When the patient goes to the imaging department for examination, the most feared is radiation, especially X-ray, CT, PET/CT, etc. Some patients repeatedly consult the doctor: 'How large is the damage to my body? Can you check the disease? Do CT? 'What's more, they have slipped the checklist. In fact, the tests that can be used in medicine are all safe. Below, we will answer several questions that people are most concerned about.
Question 1: How strong is radiation from imaging studies? Radiation is ubiquitous in nature, such as surface radiation, cosmic radiation, etc. It is called natural background radiation, usually about 2 to 3 millisieverts/year (muxir It is a measure of radiation dose units, which is represented by mSv.) There are also radiations for daily flight. The radiation dose for a flight of 10,000 kilometers is about 0.05mSv. According to data from the Australian Radiation Protection and Nuclear Safety Administration, a chest radiograph is about 0.025mSv. Flying 5000 km; Dental piece is only 0.014mSv; Mammary molybdenum target is about 0.4mSv; Skull CT is about 2.6mSv; Urinary angiography is about 3mSv; Normal CT is about 10.6mSv. PET/CT examination is automatic control because of CT, PET HD The technology reduces 1/3 of radiopharmaceuticals, and the radiation dose is 7~10mSv.
Question 2: Does all imaging studies have radiation? B-ultrasound, MRI does not have radiation. The principle of B-ultrasound is that using ultrasonic waves to encounter different tissues will produce reflected waves, while the probe emits sound waves while receiving acoustic waves and passing Calculating reflected-wave imaging. This is like picking a watermelon and knocking it, while listening to the sound to determine whether it is cooked. MRI has a 'nucleus', so many people feel that it must have radiation. But this test is equivalent to let the water in the body first vibrate. Get up and calm down, feel the vibrations inside. Its greatest advantage is to observe the soft tissue.
Question 3: Since it is safe, can I often do it? There are always people who worry about having problems with the body. They need to take a film and do CT on both ends of the day. This is not advisable. Although medical radiation harm is minimal, it is still as small as possible. Do. The State's 'Three Principles of Radiation Protection': justification of practice, optimization of radiological protection, personal dose limitation. In other words, if the condition requires it, do it; otherwise, try not to do it.
Question 4: What is the difference between nuclear medicine and radiology? Nuclear medicine requires the use of special radiopharmaceuticals to emit a variety of radiation. It is radioactive and can specifically display organs and their lesions. It is helpful for the early diagnosis and specific diagnosis of diseases. Bone scintigraphy can simultaneously show the subtle conditions of the whole body and local bones. It can diagnose tumor bone metastases more than 3 to 6 months earlier than X-ray. The radiology department can understand the whole body condition at a glance. It can be used for early detection of major diseases in tumors, heart and brain areas. And diagnosis.
Question 5: What are the hazards of radiation? Usually refers to ionizing radiation, etc. There are two kinds of randomization effects and deterministic effects. The former refers to the incidence of radiation effects (not the severity) and dose-related effects, there is no specific threshold As long as the exposure to radiation, no matter how much it may be harmful. The latter refers to the severity of radiation damage and dose-related, there is a clear threshold, short-term exposure to a larger dose, radiation dose is far beyond the threshold of acute harm, such as acute radiation sickness, Radioactive cataract, skin radiation damage, etc. Medical radiation dose is often lower than the threshold, there will be no deterministic effect, but although the randomization effect is extremely low, it is still possible, and can not be predicted and prevented.
Question 6: Did you already have an X-ray film? Do you also ask me to do CT or MRI? Take the lumbar disease examination as an example. X-ray mainly observes the general condition of bones, whether or not the bone hyperplasia is damaged, and whether there is intervertebral space Holes, septal stenosis, vertebral spondylolisthesis, etc. Since the bones are round, the slices are flat, and the images of dark tissue may overlap each other and hide, so it is sometimes necessary to take a lateral X-ray. CT can be more clear Show vertebral fractures or other bone lesions to see if there are abnormal soft tissue shadows, if there is a disc herniation, a thick yellow ligament, etc. MRI is more meticulous, accurate, the resolution of the soft tissue is higher, can see if the bone marrow is Edema and so on.
Question 7: Does radiological imaging affect husband and wife in pregnancy? Ionizing radiation can induce DNA damage, resulting in abnormal chromosome structure of spermatogenic cells, leading to apoptosis. Short-term high-dose or long-term low-dose radiation may lead to male infertility. The effect is negligible. If multiple examinations are performed in the short term, it is necessary to check sperm motility after 3 months. The American College of Obstetricians and Gynecologists recommends that women do not have to terminate their pregnancy in order to perform medical diagnostic imaging.
All in all, for the needs of the patient, they should be willing to accept the relevant checks; if they are not necessary, they should be avoided as much as possible. After all, they are potentially harmful.
