Medical ultrasound diagnostic instrument: ultrasound is the sound wave that can be heard by the normal human ear, with a frequency of more than 20000 Hz. The most common frequency for medical ultrasound diagnosis is 2 million - 13 million Hz (theoretically, the higher the frequency, the shorter the wavelength, the better the resolution of ultrasound diagnosis). Ultrasound is an examination method that uses the difference between the physical properties of ultrasound and the acoustic properties of human organs and tissues to display and record in the form of waveforms, curves or images for disease diagnosis.

B ultrasound (black and white ultrasound): gray-scale modulation type, reflecting the echo changes with different light points of light and shade, displaying images of 9 to 64 levels of gray on the shadow screen, with bright strong echo light points and dark weak echo light points. The image shows the two-dimensional sectional image of the organ or structure.

Color Doppler ultrasound: Color Doppler ultrasound, based on two-dimensional gray scale, superimposes color blood flow signals. It is mainly aimed at blood flow imaging. It can always observe the dynamic changes of blood flow, and distinguish the direction of blood flow through red and blue colors. It is a more comprehensive examination method. The image can not only display the sectional image of organs or structures, but also observe the blood flow of blood vessels using Doppler principle, such as observing whether the umbilical cord is around the neck of the fetus. Including 3D color Doppler and 4D color Doppler.

Introduction to the principle and probe of medical ultrasonic diagnostic instrument (B-ultrasonic machine)

2、 Ultrasonic equipment composition

Ultrasonic equipment mainly includes three parts: probe, host (digital scanning converter, computer control center, multi-dimensional image processing center) and display.

Ultrasonic probe (ultrasonic transducer): It is the transmitter and receiver of ultrasonic signal. It can not only convert electrical signals into ultrasonic signals, but also convert ultrasonic signals into electrical signals. Its quality and performance will directly affect the performance indicators of the whole system, such as detection depth, resolution and sensitivity.

3、 Ultrasonic diagnostic instrument probe type

1. Convex array: used for abdominal and pelvic organs, with a common frequency of 3.0-6.0MHz;

2. Linear array: used for superficial organs and peripheral blood vessels, with a common frequency of 5.0-12.0MHz;

3. Phased array: used for cardiac and craniocerebral examination, with a common frequency of 2.0-4.0MHz;

4. Intraluminal probe: used for transvaginal, transrectal and transesophageal examination, with a common frequency of 5.0-8.0MHz;

5. Special probe: intraoperative probe, laparoscopic probe.