JPS5934247A - Ultrasonic diagnostic apparatus - 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: a @ Ming's Technical Field The present invention relates to an ultrasonic diagnostic device. b Technology of the W View In an ultrasonic diagnostic device, a single blast of higher frequency ultrasonic waves can cause damage within the body. You can see detailed changes in the organization.

However, ultrasound propagating within the body undergoes attenuation proportional to propagation distance and frequency.

In other words, when fM liver waves travel within the body over long distances, their high frequency components tend to attenuate. By the way, if the high frequency component is attenuated, the center frequency becomes low, and the azimuth resolution deteriorates. At the same time, the frequency band also becomes narrow, and the distance resolution in the depth direction also deteriorates.

C. Prior Art and Problems Therefore, in the past, in order to correct the attenuation of high frequency components of ultrasound, in the receiving circuit, the reflected waves that propagate inside the body and return to the ultrasound diagnostic device are depending on,
A correction filter was applied to force high frequency components. 1st
In the figure, 1 indicates the ultrasonic transducer, 2 indicates the surface of the subject, 3 indicates the reflective surface located at a distance of from the surface 2, and 4 indicates the reflective surface located at a distance of L2 (>Lt) from the surface 2. .

In Fig. 2, ■ is the spectrum of the superfrequency wave sent from the transducer 1, (b) is the spectrum of the reflected wave returning from the reflecting surface 3, (is the spectrum of the reflected wave returning from the reflecting surface 4, shows the spectrum of turbulent noise that has been compensated for by the human power of the receiving circuit.If the spectrum Q1■ of the reflected wave obtained here is applied with an appropriate filter, the spectra ■ and ■ with the high frequency components corrected are obtained. However, in this case, even the mixed noise ■ becomes larger as ■ and ■ due to the correction filter.As a result, the S/N ratio deteriorates and the image becomes unclear. Therefore, in the present invention, when sending ultrasound to a subject,
By adding corrections to the spectrum in advance according to the propagation distance, it is possible to prevent deterioration of azimuth resolution and distance resolution caused by attenuation of high-frequency components, and also to prevent noise from increasing, so the image can be improved without deteriorating the S/N ratio. 1ψ
This is intended to improve the clarity of the above.

θ Constitution of the Invention In an ultrasonic diagnostic apparatus having a transducer that transmits ultrasonic waves to a subject and receives reflected waves of the ultrasonic waves,
It is characterized by adding eight corrections to the transmitted ultrasound spectrum according to the diagnostic depth.

f Embodiment 1 of the Invention Figure 3 shows a transmitting circuit of an ultrasonic diagnostic apparatus which is an embodiment of the present invention, in which 5 is an oscillator, 6.1.8 is a correction oscillator, and 9
1u11-circuit, 10 is a corrector, and 11 is a transducer.

FIG. 4 shows a subject and a transducer f, 1
2 is the surface of the object, 13 is the reflective surface at a distance from the surface 12, 14 is the reflective surface at a distance from the surface 12, and 15 is the reflective surface at a distance from the surface 12. (Lll>L4>1-+s). ■ in Figure 5 is
The spectrum of the difference signal created by the oscillator 5, when added to the beam, the spectrum of the correction signal that corrects the attenuation of the ultrasonic wave propagating up to the reflecting surface 13, and when added to the beam, the spectrum of the correction signal is The spectrum of the correction signal that corrects the attenuation of the ultrasonic wave propagating up to UfJ 14. When added to ■, @ indicates the spectrum of the correction signal that corrects the attenuation of the ultrasonic wave propagating up to the reflecting surface 15. , ■, ■, ■ are generated by correction oscillators 6, F, and 8, respectively.

The control circuit 9's IL is applied to the FW signal (■) generated by the oscillator 5.
By controlling J, the correction signal 0 generated by the correction oscillator 6 is
A corrector 10 adds the signal, and a transducer 11 converts the signal into an ultrasonic wave, which is transmitted from the surface 12 of the subject. Then, it propagates up to the reflecting surface 13, and the transdata
The spectrum of the ultrasonic waves returning to the sensor 11 is hardly affected by attenuation. Also, noise ゛?■''〈2 Himuna like 5.

Similarly, the correction signal ◎, generated by the correction oscillator 7.8,
The ultrasonic waves transmitted by the transducer f11 with the addition of do not have.

In this example, a correction signal corresponding to the diagnosis depth is generated and added using a separate correction oscillator, but a method may also be used in which a fixed correction wave is changed by a filter, and a correction signal is generated and added. do not have.

Furthermore, a method may be used in which the electrical signal generated by the oscillator 5 is changed using a variable filter.

g Effects of the Invention According to the present invention, the attenuation of high frequency components of ultrasonic waves is corrected and 1. By suppressing the noise, the SN ratio increases and a clear image area can be obtained.

[Brief explanation of the drawing]

FIG. 1 shows a transducer and a subject; 1 is the transducer, 2 is the surface of the subject, and 3 is L! from the surface 2!
4 indicates a reflective surface located at a distance of L2 from surface 2. ■ in (a) of Figure 2 is the spectrum of the ultrasonic wave sent from the ultrasonic transducer 1, ■ in (b) is the spectrum of the reflected wave returning from the reflecting surface 3, and ■ is the spectrum of the reflected wave returning from the reflecting surface 4. wave spectrum, 19 is the spectrum of transparent noise converted to the input of the receiving circuit, @ of (C),
(2) shows the ultrasonic spectrum Q1 (2) obtained as in <b) applied with an appropriate filter, and (2) and (2) show the noise (2) applied with the above-mentioned filter. FIG. 3 shows a transmitting circuit of an ultrasonic diagnostic apparatus which is an embodiment of the present invention, in which 5 is an oscillator, 6.7.8 is a correction oscillator, and 9 is an oscillator.
10 represents a control circuit, 10 represents a corrector, and 11 represents a transducer. Figure 4 shows the subject and transdenisa, 1
2 is the surface of the subject, 13 is a reflective surface located at a distance of L8 from the surface 12, 14 is a reflective surface located at a distance of 2 from the surface to L4, and 15 is a reflective surface located at a distance of LI+ from the surface. In Figure 5, ■ is the electric number 8 generated by the oscillator 5, 0 is a correction signal that, when added to ■, corrects the spectrum of the supersonic wave propagating up to the reflecting surface 13, and @ is added to ■, A correction signal that corrects the spectrum of the ultrasonic wave propagating up to the reflecting surface 14, @ is added to ■, a correction signal that corrects the spectrum of the ultrasonic wave propagating up to the reflecting surface 15. Each spectrum is shown. Figure 81 (Ii) cb) Figure 2 (C) Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] In an ultrasonic diagnostic apparatus having a transducer that transmits ultrasonic waves to a subject and receives reflected waves of the ultrasonic waves,
An ultrasonic diagnostic device characterized by adding correction to the spectrum of transmitted ultrasonic waves according to the diagnostic depth.