CT and X-ray is the use of X-rays for imaging, both have radiation, but CT radiation is greater, and CT machine parameters, scanning parts, scanning mode has a relationship. Nuclear magnetic resonance is the use of hydrogen nuclei in the body under the action of an applied magnetic field for imaging, nuclear magnetic no radiation, X-ray and CT have radiation and more and more advanced instruments, radiation will become smaller and smaller. The amount of radiation each time is far lower than the safety value stipulated by the state, as long as it is within the scope of reasonable medical examination, there is no problem and patients do not need to worry too much. Tumor patients need to undergo repeated examinations for diagnosis and treatment of the disease, and doctors will weigh the pros and cons, so there is no need for patients to worry too much.