Why does the ultrasound probe show signal attenuation after prolonged use?

The ultrasound transducer is one of the key components of the ultrasound instrument, and its performance directly affects the image quality. Many clinicians complain that some Brands of ultrasound will experience a decline in image quality, blurring, or even shadows after a period of use. This situation is mostly caused by the signal attenuation of the ultrasound transducer. Today, let's uncover the truth about transducer signal attenuation.

The performance of the ultrasound transducer is affected not only by the materials used (number of array elements, material quality), but also to a large extent by the manufacturing process.

Ultrasound transducers are typically composed of the following parts:

Matching layer:In order to achieve acoustic matching between the human body and the piezoelectric element, one or more impedance matching layers are often used in front of the piezoelectric element to improve the performance of the transducer.

Transducer:The functional component of the ultrasound probe, which has the function of transmitting and receiving ultrasonic wave information, and can perform energy conversion.

Backing material: Reduce vibrations from the chip, shorten the wavelength, and improve axial resolution.

Cable:Its thickness and flexibility are important, mainly for interconnection, the end is a connector, and the reliability of the connector is crucial to the whole machine.

In order to effectively focus the ultrasonic beam, an acoustic lens is often added in front of the impedance matching layer to achieve beam convergence.

Several attributes to measure whether a probe is of high quality: bandwidth, sensitivity, and resolution.

Bandwidth:That is, the range affected by the operating frequency of the transducer.

Sensitivity:It is mainly related to the acoustic characteristics such as the transduction characteristics and radiation efficiency of the transducer in the probe. Transducers with good transduction characteristics and high radiation efficiency have high detection sensitivity.

Resolution: Depends on the radiation characteristics of the transducer in the probe. If the radiation characteristics are good, the acoustic beam cross-sectional Size is small, the divergence angle is small, and the lateral resolution is high. If the transducer has a good frequency response, the distance resolution is high. At the same time, the quality of the interlayer matching of the transducer directly affects the resolution.

At present, piezoelectric ceramic materials are almost universally used in medical ultrasound transducers because of their high electro-acoustic conversion efficiency, easy matching with circuits, stable material properties, strong machinability, moisture resistance, and high mechanical strength. However, there are also shortcomings. The physical properties of ceramics are greatly affected by temperature. Once the temperature exceeds the Curie point, its piezoelectric efficiency will be damaged.

Ultrasound probe signal attenuation is manifested as: reduced sensitivity, reduced resolution, and reduced clarity. The main reasons are: the piezoelectric performance of the probe's piezoelectric ceramics gradually degrades over time, resulting in weakened transmission and reception capabilities, reduced sensitivity, and reduced bandwidth; the acoustic lens material ages, and the contact with the matching layer weakens, leading to reduced sensitivity.

This information comes from the Internet. Please contact us for deletion if there is any infringement.