Please Leave Us A Message
Privacy statement: Your privacy is very important to Us. Our company promises not to disclose your personal information to any external company with out your explicit permission.
More than 40 years ago, the Institute of Acoustics of the Chinese Academy of Sciences (hereinafter referred to as the Institute of Acoustics) medical ultrasound research team, anxious to the country's urgency, thinking of the people's thoughts, in the face of China's health care industry on the strong demand for ultrasound instrument, resolutely put forward the development of home-made ultrasound instrument. In the case of backward material conditions, lack of experimental resources, they brainstormed, overcome the difficulties, and ultimately succeeded in making a key step from scratch in the domestic ultrasound instrument, laying the foundation for mass production of ultrasound instrument and research and development of medical imaging equipment.
Nowadays, the medical ultrasound research team of the Institute of Acoustics has carried out a lot of research and development work in ultrasound imaging, focused ultrasound, energy surgery, etc., and a number of research results have been industrialised and applied, which has made an important contribution to the protection of people's lives and health.
1 First look: we should be able to do
"Go to the Jin Jiang Hotel tomorrow! There are the latest ultrasound machines there." One day in 1979, Zhou Yongchang, then head of the ultrasound department at the Shanghai Sixth People's Hospital, told Shen Zhihua, an associate researcher at the Shanghai-based Donghai Research Station of the Institute of Acoustics (hereafter referred to as the Donghai Station).
When he arrived at the site, Shen Zhihua saw that a B-type ultrasound real-time image diagnostic instrument exhibition was being held here. B-type ultrasound instrument from Japan, similar in size to an ordinary oscilloscope attracted people's attention. Just see the operator holding a flat type, about the palm width of the probe in the subject's abdomen sliding, a small rectangular display screen then appeared a dynamic black and white images, showing the liver, gallbladder, kidney form. Seeing this, we can not help but praise.
At that time, most hospitals in China were only equipped with A-type, M-type Ultrasound Diagnostic Equipment, which could only display one-dimensional waveforms, and the doctors judged the size of the organs and analysed the state of the disease according to the waveform information and experience. Only a few hospitals have imported B ultrasound instrument, which can visually display the internal tissue section of the human body, assisting doctors to find and diagnose lesions.
For the application of ultrasound instrument prospects, many domestic diagnostic ultrasound experts believe that China as a populous country, the development of medical and health care industry and the development of people's health needs a large number of ultrasound instrument, but at that time, the price of the latest imported desktop ultrasound instrument in the 300,000 yuan, China's foreign exchange is limited, it is difficult to bear the cost of importing a large number of equipment. Therefore, the experts called for the domestic development and production of ultrasound machines.
The vast majority of people present, including Shen Zhihua, were seeing for the first time an ultrasound instrument capable of visually displaying images of the body's internal tissues.
"How about it? Can we do it? If we do it, it will be a great achievement." Zhou Yongchang asked.
"Although it hasn't been done before, I think it should be possible." Shen Zhihua replied.
Shen Zhihua's confidence stemmed from his many years of experience in sonar technology research. Prior to this, a group of researchers from the East Sea Station had been dedicated to sonar technology research, and had successfully developed a series of fishing sonars, accumulating a certain amount of research experience and foundation.
"We feel that the ultrasound instrument is also a kind of sonar system, which has many similarities with the previously developed instruments. Moreover, ultrasound diagnostic technology is urgently needed by the country and desired by the people, so we researchers should do our part for the country and the people." Shen Zhihua recalled.
"The idea of developing an ultrasound instrument was supported by Zhu Xi, the then station chief of Donghai Station, and Xiang Dawei, the director of the Signal Detection Research Department. Immediately, the East China Sea Station allocated scientific research strength, laboratory equipment, set up a high-resolution sonar group of eight people, Shen Zhihua as team leader, senior engineer Zhu Ruliang as deputy leader.
2 Tackling: the probe is the core
In August 1979, the development of "B-type linear electronic scanning diagnostic system" was officially launched.
In the first eight months, the group extensively reviewed relevant literature and information at home and abroad, participated in various ultrasound conferences, visited foreign imports of ultrasound diagnostic instruments, listen to the views and suggestions of ultrasound diagnostic experts. After completing a series of research studies, the group designed the relevant development programmes for electronic circuits, probes and theoretical calculations.
For medical ultrasound instruments, the probe bears the function of transmitting and receiving ultrasound waves, the importance of which is like the "heart" of the human body. Ultrasound examination, the probe to the human body to launch a set of ultrasound beams, when the ultrasound beams reach the boundary of the tissue or organ, due to the human body blood, muscle and other different tissues between the acoustic characteristics of the impedance of the difference, part of the ultrasound waves were reflected back and was the probe in the signal receiving system to capture. The ultrasound instrument converts the time and amplitude of the received reflected waves into different depth and brightness information, and finally presents a grey-scale ultrasound image of a structure in the human body on the monitor.
The core component of the probe is the crystal sheet. When a voltage is applied to the crystal, it vibrates in response to the electrical signal, thus emitting ultrasound waves. type A ultrasound imaging requires only one set of crystals, which emits a beam of ultrasound, and therefore can only display echo time and amplitude. Ultrasound, on the other hand, is able to display a two-dimensional image, relying on an array of many crystal sheets arranged in sequence, with a single set of crystal sheets in the array known as an array element.
"The most advanced in the world at the time was a 64-array ultrasound instrument made by a Japanese manufacturer. We thought, since we are going to do it, let's do it with 64 array elements. The higher the number of array elements, the higher the diagnostic resolution." Zhu Ruliang said, "But the higher the number of array elements, the more difficult it is. Previously, Shanghai and Wuhan have research institutes tried to develop 18-array and 32-array ultrasound instrument, but the progress is slow."
The primary difficulty is material processing. In order to ensure the probe performance, the need for crystal sheet processing, grinding, 64 groups of crystals to be as small as possible between the spacing between the sheet, the requirements of the silk (1 silk is equal to 0.01 mm) level, but at that time there was no related precision machining equipment.
"If there are no conditions, we have to do it even if we create the conditions!" Shen Zhihua said, "The imported slicing machine is expensive, we can not afford to buy, so we went to the previously cooperated grinding wheel blade factory, requesting them to do the thinnest grinding wheel blades to us. The factory hadn't done it either, but made attempts over and over again at our pleading."
After getting the grinding wheel blades, with the help of an eighth-grade turner, Master Chen, at the Donghai station, the group eventually built a slicer capable of cutting concave crystal slices with an accuracy of a few filaments at intervals. Although the initial yield was low, after many improvements, the final result basically met the requirements.
Although the crystal slice problem was solved, the sensitivity of the probe was still low, which gave Zhu Ruliang and others a big headache. "At that time, I would like to buy imported probes disassembled to see, but a probe is 40,000 yuan. We can only go through the patent, check the literature, a little deduce the reason. At that time almost every day until 11 or 12 o'clock at night, but no one complained of suffering." Zhu Ruliang said.
After a series of investigation, Zhu Ruliang and others will be the cause locked in the "matching layer". Due to the crystal chip acoustic characteristic impedance is much higher than the human body tissue, most of the acoustic energy in the two contact interface is reflected back to the probe, can not enter the human body tissue, so the need to increase the matching layer in the front of the probe, in order to flexibly adjust the acoustic characteristic impedance difference between the crystal chip and the human body tissue, to ensure the effective propagation of sound waves.
"The matching layer requires a variety of materials mixed in proportion, we tried a variety of materials and proportions, such as epoxy resin, pct powder, lead glass powder, etc., added two layers of matching layer, only to make the probe sensitivity significantly improved." Zhu Ruliang said.
3 Birth: "Snowflakes" into images
On the 5th floor of the research building at No. 456 Xiaomuqiao Road in Shanghai, Zhu Ruliang was working with his assistant on the development of probes in a laboratory next to the stairway. Whenever a component is improved or improved performance, he will always be excited to take it to the end of the corridor to run to the room, and Shen Zhihua and others to develop the electronic circuit system and signal processing system integration debugging.
But the results of debugging are often disappointing, sometimes there are streaks on the display, sometimes full of snow, sometimes a cloud of fog, just no image of the organs.
"Although there is no project deadline, but the domestic hospitals on the ultrasound instrument demand is increasing day by day, the medical staff every day look forward to the immediate use of domestic ultrasound instrument, we do not dare to relax in the slightest." Shen Zhihua said.
After careful investigation, the group found that although the increase in the matching layer improved the sensitivity of the probe, it also brought a new problem - the pulse signal deterioration. They consulted the literature and learnt that one hair moves the whole body, and the series of parameters before and after the cutting of crystals and matching layers need to be strictly calculated, and the change of one parameter often affects the overall performance of the instrument.
"Due to the lack of test equipment, and the lack of parameters available for theoretical calculations, we can only test over and over again, in the test to summarise the pattern of change of parameters before and after cutting, and ultimately find a balance between different parameters." Zhu Ruliang said.
Time came to a day in October 1980, the group again improved the circuit system and calculation methods, and then get together to start debugging. Shen Zhihua took the probe and rolled it back and forth on his abdomen, adjusting the angle position, and suddenly an oval-shaped dark shadow appeared on the grey monitor, its boundary visible to the naked eye.
"Is it a success?" Someone shouted. Then, everyone excitedly tested it one by one. After confirming the results, Shen Zhihua and Zhu Ruliang all took a long breath, and a smile finally appeared on their faces.
Immediately, Shen Zhihua called Zhou Yongchang and asked him to come to the site to test. Subsequently, the group invited experts from a number of hospitals in Shanghai to the laboratory to guide the trial and repeatedly sought advice on improvements.
"At that time, in order to improve the performance, set the ultrasonic sound intensity is very high, and later learnt that this will cause cellular level damage to the human body. But at that time, where to care so much, we repeated the test on their own bodies countless times." Shen Zhihua said.
A hitch was that the ultrasound test revealed the presence of stones in Zhu Ruliang's gallbladder, and the gallbladder of Chen, the master who helped build the slicer, was enlarged. Shen Zhihua advised them to seek medical attention as soon as possible. Later, Zhu Ruliang had gallstone surgery and recovered quickly, while Master Chen didn't take it seriously and died five years later due to gallbladder disease. Shen Zhihua always felt sorry when he mentioned this.
After three months of testing, in January 1981, the prototype assembly was completed, China's first domestic medical ultrasound instrument - STS-1 line array ultrasound diagnostic instrument was born!
4 Upgrade: Doppler ultrasound is also done!
In order to test the performance of the instrument, the group sent the prototype to the Sixth People's Hospital of Shanghai, Zhongshan Hospital of the First Medical College of Shanghai (now Zhongshan Hospital of Fudan University), and Tumour Hospital of Fudan University to carry out clinical diagnostic tests in the following nearly half a year.
During this period, ultrasound doctors completed 362 cases of various diseases of clinical diagnosis, and resolution measurement and distortion level test, detected less than 2 cm in diameter of liver cancer and 1 cm in diameter of gallbladder stones, Zhongshan Hospital, and even by virtue of its completion of ultrasound-guided amniocentesis test.
The first domestic medical ultrasound instrument was put on clinical trial.
Improved according to clinical diagnosis, the ultrasound instrument has a longitudinal resolution of less than 2 mm, a transverse resolution of less than 3 mm, a 10-step grey scale displaying brightness information, and an electronic ruler measuring distance ranging from 200 to 300 mm.
"There was still a gap between the ultrasound instrument we made and the latest international models at that time, but it was not easy to make an instrument that was unanimously recognised by the ultrasound medical community at that time when there was a lack of precision machining equipment and backwardness in all conditions." Zhu Ruliang confessed.
From 14 to 16 July 1981, the Chinese Academy of Sciences organised the STS-1 line array ultrasound diagnostic instrument results appraisal meeting. Appraisal by experts, the ultrasound instrument all use domestic components, the resolution of up to 2 mm, high sensitivity, can show the upper abdominal deep large blood vessels and intrahepatic blood vessels and their branches or belonging to the branch; near the field of the small spots less, the anterior wall of the gallbladder border is clear and neat.
The appraisal team believes that the ultrasound instrument shows the image quality of the best domestic products of the same kind, and can be comparable with Japan's 1979 product Aloka SSD-202D instrument, and unanimously concluded that the prototype meets the requirements for appraisal of scientific research results.
Later, the group produced 7 sets of ultrasound machines by themselves, 1 set for Donghai Station and 1 set for the Beijing Headquarters of the Institute of Acoustics, and the rest were sold at the price of RMB 40,000 per set. They also transferred the scientific research results to two instrument factories in Shantou and Shanghai, which produced more than 100 units one after another, creating an output value of more than 4 million yuan.
In 1985, STS-1 Line Array Ultrasound Diagnostic Instrument was awarded the Third Prize of National Science and Technology Progress Award. The group used the prize money and the surplus funds from the transformation of achievements for further research and development of products and improvement of scientific research conditions.
In 1985, the first domestic medical ultrasound instrument won the Third Prize of National Science and Technology Progress Award.
In 1986, after nearly three years of research and testing, on the basis of STS-1 line array ultrasound diagnostic instrument, Shen Zhihua and others developed the second generation of ultrasound instrument - STS-2D line array ultrasound diagnostic instrument with digital scanning conversion, which added digital image storage and playback functions.
"After the Spring Festival in 1986, the relevant leaders of the hospital called to invite me to Beijing to discuss the joint development of diagnostic ultrasound instrument in the United States. Later, after another detailed discussion, we decided to go to the United States in December of that year." Shen Zhihua said.
Originally, at the beginning of that year, the Chinese Academy of Sciences belonging to the Chinese Science and Health Sciences Co., Ltd. and the United States Analogic Corporation jointly established a Sino-US joint venture company - Shenzhen Anke High-Tech Co., Ltd. to engage in the development of large-scale medical imaging equipment, production and operation, to support the domestic researchers to go Analogic Ltd. to engage in the development, production and operation of large-scale medical imaging equipment products, and support domestic researchers to go to Analogic to learn the research and development of medical imaging instruments.
At the end of the same year, Shen Zhihua, Zhu Ruliang and others rushed to the United States. "We initially developed a black-and-white phased-array ultrasound diagnostic instrument that was not yet available in China, and then developed a core prototype of a colour Doppler phased diagnostic instrument on this basis after our success." Shen said, "It was not until 1988 that all of our researchers returned to China and continued to work on the production of the colour ultrasound instrument."
5 Continuing: Medical Ultrasound Blossoms in Many Directions
In 1985, when researchers at Donghai Station were working hard to develop the second generation of domestic medical ultrasound instruments, more than a thousand kilometres away from Beijing, in the laboratory on the ground floor of the Dayou Building of the Institute of Acoustics, researcher Niu Fengqi and others were celebrating the establishment of the project of a related topic - the simulation module (ultrasound body model) for ultrasound instrument calibration and testing.
In 1994, after nine years of technical research, Niu Fengqi and others finally developed agar and synthetic gel-type ultrasound imitation of human tissue materials, and as the core, successfully developed B ultrasound and A, M ultrasound instrument calibration test with national standards of the simulation module, able to achieve the quality of ultrasound instruments, the performance of the scientific test.
"Ultrasound body model as one of the key equipment for ultrasound instrument calibration test and quality inspection, to ensure the quality of the national annual production of tens of thousands of ultrasound products and hospitals nearly 200,000 in use ultrasound instrument effective response to diagnosis, for the country to save a lot of foreign exchange." Niu Fengqi introduction.
The State Bureau of Technical Supervision held the results of the appraisal meeting concluded that the ultrasound body mould in terms of performance and service life have reached the international advanced level, after five years of promotion and application, has covered the country's 29 provinces (autonomous regions and municipalities directly under the Central Government), has produced significant economic and social benefits.
Now, the Institute of Acoustics senior engineer Zhu Chengzang took over the baton of Niu Fengqi, continue to carry out medical ultrasound instrument calibration test technology and equipment research work. Currently, the scope of their research has been expanded to include Doppler body models and blood flow control systems, ultrasound elasticity tissue models, and fetal ultrasound simulation models.
Also in the Dayou Building of the Institute of Acoustics, researcher Weijun Lin and others are continuing their scientific research and development of medical ultrasound. The high-resolution ultrasound CT prototype they are developing uses a 512-array ring transducer with a full-waveform inverse imaging algorithm, which can be used for the diagnosis of diseases in the limbs, breast and other areas.
"We have adopted a new array design and imaging algorithm, hoping to make a standard imaging device that does not rely on doctors' experience, so that ultrasound resolution can be as high as X-CT and MRI." Lin Weijun said.
Lin Weijun said, "At present, there is no international moulded similar product, and research teams from various countries are competing fiercely. After years of research accumulation, we have moved from following to parallel running stage, and look forward to leading in the future!"
LET'S GET IN TOUCH
Privacy statement: Your privacy is very important to Us. Our company promises not to disclose your personal information to any external company with out your explicit permission.
Fill in more information so that we can get in touch with you faster
Privacy statement: Your privacy is very important to Us. Our company promises not to disclose your personal information to any external company with out your explicit permission.