely set based on the data initially loaded into the shift register, which is advantageous in handling operations.

Furthermore, by setting the electronic focusing means, it is possible to perform scanning with ultrasound beams having different focal lengths, and by combining the obtained images, it is possible to obtain a high-resolution image in the entire depth direction and the entire field of view. can.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams for explaining the conventional electronic scanning system, FIG. 3 is a schematic diagram for explaining the electronic scanning system of the device of the present invention, FIG. 4 is a block diagram of an embodiment of the present invention, and FIG. This figure is a block diagram showing an example of the sector scanning control section in FIG. 4. 1: Transducer, R: Probe, 2: High-frequency pulse generator, 3: Focusing delay line group (electronic focusing means) that also serves as delay time compensation, 4: Sector scanning delay line group , 5: sector scanning control circuit, 6: control circuit, 7: linear scanning control circuit (8... shift register, 9...
... decoder), 10: receiving circuit, 11: display device, W ₂ : focused wavefront, F: focusing point of ultrasonic beam.

Claims (1)

[Claims] 1 A group of transducers arranged in parallel in a plane,
means for electronically sequentially applying high frequency pulses to the transducers of the transducer group from at least one end; means for applying controlled radio frequency pulses and means for electronically focusing the ultrasound beam on each predetermined number of transducers at least at said one end, linear scanning in a central portion of the group of transducers; An ultrasonic diagnostic apparatus characterized in that sector scanning is performed at both ends.