Radiation has always been a stone in the hearts of medical professionals and patients or medical examiners. Today, in order to let friends put down that stone in their hearts, I, Dr. Zhou Jun, still use the usual way of one question and one answer, so that everyone can understand the way of medical radiation at a glance to understand thoroughly. Q1: What types of radiation are there? A1: Radiation is mainly caused by four types of radiation: α-rays, β-rays, γ-rays and X-rays. Currently, only γ-rays and X-rays are widely used in medicine. Alpha radiation is characterized by its large mass and poor penetration ability, with a range of only a few centimeters in the air, which can be blocked by a piece of paper or healthy skin, but it has a strong ionizing effect. It poses no danger outside the human body. However, substances that release alpha particles (radium, uranium, etc.) would be very dangerous if inhaled or injected, and it can directly damage DNA inside cells. It is currently the main method of preparing isotopic neutron sources, not applied in medicine. Beta rays are very strong in penetration, weak in ionization, can penetrate skin, and can pass through several millimeters thick aluminum plate, which can cause radioactive damage. It is not used in medicine. Q2: What is γ-ray? A2: γ-rays have strong penetrating power and can be used in industry for flaw detection or automatic control of assembly lines. Gamma rays are cell-killing and are used medically to treat tumors, such as conventional I-131 or I-125 for thyroid cancer. Diagnostically, nuclear medicine departments such as SPECT/CT (formerly known as ECT) and PET/CT use γ-rays for whole body disease diagnosis. Gamma rays have an extremely strong penetrating ability. When the human body is irradiated by γ-rays, γ-rays can enter the interior of the body and ionize with the cells in the body. The ions produced by ionization can erode complex organic molecules, such as proteins, nucleic acids and enzymes, which are the main components of living cell tissues, and once they are damaged, it will lead to the disturbance of normal chemical processes in the human body and can cause cell death in serious cases. Therefore, I, Dr. Jun Zhou, believe that it is especially important to carry out various nuclear medicine treatments or diagnoses under the guidance of a doctor, follow the doctor’s instructions you can rest assured, because the doctor will weigh the relationship between the examination method and radiation according to the severity of your disease, if your heart is still not sure, you can ask your doctor to untie the knot. Q3: What are X-rays? A3: X-rays are electromagnetic waves with wavelengths between ultraviolet and gamma rays. It was discovered by German physicist Roentgen in 1895, so it is also called Roentgen ray. X-rays are used in medicine, such as radiology X-rays and CT examinations. When X-rays are irradiated to biological organisms, they can cause inhibition, destruction or even necrosis of biological cells, resulting in different degrees of physiological, pathological and biochemical changes in the organism. Different biological cells have different sensitivities to X-rays, which can be used to treat certain diseases in the human body, especially the treatment of tumors. While using X-rays, people have found problems that lead to hair loss of patients, skin burns, visual impairment of staff, leukemia and other radiation injuries. While applying X-rays, attention should be paid to their harm to the normal organism, and protective measures should be taken. Q4: I took X-ray during my menstrual period, I wonder if it will have any effect on my children in the future. A4: There is no effect. Menstruation is the period of time when the egg cells are expelled from the ovaries and are not fertilized, then they are not able to settle in the uterus and are expelled from the body, and then the hormone levels in the body drop causing the uterus to be ready for pregnancy to fade away, resulting in menstruation. Therefore, x-rays during menstruation are the least likely to affect the expelled egg, as the egg that was expelled during the current menstrual cycle is no longer in the body. The effect of X-rays is not during menstruation or not, as there are only a few hundred eggs that will develop and mature in a woman’s lifetime. If you take an X-ray, you will be irradiated to a greater or lesser extent by the immature egg cells that have not yet been eliminated from your body. But don’t panic, the dose of x-ray is like a few more days of exposure to nature’s natural cosmic rays, it’s okay. In general, women should try not to be exposed to X-rays before they become pregnant. Although it does not affect them, there is no need to be exposed to unnecessary rays. Q5: Can I have a baby if I have an x-ray during ovulation? A5: No, you can have a baby. So far there is no saying that you can’t have a baby after a normal examination. The dose of x-ray is like being exposed to nature’s natural cosmic rays for a few more days, so a person can’t get sunlight? Therefore, it does not matter. In general, we recommend that women try not to be exposed to X-rays before pregnancy. Although it does not affect, it is not necessary to be exposed to unnecessary X-rays. As doctors, we always follow the principle of no harm and no benefit and do not perform unnecessary X-ray examinations. In order for you to understand more, I, Dr. Zhou Jun, give a more extreme example: the current society has a lot of infertility patients, patients come to the clinic after taking medication still not pregnant, we have to do a hysterosalpingogram, this examination is carried out under the X-ray, more radiation than the X-ray film, but these patients after the examination and treatment, immediately to grasp the pregnancy, the result is that the vast majority of patients are The result is that the majority of patients are pregnant with children, and the whole family is happy, without any impact on the child. The few patients who did not conceive a child, mainly because of the complexity of the disease, to say more, stop. Q6: I went to the hospital for 5 x-rays, 1 CT, and 2 MRIs in the last 3 months because I have been unwell for a year. A6: There is nothing wrong with 5 x-rays and 1 CT. The radiation dose is not too high, it is within the normal range and much lower than the dose of radiology staff, it is very safe. If this can also get cancer, then patients who are sick can’t even go for X-ray and CT. Moreover, the CT and X-ray examination instruments are getting better and better nowadays, and the dose is lower than before, so you can be assured of the examination. In addition, magnetic resonance imaging (MRI) is free of ionizing radiation and does not produce static electricity. By the way, ultrasound (B-ultrasound) also has no ionizing radiation, despite the examination. Q7: Doctor, does radiation accumulate in the body and is there an upper limit for one year? Is it recalculated after one year? A7: The ionizing radiation of X-ray is disposable and does not accumulate in the body, but the human body has a certain tolerance to ionizing radiation and there is a threshold value for the total amount of radiation. That is, there is an upper limit for one year, and it is recalculated after one year. A normal person receives many times more radiation from cosmic rays (i.e., natural background) in a year than the dose from a single X-ray. Q8: I had a lumbar spine CT, and I’ve always been concerned about it. I’ve always heard that lumbar spine CT radiation is very high, 10 mSv, and radiologists limit it to 20 mSv a year, and I’ve read on the internet that a person should not have more than 2 x-rays in a year. A8: If a healthy person is not sick, there is no need to do 2 x-ray checkups a year, otherwise, you are overly concerned about your health and need psychological guidance. The dose of doing CT has to consider the emission dose and the absorbed dose of the body. For patients is to say the machine’s emission dose, for radiologists like me Dr. Zhou Jun is every day, year after year in the department, talking about the absorbed dose, can not be unified together, so do lumbar spine CT this dose do not worry. After the Fukushima nuclear power plant leak in Japan, 50 warriors rushed into the scene of the incident to deal with the disaster, known as “Fukushima 50 warriors”. Although they received strong radioactive radiation exposure, but so far there is no health condition, that is because they comply with the Australian tiling Wai 250 mSv radiation threshold. Q9: I left my necklace or other belongings in the X-ray room for a day, will there be any radiation? A9: There is no radiation. X-rays are ionizing radiation during the tens to hundreds of milliseconds (ms) when the power is applied, and no radiation after the power is removed. As for the moment of X-ray formation there will be scattered rays, that basically disappears in a few seconds, can be negligible. X-rays and radioactive isotopes are completely different, the latter take home will be formed according to the decay time or short or long radiation. I Dr. Zhou Jun thought the reason for this question, may be the principle of X-ray as the principle of radioactive isotopes. Wear it with confidence. Q10: Because of post-operative infection, I recently had a chest general CT, an upper abdomen general CT and a whole abdomen (including upper abdomen, lower abdomen and pelvis) enhanced CT consecutively, may I ask the doctor about the total radiation dose in millisieverts? A10: Actually, the radiation dose is related to the advanced level of the machine, the way of scanning and the procedure called. Nowadays, the machines are getting more and more advanced and the dose for doing the same area is decreasing significantly. CT flat scan is only one scan, and enhancement requires two scans. Upper and lower abdomen + pelvis is calculated as the dose for the whole abdomen. Based on the advanced level of the machine and the area to be scanned, I, Dr. Zhou Jun, have projected a rough estimate of about 20 mSv, which is roughly equivalent to the effect of natural cosmic radiation on you in about 8 years. Within the normal dose range for medical examinations.