What do you mean by filming in a hospital?

Electromagnetic radiation with a wavelength between ultraviolet and gamma rays. It was discovered by German physicist W.K. Roentgen in 1895, so it is also called Roentgen ray. Ultra-hard x-rays with wavelength less than 0. 1 angstrom, hard x-rays with range of 0. 1 ~ 1 angstrom, and soft x-rays with range of1~1angstrom. X-rays are produced by X-ray tubes in the laboratory. X-ray tube is a vacuum tube with cathode and anode. The cathode is made of tungsten wire, which can emit hot electrons when energized, and the anode (called target electrode) is made of high melting point metal (generally tungsten, and the X-ray tube used for crystal structure analysis can also be made of iron, copper, nickel and other materials). Electrons are accelerated by high voltage of tens of thousands of volts to hundreds of thousands of volts, and the electron beam bombards the target electrode, emitting X-rays from the target electrode. When electrons bombard the target, it will produce high temperature, so it is necessary to cool the target with water, and sometimes the target is designed to rotate.

X-ray spectrum consists of continuous spectrum and labeled spectrum. The marker spectra overlap on the background of continuous spectra. Continuous spectrum is bremsstrahlung caused by high-speed electrons being blocked by the target, and its short-wave limit λ 0 is determined by accelerating voltage V: λ 0 = hc /( ev) is Planck constant, e is electron quantity, and c is the speed of light in vacuum. The identification spectrum consists of a series of linear spectra, which are produced by the transition of electrons in the inner layer of the target element. Each element has a specific set of identification spectra, which reflects the characteristics of atomic shell structure. Synchrotron radiation source can produce high-intensity continuous spectrum X-rays and has become an important X-ray source.

X-rays have strong penetrating power and are often used for fluoroscopy in medicine.

Is medical X-ray harmful to human body?

□ Correspondent Ren Shan Intern Beibei Reporter Yu Yu

Recently, radiation protection experts in Guangzhou and Shenzhen also called for stopping children's annual physical examination and chest X-ray examination as soon as possible. As a result, the radioactive inspection, which has always been quite mysterious, has instantly become the focus of attention. Many readers called and wrote to our reporter to ask: Is X-ray harmful to human body? How many times can X-rays cause cancer? In view of these problems, the reporter specially interviewed Associate Professor Guo Liang, director of the Department of Imaging Medicine of the First Affiliated Hospital of the Soviet Union.

"X-ray storage" of employees

Just entering the image building of the First Affiliated Hospital of Su Da, the reporter found that the staff here had a "small tube" pinned to their chests. It turns out that this small tube is called "radiation measuring tube", which is specially used to measure the X-ray dose taken by professional staff every day. Every once in a while, it will be taken down to measure whether the X-ray dose taken by this staff member exceeds the standard. Director Guo told reporters that under normal circumstances, the measured results are within the normal range. A professional who has worked for many years like him has passed every test.

Guo Liang said that in modern medicine, X-ray can be said to be popular, and its importance can be seen everywhere. Familiar radiological examinations, such as CT, MRI and interventional radiology, are constantly used in clinical medicine, which greatly improves the diagnostic rate of diseases. Their daily job is to check the patient's various abnormalities through the penetration of X-rays.

Making a movie is equivalent to watching 1 hour of TV.

When a reporter asked doubtfully whether frequent medical X-ray examinations would increase the possibility of cancer, Guo Liang first listed such a set of data. He said that the dose of X-rays taken by a human body at a time is equivalent to the amount taken by watching 1 hour TV; One dose of chest X-ray is equivalent to 0.5 times of 65438+X-ray photography; If you want to say harm, it is that a chest X-ray is equivalent to smoking three cigarettes.

If receiving medical X-rays is easy to cause cancer, aren't medical professionals who work around these devices and technologies all the year round the first victims? Judging from the "radiation measuring tube" they wear to work every day, the values are generally within the normal range. That is to say, the statement that "X-ray irradiation can cause cancer several times" is unfounded.

Doing CT once a week will not affect your health.

As we all know, X-rays have a certain destructive effect on biological cells. Excessive exposure to X-rays will affect physiological functions, cause chromosomal abnormalities and lead to cancer. But proper irradiation will not affect human health. Because the dose used by medical staff for X-ray fluoroscopy and photography is very small, only within the safe dose. In particular, occasional chest x-ray, gastrointestinal examination, bone X-ray or angiography will not cause adverse reactions. Moreover, the X dose used for filming is not completely absorbed by people, most of it penetrates the human body, and only a small part is absorbed by the human body. If we want to say a specific value, it is that the human body really absorbs only a few tenths or even less of the dose used.

Moreover, the radiation inspection equipment used in major hospitals in Suzhou, such as the First Affiliated Hospital of Suzhou University, has long been replaced by digital radiography (CR) and direct digital imaging (DR), and the radiation amount has been greatly reduced, accounting for only the original 1/7.

So to be exact, it is completely correct for normal people to do ct once a week, and it will not affect their health. Director Guo emphasized that medical X-rays will never affect people's health during examination and treatment, and the public need not have any concerns.

The main reason for canceling chest X-ray examination

Regarding the cancellation of chest X-ray in primary school students' physical examination, Guo Liang thinks that the high radiation dose used in chest X-ray is one aspect, but the main reason is probably that the resolution of chest X-ray is relatively low, and only one doctor makes a diagnosis from beginning to end, so the accuracy of diagnosis can only be based on the doctor's personal level, resulting in a higher error rate, which is not conducive to follow-up like filming.

Who is not suitable for X-ray examination?

Guo Liang also pointed out that although it is difficult to determine the cause of physical discomfort, X-ray examination can be done to reassure yourself. But everything has two sides, and radioactive inspection is no exception. Some people should pay a little attention to X-ray examination. For example, pregnant women should not have an X-ray examination within three months of pregnancy, because the fetus at this stage has not yet formed. If pregnant women receive too much X-ray radiation, it will easily lead to mental retardation or microcephaly of the fetus, which will lead to an increase in the incidence of cancer after birth.

In fact, X-rays are everywhere in our daily life. Television, computers, mobile phones, microwave ovens, and even sunlight and moonlight endowed by nature also have X-rays. X-ray hazards of some objects in daily life can not be ignored, such as not letting children get too close to the microwave oven at home; Choose building materials carefully, such as granite with high radiation, and use them carefully; Don't watch TV or use the computer for a long time. If it is necessary for work, try to work for an hour or two and let yourself rest for ten minutes.