Recently, a popular science video "every time CT is done more, the risk of cancer will increase by 43%" hit the hot search, causing many netizens to worry. Is there any radiation in the radiology department? Can radiation cause cancer? Let's sort them out one by one.

  Is there any radiation in the radiology department

The word radiation is familiar to everyone, but it can't be seen or touched, so it's hard to intuitively feel its existence. In fact, not all radiology examinations have radiation. Radiology examination mainly includes "three generals": DR (digital radiography) CT (computerized tomography) MRI (magnetic resonance imaging). DR and CT do have radiation, but MRI does not have radiation.

The most common chest CT in the annual physical examination belongs to low-dose CT, whose radiation is relatively small and does not cause a great burden to the body, but can find most of the lesions that need attention. Even with chest plain scan/high-resolution/enhanced CT, the radiation dose is not enough to cause serious physical damage. In the standardized medical treatment process, The influence of CT examination on the body can be ignored. Check if necessary according to the doctor's advice without worrying about the effects of radiation.

The content displayed in the online video comes from a study published in Nature Medicine in November 2023. The subjects of this study are teenagers under 22 years old who have received CT examination, and the focus of this study is malignant tumors of the blood system. In the detailed report, it is also clearly emphasized that as long as the total radiation received is within the safe range, it can be regarded as "basically not causing additional harm to the human body, and patients do not need to worry too much".

Therefore, the statement that "every time CT is done more, the risk of cancer increases by 43%" is inaccurate.

   How much damage does radiation do to the body

When the radiation dose to the human body reaches a certain amount, it will cause some health problems, such as hair loss, leukemia and infertility. The threshold dose of radiation causing cataract is 5000 milligram. If it is lower than this dose, cataract will not be caused by radiation.

Random impact means that the probability of radiation injury (disease) is related to the dose, but the severity is not related to the dose, and there is no threshold dose.

According to the relevant standards, the background of the annual radiation dose received by the general public is 2 millisieverts, the annual average radiation dose is 20 millisieverts, and the upper limit is 50 millisieverts. The radiation dose of an ordinary X-ray examination is 0.02 millisievert, and the radiation dose of a CT examination is 2~10 millisievert.

As long as the inspection is not frequent, there is no need to worry about radiation. When these examinations are needed for clinical treatment, do not delay the diagnosis and treatment because of fear of radiation.

In fact, radiation also exists in our living environment. For example, the radiation dose for 20 hours by plane is 0.1 millisievert; Smoke 20 cigarettes a day, and the annual cumulative radiation dose is 0.5~2 millisieverts

   How to reduce radiation during inspection

When doing CT examination, pay attention to the following points to shorten the examination time and reduce the radiation dose to the body.

First, remove metal objects. Before entering the CT room, the doctor will prompt to remove the metal objects. Sometimes women also need to take off their underwear to avoid metal objects affecting the accuracy of the inspection results.

Second, cooperate with the doctor to complete the examination. When doing CT examination, the doctor will put forward some requirements that require the patient's cooperation, such as breathing in and holding his breath according to instructions.

Third, check in order. When waiting for examination in the radiology department, you need to wait in the corridor, and you cannot enter the examination room to wait. During the examination, all persons except the examinee shall leave the examination room. If others are required to accompany the inspection, the accompanying personnel shall take protective measures. Pregnant women and pregnant preparation personnel shall inform the radiologist of their own conditions in advance before conducting radiation examination.