How high is the radiation level of medical imaging tests

The radiation level of PET-CT is gradually decreasing. Due to differences in equipment accuracy, newness and oldness, the amount of radiation a PET-CT exam brings to a patient varies, but overall it is gradually decreasing over time," said Xu Baixuan. For example, the dose of a radioisotope that needed to be injected into a subject a few years ago was 0.12 millicurie per kilogram of body weight, which is now reduced to 0.08 millicurie." (1 curie is the intensity of radioactivity in 1 gram of rhenium-226; 1 curie = 1000 millicuries.) And the amount of radiation from a PET exam is also related to the patient's weight. The heavier the weight, the greater the amount of radiation exposure.

Baixuan Xu said, "The amount of radiation a person receives from a PET-CT exam using the relatively new equipment available today is about 10 millisieverts. Currently, the country has not yet set an upper limit on the amount of radiation a patient can receive during a medical examination, but there is a standard for healthcare professionals, which is no more than 20 millisieverts per year available for reference. If this is the calculation, the amount of radiation brought to the patient by a PET-CT examination is still within the safe range."

The claim that people who have undergone PET-CT examinations will become a source of radiation, which has been circulating on the Internet, is unfounded, according to Xu Baixuan. She said: "When examining a portion of cancer patients, the state stipulates that as long as the amount of radiation in the patient's body is less than 30 millisieverts, he or she can enter the public **** occasion. That limit, far exceeds the full radiation exposure of a single PET-CT. And it only takes 18 hours and 20 minutes for the radioactivity in the patient's body to completely dissipate, not to mention the effects on those around them."