JPS58198335A - Scanning line moving system of ultrasonic probe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a scanning line movement method for a split transducer type ultrasonic probe, in which weighting is applied to the transmission drive voltage and/or reception amplification gain of simultaneously selected element groups. This is intended to reduce the scanning pinch of the ultrasonic beam to less than the arrangement pinch of the elements.

Conventional technology and problems In ultrasonic diagnostic equipment that uses a linear array probe,
By sequentially changing the element groups that are driven simultaneously, the ultrasonic beam is translated in parallel as shown in FIG. 1 (al or middle). The same figure (al example shows multiple transducer elements 1, 2, 3)
．． By sequentially changing (alternating) five consecutive elements selected from the ultrasonic probe 20 consisting of or divided into -------, the ultrasonic beam 3 is focused and formed.
Translate o in the direction of the arrow. ■、■、■・・・・・・
・denotes the selection order of the element group, and 30' indicates the first beam that has been translated in parallel.If the beam scanning pitch P1 is reduced, the image quality can be made finer, but in this scanning method, the minimum value of the pitch is the division interval (element width). or element arrangement pinch) W is the limit. Therefore, in order to further improve the image quality, the division interval W must be narrowed, which causes problems such as a decrease in the mechanical strength of the element and difficulty in processing. Furthermore, if the overall width is constant, the number of lead wires for the probe 20 increases as the number of divisions increases, making it difficult to handle the probe.

In the example shown in Figure 1(b), +8) in the same figure adds one element to the right end and removes one right end at the same time, changing two elements at one time, whereas one element increases or decreases at one time (for example, ■ By adding element 6 to the right end for ■, and removing element 1 at the left end of ■ for ■, we can move -430 with a pitch of P2-W/2, which is half the element array pinch. This is what I did. This method can achieve twice the density as shown in Figure 1 (al), but even in this case, a scan pitch of less than W/2 cannot be achieved.Also, since the number of drive elements changes for each scan, There is a drawback that the received sound pressure varies from scanning line to scanning line.

OBJECTS OF THE INVENTION The present invention attempts to enable scanning in any pinch, regardless of the element arrangement pinch, by weighting the drive voltage and/or reception gain of each element in a selected element group.

Structure of the Invention The present invention arranges a large number of transmitting/receiving transducer elements,
Selecting a plurality of elements in the array as one group as an aperture surface,
In the scanning line movement method of an ultrasound probe in which the elements in the plane are activated to focus the ultrasound beam to form a scanning line and the selection element is changed to move the scanning line, one ultrasonic probe The shape of the aperture necessary to focus and form the beam and the distribution of the transmission drive sound pressure and/or reception amplification gain within the aperture are set in advance, and the scanning line is virtually moved in a pinch unrelated to the element arrangement pinch. For each scanning line, the transmission drive voltage and/or reception amplification gain of each element existing within the aperture shape is determined according to the set distribution, and the determined value is used to operate. This will be explained in detail with reference to an example.

Embodiment of the invention FIG. 2 is an explanatory diagram showing an embodiment of the invention, in which the solid line curve 4
1 is the ideal intensity distribution of the driving or receiving beam,
To achieve this, each element 1 to 7 has a solid line bar graph 42.
Give the weighting shown by . In this way, it is clear that the transmitted or received ultrasound beam 30 will have the same distribution centered on the element 4 as shown in the figure.If we change the distribution to the zero-order dashed curve 43, the ultrasound beam 30' The center of is moved to the centroid point of the distribution between elements 4 and 5.

This amount of movement can be set at any position between elements 4 and 5 based on the value set by curve 43. The table below shows an example of weighting in which pitch P3 is set to W/3.

Table 1 An easy way to obtain such a table is to first use curve 41 in Figure 2.
, move it along the probe 20 in the desired pinch and read the bar graph 42 at each point of movement. Each end of the bar graph 42 is an indicator of the transmission drive voltage or reception amplification gain of each element in the part covered by the curve 41 (aperture surface) of the probe, but in order to operate the elements at a value proportional to these, reading is required. It is preferable to store each end in a dedicated memory (ROM), read it out, and input it as a coefficient to the drive and amplification circuit for the in-aperture element group.

Distribution curve 41.43 for weighting is glass distribution, COS
If the distribution is a C082 distribution, etc., the beam shape becomes better, but it is not necessarily limited to this.The point is that if the distribution is not uniform, the beam center can be moved to an arbitrary position without the restriction of the element width W.

Furthermore, the number of elements to be selected at once is not limited to the above example.

FIG. 3 shows an example of application to a fan-shaped scanning probe in which the element array is curved in an arcuate manner, where 21 is a front chamber filled with an ultrasonic transmission medium, and 22 is an object to be measured. The example in (a) is a case where the ultrasonic propagation velocity v1 of the medium in the front room is approximately equal to that of the object to be measured 22 v2. At this time, the beam 30 passes approximately through the center 23 of the curvature of the probe 20 and scans inside the object to be measured 22 in a fan shape. Therefore, it is effective when observing the heart through the gap between the ribs. (In the example of bl, the beam 30 is refracted so that v 1 < v 2 (θ2>θ1), and the probe is made smaller in both the width of the element array and the depth of the front chamber.

In this case, even if the element spacing of the probe 20 is uniform and the scanning pinch of the front chamber ultrasound beam is uniform, the scanning pinch in the object to be measured 22 becomes coarser toward the periphery. The density of this scanning pinch can also be corrected. That is, the weighting may be changed so that the scanning pitch in the peripheral area is denser than that in the central area.

FIG. 4 shows a probe in which arc-shaped probes 20 and 20' are disposed in an intersecting manner so that two cross sections can be observed simultaneously, and the present invention can be applied to this probe. The present invention can also be applied to a two-dimensional scanning plane array type probe in which the probe 20 is divided into a matrix as shown in FIG. In this case, the weighting becomes a three-dimensional mountain shape. In this case, in order to obtain the same scanning pinch, the number of divisions can be reduced due to the driving performance of the present invention. For example, if the number of divisions is reduced to 1/2 in both the vertical and horizontal directions, the total number of divisions will be reduced to 1/4, and the manufacturing cost will be reduced. There are advantages such as improved scanning performance due to reduced number of lead wires.

FIG. 6 shows a configuration example of a weighted drive and reception circuit for the vibrator 20. A signal from the timing generation circuit 50 is guided to a drive waveform generation circuit 51, where a drive waveform is generated. This drive waveform is, for example, an impulse or the vibrator 2
These are waves 1 to 3 of the sine wave corresponding to the resonance frequency of 0, etc. Weighting data as shown in Table 1 above is stored in a memory (ROM) 52 as digital values. This memory 5
The weighted data read out from RA 2 is converted into an analog value by a D/A converter 53, and is used by a gain controller 54 to adjust the gains of a receiving amplifier (RA) 55 and a driving amplifier (DA) 56. These amplifiers 55 and 56 are provided for the number of divided elements of the vibrator 20, respectively. 57 is a limiter that prevents excessive voltage from being input to the receiving amplifier 55 during driving, 58 is an adder that combines all the outputs of the receiving amplifier 55, 59 is a rectifier circuit that rectifies the output, and 60 is a cathode ray tube (CR). 'l'). During ultrasonic transmission, some of the multiple elements in the probe 20 are simultaneously selected, the selected elements are sequentially changed, and the drive voltages of the selected elements are changed according to the distribution curve, but these controls can be achieved only by controlling the gain of the amplifier. That is, the gain of the amplifier of the non-selected element may be set to 0, and the gain of the amplifier of the selected element may be set to a value that follows the distribution curve. In this way, parallel scanning, fan-shaped scanning, etc. are performed using the ultrasonic beam as a scanning line, and the reflected waves are the same (although they do not have to be the same) between the probes 2 and 3.
0, the weighting is amplified by the amplifier 55, and the summation is performed.
After rectification, it is displayed on the CRT 60.

In this example, weighting is performed both at the time of transmission (driving) and at the time of reception, but it is effective even if only one of them is used. If only the receiving side is weighted, ultrasonic waves are repeatedly transmitted from the front of the probe, and the reflected waves are scanned and captured on the receiving side, or the transmitting side repeatedly performs coarse scanning at a pitch determined by the element arrangement, and then the receiving side Then, a method such as capturing it with a small pinch may be considered.

Effects of the Invention As described above, according to the present invention, it is possible to obtain a fine scanning pinch that is smaller than the dividing interval of the vibrator, so there is no need to divide the vibrator into small pieces. This not only facilitates the manufacture of the vibrator and greatly improves the cost, but also has the advantage of reducing the number of lead wires and improving operability.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of a conventional linear array type ultrasound probe.
Fig. 2 is an explanatory diagram of the main parts showing one embodiment of the present invention, and Figs.
FIG. 5 is an explanatory diagram of various probes to which the present invention can be applied, and FIG. 6 is a configuration diagram of a vibrator weighting drive and reception circuit according to the present invention. In the figure, 1 to 10 are transmitting/receiving transducer elements, 20 is a probe, 30.30' is an ultrasonic beam, and 41.43 is a distribution curve. Applicant Fujitsu Limited Representative Patent Attorney Minoru Aoyagi

Claims (1)

[Claims] +l) Arranging a large number of transmitting/receiving transducer elements, selecting a plurality of elements in the array as one group to form an aperture plane, and focusing the ultrasonic beam by activating the elements in the linear plane. In an ultrasonic probe scanning line movement method in which a scanning line is formed and a selection element is changed to move the scanning line, the aperture shape necessary to focus and form one ultrasonic beam, and the The distribution of the transmission driving sound pressure and/or reception amplification gain within the aperture plane is set in advance, and the scanning line is virtually moved in a pinch independent of the element arrangement pitch, and each scanning line is moved within the aperture shape. A scanning line movement method for an ultrasonic probe, characterized in that the transmission drive voltage and/or reception amplification gain of each existing element is determined according to the set distribution, and the determined value is used to operate. (2) Scanning line movement of the ultrasound probe according to claim 1, characterized in that a large number of transmitting and receiving transducer elements are arranged in a linear, arcuate, spherical, or planar shape. method.