Recently, Tongji Hospital affiliated with Tongji Medical College of Huazhong University of Science and Technology issued a situation report regarding the incident of "a patient being forgotten for 6 hours during MRI", clarifying that the problem was caused by the on duty personnel violating work discipline and shift handover system. While clarifying responsibilities, the public is more concerned about whether being forgotten in the MRI room for six hours will cause serious health damage; There are many patients who are concerned about the presence of radiation. As the main method of current medical examination projects, CT、 Do different imaging examinations such as MRI and B-ultrasound have radiation? What issues should be noted when conducting inspections? CCTV reporters interviewed multiple experts to uncover the key points of different imaging examinations. Li Hongjun, Chief Medical Radiodiagnosis Expert at Beijing You'an Hospital affiliated with Capital Medical University, introduced that in order to understand whether there is radiation in the MRI that the public is concerned about, the first step is to understand how this examination is conducted. The "nucleus" in the name of nuclear magnetic resonance refers to the hydrogen atomic nucleus, which uses magnetic fields and radio waves to adjust the magnetic direction of the hydrogen atomic nucleus to achieve imaging of soft tissues in the human body, and does not cause the commonly feared "radiation" damage to the human body. At present, this examination is an important tool for diagnosing diseases of the nervous system, musculoskeletal system, and abdominal and pelvic organs. Li Hongjun: Magnetic resonance imaging (MRI) uses strong magnetic fields and radio frequency pulses, rather than X-rays or radioactive isotopes, and there is no ionizing radiation in the entire process. During those 6 hours, the patient mainly suffered from the psychological pressure brought by the confined space, machine noise, and physical exhaustion, but there was no risk of "radiation" injury. Many times, ordinary people equate "radiological examination" with "radiation", but in reality, there is no "radiation" problem in imaging examinations such as B-ultrasound and MRI. Ma Ning, chief physician of the Ultrasound Department at Beijing Children's Hospital affiliated with Capital Medical University, explained that compared to CT and other examination items, ultrasound examination uses real-time imaging of ultrasound echoes. Due to its non-invasive and convenient nature, as well as no radiation risk, it is suitable for pregnant women and children to use. It is also suitable for examining organ structures such as liver, gallbladder, and pancreas, as well as thyroid and breast structures. Ma Ning: The biggest weakness of ultrasound is that it cannot penetrate bone structures or hollow organs with high gas content, because the penetration power of ultrasound is very poor. However, ultrasound can scan organs from multiple perspectives and angles, and Doppler technology can be applied to monitor blood flow, such as observing blood vessels. It can not only observe the morphology, structure, and course of blood vessels, but also dynamically monitor the blood flow inside them. Doppler technology can measure flow velocity and pressure difference, determine the presence and degree of stenosis, and evaluate hemodynamics. However, nuclear medicine examinations such as X-rays, CT scans, and PET-CT, commonly known as chest X-rays, only involve the need to prevent ionizing radiation. Li Hongjun introduced that these projects belong to precise "special examinations", which can provide clearer judgments for subtle lesions in the lungs and brain. Li Hongjun: X-ray photography is the use of X-rays to penetrate the human body to form a flat image, commonly used to examine fractures, lung inflammation, and other conditions. The radiation dose is very low, one dose is equivalent to 10 days of natural background radiation; CT scans multiple layers of X-rays to reconstruct tomographic images, which contain much more information than X-rays. It can clearly display subtle lesions in various organs throughout the body, such as early lung cancer and cerebral hemorrhage. But the radiation dose is relatively high, and 'doing one CT is equivalent to taking hundreds of X-rays' is basically accurate. A chest CT scan is equivalent to 2-3 years of natural background radiation. PET-CT requires injection of radioactive tracers, combined with functional metabolism and anatomical imaging, and is mainly used for early diagnosis, staging, and efficacy evaluation of tumors. It is the "ace" of tumor diagnosis. How to evaluate the radiation risks and benefits of CT and other examinations? Experts suggest that the risk of a single necessary examination is extremely low, and patients are advised not to give up eating due to choking. Xue Qi, chief physician of the Cancer Hospital of the Chinese Academy of Medical Sciences, reminds that for high-risk populations of lung cancer, annual low-dose spiral CT screening is an important early screening method. Xue Qi: Long term smokers or passive smokers, those with obstructive pulmonary disease, as well as long-term environmental exposures to harmful substances such as asbestos, radon gas, coal smoke, and paint; There are also families with direct relatives suffering from lung cancer, and these individuals need to undergo chest CT scans. Li Hongjun reminds that compared to the general healthy population, special groups such as pregnant women, couples preparing for pregnancy, and infants and young children may need to pay more attention to the health risks of different examination items and can prioritize non radiation examinations. Li Hongjun: B-ultrasound is the preferred option, which is absolutely safe for pregnant women and fetuses; The second choice is nuclear magnetic resonance imaging, which also has no radiation, but it is not recommended to do it in early pregnancy. Infants and young children may need sedation and cooperation; Be cautious when choosing X-rays, and if necessary, they can be performed under lead clothing protection. It is recommended to wait 3-6 months before preparing for pregnancy after examination; Strictly limit CT and PET-CT. For patients who require multiple examinations, it is necessary to establish personal medical records, properly store imaging data, and bring them to the doctor for reference during the visit; Proactively communicate recent inspection history; Follow medical advice. CT and other examination items need to be protected before conducting nuclear magnetic resonance examination. Although there is no ionizing radiation, it is necessary to prevent the risks that may be brought by the strong magnetic field environment. Li Hongjun reminds that fully understanding the relevant risks before the examination, thoroughly removing any metal objects carried on the body, and truthfully informing the doctor whether they are carrying a pacemaker and other personal conditions are key to ensuring the safety of the examination. Li Hongjun: Magnetic resonance imaging (MRI) is most afraid of "metal", and individuals with ferromagnetic metal implants such as pacemakers and cochlear implants are strictly prohibited from undergoing the examination. Mobile phones, keys, bank cards, card issuers and other metal items must not be brought into the examination room; Tattoo paint may contain metals, please inform your doctor in advance. CT and X-ray examinations are most afraid of "moving around" and "not protecting", otherwise the image will be blurry and cause re shooting, increasing unnecessary radiation. Enhanced examination is most afraid of "allergies". After injecting contrast agent, observe in the rest area for 30 minutes before leaving to prevent delayed allergic reactions; Drink plenty of water after returning home to accelerate the excretion of contrast agent. (New Society)