Do you know how much radioactivity is emitted by X-rays taken in hospitals?

At present, as we pay more and more attention to health, people go to the hospital for health check-ups and medical examinations more and more frequently. Walking on the street, we often see people carrying "X-rays" taken in the hospital in bags. X-rays are an indispensable auxiliary detection method commonly used by doctors. Speaking of X-rays, many people can't help but associate it with radioactivity.

Do X-rays have radioactivity? Which X-rays have radioactivity? Which have high radioactivity and which have low radioactivity? I believe this is a topic that many people are generally concerned about and confused about. Today, I will discuss this topic with you.

First of all, when it comes to filming, many people think of "nuclear", and associate it with nuclear radiation and "mushroom clouds", and are very afraid of the word "nuclear". In fact, this is not the case.

At present, the common examination and filming items in hospitals mainly include color Doppler ultrasound, chest X-ray, chest radiography, CT, X-ray, MRI, etc. In the medical field, the nuclear radiation we usually refer to is ionizing radiation. Nuclear radiation can ionize or excite matter, so it is called ionizing radiation. Ionizing radiation is harmful to the human body and can cause vision loss, affect the reproductive system, central nervous system disorders, induce cancer, etc.

Color Doppler ultrasound is an imaging examination. It produces ultrasonic waves, not radioactive rays, and does not pose the hazard of ionizing radiation.

Nuclear magnetic resonance imaging usually does not have radiation. Although the word "nuclear" in nuclear magnetic resonance looks quite "scary", the nucleus is not the so-called nucleus of nuclear radiation, but refers to the hydrogen proton nucleus, which is a component of water molecules in the human body. Nuclear magnetic resonance imaging mainly uses the principle of electromagnetic waves. The amount of electromagnetic waves emitted is equivalent to the amount released by using a mobile phone or watching TV. Patients will not be harmed by radioactive rays.

X-rays are also called digital photography (CR, DR), which uses the penetrating, fluorescent and photographic properties of X-rays to pass through the human body to form an image. Therefore, X-rays do emit radiation.

Does X-rays cause a lot of radiation?

The annual whole-body dose equivalent limit for the public promulgated by our country is 5mSv. The radiation dose of a routine chest X-ray is 0.1mSv. The radiation exposure to flight passengers is usually 0.05mSv/hour. The radiation dose of a chest X-ray is about the radiation exposure received during a two-hour flight. There is no need to worry about routine physical examinations and checks.

A chest X-ray is actually an X-ray, but the detection position is on the chest. The principle is the same as that of an X-ray. The effective dose equivalent of a chest X-ray is 0.01-0.1 mSv, which is much smaller than the average radiation dose equivalent that a person receives in a year.

Chest X-ray is a chest X-ray, which also uses X-rays for imaging. Although both chest films and chest X-rays use X-rays to form images, in fact, the principle of chest films is different from that of chest X-rays, and they are two different clinical examination methods. The two have different examination methods and imaging modalities, and the amount of radiation caused to the human body is also very different. As a physical examination item once a year, chest X-rays pose very little radiation risk to the human body. The amount of radiation in a chest X-ray is equivalent to 10 X-rays. Therefore, patients should not undergo too many chest X-rays, nor should they undergo multiple repeated examinations in a short period of time. In particular, when undergoing chest X-rays, do not blindly ask the doctor to look longer or more carefully.

CT (Computed Tomography) is a computerized tomography scan. It can be divided into X-ray CT (X-CT) and gamma-ray CT (γ-CT) according to the different rays used. It uses a precisely collimated beam of rays and a highly sensitive detector to scan sections of a certain part of the human body one by one. It has the characteristics of fast scanning time and clear images, and can be used to examine a variety of diseases. Therefore, CT also has radiation to the human body.

Generally speaking, the radiation dose of CT and chest X-ray is higher than that of chest radiographs and X-rays. Of course, the radiation dose of each test also depends on factors such as different parts of the human body and the time of test.

In summary, the radiation dose of these normal radioactive examinations is within the safe range for the human body, and we do not need to be too afraid. In life, when it comes to "filming", we should not be afraid of "nuclear", act as our own doctors without relevant knowledge, and avoid necessary examinations, especially those used by doctors for diagnosis and treatment; at the same time, we should also improve our self-protection awareness and avoid blindly doing too many unnecessary repetitive examinations. When achieving the same examination purpose and effect, we should follow the doctor's advice and try to choose examination items with a smaller radiation dose or even no radiation.

Author: Sun Yucong, Master of Nuclear Technology and Applications at the University of Science and Technology of China, currently Director of the Popularization Department of the Shiyan Science and Technology Association of Hubei Province

(The above views are for reference only. Due to my limited knowledge and understanding, please correct me if I find any mistakes.)