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As for the general public's understanding of hospital inspection instruments and equipment, besides ECG and X-ray, the most familiar is B-ultrasound. Since 1980s, the application of ultrasonic imaging diagnosis technology in obstetrics has been expanded unprecedentedly, which is of great significance for evaluating whether the fetal structure is abnormal, multiple pregnancies, fetal size and pregnancy cycle. Obstetric B-ultrasound is famous for its three advantages: painless, non-invasive and rapid. According to the data, in countries and regions with rapid development of medical technology, more than 90% of pregnant women receive ultrasound examination more than once during pregnancy, even reaching 100%. However, the safety of obstetric B-ultrasound has been questioned recently, and some medical experts even suggested that B-ultrasound should be prohibited within three months of pregnancy. This is a serious medical topic. So, what does Professor Kong Qiuying think of this problem?
Thinking is as agile as action. Professor Kong devoted himself to research, worked hard in the fields of B-ultrasound diagnosis, clinic and experiment in obstetrics, received tens of thousands of pregnant women and enthusiastically accepted interviews. Professor Kong said briefly: "Ultrasonic wave is a kind of non-ionizing radiation, it is a physical factor and an energy, so there is a problem of safe dose. At present, there are diagnostic ultrasound and therapeutic ultrasound. The power of the former is lower than that of the latter 100 ~ 1000 times. Whether B-ultrasound is harmful to human body or fetus depends on the dose of ultrasound, which is also called threshold safe dose. That is to say, when the dosage of B-ultrasound used in obstetrics is less than this value, it is harmless, otherwise, it may have harmful effects or injuries. As far as dosage is concerned, therapeutic ultrasound has certain damage or influence on human body, while diagnostic ultrasound, under the operation of doctors or technicians who have undergone strict professional training in regular hospitals, the power of ultrasonic instruments is less than 10 MW/cm2, which will not cause damage to human body or fetus. "
Professor Kong took a deep breath and continued: "The dose of ultrasonic wave is not only related to the power of the instrument, but also related to the radiation time. It has been suggested that it is forbidden to do B-ultrasound in the third month of pregnancy. I think the word' ban' is too absolute. If clinical diagnosis is needed, B-ultrasound can still be done, otherwise the diagnosis will be delayed and measures will not be taken in time for the problematic fetus, and the consequences will be unimaginable. " For example, Professor Kong said that there was a woman who was pregnant for more than three months and had been bleeding for more than 20 days. The doctor arranged a B-ultrasound examination to determine whether the fetus was alive. However, when she saw that B-ultrasound was forbidden in the newspaper, she refused to check and continued to "protect the fetus". Finally, because the fetus died in the uterus for a long time, there was a coagulation mechanism disorder, which led to massive bleeding during curettage. This heavy lesson is worth pondering. Strictly control the examination time. After nearly 20 years of exploration in the academic field of B-ultrasound, Professor Kong, who picked up the probe with ease, went on to explain: "The safety of ultrasonic diagnosis is indeed the frontier basic research topic of ultrasonic medicine, which is related to the correct use and promotion of ultrasonic image diagnosis in obstetrics and gynecology, and to prenatal and postnatal care. Ultrasound is widely used in medicine, and it is unique to provide information for clinicians accurately, conveniently and quickly. For example, fetal malformation can't be touched. Early diagnosis and treatment by B-mode ultrasound plays a decisive role in monitoring fetal development, amniotic fluid volume and placenta normality, and has positive significance in reducing perinatal neonatal mortality and prenatal and postnatal care. At present, almost all hospitals, including most primary hospitals, have B-ultrasound diagnostic equipment. The hidden worry of the problem is that a large number of primary hospitals have not mastered the indications of ultrasound examination, done too much B-ultrasound, and have not mastered the irradiation time. " Professor Kong solemnly stressed: "The time for pregnant women to do B-ultrasound examination should not exceed 5 minutes, and the power of the instrument and the continuous abdominal irradiation time determine the ultrasound dose."
In order to grasp and understand the situation more scientifically and accurately, Professor Kong has led graduate students to do detailed basic research in recent years. It was found that after 5 minutes of B-ultrasound irradiation, fetal cornea was slightly edematous, and villus lipid peroxidation was slightly affected, but this was reversible, and the effect of 20 minutes of irradiation was great and irreversible. The research paper has been published, and it was exchanged at the International Ultrasonic Academic Exchange Conference held in Beijing in August, 1998, which was well received and affirmed by experts. Professor Feng Ruojiao, chairman of the China Ultrasound Safety Committee, commented on this research: "This research content has pushed the ultrasound safety research to a new height, which may be a pioneering work and a new breakthrough in the world." Professor Kong's research makes the obstetrical B-ultrasound examination appear "justified" in clinic, that is, early pregnant women can have B-ultrasound examination when necessary, but the time of each examination should be strictly controlled within 5 minutes. Pregnant women should be active and cautious, and being serious is the attitude that B-ultrasound doctors should hold.
Professor Kong took out a stack of clinical data and several scientific research papers, and concluded that there are clear guiding principles for the application of ultrasound in obstetrics, which is a requirement for people in the industry, and can also make readers understand it and become a "pregnant woman's notice", so that everyone can know fairly well.
Precautions 1: If there is a real need for diagnosis, B-ultrasound should be actively used, such as whether the fetus is alive or abnormal, whether there is too much amniotic fluid, etc.
Note 2: Adhere to the principle of minimum dose, use the minimum radiation intensity and the shortest time as much as possible, and obtain the necessary diagnostic data. The time of an examination (the time when the probe touches the abdomen) should be less than 5 minutes; The power of ultrasonic instrument should be less than 10 MW/cm2 (the manufacturer has generally determined this safety threshold when leaving the factory).
Note 3: It is forbidden for medical staff to identify the sex of the fetus through B-ultrasound examination to decide whether to choose. It has been reported that long-term irradiation of fetal testis will damage spermatogonia.
Note 4: B-ultrasound examination of the fetus should not be solely for commercial purposes and publicity needs, and the radiation time should not be extended at will.
Note 5: There are no special circumstances in the first trimester, so routine B-ultrasound examination is generally unnecessary. During the whole pregnancy, we usually do 1 ~ 2 B-ultrasound examinations. If you really need to check and diagnose many times, you must master the irradiation time.
Color Doppler ultrasound is not icing on the cake. Some wealthy couples take it for granted that, just like TV sets, color is better than black and white, so should B-ultrasound, which is better than black and white B-ultrasound. Therefore, it is often heard that pregnant women or their husbands clamor to do color Doppler ultrasound for doctors. This is a misunderstanding. Professor Kong said with a smile: "The application of color Doppler ultrasound in obstetrics has no characteristics. The blue and red colors of color Doppler ultrasound only represent the direction of blood flow, which is very beneficial to the diagnosis of cardiac vessels, but only plays an auxiliary role in the diagnosis of gynecological diseases. Generally, black-and-white two-dimensional ultrasound is enough. Moreover, the dose of color Doppler ultrasound is large, the biological effect is obvious, and the negative impact on the fetus is also great. Be cautious. " Finally, Professor Kong repeatedly stressed that both black-and-white B-ultrasound and color Doppler ultrasound should be examined under the guidance of specialists, and pregnant women or their families should not put forward unscientific requirements for the "high-grade", "low-grade" and "high-consumption" of instruments.