What are the dangers of X-rays? Doctors wear lead coats while patients seem to have no protection whatsoever?
"Taking an X-ray" is an action you might hear in a hospital, especially in a department like orthopedic surgery.
The strong penetration of X-ray can penetrate the human body structure, and form images on film or screen based on fluorescence effect and photosensitive effect. It is a very important auxiliary diagnostic standard in medical history. examine.
Because X-rays have radiation, they are guided by special personnel in the hospital. In some operating rooms where X-rays are used to perform interventional operations on patients, doctors wear lead coats to avoid damage caused by prolonged exposure to radiation, but patients seem to have no protection. Why is this?
The Newtonian classical mechanics system marked the birth of modern physics, and the advent of X-rays marked the arrival of the era of modern physics. X-rays are electromagnetic radiation with wavelengths between ultraviolet rays and gamma rays. In the preliminary reference to the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization in 2017, they belong to a class of carcinogens, but their carcinogenic hazard is possible. It cannot be controlled, nor can it affect its value in the medical field and even the entire scientific community.
X-rays are also known as Roentgen rays. In 1895, when W.K. Roentgen was engaged in cathode ray research in a laboratory in Germany, he saw a yellow-green fluorescence on a screen coated with barium platinum cyanide not far from the cathode ray. More penetrating X-rays.
In a related story, Roentgen's hand was X-rayed and left an image of the hand bone on the wall, and Roentgen then took a picture of his wife's X-rayed hand bone and displayed it when the discovery was announced. The discovery of X-rays also earned Roentgen the Nobel Prize in Physics in 1901.
And the discovery of X-rays soon led to a new discovery: radioactivity.
At the beginning of the discovery of X-rays, scientists had not figured out whether it was an electromagnetic wave or particle radiation, until the German physicist Laue published "The Interference Phenomena of X-rays" in 1912, proving that X-rays are an electromagnetic wave, and in 1912 In the later proofs of scientists, the physics and chemistry circles gradually accepted the effectiveness of X-ray diffraction in analyzing crystal structures.
During that time, the scientific community was caught up in the research boom of X-rays. Under the assumption that fluorescence originated from X-rays, the French physicist Becquerel irradiated a crystalline uranium salt material under the sun, and accidentally found that the uranium salt was obtained from the photo negative. The same result can be obtained without being irradiated by the sun, which is the first radioactive phenomenon discovered by the scientific community.
Uranium has also become the first radioactive element to be discovered, and the news of the discovery of radioactivity attracted Marie Curie's attention, which also enabled mankind to enter a new era of scientific research in the atomic world.
X-rays and radioactivity were discovered one after another, but X-rays are not radiation and cannot be produced by matter alone. The principle of its generation is that the high-speed moving electrons bombard the tungsten target, causing the outer electrons of tungsten to produce transitions and release energy. The harm to the human body is caused by radiation.
Although both can harm the human body, "radiation" is different from "radioactivity". Radioactivity refers to the spontaneous emission of rays from unstable atomic nuclei, such as alpha rays, beta rays, gamma rays, etc. Radiation refers to heat, light, sound, electromagnetic waves, etc. A state in which matter spreads around.
Long-term exposure to radiation will cause lesions in human organs and systems, and may cause genetic mutations, leading to leukemia, aplastic anemia, cancer, premature aging and other diseases. If the electromagnetic waves that generate radiation are shielded, the radiation will also disappear, so The X-ray system will no longer generate radiation as long as the high voltage is cut off after use.
Why doesn't the patient wear it?
In the operating room where X-rays are used to perform interventional operations on patients, doctors will wear heavy lead clothing. Lead clothing, that is, lead isolation clothing, is a radiation protection tool that can shield rays during radiological examinations.
Interventional surgery is a minimally invasive surgery under the guidance of medical imaging equipment. It is introduced into the patient's body using a guide wire catheter, etc. It is a surgery with high sensitivity to the doctor's operation. Such as cardiac interventional surgery, aneurysm interventional surgery, liver cancer interventional surgery, etc., it takes one to four or five hours for one unit.
Doctors who perform surgery are exposed to radiation for a long time, and may be exposed to radiation for more than ten hours a day, which is equivalent to taking thousands of X-rays continuously. Therefore, they need to wear lead clothing to minimize radiation damage.
For patients undergoing interventional surgery, they need to use an angiography machine to visualize the blood vessels in their bodies with the cooperation of X-rays and contrast agents in this kind of surgery that can expose the lesions to the doctor without surgery. Once the X-rays are shielded by lead clothing, the lesions cannot be seen, and the operation cannot be performed.
And each patient is only exposed to X-rays for the length of one operation, unlike doctors working in an operating room who are exposed to X-rays day in and day out, so patients don't need to wear lead clothing, but doctors do.
In fact, lead clothing comes in various shapes. According to the needs, there are sleeveless, long-sleeved, vest, protective lead scarf, lead apron, lead cap, etc. In the radiographic examination required by the state, the unexamined parts of the patient are not examined. , In particular, the gonads and thyroid glands are also shielded and protected with lead clothing. For example, when performing head CT, doctors will wear lead clothing for protection of the patient's abdomen.
Disadvantages of lead coats
In fact, at the very beginning of the discovery of X-rays, Roentgen noticed that X-rays with extremely strong penetration can penetrate thousands of pages of books, several centimeters of wood and hard rubber, as well as fifteen centimeters of aluminum plates, but 1.5 millimeters thick. The lead plate could not pass through. This is because the higher the atomic number and the higher the density of the material, the stronger the ability to resist radiation, the higher the atomic number of lead, the more electrons outside the nucleus, the higher the probability of photoelectric effect and Compton scattering, so it can resist X-rays.
In fact, elements with a heavy metal proportion greater than 4 have a certain ability to defend against high-frequency rays, including gold, silver, copper, iron, and lead. In reality, concrete and steel can shield rays. The outer layer of the reactor of a nuclear power plant is made of very thick concrete. Shields radiation, but these materials are inefficient and not suitable for making protective clothing. Needless to say, gold and silver are denser than lead, but expensive. Judging from the raw materials that can be considered at present, lead is relatively cheap and stable in nature, so it has become a manufacturing material for protective clothing.
Under these considerations, it can be seen that the birth of lead clothing is the result of a trade-off between application scenarios, radiation blocking capabilities and material costs, so it also has its shortcomings.
First of all, lead clothing cannot provide absolute protection for the wearer in the radiation environment, especially for doctors who have been exposed to radiation for a long time. Due to the convenience of aseptic operation and surgical operation, it is not to cover the whole body with lead clothing. For example, we can see lead coats without sleeves.
In addition, the weight of the lead coat is not small, it can weigh up to 40 catties, which is a great burden for doctors who have performed operations for a long time; and the lead coat has a different service life and requires proper maintenance and management. In order to avoid reducing the service life and affecting the protection effect.
Future directions for improvement
From surgery without anesthesia to the emergence of new disciplines such as biomedical engineering, medicine has experienced the development of traditional medicine, experimental medicine and modern systems medicine.
In the practice of fighting against diseases for a long time, it has developed technologies such as organ transplantation and artificial organ implantation that could only appear in science fiction many years ago. As many soldiers in white have said, what medicine can do now seems to have been Not a lot. But when people face the disease, they realize that medicine can do too little.
Interventional surgery, together with surgery and internal medicine, is now known as the three pillar disciplines, and it is an inevitable trend of future medical development. However, the radiation damage to medical personnel cannot be avoided in the process, protective measures need to be strengthened, and medical technology needs to continue to improve.
