JPS6252572B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic diagnostic device that emits ultrasonic pulses into a living body and obtains information about the inside of the living body from reflected waves, and particularly for water immersion ultrasound diagnostics used for mass breast cancer screening. Regarding equipment.

Ultrasonic diagnostic equipment for breast cancer screening generally uses a water immersion method because the shape of the breast is complex and uneven, and arc scanning or linear scanning is used for the movement of the transducer. The distance from the transducer to the body surface on which the ultrasonic waves are incident largely depends on the body shape of the subject. Therefore, when improving resolution, the width of the ultrasonic beam emitted from the transducer is
It is required to be thin from the vicinity of the transducer to a sufficiently far distance. However, if you try to narrow the beam width at short distances, it will become wider at long distances, and at long distances the beam width will widen in proportion to the distance.
It is difficult to obtain a uniformly narrow beam width. Furthermore, in electronic scanning ultrasonic diagnostic equipment that has developed significantly in recent years, techniques such as electronic focusing, variable focus, and variable aperture are known for the purpose of narrowing the beam width. However, even with these techniques, it is difficult to uniformly narrow the beam width over a wide range.

The present invention has been made in view of these points, and an object of the present invention is to provide an apparatus that maintains a constant distance between a transducer and a living body and uses a narrow range of ultrasonic beams.

This invention uses means for measuring the distance from the time when an ultrasound pulse is emitted to the time when the first signal is received, and controlling the distance between the transducer and the living body.

An embodiment of the present invention will be described with reference to FIG.
The ultrasonic transducer 2 is transmitted by the wave transmitter/receiver 1.
Ultrasonic pulses are emitted from the living body 3 and the reflected waves are received by the same transducer 2. The received signal is input to the position control circuit 4, and its output drives the motor 5 to adjust the distance between the ultrasonic transducer 2 and the living body 3 to l. The transducer 2 is moved laterally along the guide 6 at a constant speed while adjusting the distance one after another. For example, even when the transducer 2' is located, the distance between the transducer and the living body is maintained at l. In addition, container 7
contains a liquid 8 having a suitable acoustic impedance.

When the aperture of the ultrasonic transducer used here is D, the wavelength of the ultrasonic wave is λ, and the distance between the transducer and the focal point is F, the beam is focused so that D ₂ /4λ/F=1. FIG. 2 shows a schematic diagram of the ultrasonic beam width when With this ultrasonic beam width, by always using the range where the ultrasonic beam width is equal to the next from a distance l from the transducer, that is, the range surrounded by diagonal lines, images with good directional resolution can be obtained. will be obtained.

The output of the control circuit 4 shown in FIG. 1 may be obtained by processing the received signal as shown in FIG. 3, for example. First, the received signal a is cut out at a certain level, and pulses b and c are
, and performs integration with the pulse d of that pulse interval to create a signal like e. Next, the peak value of the integral waveform e is passed through a comparator, and the output thereof is used to drive the motor shown in FIG. These processes can be accomplished using conventional circuit techniques.

According to the present invention, a narrow range of ultrasonic beam width can be effectively used with a relatively simple circuit, and an image with good resolution can be easily obtained.

Although the case in which one transducer is used has been described in FIG. 1, a plurality of electronic scanning type transducers may be used. With electronic scanning probes, it is possible to narrow the ultrasonic beam width in the direction of the transducer row using techniques such as the electronic focusing method, moving focus method, and variable aperture described above, but the width is perpendicular to the transducer row. In this direction, the focus is fixed by a lens or the like, so the method described in this invention is particularly effective.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of one embodiment of the present invention, Fig. 2 is a diagram showing the thickness of the ultrasonic beam, and Fig. 3 is a diagram showing the thickness of the ultrasonic beam.
FIG. 2 is an explanatory diagram of signal processing of the circuit shown in the figure. DESCRIPTION OF SYMBOLS 1... Wave transmitting/receiving device, 2... Ultrasonic transducer, 3... Human body (living body), 4... Position control circuit, 5... Motor, 8... Liquid.

Claims (1)

[Claims] 1. An ultrasonic transducer that transmits ultrasonic pulses into a living body via a liquid and receives reflected waves from the living body; A wave transmitting/receiving device that transmits pulses and processes reflected signals obtained by the transducer to obtain an ultrasonic cross-sectional image; a conveyance means for moving the transducer at a predetermined speed along a predetermined guide; and the conveyance means a detection means for detecting the distance between the transducer and the living body surface; and a distance between the transducer and the living body surface becomes a constant distance according to the distance detected by the detection means. An ultrasonic diagnostic apparatus for multiple breast cancer examinations, comprising: position control means for controlling the position of the transducer. 2. The detection means detects the distance between the transducer and the biological surface from the reflected signal of the ultrasonic pulse transmitted from the ultrasonic transducer. Ultrasound diagnostic equipment for breast cancer screening.