Ultrasonic diagnostic equipment and ultrasonic image generation method
View Patent ↗The difference frequency component between a first fundamental wave of frequency f and a second fundamental wave of frequency f 2 is caused to interact with a second harmonic wave, thereby to attain the enhancement of a second harmonic signal, etc., whereby a reflected wave component to be imaged is extracted at a high S/N ratio. By way of example, in a case where the difference frequency component is to appear on the lower frequency side of the second harmonic wave of the first fundamental wave so as to be superposed on this second harmonic wave, the frequencies are set at f 2 =2.8 f or so. Besides, in a case where the difference frequency component is to appear on the higher frequency side of the second harmonic wave of the first fundamental wave so as to be superposed on this second harmonic wave, the frequencies are set at f 2 =3.2 f or so.
1. An ultrasonic diagnostic equipment comprising:
a transmission ultrasonic wave generation unit which generates a transmission ultrasonic wave that has, at least, a first frequency component, and a second frequency component at a frequency higher than that of the first frequency component, and which generates the transmission ultrasonic wave by controlling the frequency of at least one of the first and second frequency components so that, in a case of transmitting the transmission ultrasonic wave to a patient and receiving a reflected wave therefrom, a difference frequency component between the first frequency component and the second frequency component as is included in the reflected wave may interact with a second harmonic wave of the first frequency component, and also by controlling a phase difference between the first frequency component and the second frequency component to control the interaction;
a transmission unit which transmits the transmission ultrasonic wave including the first frequency component and the second frequency component to the patient;
a reception unit which receives the reflected wave of the transmission ultrasonic wave from the patient; and
an image generation unit which generates an ultrasonic image on the basis of the reflected wave.
2. An ultrasonic diagnostic equipment as defined in claim 1 ,
wherein said transmission ultrasonic wave generation unit generates the transmission ultrasonic wave by controlling the phase of at least one of the first and second frequency components so that the second harmonic wave and the difference frequency component may become in phase.
3. An ultrasonic diagnostic equipment as defined in claim 2 ,
wherein said transmission ultrasonic wave generation unit:
sets a phase difference of the second frequency component relative to the first frequency component, at π in a case where the first frequency component and the second frequency component are of sine type; and
sets a phase difference of the second frequency component relative to the first frequency component, at 0 or 2π in a case where the first frequency component and the second frequency component are of cosine type.
4. An ultrasonic diagnostic equipment as defined in claim 1 ,
wherein said transmission ultrasonic wave generation unit generates the transmission ultrasonic wave by controlling the phase of at least one of the first and second frequency components so that the second harmonic wave and the difference frequency component may become opposite phases.
5. An ultrasonic diagnostic equipment as defined in claim 4 ,
wherein said transmission ultrasonic wave generation unit:
sets a phase difference of the second frequency component relative to the first frequency component, at 0 or 2π in a case where the first frequency component and the second frequency component are of sine type; and
sets a phase difference of the second frequency component relative to the first frequency component, at π in a case where the first frequency component and the second frequency component are of cosine type.
6. An ultrasonic diagnostic equipment as defined in claim 1 ,
wherein said transmission ultrasonic wave generation unit controls the frequency of the second frequency component to be lower than triple the frequency of the first frequency component, so that the difference frequency component may be superposed on the second harmonic wave on a lower frequency side of the second harmonic wave.
7. An ultrasonic diagnostic equipment as defined in claim 1 ,
wherein said transmission ultrasonic wave generation unit controls the frequency of the second frequency component to be, at least, equal to triple the frequency of the first frequency component, so that the difference frequency component may be superposed on the second harmonic wave on a higher frequency side of the second harmonic wave.
8. An ultrasonic diagnostic equipment as defined in claim 1 ,
wherein said transmission ultrasonic wave generation unit generates the transmission ultrasonic wave by controlling the phase of the second frequency component so that the difference frequency component may be superposed on the second harmonic wave on a lower frequency side and a higher frequency side of the second harmonic wave.
9. An ultrasonic image generation method comprising:
generating a transmission ultrasonic wave that has, at least, a first frequency component, and a second first frequency component, by controlling the frequency of at least one of the first and second frequency components so that, in a case of transmitting the transmission ultrasonic wave to a patient and receiving a reflected wave therefrom, a difference frequency component between the first frequency component and the second frequency component as is included in the reflected wave may interact with a second harmonic wave of the first frequency component, and also by controlling a phase difference between the first frequency component and the second frequency component to control the interaction;
transmitting the transmission ultrasonic wave to the patient;
receiving the reflected wave of the transmission ultrasonic wave from the patient; and
generating an ultrasonic image on the basis of the reflected wave.