Repair and maintenance of medical ultrasound probe
With the wide application of computer technology, the application of ultrasonic probes is also increasingly widespread, and its technical structure is constantly updated. The volume is getting smaller and smaller, and the image clarity is also improving. The ultrasound of medical ultrasound diagnostic equipment is converted into images for clinical diagnosis after computer processing. Ultrasound probe is the most critical component in ultrasonic diagnostic equipment, and it is frequently in direct contact with the subject, so it is more prone to failure. By consulting relevant literature, the causes of common failures that are prone to occur in ultrasonic probes and corresponding maintenance and repairs The measures are summarized below.
1 Classification of Ultrasound Probe Types
According to the diagnosis site, it can be divided into: eye, heart, abdomen, skull, intracavity and children probe, etc.; according to the application method, it can be divided into in vivo, in vitro, needle biopsy probe, etc.; according to the number of vibration elements used in the transducer in the probe Divided into unit probe and multi-element probe; according to the beam control method, it can be divided into line scan probe, phased array probe, mechanical fan scan probe and volume (square array) probe, etc. Usually, the commonly used classifications are rectangular probes, cylindrical probes, arc probes, circular probes, etc. The main structure of the probe is composed of surface acoustic lens, matching layer, wafer, sound absorption block and support frame.
2 Types and causes of common probe failures
2.1 Appearance failure of the probe
Usually the faults with poor appearance are more intuitive, generally the acoustic lens of the probe surface is aging or worn. If the surface acoustic lens is damaged, cracked, blistered, degummed, and air enters the interior, it needs to be pressed hard to get an image during use.
During the use and maintenance of the probe, improper use, such as strong impact and use of unqualified couplant, will cause probe leakage, signal attenuation, image loss or image interference, and there is a risk of scratching the patient's skin. If an unqualified couplant is used or the probe is improperly maintained, exposed to direct sunlight for a long time, the ambient temperature difference is large, and the couplant is corroded for a long time, the surface of the probe will be aged and the appearance will be seriously damaged.
If the acoustic lens and the matching layer are degummed or foamed, 704 liquid silicone rubber can be injected into the degummed area to drive out the air bubbles, and the probe can be tightly tied with gauze tape and placed for 24 hours, and then loosened. The fault disappears and the probe returns to normal. This failure is therefore caused by debonding between the acoustic lens layer and the matching layer. When dealing with this kind of failure, liquid silicone rubber is used as the repair material for the acoustic lens of the probe and the bonding material between the acoustic lens layer and the matching layer.
2.2 There are black shadows in the imaging display area
If there is a black shadow or image defect in the imaging display area, there is no obvious damage to the acoustic lens on the surface of the probe, and another possibility for such a failure is that the probe's crystal is aging and short-circuited.
Most of the B-ultrasound probes use piezoelectric crystals. Long-term use will cause natural aging of the crystals. Irregular use or external forces such as falls and bumps will cause damage to the probe crystals. The images detected by the B-ultrasound detector after the crystal is damaged. There will be signal attenuation, black shadows, black bars, interference, defects and other blind spots in the image. In severe cases, the image will be "blind", affecting the quality of diagnosis.
The short circuit of the chip can be judged by measuring the power supply voltage of the chip. If the power supply voltage of a chip or chip group is lower than the other, it can be judged that there is a short circuit in the chip or chip group. Replace the corresponding element, so that the probe returns to its previous characteristics and the interference disappears.
2.3 Maintenance overhaul of damaged probe sheath, casing and circuit board
The B-ultrasound probe sheath is a rubber sleeve that reinforces the connection between the B-ultrasound probe and the cable. The important function of the B-ultrasound probe sheath is to prevent the cable from being bent at right angles. Prolonged use can cause the sheath to break, fall off and be missing, which can lead to probe failure.
3 Care and maintenance of the ultrasound probe
3.1 Handle with care
The ultrasonic probe must be handled with care during use to avoid damage to the chip inside the probe caused by impact. When the probe is used, the probe connecting wire is not folded or tangled.
3.2 Probe plugging and unplugging
In the daily application of the ultrasonic probe, to replace the ultrasonic probe, be sure to turn off the power of the host. If the host does not freeze without power failure, plug and unplug the probe directly, the circuit board and crystal inside the probe may be damaged due to the instantaneous strong current. At the same time, it will accelerate the oxidation of the probe plug pins, which directly affects the normal use of the probe.
3.3 Probe cleaning and disinfection
Avoid contact between the probe socket and the disinfectant. If the probe socket is contaminated with cleaning agents and disinfectants, it will directly corrode and accelerate the oxidation of the probe socket pins. In short, in the actual maintenance process of medical equipment, maintenance and maintenance of ultrasonic probes are both important tasks, because the effective accuracy of ultrasonic probes directly affects the efficiency of ultrasonic inspection. Daily maintenance should be followed up regularly to reduce damage caused by human factors and prolong the service life of the ultrasonic probe.
