With the development of society, the color doppler digital ultrasonic machine with its easy operation, non-invasive, rapid imaging, economic and other characteristics, the clinical use of medical machines at all levels for an increasingly long time, and in the clinical diagnosis of the role played more and more important, is widely used in the abdomen, gynaecology, obstetrics, heart, small organs, peripheral vascular and prostate and another different clinical diagnosis. However, due to the high sensitivity of the ultrasound probe and the whole machine's wide passband and high gain characteristics, some interference failure phenomena come along. Therefore, it is necessary to master the analysis and troubleshooting of interference in color doppler digital ultrasonic machine, which will be analyzed in detail with several examples.

1. color doppler digital ultrasonic machine began to appear as intermittent strips of interference lines. After one week of observation, the interference continues to appear.

(1) Firstly, we investigated whether there was any problem with the probe. Through communication with the clinician, it was found that the color doppler digital ultrasonic machine only showed interference under the C5-1 probe, and the images showed normal under the superficial probe and the cardiac probe.

(2) We took another C5-1 probe for a replacement test, and the image was normal.

(3) Replace the C5-1 probe with a new one, and the image returned to normal. Ultrasound probes with high sensitivity make it easy to accept the electromagnetic wave from the outside, so the phenomenon of interference; in addition, its acoustic lens, chip, internal wiring and other failures also easily cause interference.

2. color doppler digital ultrasonic machine images frequently appear streak interference phenomenon in two-dimensional mode, and color mode is present.

(1) Any switching of the abdominal probe, cardiac probe and superficial probe, the interference phenomenon will appear, excluding the probe problem.

(2) Confirm that the color doppler digital ultrasonic machine is connected to a separate ground, detecting zero ground voltage of 1.1V (less than 2V), excluding the ground problem.

(3) Measure the AC input 221V to see if it is within the normal range.

(4) Confirm that there is no large medical equipment on the upper and lower floors.

(5) gradually turn off other electronic equipment in the room (fluorescent lights, air conditioning, printers, desk lamps, card readers, workstation computer host, etc.), found that the computer host stopped working, and the interference disappeared. The image was normal after the workstation was switched to the next room. So far, it has been judged that the workstation computer host interference was caused by an in-depth investigation, which found that the original workstation computer and ultrasound instruments connected to the same plug row, suspected that the workstation computer power supply generated electromagnetic interference into the grid, and then caused interference to the ultrasound instrument.

When it is suspected that the external equipment through electromagnetic radiation causes interference to the equipment, we need to patiently check one by one because of the need to exclude more equipment. To block the introduction of interfering electromagnetic waves from the power supply line as much as possible, the clinical department was equipped with a special AC voltage regulator so that the electromagnetic wave interference introduced from the power supply network was greatly suppressed and attenuated the problem was completely solved.

3. The color doppler digital ultrasonic machine worked normally every time it was turned on, but intermittent white dot interference began to appear on the image after about 40 min of use.

(1) gradually rule out probe problems, ground problems, other electronic equipment in the same room and other problems.

(2) The machine was moved to other rooms at a distance, and the interference still existed.

(3) began to focus on the machine itself because the interference always appears after some time after the power is on, considering whether the internal electronic components of the machine are caused by poor thermal stability. Dismantled the front and rear end and found that the machine is very dusty inside, dust removal after the boot, the fault still exists.

(4) sequentially adjust the front-end control board, high voltage board, channel board, etc., found the problem in one of the channel boards. Replace the channel board. Back to normal.

Color doppler digital ultrasonic machine circuit board integration is gradually increasing, and the structure is becoming more closely, the front-end module in particular, the space is increasingly closed, and the machine is not well-ventilated. With ultrasonic instruments' operation, the chassis' internal temperature continues to be too high, thus accelerating the ageing of electronic components. Therefore, it is necessary to carry out regular maintenance and dust removal for ultrasonic instruments to avoid damage to the circuit board due to continuous high temperatures, which will lead to higher maintenance costs.

4. Summary.

Interference failure, especially the intermittent failure phenomenon, is usually more difficult to deal with the problems of medical industry colleagues. You need to follow the principle of easy to difficult, make full use of tools, close communication with clinicians, and use the exclusion method to gradually identify the source of interference. The process of troubleshooting has the following general steps.

(1) check the probe. If all the probes appear to malfunction phenomenon, exclude the probe, and vice versa, consider the probe problem.

(2) Examine the power supply and ground, measuring the relevant voltage and other parameters to meet the requirements.

(3) check the external space interference by sequentially shutting down the indoor electronic equipment and moving the machine to other rooms and other means to determine the source of interference.

Through the analysis and processing of such interference faults, the principle and characteristics of ultrasonic instruments have been further understood to accumulate experience for future maintenance work. If you need more detailed information, welcome to contact us!